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  • 1.
    Adolfsson, Dan E.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tyagi, Mohit
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Singh, Pardeep
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Deuschmann, Adrian
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gharibyan, Anna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Jayaweera, Sanduni Wasana
    Lindgren, Anders E. G.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Intramolecular Povarov Reactions for the Synthesis of Chromenopyridine fused 2-Pyridone Polyheterocycles Binding to α-Synuclein and Amyloid-β fibrils2020In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 85, no 21, p. 14174-14189Article in journal (Other academic)
    Abstract [en]

    A BF3×OEt2 catalyzed intramolecular Povarov reaction was used to synthesize a library of 15 chromenopyridine fused thiazolino-2-pyridone peptidomimetics. The reaction works with a range of O-alkylated salicylaldehydes and amino functionalized thiazolino-2-pyridones, to generate polyheterocycles with diverse substitution. The synthesized compounds were screened for their ability to bind α-synuclein and amyloid β fibrils in vitro. Analogs substituted with a nitro group bind to mature amyloid fibrils, and the activity moreover depends on the positioning of this functional group.

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  • 2.
    Adolfsson, Dan E.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tyagi, Mohit
    Singh, Pardeep
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kaur, Amandeep
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bharate, Jaideep B.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Enhanement of amyloid fibril binding by ring expansion of thiazolino fused 2-pyridone peptidomimeticsManuscript (preprint) (Other academic)
    Abstract [en]

    Thiazolino fused 2-pyridones undergo thiazoline ring opening by reaction with 2-nitrobenzyl bromide through thi- oether attack, and base promoted fragmentation of the resulting sulfonium ions. Subsequent deprotonation of the benzylic carbon and intramolecular 1,4-addition leads to ring closure, generating dihydrothiazine fused 2-pyridones by net ring expansion of the thiazoline ring. Application of the ring expansion procedure to the pyridine and pyrimidine fused thiazolino 2-pyridones provided compounds with enhanced fibril binding activity.

  • 3.
    Alam, Athar
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Golovliov, Igor
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Javed, Eram
    Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Kumar, Rajender
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sjöstedt, Anders
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Dissociation between the critical role of ClpB of Francisella tularensis for the heat shock response and the DnaK interaction and its important role for efficient type VI secretion and bacterial virulence2020In: PLoS Pathogens, ISSN 1553-7366, E-ISSN 1553-7374, Vol. 16, no 4, p. 1-27, article id e1008466Article in journal (Refereed)
    Abstract [en]

    Author summary Type VI secretion systems (T6SSs) are essential virulence determinants of many Gram-negative pathogens, including Francisella tularensis. This highly virulent bacterium encodes an atypical T6SS lacking ClpV, the ATPase crucial for prototypic T6SS sheath disassembly. It, however, possesses ClpB, a protein critical for heat shock survival via its interaction with DnaK. Since ClpB possesses ATPase activity, it has been hypothesized to provide a compensatory function for the absence of ClpV, a hypothesis supported by the recent findings from us and others. Here, we investigated how F. tularensis ClpB controls T6S. In silico modelling of the ClpB-DnaK complex identified key interactions that were experimentally verified. For example, mutating one of the DnaK-interacting residues rendered the bacterium exquisitely susceptible to heat shock, but had no effect on T6S and virulence. In contrast, removing the N-terminal of ClpB only had a slight effect on the heat shock response, but strongly compromised both T6S and virulence. Intriguingly, the Escherichia coli ClpB could fully complement the function of F. tularensis ClpB. The data demonstrate that the two critical roles of ClpB, mediating heat shock survival and effective T6S, are dissociated and that the N-terminal is crucial for T6S and virulence. Francisella tularensis, a highly infectious, intracellular bacterium possesses an atypical type VI secretion system (T6SS), which is essential for its virulence. The chaperone ClpB, a member of the Hsp100/Clp family, is involved in Francisella T6SS disassembly and type VI secretion (T6S) is impaired in its absence. We asked if the role of ClpB for T6S was related to its prototypical role for the disaggregation activity. The latter is dependent on its interaction with the DnaK/Hsp70 chaperone system. Key residues of the ClpB-DnaK interaction were identified by molecular dynamic simulation and verified by targeted mutagenesis. Using such targeted mutants, it was found that the F. novicida ClpB-DnaK interaction was dispensable for T6S, intracellular replication, and virulence in a mouse model, although essential for handling of heat shock. Moreover, by mutagenesis of key amino acids of the Walker A, Walker B, and Arginine finger motifs of each of the two Nucleotide-Binding Domains, their critical roles for heat shock, T6S, intracellular replication, and virulence were identified. In contrast, the N-terminus was dispensable for heat shock, but required for T6S, intracellular replication, and virulence. Complementation of the Delta clpB mutant with a chimeric F. novicida ClpB expressing the N-terminal of Escherichia coli, led to reconstitution of the wild-type phenotype. Collectively, the data demonstrate that the ClpB-DnaK interaction does not contribute to T6S, whereas the N-terminal and NBD domains displayed critical roles for T6S and virulence.

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  • 4.
    Bharate, Jaideep B.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gharibyan, Anna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Adolfsson, Dan E.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Jayaweera, Sanduni Wasana
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Singh, Pardeep
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Vielfort, Katarina
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Tyagi, Mohit
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bonde, Mari
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bergström, Sven
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    K2S2O8-mediated coupling of 6-amino-7-aminomethyl-thiazolino-pyridones with aldehydes to construct amyloid affecting pyrimidine-fused thiazolino-2-pyridones2021In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 19, no 44, p. 9758-9772Article in journal (Refereed)
    Abstract [en]

    We herein present the synthesis of diversely functionalized pyrimidine fused thiazolino-2-pyridones via K2S2O8-mediated oxidative coupling of 6-amino-7-(aminomethyl)-thiazolino-2-pyridones with aldehydes. The developed protocol is mild, has wide substrate scope, and does not require transition metal catalyst or base. Some of the synthesized compounds have an ability to inhibit the formation of Amyloid-β fibrils associated with Alzheimer's disease, while others bind to mature amyloid-β and α-synuclein fibrils.

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  • 5. Bharate, Jaideep B.
    et al.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gharibyan, Anna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Adolfsson, Dan E.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Jayaweera, Sanduni Wasana
    Vielfort, Katarina
    Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Singh, Pardeep
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tyagi, Mohit
    Bergström, Sven
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    K2S2O8-mediated aerobic oxidative coupling of 6-amino-7-(aminomethyl)-thiazolino-pyridones with aldehydes: Direct access to highly functionalized pyrimidine fused thiazolino-2-pyridones with amyloid fibril binding activity or inhibitors of Amyloid-β fibril formationManuscript (preprint) (Other academic)
    Abstract [en]

    We herein present the synthesis of diversely functionalized pyrimidine fused thiazolino-2-pyridones via K2S2O8-mediated oxidative coupling of 6-amino-7-(aminomethyl)- thiazolino-2-pyridones with aldehydes. The developed protocol is mild, has wide substrate scope, and does not require transition metal catalyst or base. Some of the synthesized compounds have the ability to inhibit the formation of Amyloid-β fibrils associated with Alzheimer's disease, while others bind to mature Amyloid-β and α-Synuclein fibrils.

  • 6.
    Bugaytsova, Jeanna A.
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Björnham, Oscar
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Swedish Defence Research Agency, 906 21 Umeå, Sweden.
    Chernov, Yevgen A.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Gideonsson, Pär
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Henriksson, Sara
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Mendez, Melissa
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Sjöström, Rolf
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Mahdavi, Jafar
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics. School of Life Sciences, CBS, University of Nottingham, NG7 2RD Nottingham, UK.
    Shevtsova, Anna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Ilver, Dag
    Moonens, Kristof
    Quintana-Hayashi, Macarena P.
    Moskalenko, Roman
    Aisenbrey, Christopher
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bylund, Göran
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Schmidt, Alexej
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics. Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Åberg, Anna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Brännström, Kristoffer
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Koeniger, Verena
    Vikström, Susanne
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Rakhimova, Lena
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics. Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Hofer, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Ögren, Johan
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Medicine.
    Liu, Hui
    Goldman, Matthew D.
    Whitmire, Jeannette M.
    Åden, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Younson, Justine
    Kelly, Charles G.
    Gilman, Robert H.
    Chowdhury, Abhijit
    Mukhopadhyay, Asish K.
    Nair, G. Balakrish
    Papadakos, Konstantinos S.
    Martinez-Gonzalez, Beatriz
    Sgouras, Dionyssios N.
    Engstrand, Lars
    Unemo, Magnus
    Danielsson, Dan
    Suerbaum, Sebastian
    Oscarson, Stefan
    Morozova-Roche, Ludmilla A.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Gröbner, Gerhard
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Holgersson, Jan
    Esberg, Anders
    Umeå University, Faculty of Medicine, Department of Odontology.
    Strömberg, Nicklas
    Umeå University, Faculty of Medicine, Department of Odontology.
    Landström, Maréne
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Eldridge, Angela M.
    Chromy, Brett A.
    Hansen, Lori M.
    Solnick, Jay V.
    Linden, Sara K.
    Haas, Rainer
    Dubois, Andre
    Merrell, D. Scott
    Schedin, Staffan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Remaut, Han
    Arnqvist, Anna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Berg, Douglas E.
    Boren, Thomas
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Helicobacter pylori Adapts to Chronic Infection and Gastric Disease via pH-Responsive BabA-Mediated Adherence2017In: Cell Host and Microbe, ISSN 1931-3128, E-ISSN 1934-6069, Vol. 21, no 3, p. 376-389Article in journal (Refereed)
    Abstract [en]

    The BabA adhesin mediates high-affinity binding of Helicobacter pylori to the ABO blood group antigen-glycosylated gastric mucosa. Here we show that BabA is acid responsive-binding is reduced at low pH and restored by acid neutralization. Acid responsiveness differs among strains; often correlates with different intragastric regions and evolves during chronic infection and disease progression; and depends on pH sensor sequences in BabA and on pH reversible formation of high-affinity binding BabA multimers. We propose that BabA's extraordinary reversible acid responsiveness enables tight mucosal bacterial adherence while also allowing an effective escape from epithelial cells and mucus that are shed into the acidic bactericidal lumen and that bio-selection and changes in BabA binding properties through mutation and recombination with babA-related genes are selected by differences among individuals and by changes in gastric acidity over time. These processes generate diverse H. pylori subpopulations, in which BabA's adaptive evolution contributes to H. pylori persistence and overt gastric disease.

  • 7.
    Cairns, Andrew G.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Vazquez-Romero, Ana
    Mahdi-Moein, Mohammad
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Elmore, Charles S.
    Takano, Akihiro
    Arakawa, Ryosuke
    Varrone, Andrea
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Schou, Magnus
    Increased Brain Exposure of an Alpha-Synuclein Fibrillization Modulator by Utilization of an Activated Ester Prodrug Strategy2018In: ACS Chemical Neuroscience, E-ISSN 1948-7193, Vol. 9, no 11, p. 2542-2547Article in journal (Refereed)
    Abstract [en]

    Previous work in our laboratories has identified a series of peptidomimetic 2-pyridone molecules as modulators of alpha-synuclein (α-syn) fibrillization in vitro. As a first step toward developing molecules from this scaffold as positron emission tomography imaging agents, we were interested in evaluating their blood-brain barrier permeability in nonhuman primates (NHP) in vivo. For this purpose, 2-pyridone 12 was prepared and found to accelerate α-syn fibrillization in vitro. Acid 12, and its acetoxymethyl ester analogue 14, were then radiolabeled with 11C (t1/2 = 20.4 min) at high radiochemical purity (>99%) and high specific radioactivity (>37 GBq/μmol). Following intravenous injection of each compound in NHP, a 4-fold higher radioactivity in brain was observed for [11C]14 compared to [11C]12 (0.8 vs 0.2 SUV, respectively). [11C]14 was rapidly eliminated from plasma, with [11C]12 as the major metabolic product observed by radio-HPLC. The presented prodrug approach paves the way for future development of 2-pyridones as imaging biomarkers for in vivo imaging of α-synuclein deposits in brain.

  • 8.
    Chorell, Erik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Andersson, Emma
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Evans, Margery L.
    Jain, Neha
    Götheson, Anna
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Åden, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Chapman, Matthew R.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Wittung-Stafshede, Pernilla
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bacterial Chaperones CsgE and CsgC Differentially Modulate Human α-Synuclein Amyloid Formation via Transient Contacts2015In: PLOS ONE, E-ISSN 1932-6203, Vol. 10, no 10, p. 1-11, article id e0140194Article in journal (Refereed)
    Abstract [en]

    Amyloid formation is historically associated with cytotoxicity, but many organisms produce functional amyloid fibers (e.g., curli) as a normal part of cell biology. Two E. coli genes in the curli operon encode the chaperone-like proteins CsgC and CsgE that both can reduce in vitro amyloid formation by CsgA. CsgC was also found to arrest amyloid formation of the human amyloidogenic protein α-synuclein, which is involved in Parkinson’s disease. Here, we report that the inhibitory effects of CsgC arise due to transient interactions that promote the formation of spherical α-synuclein oligomers. We find that CsgE also modulates α-synuclein amyloid formation through transient contacts but, in contrast to CsgC, CsgE accelerates α-synuclein amyloid formation. Our results demonstrate the significance of transient protein interactions in amyloid regulation and emphasize that the same protein may inhibit one type of amyloid while accelerating another.

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  • 9.
    Clifton, Luke A.
    et al.
    ISIS Neutron and Muon Source, Science and Technology Facilities Council, Didcot, United Kingdom.
    Ul Mushtaq, Ameeq
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sparrman, Tobias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wacklin-Knecht, Hanna
    European Spallation Source, European Research Infrastructure Consortium, Lund, Sweden.
    Gröbner, Gerhard
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Insight into Bcl-2 proteins' functioning at mitochondrial membrane level2023In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 122, no 3S1, p. 232a-232a, article id 1130-PosArticle in journal (Refereed)
    Abstract [en]

    Programmed cell death (apoptosis) is essential in life. In its intrinsic apoptotic pathway opposing members of the B-cell lymphoma 2 (Bcl-2) protein family control the permeability of the mitochondrial outer membrane (MOM) and the release of apoptotic factors such as cytochrome c. Any misregulation of this process can cause disorders most prominently cancer, where often upregulation of cell protecting (anti-apoptotic) Bcl-2 members such as the Bcl-2 membrane protein itself plays a notorious role by blocking MOM perforation by - often drug induced - apoptotic proteins such as Bax which would cause cancer cell death normally. Here, we apply neutron reflectometry (NR) on supported lipid bilayers which mimic MOM environment and solid state/liquid state NMR spectroscopy to unravel the molecular basis driving opposing proteins to interact with each other at the MOM; a mechanism which is not really understood yet due to lack of high-resolution structural insight. Based on our central hypothesis that Bcl-2 drives its cell-protecting function at a membrane-embedded location as revealed by NR (1), we focus i) to determine the structure of human Bcl-2 protein in its membrane setting by combining solution and solid-state NMR; ii) use NR to study the kinetics and lipid/protein pore assemblied upon binding of Bax to mitochondrial membranes and its membrane destroying activities there; and iii) unravel the nature of direct interaction between Bcl-2 and Bax to neutralize each other. Knowledge generated here, will be indispensable in understanding the regulative function of the Bcl-2 family at mitochondrial membranes.

  • 10.
    Clifton, Luke A.
    et al.
    SIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire, UK.
    Wacklin-Knecht, Hanna P.
    European Spallation Source ERIC, ESS, Lund, Sweden; Department of Chemistry, Division of Physical Chemistry, Lund University, Lund, Sweden.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ul Mushtaq, Ameeq
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sparrman, Tobias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gröbner, Gerhard
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Creation of distinctive Bax-lipid complexes at mitochondrial membrane surfaces drives pore formation to initiate apoptosis2023In: Science Advances, E-ISSN 2375-2548, Vol. 9, no 22, article id eadg7940Article in journal (Refereed)
    Abstract [en]

    Apotosis is an essential process tightly regulated by the Bcl-2 protein family where proapoptotic Bax triggers cell death by perforating the mitochondrial outer membrane. Although intensively studied, the molecular mechanism by which these proteins create apoptotic pores remains elusive. Here, we show that Bax creates pores by extracting lipids from outer mitochondrial membrane mimics by formation of Bax/lipid clusters that are deposited on the membrane surface. Time-resolved neutron reflectometry and Fourier transform infrared spectroscopy revealed two kinetically distinct phases in the pore formation process, both of which were critically dependent on cardiolipin levels. The initially fast adsorption of Bax on the mitochondrial membrane surface is followed by a slower formation of pores and Bax-lipid clusters on the membrane surface. Our findings provide a robust molecular understanding of mitochondrial membrane perforation by cell-killing Bax protein and illuminate the initial phases of programmed cellular death. Bax initiates apoptosis by perforating mitochondrial membranes via formation of pores and extramembranous Bax-lipid complexes.

  • 11.
    Dingeldein, Artur P. G.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sparrman, Tobias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wacklin, Hanna P.
    Clifton, Luke A.
    Gröbner, Gerhard
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Mitochondrial Membrane Organization under Oxidative Stress: Insight by Solid-State NMR and Neutron Reflectometry2019In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 116, no 3, p. 508A-508AArticle in journal (Other academic)
  • 12.
    Dingeldein, Artur Peter Günther
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lindberg, Mikael J.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Zhong, Xueyin
    Ruhr University of Bochum, Biomolecular NMR Spectroscopy, Bochum, Germany.
    Stoll, Raphael
    Ruhr University of Bochum, Biomolecular NMR Spectroscopy, Bochum, Germany.
    Gröbner, Gerhard
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bax to the future: A novel, high-yielding approach for purification and expression of full-length Bax protein for structural studies2019In: Protein Expression and Purification, ISSN 1046-5928, E-ISSN 1096-0279, Vol. 158, p. 20-26Article in journal (Refereed)
    Abstract [en]

    Mitochondria-mediated apoptosis (programmed cell death) involves a sophisticated signaling and regulatory network that is regulated by the Bcl-2 protein family. Members of this family have either pro- or anti-apoptotic functions. An important pro-apoptotic member of this family is the cytosolic Bax. This protein is crucial for the onset of apoptosis by perforating the mitochondrial outer membrane (MOM). This process can be seen as point of no return, since disintegration of the MOM leads to the release of apotogenic factors such as cytochrome c into the cytosol triggering the activation of caspases and subsequent apoptotic steps. Bax is able to interact with the MOM with both its termini, making it inherently difficult to express in E. coli. In this study, we present a novel approach to express and purify full-length Bax with significantly increased yields, when compared to the commonly applied strategy. Using a double fusion approach with an N-terminal GST-tag and a C-terminal Intein-CBD-tag, we were able to render both Bax termini inactive and prevent disruptive interactions from occurring during gene expression. By deploying an Intein-CBD-tag at the C-terminus we were further able to avoid the introduction of any artificial residues, hence ensuring the native like activity of the membrane-penetrating C-terminus of Bax. Further, by engineering a His6-tag to the C-terminus of the CBD-tag we greatly improved the robustness of the purification procedure. We report yields for pure, full-length Bax protein that are increased by an order of magnitude, when compared to commonly used Bax expression protocols.

  • 13.
    Dulko-Smith, Beata
    et al.
    Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas, USA.
    Ojeda-May, Pedro
    Umeå University, Faculty of Science and Technology, High Performance Computing Center North (HPC2N).
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wolf-Watz, Magnus
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nam, Kwangho
    Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas, USA.
    Mechanistic basis for a connection between the catalytic step and slow opening dynamics of adenylate kinase2023In: Journal of Chemical Information and Modeling, ISSN 1549-9596, E-ISSN 1549-960X, Vol. 63, no 5, p. 1556-1569Article in journal (Refereed)
    Abstract [en]

    Escherichia coli adenylate kinase (AdK) is a small, monomeric enzyme that synchronizes the catalytic step with the enzyme’s conformational dynamics to optimize a phosphoryl transfer reaction and the subsequent release of the product. Guided by experimental measurements of low catalytic activity in seven single-point mutation AdK variants (K13Q, R36A, R88A, R123A, R156K, R167A, and D158A), we utilized classical mechanical simulations to probe mutant dynamics linked to product release, and quantum mechanical and molecular mechanical calculations to compute a free energy barrier for the catalytic event. The goal was to establish a mechanistic connection between the two activities. Our calculations of the free energy barriers in AdK variants were in line with those from experiments, and conformational dynamics consistently demonstrated an enhanced tendency toward enzyme opening. This indicates that the catalytic residues in the wild-type AdK serve a dual role in this enzyme’s function─one to lower the energy barrier for the phosphoryl transfer reaction and another to delay enzyme opening, maintaining it in a catalytically active, closed conformation for long enough to enable the subsequent chemical step. Our study also discovers that while each catalytic residue individually contributes to facilitating the catalysis, R36, R123, R156, R167, and D158 are organized in a tightly coordinated interaction network and collectively modulate AdK’s conformational transitions. Unlike the existing notion of product release being rate-limiting, our results suggest a mechanistic interconnection between the chemical step and the enzyme’s conformational dynamics acting as the bottleneck of the catalytic process. Our results also suggest that the enzyme’s active site has evolved to optimize the chemical reaction step while slowing down the overall opening dynamics of the enzyme.

  • 14.
    Esteban-Martin, Santiago
    et al.
    Joint BSC-CRG-IRB Research Programme in Computational Biology, Barcelona Supercomputing Center - BSC, Barcelona, Spain.
    Fenwick, Robert Bryn
    Joint BSC-CRG-IRB Research Programme in Computational Biology, Institute for Research in Biomedicine – IRB Barcelona, Barcelona, Spain.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Cossins, Benjamin
    Joint BSC-CRG-IRB Research Programme in Computational Biology, Barcelona Supercomputing Center - BSC, Barcelona, Spain.
    Bertoncini, Carlos W.
    Joint BSC-CRG-IRB Research Programme in Computational Biology, Institute for Research in Biomedicine – IRB Barcelona, Barcelona, Spain.
    Guallar, Victor
    Joint BSC-CRG-IRB Research Programme in Computational Biology, Barcelona Supercomputing Center - BSC, Barcelona, Spain.
    Wolf-Watz, Magnus
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Salvatella, Xavier
    Joint BSC-CRG-IRB Research Programme in Computational Biology, Institute for Research in Biomedicine – IRB Barcelona, Barcelona, Spain.
    Correlated Inter-Domain Motions in Adenylate Kinase2014In: PloS Computational Biology, ISSN 1553-734X, E-ISSN 1553-7358, Vol. 10, no 7, p. e1003721-Article in journal (Refereed)
    Abstract [en]

    Correlated inter-domain motions in proteins can mediate fundamental biochemical processes such as signal transduction and allostery. Here we characterize at structural level the inter-domain coupling in a multidomain enzyme, Adenylate Kinase (AK), using computational methods that exploit the shape information encoded in residual dipolar couplings (RDCs) measured under steric alignment by nuclear magnetic resonance (NMR). We find experimental evidence for a multi-state equilibrium distribution along the opening/closing pathway of Adenylate Kinase, previously proposed from computational work, in which inter-domain interactions disfavour states where only the AMP binding domain is closed. In summary, we provide a robust experimental technique for study of allosteric regulation in AK and other enzymes.

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  • 15. Evans, Margery L.
    et al.
    Chorell, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Taylor, Jonathan D.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Götheson, Anna
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Li, Fei
    Koch, Marion
    Sefer, Lea
    Matthews, Steve J.
    Wittung-Stafshede, Pernilla
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Almqvist, Fredrik
    Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Chapman, Matthew R.
    Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    The Bacterial Curli System Possesses a Potent and Selective Inhibitor of Amyloid Formation2015In: Molecular Cell, ISSN 1097-2765, E-ISSN 1097-4164, Vol. 57, no 3, p. 445-455Article in journal (Refereed)
    Abstract [en]

    Summary Curli are extracellular functional amyloids that are assembled by enteric bacteria during biofilm formation and host colonization. An efficient secretion system and chaperone network ensures that the major curli fiber subunit, CsgA, does not form intracellular amyloid aggregates. We discovered that the periplasmic protein CsgC was a highly effective inhibitor of CsgA amyloid formation. In the absence of CsgC, CsgA formed toxic intracellular aggregates. In vitro, CsgC inhibited CsgA amyloid formation at substoichiometric concentrations and maintained CsgA in a non-β-sheet-rich conformation. Interestingly, CsgC inhibited amyloid assembly of human α-synuclein, but not Aβ42, in vitro. We identified a common D-Q-Φ-X0,1-G-K-N-ζ-E motif in CsgC client proteins that is not found in Aβ42. CsgC is therefore both an efficient and selective amyloid inhibitor. Dedicated functional amyloid inhibitors may be a key feature that distinguishes functional amyloids from disease-associated amyloids.

  • 16. Jain, Neha
    et al.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nagamatsu, Kanna
    Evans, Margery L.
    Li, Xinyi
    McMichael, Brennan
    Ivanova, Magdalena I.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Buxbaum, Joel N.
    Chapman, Matthew R.
    Inhibition of curli assembly and Escherichia coli biofilm formation by the human systemic amyloid precursor transthyretin2017In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 114, no 46, p. 12184-12189Article in journal (Refereed)
    Abstract [en]

    During biofilm formation, Escherichia coli and other Enterobacteriaceae produce an extracellular matrix consisting of curli amyloid fibers and cellulose. The precursor of curli fibers is the amyloidogenic protein CsgA. The human systemic amyloid precursor protein transthyretin (TTR) is known to inhibit amyloid-β (Aβ) aggregation in vitro and suppress the Alzheimer’s-like phenotypes in a transgenic mouse model of Aβ deposition. We hypothesized that TTR might have broad antiamyloid activity because the biophysical properties of amyloids are largely conserved across species and kingdoms. Here, we report that both human WT tetrameric TTR (WT-TTR) and its engineered nontetramer-forming monomer (M-TTR, F87M/L110M) inhibit CsgA amyloid formation in vitro, with M-TTR being the more efficient inhibitor. Preincubation of WT-TTR with small molecules that occupy the T4 binding site eliminated the inhibitory capacity of the tetramer; however, they did not significantly compromise the ability of M-TTR to inhibit CsgA amyloidogenesis. TTR also inhibited amyloid-dependent biofilm formation in two different bacterial species with no apparent bactericidal or bacteriostatic effects. These discoveries suggest that TTR is an effective antibiofilm agent that could potentiate antibiotic efficacy in infections associated with significant biofilm formation.

  • 17. Kelly, Rachel
    et al.
    Cairns, Andrew G.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bemelmans, Alexis-Pierre
    Brouillet, Emmanuel
    Patton, Tommy
    McKernan, Declan P.
    Dowd, Eilís
    The Small Molecule Alpha-Synuclein Aggregator, FN075, Enhances Alpha-Synuclein Pathology in Subclinical AAV Rat Models2021In: Biomolecules, E-ISSN 2218-273X, Vol. 11, no 11, article id 1685Article in journal (Refereed)
    Abstract [en]

    Animal models of Parkinson’s disease, in which the human α-synuclein transgene is overexpressed in the nigrostriatal pathway using viral vectors, are widely considered to be the most relevant models of the human condition. However, although highly valid, these models have major limitations related to reliability and variability, with many animals exhibiting pronounced α-synuclein expression failing to demonstrate nigrostriatal neurodegeneration or motor dysfunction. Therefore, the aim of this study was to determine if sequential intra-nigral administration of AAV-α-synuclein followed by the small α-synuclein aggregating molecule, FN075, would enhance or precipitate the associated α-synucleinopathy, nigrostriatal pathology and motor dysfunction in subclinical models. Rats were given unilateral intra-nigral injections of AAV-α-synuclein (either wild-type or A53T mutant) followed four weeks later by a unilateral intra-nigral injection of FN075, after which they underwent behavioral testing for lateralized motor functionality until they were sacrificed for immunohistological assessment at 20 weeks after AAV administration. In line with expectations, both of the AAV vectors induced widespread overexpression of human α-synuclein in the substantia nigra and striatum. Sequential administration of FN075 significantly enhanced the α-synuclein pathology with increased density and accumulation of the pathological form of the protein phosphorylated at serine 129 (pS129-α-synuclein). However, despite this enhanced α-synuclein pathology, FN075 did not precipitate nigrostriatal degeneration or motor dysfunction in these subclinical AAV models. In conclusion, FN075 holds significant promise as an approach to enhancing the α-synuclein pathology in viral overexpression models, but further studies are required to determine if alternative administration regimes for this molecule could improve the reliability and variability in these models.

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  • 18.
    Kovermann, Michael
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Grundström, Christin
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sauer-Eriksson, A. Elisabeth
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sauer, Uwe H
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wolf-Watz, Magnus
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Structural basis for catalytically restrictive dynamics of a high-energy enzyme state2015In: Nature Communications, E-ISSN 2041-1723, Vol. 6, article id 7644Article in journal (Refereed)
    Abstract [en]

    An emerging paradigm in enzymology is that transient high-energy structural states play crucial roles in enzymatic reaction cycles. Generally, these high-energy or ‘invisible’ states cannot be studied directly at atomic resolution using existing structural and spectroscopic techniques owing to their low populations or short residence times. Here we report the direct NMR-based detection of the molecular topology and conformational dynamics of a catalytically indispensable high-energy state of an adenylate kinase variant. On the basis of matching energy barriers for conformational dynamics and catalytic turnover, it was found that the enzyme’s catalytic activity is governed by its dynamic interconversion between the high-energy state and a ground state structure that was determined by X-ray crystallography. Our results show that it is possible to rationally tune enzymes’ conformational dynamics and hence their catalytic power—a key aspect in rational design of enzymes catalysing novel reactions.

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  • 19.
    Mikaelsson, Therese
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Johansson, Lennart B-Å
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wittung-Stafshede, Pernilla
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Direct Observation of Protein Unfolded State Compaction in the Presence of Macromolecular Crowding2013In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 104, no 3, p. 694-704Article in journal (Refereed)
    Abstract [en]

    Proteins fold and function in cellular environments that are crowded with other macromolecules. As a consequence of excluded volume effects, compact folded states of proteins should be indirectly stabilized due to destabilization of extended unfolded conformations. Here, we assess the role of excluded volume in terms of protein stability, structural dimensions and folding dynamics using a sugar-based crowding agent, dextran 20, and the small ribosomal protein S16 as a model system. To specifically address dimensions, we labeled the protein with BODIPY at two positions and measured Trp-BODIPY distances under different conditions. As expected, we found that dextran 20 (200 mg/ml) stabilized the variants against urea-induced unfolding. At conditions where the protein is unfolded, Förster resonance energy transfer measurements reveal that in the presence of dextran, the unfolded ensemble is more compact and there is residual structure left as probed by far-ultraviolet circular dichroism. In the presence of a crowding agent, folding rates are faster in the two-state regime, and at low denaturant concentrations, a kinetic intermediate is favored. Our study provides direct evidence for protein unfolded-state compaction in the presence of macromolecular crowding along with its energetic and kinetic consequences.

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    Direct Observation of Protein Unfolded State Compaction in the Presence of Macromolecular Crowding
  • 20.
    Mikaelsson, Therese
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wittung-Stafshede, Pernilla
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Johansson, Lennart B-Å
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Macromolecular crowding effects on two homologs of ribosomal protein S16: protein-dependent structural changes and local interactions2014In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 107, no 2, p. 401-410Article in journal (Refereed)
    Abstract [en]

    Proteins function in cellular environments that are crowded with biomolecules, and in this reduced available space, their biophysical properties may differ from those observed in dilute solutions in vitro. Here, we investigated the effects of a synthetic macromolecular crowding agent, dextran 20, on the folded states of hyperthermophilic (S16T(herme)) and mesophilic (S161homologs of the ribosomal protein S16. As expected for an excluded-volume effect, the resistance of the mesophilic Meso, protein to heat-induced unfolding increased in the presence of dextran 20, and chemical denaturation experiments at different fixed temperatures showed the macromolecular crowding effect to be temperature-independent. Forster resonance energy transfer experiments show that intramolecular distances between an intrinsic Trp residue and BODIPY-labeled S16 Meso depend on the level of the crowding agent. The BODIPY group was attached at three specific positions in S16me, allowing measurements of three intraprotein distances. All S16meso variants exhibited a decrease in the average Trp-BODIPY distance at up to 100 mg/mL dextran 20, whereas the changes in distance became anisotropic (one distance increased, two distances decreased) at higher dextran concentrations. In contrast, the two 516-rhermo mutants did not show any changes in Trp-BODIPY distances upon increase of dextran 20 concentrations. It should be noted that the fluorescence quantum yields and lifetimes of BODIPY attached to the two S16 homologs decreased gradually in the presence of dextran 20. To investigate the origin of this decrease, we studied the BODIPY quantum yield in three protein variants in the presence of a tyrosine-labeled dextran. The experiments revealed distinct tyrosine quenching behaviors of BODIPY in the three variants, suggesting a dynamic local interaction between dextran and one particular S16 variant.

  • 21.
    Mondol, Tanumoy
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wittung-Stafshede, Pernilla
    Biology and Biological Engineering Department, Chalmers University of Technology, Gothenburg, Sweden.
    Copper binding triggers compaction in N-terminal tail of human copper pump ATP7B2016In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 470, no 3, p. 663-669Article in journal (Refereed)
    Abstract [en]

    Protein conformational changes are fundamental to biological reactions. For copper ion transport, the multi-domain protein ATP7B in the Golgi network receives copper from the cytoplasmic copper chaperone Atox1 and, with energy from ATP hydrolysis, moves the metal to the lumen for loading of copper dependent enzymes. Although anticipated, conformational changes involved in ATP7B's functional cycle remain elusive. Using spectroscopic methods we here demonstrate that the four most N-terminal metal binding domains in ATP7B, upon stoichiometric copper addition, adopt a more compact arrangement which has a higher thermal stability than in the absence of copper. In contrast to previous reports, no stable complex was found in solution between the metal-binding domains and the nucleotide-binding domain of ATP7B. Metal-dependent movement of the first four metal-binding domains in ATP7B may be a trigger that initiates the overall catalytic cycle.

  • 22.
    Nadeem, Aftab
    et al.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Berg, Alexandra
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Pace, Hudson
    Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM).
    Alam, Athar
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Toh, Eric
    Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Zlatkov, Nikola
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Myint, Si Lhyam
    Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Persson, Karina
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Gröbner, Gerhard
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Sjöstedt, Anders
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology. Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Bally, Marta
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology. Umeå University, Faculty of Medicine, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Barandun, Jonas
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
    Uhlin, Bernt Eric
    Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Wai, Sun Nyunt
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Protein-lipid interaction at low pH induces oligomerization of the MakA cytotoxin from Vibrio cholerae2022In: eLIFE, E-ISSN 2050-084X, Vol. 11, article id e73439Article in journal (Refereed)
    Abstract [en]

    The α-pore-forming toxins (α-PFTs) from pathogenic bacteria damage host cell membranes by pore formation. We demonstrate a remarkable, hitherto unknown mechanism by an α-PFT protein from Vibrio cholerae. As part of the MakA/B/E tripartite toxin, MakA is involved in membrane pore formation similar to other α-PFTs. In contrast, MakA in isolation induces tube-like structures in acidic endosomal compartments of epithelial cells in vitro. The present study unravels the dynamics of tubular growth, which occurs in a pH-, lipid-, and concentration-dependent manner. Within acidified organelle lumens or when incubated with cells in acidic media, MakA forms oligomers and remodels membranes into high-curvature tubes leading to loss of membrane integrity. A 3.7 Å cryo-electron microscopy structure of MakA filaments reveals a unique protein-lipid superstructure. MakA forms a pinecone-like spiral with a central cavity and a thin annular lipid bilayer embedded between the MakA transmembrane helices in its active α-PFT conformation. Our study provides insights into a novel tubulation mechanism of an α-PFT protein and a new mode of action by a secreted bacterial toxin.

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  • 23.
    Nilsson, Lina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Niemiec, Moritz S.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nam, Kwangho
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Computational Life Science Center (CLiC), Umeå University,.
    Wittung-Stafshede, Pernilla
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Small pH and Salt Variations Radically Alter the Thermal Stability of Metal-Binding Domains in the Copper Transporter, Wilson Disease Protein2013In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 117, no 42, p. 13038-13050Article in journal (Refereed)
    Abstract [en]

    Although strictly regulated, pH and solute concentrations in cells may exhibit temporal and spatial fluctuations. Here we study the effect of such changes on the stability, structure, and dynamics in vitro and in silico of a two-domain construct (WD56) of the fifth and sixth metal-binding domains of the copper transport protein, ATP7B (Wilson disease protein). We find that the thermal stability of WD56 is increased by 40 °C when increasing the pH from 5.0 to 7.5. In contrast, addition of salt at pH 7.2 decreases WD56 stability by up to 30 °C. In agreement with domain-domain coupling, fractional copper loading increases the stability of both domains. HSQC chemical shift changes demonstrate that, upon lowering the pH from 7.2 to 6, both His in WD6 as well as the second Cys of the copper site in each domain become protonated. MD simulations reveal increased domain-domain fluctuations at pH 6 and in the presence of high salt concentration, as compared to at pH 7 and low salt concentration. Thus, the surface charge distribution at high pH contributes favorably to overall WD56 stability. By introducing more positive charges by lowering the pH, or by diminishing charge-charge interactions by salt, fluctuations among the domains are increased and thereby overall stability is reduced. Copper transfer activity also depends on pH: delivery of copper from chaperone Atox1 to WD56 is more efficient at pH 7.2 than at pH 6 by a factor of 30. It appears that WD56 is an example where the free energy landscapes for folding and function are linked via structural stability.

  • 24. Näsström, Thomas
    et al.
    Dahlberg, Tobias
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Malyshev, Dmitry
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Andersson, Per Ola
    Andersson, Magnus
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Karlsson, Björn C. G.
    Synthetic NAC 71-82 Peptides Designed to Produce Fibrils with Different Protofilament Interface Contacts2021In: International Journal of Molecular Sciences, ISSN 1661-6596, E-ISSN 1422-0067, Vol. 22, no 17, article id 9334Article in journal (Refereed)
    Abstract [en]

    Alpha-synucleinopathies are featured by fibrillar inclusions in brain cells. Although α-synuclein fibrils display structural diversity, the origin of this diversity is not fully understood. We used molecular dynamics simulations to design synthetic peptides, based on the NAC 71-82 amino acid fragment of α-synuclein, that govern protofilament contacts and generation of twisted fibrillar polymorphs. Four peptides with structures based on either single or double fragments and capped or non-capped ends were selected for further analysis. We determined the fibrillar yield and the structures from these peptides found in the solution after fibrillisation using protein concentration determination assay and circular dichroism spectroscopy. In addition, we characterised secondary structures formed by individual fibrillar complexes using laser-tweezers Raman spectroscopy. Results suggest less mature fibrils, based on the lower relative β-sheet content for double- than single-fragment peptide fibrils. We confirmed this structural difference by TEM analysis which revealed, in addition to short protofibrils, more elongated, twisted and rod-like fibril structures in non-capped and capped double-fragment peptide systems, respectively. Finally, time-correlated single-photon counting demonstrated a difference in the Thioflavin T fluorescence lifetime profiles upon fibril binding. It could be proposed that this difference originated from morphological differences in the fibril samples. Altogether, these results highlight the potential of using peptide models for the generation of fibrils that share morphological features relevant for disease, e.g., twisted and rod-like polymorphs.

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  • 25. Näsström, Thomas
    et al.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Shibata, Fumina
    Andersson, Per Ola
    Karlsson, Björn C.G.
    A Capped Peptide of the Aggregation Prone NAC 71-82 Amino Acid Stretch of α-Synuclein Folds into Soluble β-Sheet Oligomers at Low and Elevated Peptide Concentrations2020In: International Journal of Molecular Sciences, ISSN 1661-6596, E-ISSN 1422-0067, Vol. 21, no 5, article id 1629Article in journal (Refereed)
    Abstract [en]

    Although Lewy bodies and Lewy neurites are hallmarks of Parkinson's disease (PD) and dementia with Lewy bodies (DLB), misfolded α-synuclein oligomers are nowadays believed to be key for the development of these diseases. Attempts to target soluble misfolded species of the full-length protein have been limited so far, probably due to the fast aggregation kinetics and burial of aggregation prone segments in final cross-β-sheet fibrils. A previous characterisation study of fibrils prepared from a capped peptide of the non-amyloid β-component (NAC) 71-82 amino acid stretch of α-synuclein demonstrated an increased aggregation propensity resulting in a cross-β-structure that is also found in prion proteins. From this, it was suggested that capped NAC 71-82 peptide oligomers would provide interesting motifs with a capacity to regulate disease development. Here, we demonstrated, from a series of circular dichroism spectroscopic measurements and molecular dynamics simulations, the molecular-environment-sensitive behaviour of the capped NAC 71-82 peptide in a solution phase and the formation of β-sheet oligomeric structures in the supernatant of a fibrillisation mixture. These results highlighted the use of the capped NAC 71-82 peptide as a motif in the preparation of oligomeric β-sheet structures that potentially could be used in therapeutic strategies in the fight against progressive neurodegenerative disorders, such as PD and DLB.

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  • 26. Olsen, Laura K.
    et al.
    Cairns, Andrew G.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Moriarty, Niamh
    Cabre, Silvia
    Alamilla, Veronica R.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Dowd, Eilís
    McKernan, Declan P.
    Viral mimetic priming enhances α-synuclein-induced degeneration: implications for Parkinson's disease2019In: Brain, behavior, and immunity, ISSN 0889-1591, E-ISSN 1090-2139, Vol. 80, p. 525-535Article in journal (Refereed)
    Abstract [en]

    Evidence is accumulating to suggest that viral infections and consequent viral-mediated neuroinflammation may contribute to the etiology of idiopathic Parkinson’s disease. Moreover, viruses have been shown to influence α-synuclein oligomerization as well as the autophagic clearance of abnormal intra-cellular proteins aggregations, both of which are key neuropathological events in Parkinson’s disease pathogenesis. To further investigate the interaction between viral-mediated neuroinflammation and α-synuclein aggregation in the context of Parkinson’s disease, this study sought to determine the impact of viral neuroinflammatory priming on α-synuclein aggregate-induced neuroinflammation and neurotoxicity in the rat nigrostriatal pathway. To do so, male Sprague-Dawley rats were intra-nigrally injected with a synthetic mimetic of viral dsRNA (poly I:C) followed two weeks later by a peptidomimetic small molecule which accelerates α-synuclein fibril formation (FN075). The impact of the viral priming on α-synuclein aggregation-induced neuroinflammation, neurodegeneration and motor dysfunction was assessed. We found that prior administration of the viral mimetic poly I:C significantly exacerbated or precipitated the α-synuclein aggregate induced neuropathological and behavioral effects. Specifically, sequential exposure to the two challenges caused a significant increase in nigral microgliosis (p < 0.001) and astrocytosis (p < 0.01); precipitated a significant degeneration of the nigrostriatal cell bodies (p < 0.05); and precipitated a significant impairment in forelimb kinesis (p < 0.01) and sensorimotor integration (p < 0.01). The enhanced sensitivity of the nigrostriatal neurons to pathological α-synuclein aggregation after viral neuroinflammatory priming further suggests that viral infections may contribute to the etiology and pathogenesis of Parkinson’s disease.

  • 27.
    Petzoldt, Svenja
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Center of Life and Food Sciences, Technische Universität München, Freising, Germany.
    Kahra, Dana
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kovermann, Michael
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Dingeldein, Artur PG
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Niemiec, Moritz S.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wittung-Stafshede, Pernilla
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Human cytoplasmic copper chaperones Atox1 and CCS exchange copper ions in vitro2015In: Biometals, ISSN 0966-0844, E-ISSN 1572-8773, Vol. 28, no 3, p. 577-585Article in journal (Refereed)
    Abstract [en]

    After Ctr1-mediated copper ion (Cu) entry into the human cytoplasm, chaperones Atox1 and CCS deliver Cu to P-1B-type ATPases and to superoxide dismutase, respectively, via direct protein-protein interactions. Although the two Cu chaperones are presumed to work along independent pathways, we here assessed cross-reactivity between Atox1 and the first domain of CCS (CCS1) using biochemical and biophysical methods in vitro. By NMR we show that CCS1 is monomeric although it elutes differently from Atox1 in size exclusion chromatography (SEC). This property allows separation of Atox1 and CCS1 by SEC and, combined with the 254/280 nm ratio as an indicator of Cu loading, we demonstrate that Cu can be transferred from one protein to the other. Cu exchange also occurs with full-length CCS and, as expected, the interaction involves the metal binding sites since mutation of Cu-binding cysteine in Atox1 eliminates Cu transfer from CCS1. Cross-reactivity between CCS and Atox1 may aid in regulation of Cu distribution in the cytoplasm.

  • 28.
    Rundqvist, Louise
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sparrman, Tobias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wallgren, Marcus
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Olsson, Ulrika
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wolf-Watz, Magnus
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Noncooperative folding of subdomains in Adenylate Kinase2009In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 48, no 9, p. 1911-1927Article in journal (Refereed)
    Abstract [en]

    Conformational change is regulating the biological activity of a large number of proteins and enzymes. Efforts in structural biology have provided molecular descriptions of the interactions that stabilize the stable ground states on the reaction trajectories during conformational change. Less is known about equilibrium thermodynamic stabilities of the polypeptide segments that participate in structural changes and whether the stabilities are relevant for the reaction pathway. Adenylate kinase (Adk) is composed of three subdomains: CORE, ATPlid, and AMPbd. ATPlid and AMPbd are flexible nucleotide binding subdomains where large-scale conformational changes are directly coupled to catalytic activity. In this report, the equilibrium thermodynamic stabilities of Adk from both mesophilic and hyperthermophilic bacteria were investigated using solution state NMR spectroscopy together with protein engineering experiments. Equilibrium hydrogen to deuterium exchange experiments indicate that the flexible subdomains are of significantly lower thermodynamic stability compared to the CORE subdomain. Using site-directed mutagenesis, parts of ATPlid and AMPbd could be selectively unfolded as a result of perturbation of hydrophobic clusters located in these respective subdomains. Analysis of the perturbed Adk variants using NMR spin relaxation and Cα chemical shifts shows that the CORE subdomain can fold independently of ATPlid and AMPbd; consequently, folding of the two flexible subdomains occurs independently of each other. Based on the experimental results it is apparent that the flexible subdomains fold into their native structure in a noncooperative manner with respect to the CORE subdomain. These results are discussed in light of the catalytically relevant conformational change of ATPlid and AMPbd.

  • 29.
    Singh, Pardeep
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Adolfsson, Dan E.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Cairns, Andrew G.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bartens, Christian
    Brännström, Kristoffer
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pyridine-Fused 2-Pyridones via Povarov and A3 Reactions: Rapid Generation of Highly Functionalized Tricyclic Heterocycles Capable of Amyloid Fibril Binding2019In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 84, no 7, p. 3887-3903Article in journal (Refereed)
    Abstract [en]

    We here describe the use of three-component reactions to synthesize tricyclic pyridine ring-fused 2-pyridones. The developed protocols have a wide substrate scope and allow for the installation of diverse chemical functionalities on the tricyclic central fragment. Several of these pyridine-fused rigid polyheterocycles are shown to bind to Aβ and α-synuclein fibrils, which are associated with neurodegenerative diseases.

  • 30.
    Singh, Pardeep
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Cairns, Andrew G.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Adolfsson, Dan E.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sauer, Uwe H.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Synthesis of Densely Functionalized N-Alkenyl 2-Pyridones via Benzyne-Induced Ring Opening of Thiazolino-Fused 2-Pyridones2019In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 21, p. 6946-6950Article in journal (Refereed)
    Abstract [en]

    We report the synthesis of 6-arylthio-substituted-N-alkenyl 2-pyridones by ring opening of bicyclic thiazolino-2-pyridones with arynes. Varied functionalization was used to investigate scope and substituent influences on reactivity. Selected conditions favor thioether ring opening over [4 + 2] cycloaddition and an unusual aryne incorporating ring expansion. Deuterium labeling was used to clarify observed reactivity. Using the knowledge, we produced drug-like molecules with complex substitution patterns and show how thioether ring opening can be used on scaffolds with competing reactivities.

  • 31.
    Singh, Pardeep
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Chorell, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Krishnan, K Syam
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kindahl, Tomas
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wittung-Stafshede, Pernilla
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Synthesis of multiring fused 2‑pyridones via a nitrene insertion reaction: fluorescent modulators of α‑synuclein amyloid formation2015In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 17, no 24, p. 6194-6197Article in journal (Refereed)
    Abstract [en]

    An efficient, straightforward method for the synthesis of thiazolo-2-pyridone embedded peptidomimetic polyheterocycles via a catalyst-free, microwave-assisted, intramolecular C−H amination reaction is reported. All the synthesized polyheterocycles were evaluated for their fluorescent properties and effect on α-synuclein amyloid formation.

  • 32.
    Tyagi, Mohit
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Adolfsson, Dan E.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Singh, Pardeep
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Jayaweera, Sanduni Wasana
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Gharibyan, Anna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Bharate, Jaideep B.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kiss, Anita
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sarkar, Souvik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tandem Ring Opening/Intramolecular [2 + 2] Cycloaddition Reaction for the Synthesis of Cyclobutane Fused Thiazolino-2-Pyridones2021In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 86, no 23, p. 16582-16592Article in journal (Refereed)
    Abstract [en]

    Reaction of thiazoline fused 2-pyridones with alkyl halides in the presence of cesium carbonate opens the thiazoline ring via S-alkylation and generates N-alkenyl functionalized 2-pyridones. In the reaction with propargyl bromide, the thiazoline ring opens and subsequently closes via a [2 + 2] cycloaddition between an in situ generated allene and the α,β-unsaturated methyl ester. This method enabled the synthesis of a variety of cyclobutane fused thiazolino-2-pyridones, of which a few analogues inhibit amyloid β1–40 fibril formation. Furthermore, other analogues were able to bind mature α-synuclein and amyloid β1−40 fibrils. Several thiazoline fused 2-pyridones with biological activity tolerate this transformation, which in addition provides an exocyclic alkene as a potential handle for tuning bioactivity.

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  • 33. Tyagi, Mohit
    et al.
    Adolfsson, Dan E.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Singh, Pardeep
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sarkar, Souvik
    Kiss, Anita
    Bharate, Jaideep B.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
    Functionalization of Thiazolino fused 2-Pyridones by thiazoline ring opening and closing: Identification of new Amyloid Binding HeterocyclesManuscript (preprint) (Other academic)
    Abstract [en]

    Reaction of thiazolino fused 2-pyridones with alkyl halides in the presence of cesium carbonate opens the thiazoline ring via S-alkylation and generate N-alkenyl functionalized 2-pyridones. In the reaction with propargyl bromide, the thiazoline ring opens and subsequently closes via an intramolecular [2 + 2] cycloaddition between in situ generated allene and the α,β-unsaturated carbonyl moiety. This method enabled the synthesis of a variety of cyclobutane and thiazolino fused 2-pyridones, which were tested for α-synuclein binding activity. Most of the bioactive thiazolino fused 2-pyridones tolerated this transformation and in addition provided an exocyclic alkene as a handle for tuning bioactivity.

  • 34.
    Ul Mushtaq, Ameeq
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Alam, Athar
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Sjöstedt, Anders
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Gröbner, Gerhard
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Backbone chemical shift assignment and dynamics of the N-terminal domain of ClpB from Francisella tularensis type VI secretion system2022In: Biomolecular NMR Assignments, ISSN 1874-2718, E-ISSN 1874-270X, Vol. 16, p. 75-79Article in journal (Refereed)
    Abstract [en]

    The Hsp100 family member ClpB is a protein disaggregase which solubilizes and reactivates stress-induced protein aggregates in cooperation with the DnaK/Hsp70 chaperone system. In the pathogenic bacterium Francisella tularensis, ClpB is involved in type VI secretion system (T6SS) disassembly through depolymerization of the IglA-IglB sheath. This leads to recycling and reassembly of T6SS components and this process is essential for the virulence of the bacterium. Here we report the backbone chemical shift assignments and 15N relaxation-based backbone dynamics of the N-terminal substrate-binding domain of ClpB (1-156).

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  • 35.
    Ul Mushtaq, Ameeq
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ådén, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ali, Katan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gröbner, Gerhard
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Domain-specific insight into the recognition of BH3-death motifs by the pro-survival Bcl-2 protein2022In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 121, no 23, p. 4517-4525Article in journal (Refereed)
    Abstract [en]