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Publications (10 of 34) Show all publications
Hussein, R., Graça, A. T., Forsman, J., Aydin, A. O., Hall, M., Gaetcke, J., . . . Schröder, W. P. (2024). Cryo-electron microscopy reveals hydrogen positions and water networks in photosystem II. Science, 384(6702), 1349-1355
Open this publication in new window or tab >>Cryo-electron microscopy reveals hydrogen positions and water networks in photosystem II
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2024 (English)In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 384, no 6702, p. 1349-1355Article in journal (Refereed) Published
Abstract [en]

Photosystem II starts the photosynthetic electron transport chain that converts solar energy into chemical energy and thus sustains life on Earth. It catalyzes two chemical reactions: water oxidation to molecular oxygen and plastoquinone reduction. Coupling of electron and proton transfer is crucial for efficiency; however, the molecular basis of these processes remains speculative owing to uncertain water binding sites and the lack of experimentally determined hydrogen positions. We thus collected high-resolution cryo-electron microscopy data of fully hydrated photosystem II from the thermophilic cyanobacterium Thermosynechococcus vestitus to a final resolution of 1.71 angstroms. The structure reveals several previously undetected partially occupied water binding sites and more than half of the hydrogen and proton positions. This clarifies the pathways of substrate water binding and plastoquinone B protonation.

Place, publisher, year, edition, pages
American Association for the Advancement of Science (AAAS), 2024
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-227578 (URN)10.1126/science.adn6541 (DOI)38900892 (PubMedID)2-s2.0-85196874000 (Scopus ID)
Funder
Swedish Research Council, 2020-03809Carl Tryggers foundation , 19.324The Kempe Foundations, JCK-2030 2021-2023
Available from: 2024-07-01 Created: 2024-07-01 Last updated: 2024-07-05Bibliographically approved
Hall, M., Schexnaydre, E., Holmlund, C. & Carroni, M. (2023). Protein structural analysis by cryogenic electron microscopy (1ed.). In: Ângela Sousa; Luis Passarinha (Ed.), Advanced methods in structural biology: (pp. 439-463). New York: Humana Press, 2652
Open this publication in new window or tab >>Protein structural analysis by cryogenic electron microscopy
2023 (English)In: Advanced methods in structural biology / [ed] Ângela Sousa; Luis Passarinha, New York: Humana Press, 2023, 1, Vol. 2652, p. 439-463Chapter in book (Refereed)
Abstract [en]

Cryogenic electron microscopy (cryo-EM) is constantly developing and growing as a major technique for structure determination of protein complexes. Here, we detail the first steps of any cryo-EM project: specimen preparation and data collection. Step by step, a list of material needed is provided and the sequence of actions to carry out is given. We hope that these protocols will be useful to all people getting started with cryo-EM.

Place, publisher, year, edition, pages
New York: Humana Press, 2023 Edition: 1
Series
Methods in Molecular Biology, ISSN 1064-3745, E-ISSN 1940-6029 ; 2652
Keywords
Cryo electron microscopy, Protein structure, Single particle analysis, Vitrification
National Category
Biochemistry and Molecular Biology Other Chemistry Topics
Identifiers
urn:nbn:se:umu:diva-207882 (URN)10.1007/978-1-0716-3147-8_24 (DOI)37093490 (PubMedID)2-s2.0-85153687301 (Scopus ID)9781071631461 (ISBN)9781071631478 (ISBN)
Available from: 2023-05-05 Created: 2023-05-05 Last updated: 2023-06-09Bibliographically approved
Baird, T., Hall, C. M., Castka, P. & Ramkissoon, H. (2022). Innovation, wine tourism, and sustainable winegrowing in cool climate regions: a longitudinal international comparative analysis. In: Irma Booyens; Patrick Brouder (Ed.), Handbook of innovation for sustainable tourism: (pp. 167-191). Edward Elgar Publishing
Open this publication in new window or tab >>Innovation, wine tourism, and sustainable winegrowing in cool climate regions: a longitudinal international comparative analysis
2022 (English)In: Handbook of innovation for sustainable tourism / [ed] Irma Booyens; Patrick Brouder, Edward Elgar Publishing, 2022, p. 167-191Chapter in book (Refereed)
Abstract [en]

This study examined wineries' perceptions towards innovation within the context of sustainable winegrowing practices and wine tourism in New Zealand. In order to investigate the current situation in New Zealand, the National Wineries' Survey was extended to provide a longitudinal time series of data from the New Zealand wine industry. This data was also utilised to provide a comparison of the New Zealand perceptions of innovation with that of the Australian cool climate regions of Tasmania and Western Australia. The findings indicated that substantial concerns existed regarding the value of innovation within both wine tourism and sustainable winegrowing practices.

Place, publisher, year, edition, pages
Edward Elgar Publishing, 2022
National Category
Business Administration
Identifiers
urn:nbn:se:umu:diva-215096 (URN)10.4337/9781800372740.00018 (DOI)2-s2.0-85172672606 (Scopus ID)9781800372740 (ISBN)9781800372733 (ISBN)
Available from: 2023-10-13 Created: 2023-10-13 Last updated: 2023-10-13Bibliographically approved
Graça, A. T., Hall, M., Persson, K. & Schröder, W. P. (2021). High-resolution model of Arabidopsis Photosystem II reveals the structural consequences of digitonin-extraction. Scientific Reports, 11(1), Article ID 15534.
Open this publication in new window or tab >>High-resolution model of Arabidopsis Photosystem II reveals the structural consequences of digitonin-extraction
2021 (English)In: Scientific Reports, E-ISSN 2045-2322, Vol. 11, no 1, article id 15534Article in journal (Refereed) Published
Abstract [en]

In higher plants, the photosynthetic process is performed and regulated by Photosystem II (PSII). Arabidopsis thaliana was the first higher plant with a fully sequenced genome, conferring it the status of a model organism; nonetheless, a high-resolution structure of its Photosystem II is missing. We present the first Cryo-EM high-resolution structure of Arabidopsis PSII supercomplex with average resolution of 2.79 Å, an important model for future PSII studies. The digitonin extracted PSII complexes demonstrate the importance of: the LHG2630-lipid-headgroup in the trimerization of the light-harvesting complex II; the stabilization of the PsbJ subunit and the CP43-loop E by DGD520-lipid; the choice of detergent for the integrity of membrane protein complexes. Furthermore, our data shows at the anticipated Mn4CaO5-site a single metal ion density as a reminiscent early stage of Photosystem II photoactivation.

Place, publisher, year, edition, pages
Nature Publishing Group, 2021
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-186557 (URN)10.1038/s41598-021-94914-x (DOI)000683319500011 ()2-s2.0-85111686355 (Scopus ID)
Available from: 2021-08-11 Created: 2021-08-11 Last updated: 2024-07-05Bibliographically approved
Iakovleva, I., Hall, M., Oelker, M., Sandblad, L., Anan, I. & Sauer-Eriksson, A. E. (2021). Structural basis for transthyretin amyloid formation in vitreous body of the eye. Nature Communications, 12(1), Article ID 7141.
Open this publication in new window or tab >>Structural basis for transthyretin amyloid formation in vitreous body of the eye
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2021 (English)In: Nature Communications, E-ISSN 2041-1723, Vol. 12, no 1, article id 7141Article in journal (Refereed) Published
Abstract [en]

Amyloid transthyretin (ATTR) amyloidosis is characterized by the abnormal accumulation of ATTR fibrils in multiple organs. However, the structure of ATTR fibrils from the eye is poorly understood. Here, we used cryo-EM to structurally characterize vitreous body ATTR fibrils. These structures were distinct from previously characterized heart fibrils, even though both have the same mutation and type A pathology. Differences were observed at several structural levels: in both the number and arrangement of protofilaments, and the conformation of the protein fibril in each layer of protofilaments. Thus, our results show that ATTR protein structure and its assembly into protofilaments in the type A fibrils can vary between patients carrying the same mutation. By analyzing and matching the interfaces between the amino acids in the ATTR fibril with those in the natively folded TTR, we are able to propose a mechanism for the structural conversion of TTR into a fibrillar form.

Place, publisher, year, edition, pages
Nature Publishing Group, 2021
National Category
Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy) Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-190576 (URN)10.1038/s41467-021-27481-4 (DOI)000728313100019 ()34880242 (PubMedID)2-s2.0-85120856247 (Scopus ID)
Funder
Swedish Research Council, 2015-03607
Available from: 2021-12-20 Created: 2021-12-20 Last updated: 2023-03-28Bibliographically approved
Hansen, S., Hall, M., Grundström, C., Brännström, K., Sauer-Eriksson, A. E. & Johansson, J. (2020). A Novel Growth-Based Selection Strategy Identifies New Constitutively Active Variants of the Major Virulence Regulator PrfA in Listeria monocytogenes. Journal of Bacteriology, 202(11), Article ID e00115-20.
Open this publication in new window or tab >>A Novel Growth-Based Selection Strategy Identifies New Constitutively Active Variants of the Major Virulence Regulator PrfA in Listeria monocytogenes
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2020 (English)In: Journal of Bacteriology, ISSN 0021-9193, E-ISSN 1098-5530, Vol. 202, no 11, article id e00115-20Article in journal (Refereed) Published
Abstract [en]

Listeria monocytogenes is a Gram-positive pathogen able to cause severe human infections. Its major virulence regulator is the transcriptional activator PrfA, a member of the Crp/Fnr family of transcriptional regulators. To establish a successful L. monocytogenes infection, the PrfA protein needs to be in an active conformation, either by binding the cognate inducer glutathione (GSH) or by possessing amino acid substitutions rendering the protein constitutively active (PrfA*). By a yet unknown mechanism, phosphotransferase system (PTS) sugars repress the activity of PrfA. We therefore took a transposon-based approach to identify the mechanism by which PTS sugars repress PrfA activity. For this, we screened a transposon mutant bank to identify clones able to grow in the presence of glucose-6-phosphate as the sole carbon source. Surprisingly, most of the isolated transposon mutants also carried amino acid substitutions in PrfA. In transposon-free strains, the PrfA amino acid substitution mutants displayed growth, virulence factor expression, infectivity, and DNA binding, agreeing with previously identified PrIA* mutants. Hence, the initial growth phenotype observed in the isolated clone was due to the amino acid substitution in PrfA and unrelated to the loci inactivated by the transposon mutant. Finally, we provide structural evidence for the existence of an intermediately activated PrfA state, which gives new insights into PrfA protein activation. IMPORTANCE The Gram-positive bacterium Listeria monocytogenes is a human pathogen affecting mainly the elderly, immunocompromised people, and pregnant women. It can lead to meningoencephalitis, septicemia, and abortion. The major virulence regulator in L. monocytogenes is the PrfA protein, a transcriptional activator. Using a growth-based selection strategy, we identified mutations in the PrfA protein leading to constitutively active virulence factor expression. We provide structural evidence for the existence of an intermediately activated PrfA state, which gives new insights into PrfA protein activation.

Place, publisher, year, edition, pages
American Society for Microbiology, 2020
Keywords
Listeria monocytogenes, PrfA, PrfA*, crystal structure, LLO, ActA
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-171908 (URN)10.1128/JB.00115-20 (DOI)000532732400005 ()32179627 (PubMedID)2-s2.0-85084695335 (Scopus ID)
Available from: 2020-06-17 Created: 2020-06-17 Last updated: 2023-03-23Bibliographically approved
Hall, M., Hasegawa, Y., Yoshimura, F. & Persson, K. (2018). Structural and functional characterization of shaft, anchor, and tip proteins of the Mfa1 fimbria from the periodontal pathogen Porphyromonas gingivalis. Scientific Reports, 8, Article ID 1793.
Open this publication in new window or tab >>Structural and functional characterization of shaft, anchor, and tip proteins of the Mfa1 fimbria from the periodontal pathogen Porphyromonas gingivalis
2018 (English)In: Scientific Reports, E-ISSN 2045-2322, Vol. 8, article id 1793Article in journal (Refereed) Published
Abstract [en]

Very little is known about how fimbriae of Bacteroidetes bacteria are assembled. To shed more light on this process, we solved the crystal structures of the shaft protein Mfa1, the regulatory protein Mfa2, and the tip protein Mfa3 from the periodontal pathogen Porphyromonas gingivalis. Together these build up part of the Mfa1 fimbria and represent three of the five proteins, Mfa1-5, encoded by the mfa1 gene cluster. Mfa1, Mfa2 and Mfa3 have the same overall fold i.e., two β-sandwich domains. Upon polymerization, the first β-strand of the shaft or tip protein is removed by indigenous proteases. Although the resulting void is expected to be filled by a donor-strand from another fimbrial protein, the mechanism by which it does so is still not established. In contrast, the first β-strand in Mfa2, the anchoring protein, is firmly attached by a disulphide bond and is not cleaved. Based on the structural information, we created multiple mutations in P. gingivalis and analysed their effect on fimbrial polymerization and assembly in vivo. Collectively, these data suggest an important role for the C-terminal tail of Mfa1, but not of Mfa3, affecting both polymerization and maturation of downstream fimbrial proteins.

National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-144501 (URN)10.1038/s41598-018-20067-z (DOI)000423430400005 ()29379120 (PubMedID)2-s2.0-85041326581 (Scopus ID)
Available from: 2018-02-05 Created: 2018-02-05 Last updated: 2023-03-23Bibliographically approved
Persson, K., Hall, M., Heidler, T. & Hasegawa, Y. (2018). Structural studies of the five pilin proteins building up the type-V pilus Mfa1 of Porphyromonas gingivalis. Acta Crystallographica Section A: Foundations and Advances, 74, E425-E425
Open this publication in new window or tab >>Structural studies of the five pilin proteins building up the type-V pilus Mfa1 of Porphyromonas gingivalis
2018 (English)In: Acta Crystallographica Section A: Foundations and Advances, E-ISSN 2053-2733, Vol. 74, p. E425-E425Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
International Union of Crystallography, 2018
Keywords
pill, polynraerizaticxaa, bacteria
Identifiers
urn:nbn:se:umu:diva-161753 (URN)10.1107/S2053273318088800 (DOI)000474406600648 ()
Available from: 2019-07-25 Created: 2019-07-25 Last updated: 2024-01-05Bibliographically approved
Kulén, M., Lindgren, M., Hansen, S., Cairns, A. G., Grundström, C., Begum, A., . . . Almqvist, F. (2018). Structure-based design of inhibitors targeting PrfA, the master virulence regulator of Listeria monocytogenes. Journal of Medicinal Chemistry, 61(9), 4165-4175
Open this publication in new window or tab >>Structure-based design of inhibitors targeting PrfA, the master virulence regulator of Listeria monocytogenes
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2018 (English)In: Journal of Medicinal Chemistry, ISSN 0022-2623, E-ISSN 1520-4804, Vol. 61, no 9, p. 4165-4175Article in journal (Refereed) Published
Abstract [en]

Listeria monocytogenes is a bacterial pathogen that controls much of its virulence through the transcriptional regulator PrfA. In this study, we describe structure guided design and synthesis of a set of PrfA inhibitors based on ring-fused 2-pyridone heterocycles. Our most effective compound decreased virulence factor expression, reduced bacterial uptake into eukaryotic cells, and improved survival of chicken embryos infected with L. monocytogenes compared to previously identified compounds. Crystal structures identified an intraprotein "tunnel" as the main inhibitor binding site (A1), where the compounds participate in an extensive hydrophobic network that restricts the protein's ability to form functional DNA-binding helix−turn−helix (HTH) motifs. Our studies also revealed a hitherto unsuspected structural plasticity of the HTH motif. In conclusion, we have designed 2-pyridone analogues that function as site-A1 selective PrfA inhibitors with potent antivirulence properties.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Medicinal Chemistry
Identifiers
urn:nbn:se:umu:diva-148830 (URN)10.1021/acs.jmedchem.8b00289 (DOI)000432204800027 ()29667825 (PubMedID)2-s2.0-85046422455 (Scopus ID)
Available from: 2018-06-13 Created: 2018-06-13 Last updated: 2021-12-20Bibliographically approved
Mishra, Y., Hall, M., Locmelis, R., Nam, K., Söderberg, C. A. G., Storm, P., . . . Sauer, U. H. (2017). Active-site plasticity revealed in the asymmetric dimer of AnPrx6 the 1-Cys peroxiredoxin and molecular chaperone from Anabaena sp. PCC 7120. Scientific Reports, 7, Article ID 17151.
Open this publication in new window or tab >>Active-site plasticity revealed in the asymmetric dimer of AnPrx6 the 1-Cys peroxiredoxin and molecular chaperone from Anabaena sp. PCC 7120
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2017 (English)In: Scientific Reports, E-ISSN 2045-2322, Vol. 7, article id 17151Article in journal (Refereed) Published
Abstract [en]

Peroxiredoxins (Prxs) are vital regulators of intracellular reactive oxygen species levels in all living organisms. Their activity depends on one or two catalytically active cysteine residues, the peroxidatic Cys (C-P) and, if present, the resolving Cys (C-R). A detailed catalytic cycle has been derived for typical 2-Cys Prxs, however, little is known about the catalytic cycle of 1-Cys Prxs. We have characterized Prx6 from the cyanobacterium Anabaena sp. strain PCC7120 (AnPrx6) and found that in addition to the expected peroxidase activity, AnPrx6 can act as a molecular chaperone in its dimeric state, contrary to other Prxs. The AnPrx6 crystal structure at 2.3 angstrom resolution reveals different active site conformations in each monomer of the asymmetric obligate homo-dimer. Molecular dynamic simulations support the observed structural plasticity. A FSH motif, conserved in 1-Cys Prxs, precedes the active site PxxxTxxCp signature and might contribute to the 1-Cys Prx reaction cycle.

Place, publisher, year, edition, pages
Nature Publishing Group, 2017
National Category
Structural Biology
Identifiers
urn:nbn:se:umu:diva-143523 (URN)10.1038/s41598-017-17044-3 (DOI)000417354200004 ()29215017 (PubMedID)2-s2.0-85038074530 (Scopus ID)
Note

The original version of this Article contained an error in the title of the paper, where “Anabaena sp. PCC 7120” was incorrectly given as “Anabaena sp. PCC 7210”. This has now been corrected in the PDF and HTML versions of the Article, and in the accompanying Supplementary Information file.

Errata: Author Correction: Active-site plasticity revealed in the asymmetric dimer of AnPrx6 the 1-Cys peroxiredoxin and molecular chaperone from Anabaena sp. PCC 7120. Scientifc reports. 2018;8:8658. DOI: 10.1038/s41598-018-26715-8

Available from: 2018-01-04 Created: 2018-01-04 Last updated: 2024-07-02Bibliographically approved
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