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  • 1.
    Berglund, Anders
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Brorsson, Ann-Christin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Jonsson, Bengt-Harald
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    The equilibrium unfolding of MerP characterized by multivariate analysis of 2D NMR data2005Ingår i: Journal of magnetic resonance, ISSN 1090-7807, E-ISSN 1096-0856, Vol. 172, nr 1, s. 24-30Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A general problem when analysing NMR spectra that reflect variations in the environment of target molecules is that different resonances are affected to various extents. Often a few resonances that display the largest frequency changes are selected as probes to reflect the examined variation, especially in the case, where the NMR spectra contain numerous resonances. Such a selection is dependent on more or less intuitive judgements and relying on the observed spectral variation being primarily caused by changes in the NMR sample. Second, recording changes observed for a few (albeit significant) resonances is inevitably accompanied by not using all available information in the analysis. Likewise, the commonly used chemical shift mapping (CSM) [Biochemistry 39 (2000) 26, Biochemistry 39 (2000) 12595] constitutes a loss of information since the total variation in the data is not retained in the projection into this single variable. Here, we describe a method for subjecting 2D NMR time-domain data to multivariate analysis and illustrate it with an analysis of multiple NNIR experiments recorded at various folding conditions for the protein MerP. The calculated principal components provide an unbiased model of variations in the NNIR spectra and they can consequently be processed as NMR data, and all the changes as reflected in the principal components are thereby made available for visual inspection in one single NMR spectrum. This approach is much less laborious than consideration of large numbers of individual spectra, and it greatly increases the interpretative power of the analysis.

  • 2.
    Berglund, Anders
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Analysis of 2D-NMR data in the time domain, a study of the unfolding of MERP2004Ingår i: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, ISSN 0065-7727, Vol. 228, nr 1, s. U111-U111Artikel i tidskrift (Övrigt vetenskapligt)
  • 3.
    Blomberg, David
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Kreye, Paul
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Brickmann, Kay
    AstraZeneca R&D Mölndal, Mölndal, Sweden.
    Kihlberg, Jan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Synthesis and conformational studies of a β-turn mimetic incorporated in Leu-enkephalin2004Ingår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 69, nr 10, s. 3500-3508Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A β-turn mimetic in which the four amino acids of a β-turn have been replaced by a 10-membered ring has been designed, synthesized, and subjected to conformational studies. In the mimetic, the intramolecular COi − HNi+3 hydrogen bond that is often found in β-turns has been replaced by an ethylene bridge. In addition, the amide bond between residues i and i + 1 was exchanged for a methylene ether isoster. Such a β-turn mimetic, based on the first four residues of Leu-enkephalin (Tyr-Gly-Gly-Phe-Leu), was prepared in 15 steps. The synthesis relied on a β-azido alcohol prepared in five steps from Cbz-Tyr(tBu)-OH as a key, i-position building block. tert-Butyl bromoacetate, glycine, and a Phe-Leu dipetide were then used as building blocks for positions i + 1, i + 2, and i + 3, respectively. Conformational studies based on 1H NMR data showed that the β-turn mimetic was flexible, but that it resembled a type-II β-turn at low temperature. This low energy conformer closely resembled the structure determined for crystalline Leu-enkephalin.

  • 4.
    Brorsson, Ann-Christin
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Kjellson, Annika
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Aronsson, Göran
    Biopool, Umeå, Sweden.
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hambraeus, Charlotta
    University of Southern Stockholm, Center for Structural Biochemistry, Huddinge, Sweden.
    Jonsson, Bengt-Harald
    Molecular Biotechnology/IFM, Linköping University, Linköping, Sweden.
    The “Two-State folder” MerP forms partially unfolded structures that show temperature dependent hydrogen exchange2004Ingår i: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 340, nr 2, s. 333-344Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have analysed the folding energy landscape of the 72 amino acid protein MerP by monitoring native state hydrogen exchange as a function of temperature in the range of 7-55 degrees C. The temperature dependence of the hydrogen exchange has allowed us to determine DeltaG, DeltaH and DeltaC(p) values for the conformational processes that permit hydrogen exchange. When studied with the traditional probes, fluorescence and CD, MerP appears to behave as a typical two-state protein, but the results from the hydrogen exchange analysis reveal a much more complex energy landscape. Analysis at the individual amino acid level show that exchange is allowed from an ensemble of partially unfolded structures (i.e. intermediates) in which the stabilities at the amino acid level form a broad distribution throughout the protein. The formation of partially unfolded structures might contribute to the unusually slow folding of MerP.

  • 5.
    Brorsson, Ann-Christin
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Lundqvist, Martin
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Jonsson, Bengt-Harald
    GuHCl and NaCl-dependent hydrogen exchange in MerP reveals a well-defined core with an unusual exchange pattern2006Ingår i: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 357, nr 5, s. 1634-46Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have analysed hydrogen exchange at amide groups to characterise the energy landscape of the 72 amino acid residue protein MerP. From the guanidine hydrochloride (GuHCl) dependence of exchange in the pre-transitional region we have determined free energy values of exchange (DeltaG(HX)) and corresponding m-values for individual amide protons. Detailed analysis of the exchange patterns indicates that for one set of amide protons there is a weak dependence on denaturant, indicating that the exchange is dominated by local fluctuations. For another set of amide protons a linear, but much stronger, denaturant dependence is observed. Notably, the plots of free energy of exchange versus [GuHCl] for 16 amide protons show pronounced upward curvature, and a close inspection of the structure shows that these residues form a well-defined core in the protein. The hydrogen exchange that was measured at various concentrations of NaCl shows an apparent selective stabilisation of this core. Detailed analysis of this exchange pattern indicates that it may originate from selective destabilisation of the unfolded state by guanidinium ions and/or selective stabilisation of the core in the native state by chloride ions.

  • 6.
    Buevich, Alexei V
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Lundberg, Susanne
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Edlund, Ulf
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Backman, Lars
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    NMR studies of calcium-binding to mutant alpha-spectrin EF-hands2004Ingår i: CELLULAR & MOLECULAR BIOLOGY LETTERS, ISSN 1425-8153, Vol. 9, nr 1, s. 167-86Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The co-operative calcium binding mechanism of the two C-terminal EF-hands of human all-spectrin has been investigated by site-specific mutagenesis and multi-dimensional NMR spectroscopy. To analyse the calcium binding of each EF-hand independently, two mutant structures (E33A and D69S) of wild type alpha-spectrin were prepared. According to NMR analysis both E33A and D69S were properly folded. The unmutated EF-hand in these mutants remained nearly intact and active in calcium binding, whereas the mutated EF-hand lost its affinity for calcium completely. The apparent calcium binding affinity of the E33A mutant was much lower compared to the D39S mutant (similar to2470 muM and similar to240 muM, respectively). When the chemical shift perturbations were followed upon calcium titration, a positive correlation between the D69S mutant and the binding of the first calcium ion to the wild type was revealed. These observations showed that the first EF-hand in spectrin binds the first calcium ion and thereby triggers a conformational change that allows the second calcium ion to bind to the other EF-hand.

  • 7.
    Hedenström, Mattias
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Emtenäs, Hans
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Pemberton, Nils
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Åberg, Veronica
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hultgren, Scott J.
    Pinkner, Jerome S.
    Tegman, Viola
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Almqvist, Fredrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Kihlberg, Jan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    NMR studies of interactions between periplasmic chaperones from uropathogenic E-coli and pilicides that interfere with chaperone function and pilus assembly2005Ingår i: ORGANIC & BIOMOLECULAR CHEMISTRY, ISSN 1477-0520, Vol. 3, nr 23, s. 4193-4200Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Adherence of uropathogenic Escherichia coli to host tissue is mediated by pili, which are hair-like protein structures extending from the outer cell membrane of the bacterium. The chaperones FimC and PapD are key components in pilus assembly since they catalyse folding of subunits that are incorporated in type 1 and P pili, respectively, and also transport the subunits across the periplasmic space. Recently, compounds that inhibit pilus biogenesis and interfere with chaperone-subunit interactions have been discovered and termed pilicides. In this paper NMR spectroscopy was used to study the interaction of different pilicides with PapD and FimC in order to gain structural knowledge that would explain the effect that some pilicides have on pilus assembly. First relaxation-edited NMR experiments revealed that the pilicides bound to the PapD chaperone with mM affinity. Then the pilicide-chaperone interaction surface was investigated through chemical shift mapping using N-15-labelled FimC. Principal component analysis performed on the chemical shift perturbation data revealed the presence of three binding sites on the surface of FimC, which interacted with three different classes of pilicides. Analysis of structure-activity relationships suggested that pilicides reduce pilus assembly in E. coli either by binding in the cleft of the chaperone, or by influencing the orientation of the flexible F1-G1 loop, both of which are part of the surface by which the chaperone forms complexes with pilus subunits. It is suggested that binding to either of these sites interferes with folding of the pilus subunits, which occurs during formation of the chaperone-subunit complexes. In addition, pilicides that influence the F1-G1 loop also appear to reduce pilus formation by their ability to dissociate chaperone-subunit complexes.

  • 8.
    Hedenström, Mattias
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Yuan, ZhongQing
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Brickmann, Kay
    Carlsson, Jolanta
    Ekholm, Kjell
    Johansson, Birgitta
    Kreutz, Eva
    Nilsson, Anders
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Kihlberg, Jan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Conformations and Receptor Activity of Desmopressin Analogues, Which Contain -Turn Mimetics or a [CH2O] Isostere2002Ingår i: Journal of Medicinal Chemistry, Vol. 45, nr 12, s. 2501-11Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Three analogues of the antidiuretic drug desmopressin ([1-desamino,8-D-arginine]vasopressin) have been prepared. In two of these, -turn mimetics based on a morpholin-3-one framework have been inserted instead of residues Phe3-Asn5, whereas the third analogue has a methylene ether isostere in place of the amide bond between residues 3 and 4. The three analogues were used to probe if the structure determined for desmopressin in aqueous solution, which contains an inverse -turn centered around Gln4, is important in interactions with the vasopressin V2 receptor. Conformational studies revealed that the analogues that contain either an inverse -turn mimetic or a methylene ether isostere mimicked the conformation of desmopressin fairly well and very well, respectively. Despite this, the analogues displayed only very low agonistic activities at the vasopressin V2 receptor. Consequently, an inverse -turn involving residues Phe3-Asn5 does not appear to be important when desmopressin is bound to the V2 receptor. In addition, it was concluded that the amide bond between Phe3 and Gln4 in desmopressin is crucial for interactions with the antidiuretic V2 receptor.

  • 9.
    Jonasson, Per
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Kjellsson, Annika
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Jonsson, Bengt-Harald
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Denatured states of human carbonic anhydrase II: An NMR study of hydrogen/deuterium exchange at tryptophan-indole-HN sites1999Ingår i: FEBS Letters, Vol. 445, s. 361-365Artikel i tidskrift (Refereegranskat)
  • 10. Lundqvist, Martin
    et al.
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Jonsson, Bengt-Harald
    High-resolution 2D 1H-15N NMR characterization of persistent structural alterations of proteins induced by interactions with silica nanoparticles.2005Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 21, nr 13, s. 5974-9Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The binding of protein to solid surfaces often induces changes in the structure, and to investigate these matters we have selected two different protein-nanoparticle systems. The first system concerns the enzyme human carbonic anhydrase II which binds essentially irreversibly to the nanoparticles, and the second system concerns human carbonic anhydrase I which alternate between the adsorbed and free state upon interaction with nanoparticles. Application of the TROSY pulse sequence has allowed high-resolution NMR analysis for both of the protein-nanoparticle systems. For HCAII it was possible to observe spectra of protein when bound to the nanoparticles. The results indicated that HCAII undergoes large rearrangements, forming an ensemble of molten globule-like structures on the surface. The spectra from the HCAI-nanoparticle system are dominated by HCAI molecules in solution. A comparative analysis of variations in intensity from 97 amide resonances in a 1H-15N TROSY spectrum revealed the effects from interaction with nanoparticle on the protein structure at amino acid resolution.

  • 11. Lundqvist, Martin
    et al.
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Jonsson, Bengt-Harald
    Protein adsorption onto silica nanoparticles: Conformational changes depend on the particles' curvature and the protein stability2004Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Langmuir, Vol. 20, nr 24, s. 10639-47Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have analyzed the adsorption of protein to the surfaces of silica nanoparticles with diameters of 6, 9, and 15 nm. The effects upon adsorption on variants of human carbonic anhydrase with differing conformational stabilities have been monitored using methods that give complementary information, i.e., circular dichroism (CD), nuclear magnetic resonance (NMR), analytical ultracentrifugation (AUC), and gel permeation chromatography. Human carbonic anhydrase I (HCAI), which is the most stable of the protein variants, establishes a dynamic equilibrium between bound and unbound protein following mixture with silica particles. Gel permeation and AUC experiments indicate that the residence time of HCAI is on the order of approximately 10 min and slowly increases with time, which allows us to study the effects of the interaction with the solid surface on the protein structure in more detail than would be possible for a process with faster kinetics. The effects on the protein conformation from the interaction have been characterized using CD and NMR measurements. This study shows that differences in particle curvature strongly influence the amount of the protein's secondary structure that is perturbed. Particles with a longer diameter allow formation of larger particle-protein interaction surfaces and cause larger perturbations of the protein's secondary structure upon interaction. In contrast, the effects on the tertiary structure seem to be independent of the particles' curvature.

  • 12. Lundqvist, Martin
    et al.
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Jonsson, Bengt-Harald
    Transient Interaction with Nanoparticles "Freezes" a Protein in an Ensemble of Metastable Near-Native Conformations2005Ingår i: Biochemistry including biophysical chemistry& molecular biology, Vol. 44, nr 30, s. 10093-9Artikel i tidskrift (Refereegranskat)
    Abstract [en]

     

    It is well-known that adsorption of proteins on interfaces often induces substantial alterations of the protein structure. However, very little is known about whether these conformational changes have any consequence for the protein conformation after desorption from the interface. To investigate this matter, we have selected a protein-particle system in which the enzyme human carbonic anhydrase I (HCAI) alternates between the adsorbed and free state upon interaction with the silica nanoparticles. High-resolution NMR analysis of the protein with the particles present in the sample shows a spectrum that indicates a molten globular-like structure. Removal of particles results in refolding of virtually all HCAI molecules to a fully active form. However, the two-dimensional NMR analysis shows that refolding does not result in a single well-defined protein structure but rather provides an ensemble of protein molecules with near-native conformations. A detailed comparative chemical shift analysis of 108 amide signals in 1H-15N HSQC spectra of native and desorbed HCAI reveals that the most profound effects are located at β-strands in the center of the molecule. The observation of very slow H-D exchange in the central β-strands of HCAI [Kjellsson, A., Sethson, I., and Jonsson, B. H. (2003) Biochemistry 42, 363-374] in conjunction with our results indicates that the kinetic barriers for conformational rearrangements in the central core of the protein are low in the presence of nanoparticles but are very high under native conditions.

  • 13. Siedlecka, A
    et al.
    Wiklund, Susanne
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Péronne, M-A
    Micheli, F
    Lesniewska, J
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Edlund, Ulf
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Lindberg, Richard
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sundberg, B
    Mellerowicz, J. E
    Pectin methyl esterase inhibits intrusive and symplastic cell growth in developing wood of Populus treesManuskript (Övrigt vetenskapligt)
  • 14. Siedlecka, Anna
    et al.
    Wiklund, Susanne
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Peronne, Marie-Amelie
    Micheli, Fabienne
    Lesniewska, Joanna
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Edlund, Ulf
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Richard, Luc
    Sundberg, Björn
    Mellerowicz, Ewa J
    Pectin methyl esterase inhibits intrusive and symplastic cell growth in developing wood cells of Populus2008Ingår i: Plant Physiology, ISSN 0032-0889, Vol. 146, s. 554-65Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Wood cells, unlike most other cells in plants, grow by a unique combination of intrusive and symplastic growth. Fibers grow in diameter by diffuse symplastic growth, but they elongate solely by intrusive apical growth penetrating the pectin-rich middle lamella that cements neighboring cells together. In contrast, vessel elements grow in diameter by a combination of intrusive and symplastic growth. We demonstrate that an abundant pectin methyl esterase (PME, EC 3.1.1.11) from wood-forming tissues of hybrid aspen (Populus tremula L. x tremuloides Michx.) acts as a negative regulator of both symplastic and intrusive growth of developing wood cells. When PttPME1expression was up- and down-regulated in transgenic aspen trees, the PME activity in wood-forming tissues was correspondingly altered. PME removes methyl ester groups from homogalacturonan, and the transgenic trees had modified homogalacturonan methylesterification patterns, as demonstrated by two-dimensional NMR and immunostaining using PAM1 and LM7 antibodies. The in situ distributions of PAM1 and LM7 epitopes revealed changes in pectin methylesterification in the transgenic trees that were specifically localized in expanding wood cells. The results show that en-block de-esterification of homogalacturonan by PttPME1 inhibits both symplastic growth and intrusive growth. PttPME1 is therefore involved in mechanisms determining fiber width and length in the wood of aspen trees.

  • 15.
    Tengel, Tobias
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Fex, Tomas
    Emtenäs, Hans
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Almqvist, Fredrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Kihlberg, Jan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Use of 19F NMR spectroscopy to screen chemical libraries for ligands that bind to proteins2004Ingår i: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 2, nr 5, s. 725-731Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Identification of compounds from chemical libraries that bind to macromolecules by use of NMR spectroscopy has gained increasing importance during recent years. A simple methodology based on F-19 NMR spectroscopy for the screening of ligands that bind to proteins, which also provides qualitative information about relative binding strengths and the presence of multiple binding sites, is presented here. A library of fluorinated compounds was assembled and investigated for binding to the two bacterial chaperones PapD and FimC, and also to human serum albumin (HSA). It was found that library members which are bound to a target protein could be identified directly from line broadening and/or induced chemical shifts in a single, one-dimensional F-19 NMR spectrum. The results obtained for binding to PapD using F-19 NMR spectroscopy agreed well with independent studies based on surface plasmon resonance, providing support for the versatility and accuracy of the technique. When the library was titrated to a solution of PapD chemical shift and linewidth changes were observed with increasing ligand concentration, which indicated the presence of several binding sites on PapD and enabled the assessment of relative binding strengths for the different ligands. Screening by F-19 NMR spectroscopy should thus be a valuable addition to existing NMR techniques for evaluation of chemical libraries in bioorganic and medicinal chemistry.

  • 16.
    Tengel, Tobias
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Francis, Matthew
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet). Umeå universitet, Medicinska fakulteten, Umeå Centre for Microbial Research (UCMR).
    Conformational analysis by CD and NMR spectroscopy of a peptide encompassing the amphipathic domain of YopD from Yersinia2002Ingår i: European Journal of Biochemistry, ISSN 0014-2956, E-ISSN 1432-1033, Vol. 269, nr 15, s. 3659-3668Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To establish an infection, Yersinia pseudotuberculosis utilizes a plasmid-encoded type III secretion machine that permits the translocation of several anti-host factors into the cytosol of target eukaryotic cells. Secreted YopD is essential for this process. Pre-secretory stabilization of YopD is mediated by an interaction with its cognate chaperone, LcrH. YopD possesses LcrH binding domains located in the N-terminus and in a predicted amphipathic domain located near the C-terminus. This latter domain is also critical for Yersinia virulence. In this study, we designed synthetic peptides encompassing the C-terminal amphipathic domain of YopD. A solution structure of YopD278−300, a peptide that strongly interacted with LcrH, was obtained by NMR methods. The structure is composed of a well-defined amphipathic α helix ranging from Phe280 to Tyr291, followed by a type I β turn between residues Val292 and His295. The C-terminal truncated peptides, YopD278−292 and YopD271−292, lacked helical structure, implicating the β turn in helix stability. An interaction between YopD278−300 and its cognate chaperone, LcrH, was observed by NMR through line-broadening effects and chemical shift differences between the free peptide and the peptide–LcrH complex. These effects were not observed for the unstructured peptide, YopD278−292, which confirms that the α helical structure of the YopD amphipathic domain is a critical binding region of LcrH.

  • 17.
    Tengel, Tobias
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Sethson, Ingmar
    Francis, Matthew
    Conformational analysis by CD and NMR spectroscopy of a peptide encompassing the amphipathic domain of YopD from Yersinia2002Ingår i: European Journal of Biochemistry, ISSN 0014-2956, E-ISSN 1432-1033, Vol. 269, nr 15, s. 3659-3668Artikel i tidskrift (Refereegranskat)
  • 18.
    Wågberg, Thomas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Talyzin, Alexandr V
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Tsybin, Yury O
    Purcell, Jeremiah M
    Marshall, Alan G
    Noréus, Dag
    Johnels, Dan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Synthesis and Structural Characterization of C70H382008Ingår i: Angewandte Chemie International Edition, Vol. 47, nr 15, s. 2796-9Artikel i tidskrift (Refereegranskat)
1 - 18 av 18
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