1ep8

CRYSTAL STRUCTURE OF A MUTATED THIOREDOXIN, D30A, FROM CHLAMYDOMONAS REINHARDTII

spinqualitylabelsall models 1ep8, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1ep8 is a 2 chain structure with sequence from Chlamydomonas reinhardtii. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.2Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TRXH_CHLRE Participates in various redox reactions through the reversible oxidation of the active center dithiol to a disulfide. The H form is known to activate a number of cytosolic enzymes. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Thioredoxins are ubiquitous proteins which catalyse the reduction of disulphide bridges on target proteins. The catalytic mechanism proceeds via a mixed disulphide intermediate whose breakdown should be enhanced by the involvement of a conserved buried residue, Asp-30, as a base catalyst towards residue Cys-39. We report here the crystal structure of wild-type and D30A mutant thioredoxin h from Chlamydomonas reinhardtii, which constitutes the first crystal structure of a cytosolic thioredoxin isolated from a eukaryotic plant organism. The role of residue Asp-30 in catalysis has been revisited since the distance between the carboxylate OD1 of Asp-30 and the sulphur SG of Cys-39 is too great to support the hypothesis of direct proton transfer. A careful analysis of all available crystal structures reveals that the relative positioning of residues Asp-30 and Cys-39 as well as hydrophobic contacts in the vicinity of residue Asp-30 do not allow a conformational change sufficient to bring the two residues close enough for a direct proton transfer. This suggests that protonation/deprotonation of Cys-39 should be mediated by a water molecule. Molecular-dynamics simulations, carried out either in vacuo or in water, as well as proton-inventory experiments, support this hypothesis. The results are discussed with respect to biochemical and structural data. Crystal structure of the wild-type and D30A mutant thioredoxin h of Chlamydomonas reinhardtii and implications for the catalytic mechanism.,Menchise V, Corbier C, Didierjean C, Saviano M, Benedetti E, Jacquot JP, Aubry A Biochem J. 2001 Oct 1;359(Pt 1):65-75. PMID:11563970 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Thioredoxin 3D structures

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