1ep8: Difference between revisions
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[[Image:1ep8.gif|left|200px]] | [[Image:1ep8.gif|left|200px]] | ||
'''CRYSTAL STRUCTURE OF A MUTATED THIOREDOXIN, D30A, FROM CHLAMYDOMONAS REINHARDTII''' | {{Structure | ||
|PDB= 1ep8 |SIZE=350|CAPTION= <scene name='initialview01'>1ep8</scene>, resolution 2.20Å | |||
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'''CRYSTAL STRUCTURE OF A MUTATED THIOREDOXIN, D30A, FROM CHLAMYDOMONAS REINHARDTII''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1EP8 is a [ | 1EP8 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Chlamydomonas_reinhardtii Chlamydomonas reinhardtii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1EP8 OCA]. | ||
==Reference== | ==Reference== | ||
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:[http:// | 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:[http://www.ncbi.nlm.nih.gov/pubmed/11563970 11563970] | ||
[[Category: Chlamydomonas reinhardtii]] | [[Category: Chlamydomonas reinhardtii]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
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[[Category: mutant]] | [[Category: mutant]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 10:58:41 2008'' | ||
Revision as of 11:58, 20 March 2008
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CRYSTAL STRUCTURE OF A MUTATED THIOREDOXIN, D30A, FROM CHLAMYDOMONAS REINHARDTII
OverviewOverview
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.
About this StructureAbout this Structure
1EP8 is a Single protein structure of sequence from Chlamydomonas reinhardtii. Full crystallographic information is available from OCA.
ReferenceReference
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
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