1EP8

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

1EP8 の概要

• エントリーDOI: 10.2210/pdb1ep8/pdb
• 関連するPDBエントリー: 1EP7
• 分子名称: THIOREDOXIN CH1, H-TYPE (2 entities in total)
• 機能のキーワード: mutant, electron transport
• 由来する生物種: Chlamydomonas reinhardtii
• 細胞内の位置: Cytoplasm: P80028
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 23367.05

構造登録者

Menchise, V.,Corbier, C.,Didierjean, C.,Saviano, M.,Benedetti, E.,Jacquot, J.P.,Aubry, A. (登録日: 2000-03-28, 公開日: 2001-12-12, 最終更新日: 2021-11-03)

主引用文献

Menchise, V.,Corbier, C.,Didierjean, C.,Saviano, M.,Benedetti, E.,Jacquot, J.P.,Aubry, A.
Crystal structure of the wild-type and D30A mutant thioredoxin h of Chlamydomonas reinhardtii and implications for the catalytic mechanism.
Biochem.J., 359:65-75, 2001

PubMed Abstract: 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.

PubMed: 11563970
DOI: 10.1042/0264-6021:3590065

実験手法

X-RAY DIFFRACTION (2.2 Å)