4TXO

Crystal structure of the mixed disulfide complex of thioredoxin-like TlpAs(C110S) and copper chaperone ScoIs(C74S)

4TXO の概要

• エントリーDOI: 10.2210/pdb4txo/pdb
• 関連するPDBエントリー: 4TXV
• 分子名称: Thiol:disulfide interchange protein TlpA, Blr1131 protein, THIOCYANATE ION, ... (6 entities in total)
• 機能のキーワード: mixed disulfide, soluble domain of membrane protein, thioredoxin fold, copper protein, protein binding, oxidodreductase/copper binding protein, oxidodreductase-copper binding protein complex
• 由来する生物種: Bradyrhizobium diazoefficiens USDA 110; 詳細
• 細胞内の位置: Cell membrane; Single-pass type II membrane protein; Periplasmic side: P43221
• タンパク質・核酸の鎖数: 8
• 化学式量合計: 155686.20

構造登録者

Scharer, M.A.,Abicht, H.K.,Glockshuber, R.,Hennecke, H. (登録日: 2014-07-04, 公開日: 2014-10-01, 最終更新日: 2024-11-13)

主引用文献

Abicht, H.K.,Scharer, M.A.,Quade, N.,Ledermann, R.,Mohorko, E.,Capitani, G.,Hennecke, H.,Glockshuber, R.
How Periplasmic Thioredoxin TlpA Reduces Bacterial Copper Chaperone ScoI and Cytochrome Oxidase Subunit II (CoxB) Prior to Metallation.
J.Biol.Chem., 289:32431-32444, 2014

PubMed Abstract: Two critical cysteine residues in the copper-A site (Cu(A)) on subunit II (CoxB) of bacterial cytochrome c oxidase lie on the periplasmic side of the cytoplasmic membrane. As the periplasm is an oxidizing environment as compared with the reducing cytoplasm, the prediction was that a disulfide bond formed between these cysteines must be eliminated by reduction prior to copper insertion. We show here that a periplasmic thioredoxin (TlpA) acts as a specific reductant not only for the Cu(2+) transfer chaperone ScoI but also for CoxB. The dual role of TlpA was documented best with high-resolution crystal structures of the kinetically trapped TlpA-ScoI and TlpA-CoxB mixed disulfide intermediates. They uncovered surprisingly disparate contact sites on TlpA for each of the two protein substrates. The equilibrium of CoxB reduction by TlpA revealed a thermodynamically favorable reaction, with a less negative redox potential of CoxB (E'0 = -231 mV) as compared with that of TlpA (E'0 = -256 mV). The reduction of CoxB by TlpA via disulfide exchange proved to be very fast, with a rate constant of 8.4 × 10(4) M(-1) s(-1) that is similar to that found previously for ScoI reduction. Hence, TlpA is a physiologically relevant reductase for both ScoI and CoxB. Although the requirement of ScoI for assembly of the Cu(A)-CoxB complex may be bypassed in vivo by high environmental Cu(2+) concentrations, TlpA is essential in this process because only reduced CoxB can bind copper ions.

PubMed: 25274631
DOI: 10.1074/jbc.M114.607127

実験手法

X-RAY DIFFRACTION (2.2 Å)