1XJH

NMR structure of the redox switch domain of the E. coli Hsp33

1XJH の概要

• エントリーDOI: 10.2210/pdb1xjh/pdb
• 関連するPDBエントリー: 1HW7 1I7F
• NMR情報: BMRB: 6335
• 分子名称: 33 kDa chaperonin, ZINC ION (2 entities in total)
• 機能のキーワード: redox-switch domain, zinc-binding domain, four cysteins coordinating zinc, chaperone
• 由来する生物種: Escherichia coli
• 細胞内の位置: Cytoplasm: P0A6Y5
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 7105.21

構造登録者

Won, H.S.,Low, L.Y.,De Guzman, R.N.,Martinez-Yamout, M.A.,Jakob, U.,Dyson, H.J. (登録日: 2004-09-23, 公開日: 2004-10-05, 最終更新日: 2024-05-22)

主引用文献

Won, H.S.,Low, L.Y.,De Guzman, R.N.,Martinez-Yamout, M.A.,Jakob, U.,Dyson, H.J.
The Zinc-dependent Redox Switch Domain of the Chaperone Hsp33 has a Novel Fold
J.Mol.Biol., 341:893-899, 2004

PubMed Abstract: The Escherichia coli chaperone Hsp33 contains a C-terminal zinc-binding domain that modulates activity by a so-called "redox switch". The oxidized form in the absence of zinc is active, while the reduced form in the presence of zinc is inactive. X-ray crystal structures of Hsp33 invariably omit details of the C-terminal domain, which is truncated in protein constructs that are capable of forming crystals. We report the solution structure of a recombinant 61-residue protein containing the zinc-binding domain (residues 227-287) of Hsp33, in the presence of stoichiometric amounts of Zn2+. The zinc-bound protein is well folded, and forms a novel structure unlike other published zinc-binding domains. The structure consists of two helices at right-angles to each other, a two-stranded B-hairpin and a third helix at the C terminus. The zinc site comprises the side-chains of the conserved cysteine residues 232, 234, 262 and 265, and connects a short sequence before the first helix with the tight turn in the middle of the B-hairpin. The structure of the C-terminal zinc-binding domain suggests a mechanism for the operation of the redox switch: loss of the bound zinc ion disrupts the folded structure, allowing the ligand cysteine residues to be oxidized, probably to disulfide bonds. The observation that the C-terminal domain is poorly structured in the active oxidized form suggests that the loss of zinc and unfolding of the domain precedes the oxidation of the thiolate groups of the cysteine residues, since the formation of disulfides between distant parts of the domain sequence would presumably promote the formation of stable three-dimensional structure in the oxidized form.Hsp33 provides an example of a redox signaling system that utilizes protein folding and unfolding together with chemical modification for transduction of external stimuli, in this case oxidative stress, to activate the machinery of the cell that is designed to deal with that stress.

PubMed: 15328602
DOI: 10.1016/j.jmb.2004.06.046

実験手法

SOLUTION NMR