6GQ8

Superoxide reductase from Nanoarchaeum equitans

「4BV1」から置き換えられました

6GQ8 の概要

• エントリーDOI: 10.2210/pdb6gq8/pdb
• 分子名称: NEQ011, FE (III) ION (3 entities in total)
• 機能のキーワード: neelaredoxin, superoxide anion, reactive oxygen species, archaea, enzyme, oxidoreductase
• 由来する生物種: Nanoarchaeum equitans Kin4-M
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 51173.68

構造登録者

Romao, C.V.,Matias, P.M.,Teixeira, M.,Bandeiras, T.M. (登録日: 2018-06-07, 公開日: 2018-06-20, 最終更新日: 2024-01-17)

主引用文献

Romao, C.V.,Matias, P.M.,Sousa, C.M.,Pinho, F.G.,Pinto, A.F.,Teixeira, M.,Bandeiras, T.M.
Insights into the Structures of Superoxide Reductases from the Symbionts Ignicoccus hospitalis and Nanoarchaeum equitans.
Biochemistry, 57:5271-5281, 2018

PubMed Abstract: Superoxide reductases (SORs) are enzymes that detoxify the superoxide anion through its reduction to hydrogen peroxide and exist in both prokaryotes and eukaryotes. The substrate is transformed at an iron catalytic center, pentacoordinated in the ferrous state by four histidines and one cysteine. SORs have a highly conserved motif, (E)(K)HxP-, in which the glutamate is associated with a redox-driven structural change, completing the octahedral coordination of the iron in the ferric state, whereas the lysine may be responsible for stabilization and donation of a proton to catalytic intermediates. We aimed to understand at the structural level the role of these two residues, by determining the X-ray structures of the SORs from the hyperthermophilic archaea Ignicoccus hospitalis and Nanoarchaeum equitans that lack the quasi-conserved lysine and glutamate, respectively, but have catalytic rate constants similar to those of the canonical enzymes, as we previously demonstrated. Furthermore, we have determined the crystal structure of the E23A mutant of I. hospitalis SOR, which mimics several enzymes that lack both residues. The structures revealed distinct structural arrangements of the catalytic center that simulate several catalytic cycle intermediates, namely, the reduced and the oxidized forms, and the glutamate-free and deprotonated ferric forms. Moreover, the structure of the I. hospitalis SOR provides evidence for the presence of an alternative lysine close to the iron center in the reduced state that may be a functional substitute for the "canonical" lysine.

PubMed: 29939726
DOI: 10.1021/acs.biochem.8b00334

実験手法

X-RAY DIFFRACTION (1.9 Å)