1T6I

Nickel Superoxide Dismutase (NiSOD) Apo Structure

1T6I の概要

• エントリーDOI: 10.2210/pdb1t6i/pdb
• 分子名称: Superoxide dismutase [Ni] (2 entities in total)
• 機能のキーワード: nickel, 4-helix bundle, hexamer, superoxide dismutase, nisod, sod, apo, oxidoreductase
• 由来する生物種: Streptomyces coelicolor
• 細胞内の位置: Cytoplasm: P80735
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 40538.65

構造登録者

Barondeau, D.P.,Kassmann, C.J.,Bruns, C.K.,Tainer, J.A.,Getzoff, E.D. (登録日: 2004-05-06, 公開日: 2004-07-13, 最終更新日: 2024-10-09)

主引用文献

Barondeau, D.P.,Kassmann, C.J.,Bruns, C.K.,Tainer, J.A.,Getzoff, E.D.
Nickel superoxide dismutase structure and mechanism.
Biochemistry, 43:8038-8047, 2004

PubMed Abstract: The 1.30 A resolution crystal structure of nickel superoxide dismutase (NiSOD) identifies a novel SOD fold, assembly, and Ni active site. NiSOD is a hexameric assembly of right-handed 4-helix bundles of up-down-up-down topology with N-terminal hooks chelating the active site Ni ions. This newly identified nine-residue Ni-hook structural motif (His-Cys-X-X-Pro-Cys-Gly-X-Tyr) provides almost all interactions critical for metal binding and catalysis, and thus will likely be diagnostic of NiSODs. Conserved lysine residues are positioned for electrostatic guidance of the superoxide anion to the narrow active site channel. Apo structures show that the Ni-hook motif is unfolded prior to metal binding. The active site Ni geometry cycles from square planar Ni(II), with thiolate (Cys2 and Cys6) and backbone nitrogen (His1 and Cys2) ligands, to square pyramidal Ni(III) with an added axial His1 side chain ligand, consistent with electron paramagentic resonance spectroscopy. Analyses of the three NiSOD structures and comparisons to the Cu,Zn and Mn/Fe SODs support specific molecular mechanisms for NiSOD maturation and catalysis, and identify important structure-function relationships conserved among SODs.

PubMed: 15209499
DOI: 10.1021/bi0496081

実験手法

X-RAY DIFFRACTION (2.81 Å)