3K9S

Crystal structure of the peroxide-bound manganese superoxide dismutase.

3K9S の概要

• エントリーDOI: 10.2210/pdb3k9s/pdb
• 分子名称: Superoxide dismutase [Mn], MANGANESE (II) ION, HYDROGEN PEROXIDE, ... (4 entities in total)
• 機能のキーワード: manganese superoxide dismutase, peroxide-bound, manganese, metal-binding, oxidoreductase
• 由来する生物種: Escherichia coli K-12
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 92309.30

構造登録者

Porta, J.C.,Vahedi-Faridi, A.,Borgstahl, G.E.O. (登録日: 2009-10-16, 公開日: 2010-05-12, 最終更新日: 2023-09-06)

主引用文献

Porta, J.,Vahedi-Faridi, A.,Borgstahl, G.E.
Structural Analysis of Peroxide-Soaked MnSOD Crystals Reveals Side-On Binding of Peroxide to Active-Site Manganese.
J.Mol.Biol., 399:377-384, 2010

PubMed Abstract: The superoxide dismutase (SOD) enzymes are important antioxidant agents that protect cells from reactive oxygen species. The SOD family is responsible for catalyzing the disproportionation of superoxide radical to oxygen and hydrogen peroxide. Manganese- and iron-containing SOD exhibit product inhibition whereas Cu/ZnSOD does not. Here, we report the crystal structure of Escherichia coli MnSOD with hydrogen peroxide cryotrapped in the active site. Crystallographic refinement to 1.55 A and close inspection revealed electron density for hydrogen peroxide in three of the four active sites in the asymmetric unit. The hydrogen peroxide molecules are in the position opposite His26 that is normally assumed by water in the trigonal bipyramidal resting state of the enzyme. Hydrogen peroxide is present in active sites B, C, and D and is side-on coordinated to the active-site manganese. In chains B and D, the peroxide is oriented in the plane formed by manganese and ligands Asp167 and His26. In chain C, the peroxide is bound, making a 70 degrees angle to the plane. Comparison of the peroxide-bound active site with the hydroxide-bound octahedral form shows a shifting of residue Tyr34 towards the active site when peroxide is bound. Comparison with peroxide-soaked Cu/ZnSOD indicates end-on binding of peroxide when the SOD does not exhibit inhibition by peroxide and side-on binding of peroxide in the product-inhibited state of MnSOD.

PubMed: 20417642
DOI: 10.1016/j.jmb.2010.04.031

実験手法

X-RAY DIFFRACTION (1.55 Å)