2WD4

Ascorbate Peroxidase as a heme oxygenase: w41A variant product with t-butyl peroxide

2WD4 の概要

• エントリーDOI: 10.2210/pdb2wd4/pdb
• 関連するPDBエントリー: 1OAF 1OAG 1V0H 2CL4 2GGN 2GHC 2GHD 2GHE 2GHH 2GHK 2VCF 2VCN 2VCS 2VNX 2VNZ 2VO2
• 分子名称: ASCORBATE PEROXIDASE, FE (III) ION, SODIUM ION, ... (6 entities in total)
• 機能のキーワード: oxidoreductase, tert-butyl peroxide, heme peroxidase, peroxide scavenge
• 由来する生物種: GLYCINE MAX (SOYBEAN)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 29160.52

構造登録者

Badyal, S.K.,Metcalfe, C.L.,Gumiero, A.,Raven, E.L.,Moody, P.C.E. (登録日: 2009-03-19, 公開日: 2009-04-07, 最終更新日: 2023-12-13)

主引用文献

Raven, E.L.,Badyal, S.K.,Eaton, G.,Mistry, S.,Pipirou, Z.,Basran, J.,Metcalfe, C.L.,Gumiero, A.,Handa, S.,Moody, P.C.E.
Evidence for Heme Oxygenase Activity in a Heme Peroxidase.
Biochemistry, 48:4738-, 2009

PubMed Abstract: The heme peroxidase and heme oxygenase enzymes share a common heme prosthetic group but catalyze fundamentally different reactions, the first being H(2)O(2)-dependent oxidation of substrate using an oxidized Compound I intermediate, and the second O(2)-dependent degradation of heme. It has been proposed that these enzymes utilize a common reaction intermediate, a ferric hydroperoxide species, that sits at a crossroads in the mechanism and beyond which there are two mutually exclusive mechanistic pathways. Here, we present evidence to support this proposal in a heme peroxidase. Hence, we describe kinetic data for a variant of ascorbate peroxidase (W41A) which reacts slowly with tert-butyl hydroperoxide and does not form the usual peroxidase Compound I intermediate; instead, structural data show that a product is formed in which the heme has been cleaved at the alpha-meso position, analogous to the heme oxygenase mechanism. We interpret this to mean that the Compound I (peroxidase) pathway is shut down, so that instead the reaction intermediate diverts through the alternative (heme oxygenase) route. A mechanism for formation of the product is proposed and discussed in the light of what is known about the heme oxygenase reaction mechanism.

PubMed: 19309109
DOI: 10.1021/BI900118J

実験手法

X-RAY DIFFRACTION (1.4 Å)