1DJ1

CRYSTAL STRUCTURE OF R48A MUTANT OF CYTOCHROME C PEROXIDASE

1DJ1 の概要

• エントリーDOI: 10.2210/pdb1dj1/pdb
• 関連するPDBエントリー: 1CCA
• 分子名称: CYTOCHROME C PEROXIDASE, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• 機能のキーワード: heme enzyme, cavity mutant, oxidoreductase
• 由来する生物種: Saccharomyces cerevisiae (baker's yeast)
• 細胞内の位置: Mitochondrion matrix: P00431
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 33756.31

構造登録者

Hirst, J.,Goodin, D.B. (登録日: 1999-11-30, 公開日: 1999-12-10, 最終更新日: 2024-03-13)

主引用文献

Hirst, J.,Goodin, D.B.
Unusual oxidative chemistry of N(omega)-hydroxyarginine and N-hydroxyguanidine catalyzed at an engineered cavity in a heme peroxidase.
J.Biol.Chem., 275:8582-8591, 2000

PubMed Abstract: Heme enzymes are capable of catalyzing a range of oxidative chemistry with high specificity, depending on the surrounding protein environment. We describe here a reaction catalyzed by a mutant of cytochrome c peroxidase, which is similar but distinct from those catalyzed by nitric-oxide synthase. In the R48A mutant, an expanded water-filled cavity was created above the distal heme face. N-hydroxyguanidine (NHG) but not guanidine was shown to bind in the cavity with K(d) = 8.5 mM, and coordinate to the heme to give a low spin state. Reaction of R48A with peroxide produced a Fe(IV)=O/Trp(.+) center capable of oxidizing either NHG or N(omega)-hydroxyarginine (NHA), but not arginine or guanidine, by a multi-turnover catalytic process. Oxidation of either NHG or NHA by R48A did not result in the accumulation of NO, NO(2)(-), NO(3)(-), urea, or citrulline, but instead afforded a yellow product with absorption maxima of 257 and 400 nm. Mass spectrometry of the derivatized NHA products identified the yellow species as N-nitrosoarginine. We suggest that a nitrosylating agent, possibly derived from HNO, is produced by the oxidation of one molecule of substrate. This then reacts with a second substrate molecule to form the observed N-nitroso products. This complex chemistry illustrates how the active sites of enzymes such as nitric-oxide synthase may serve to prevent alternative reactions from occurring, in addition to enabling those desired.

PubMed: 10722697
DOI: 10.1074/jbc.275.12.8582

実験手法

X-RAY DIFFRACTION (1.93 Å)