期刊
BIOCHEMISTRY
卷 42, 期 19, 页码 5600-5608出版社
AMER CHEMICAL SOC
DOI: 10.1021/bi034058c
关键词
-
资金
- NIGMS NIH HHS [GM41049, R01 GM041049, GM42614] Funding Source: Medline
Cytochrome c peroxidase (CCP) is a 32.5 kDa mitochondrial intermembrane space heme peroxidase from Saccharomyces cerevisiae that reduces H2O2 to 2H2O by oxidizing two molecules of cytochrome c (cyt c). Here we compare the 1.2 Angstrom native structure (CCP) with the 1.3 Angstrom structure of its stable oxidized reaction intermediate, Compound I (CCP1). In addition, crystals were analyzed by UV-vis absorption and electron paramagnetic resonance spectroscopies before and after data collection to determine the state of the Fe(IV) center and the cationic Trp191 radical formed in Compound I. The results show that X-ray exposure does not lead to reduction of Fe(IV) and only partial reduction of the Trp radical. A comparison of the two structures reveals subtle but important conformational changes that aid in the stabilization of the Trp191 cationic radical in Compound I. The higher-resolution data also enable a more accurate determination of changes in heme parameters. Most importantly, when one goes from resting state Fe(III) to Compound I, the His-Fe bond distance increases, the iron moves into the porphyrin plane leading to shorter pyrrole N-Fe bonds, and the Fe(IV)-O bond distance is 1.87 Angstrom suggesting a single Fe(IV)-O bond and not the generally accepted double bond.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据