舍瓦内拉
周质间隙
大肠杆菌
亚硝酸盐还原酶
化学
还原酶
希瓦氏菌属
生物化学
血红素
细胞色素
电子传输链
辅因子
金属蛋白
立体化学
细菌
生物
酶
硝酸还原酶
基因
遗传学
作者
Thomas A. Clarke,Tracey M. Holley,Robert S. Hartshorne,Jim Fredrickson,John M. Zachara,Liang Shi,David J. Richardson
出处
期刊:Biochemical Society Transactions
[Portland Press]
日期:2008-09-19
卷期号:36 (5): 1005-1010
被引量:20
摘要
The periplasmic nitrite reductase system from Escherichia coli and the extracellular Fe(III) reductase system from Shewanella oneidensis contain multihaem c-type cytochromes as electron carriers and terminal reductases. The position and orientation of the haem cofactors in multihaem cytochromes from different bacteria often show significant conservation despite different arrangements of the polypeptide chain. We propose that the decahaem cytochromes of the iron reductase system MtrA, MtrC and OmcA comprise pentahaem ‘modules’ similar to the electron donor protein, NrfB, from E. coli. To demonstrate this, we have isolated and characterized the N-terminal pentahaem module of MtrA by preparing a truncated form containing five covalently attached haems. UV–visible spectroscopy indicated that all five haems were low-spin, consistent with the presence of bis-His ligand co-ordination as found in full-length MtrA.
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