Probing heme delivery processes in cytochrome c biogenesis System I.
Probing heme delivery processes in cytochrome c biogenesis System I.
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DOI：
10.1021/bi400398t
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发表时间：
2013-10-15
期刊：
影响因子：
2.9
通讯作者：
Stevens, Julie M.
中科院分区：
文献类型：
--
作者：
Mavridou, Despoina A. I.;Clark, Matthew N.;Choulat, Cendie;Ferguson, Stuart J.;Stevens, Julie M.
细胞色素c包括一个多样化和广泛的蛋白质家族，其含有共价结合的血红素，对大多数生物体的生命至关重要。在许多细菌和某些线粒体中，细胞色素c的合成是由一个复杂的翻译后修饰装置进行的，称为系统I（或细胞色素c成熟，Ccm，系统）。在大肠杆菌中，有八种成熟蛋白，其中几种参与血红素处理，但血红素从一种蛋白转移到另一种蛋白的机制尚不清楚。血红素与脱辅基细胞色素的连接通过与血红素伴侣CcmE的组氨酸残基的新型共价键发生。变体成熟系统（System I*）的发现为研究细胞色素c组装提供了新的工具，因为变体CcmE通过半胱氨酸残基代替System I的组氨酸发挥功能。在这项工作中，我们使用两个成熟系统的定点诱变，以探测的功能，以及它们的协同作用，在转移血红素的细胞色素c基板的个别组件蛋白质。CcmA，CcmC，CcmE和CcmF在血红素传递过程中的作用进行了比较系统I和I* 之间。我们表明，以前提出的醌结合位点CCMF是不是必不可少的系统。在变异系统中，参与细胞色素c形成的血红素化学的显着差异为细胞色素c的生物发生之谜增添了新的碎片。
Cytochromes c comprise a diverse and widespread family of proteins containing covalently bound heme that are central to the life of most organisms. In many bacteria and in certain mitochondria, the synthesis of cytochromes c is performed by a complex post-translational modification apparatus called System I (or cytochrome c maturation, Ccm, system). In Escherichia coli, there are eight maturation proteins, several of which are involved in heme handling, but the mechanism of heme transfer from one protein to the next is not known. Attachment of the heme to the apocytochrome occurs via a novel covalent bond to a histidine residue of the heme chaperone CcmE. The discovery of a variant maturation system (System I*) has provided a new tool for studying cytochrome c assembly because the variant CcmE functions via a cysteine residue in the place of the histidine of System I. In this work, we use site-directed mutagenesis on both maturation systems to probe the function of the individual component proteins as well as their concerted action in transferring heme to the cytochrome c substrate. The roles of CcmA, CcmC, CcmE, and CcmF in the heme delivery process are compared between Systems I and I*. We show that a previously proposed quinone-binding site on CcmF is not essential for either system. Significant differences in the heme chemistry involved in the formation of cytochromes c in the variant system add new pieces to the cytochrome c biogenesis puzzle.
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影响因子：
2.9
作者：
BARKER, PD;NEROU, EP;FEARNLEY, IM
通讯作者：
FEARNLEY, IM
DOI：
10.1016/0005-2728(86)90234-3
发表时间：
1986-12-03
期刊：
BIOCHIMICA ET BIOPHYSICA ACTA
影响因子：
--
作者：
GOODHEW, CF;BROWN, KR;PETTIGREW, GW
通讯作者：
PETTIGREW, GW
影响因子：
3.5
作者：
Allen, James W. A.;Harvat, Edgar M.;Ferguson, Stuart J.
通讯作者：
Ferguson, Stuart J.
影响因子：
4.8
作者：
Rayapuram, Naganand;Hagenmuller, Jeremie;Giege, Philippe
通讯作者：
Giege, Philippe
影响因子：
5.4
作者：
Christensen, Olaf;Harvat, Edgar M.;Stevens, Julie M.
通讯作者：
Stevens, Julie M.