A variant System I for cytochrome c biogenesis in archaea and some bacteria has a novel CcmE and no CcmH
A variant System I for cytochrome c biogenesis in archaea and some bacteria has a novel CcmE and no CcmH
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DOI：
10.1016/j.febslet.2006.07.073
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发表时间：
2006-09-04
期刊：
影响因子：
3.5
通讯作者：
Ferguson, Stuart J.
中科院分区：
文献类型：
--
作者：
Allen, James W. A.;Harvat, Edgar M.;Ferguson, Stuart J.
C型细胞色素的特征是以Cys-xxx-xxx-Cys-His基序形式存在的血红素与硫醇翻译后的共价结合。已知有三种不同的生物发生系统来实现这种血红素附着。古生菌现在被证明含有一种显着修饰的细胞色素C成熟系统I(CCM系统)。与蛋白质细菌和植物中研究得最好的器官相比，最值得注意的适应是一种新形式的血红素伴侣CCME，它缺乏高度保守的组氨酸，该组氨酸与血红素共价结合，是大肠杆菌发挥功能所必需的。在大多数古生代CcmEs中，这种通常存在于His-xxx-Tyr基序中的组氨酸被出现在Cys-xxx-Tyr基序中的半胱氨酸残基取代。来自两个盐杆菌的CcmE含有另一种形式的CCME，其HxxxHxxxH大致对应于H/CxxxY基序。令人惊讶的是，CxxxY型CCME也存在于一些细菌基因组中(包括脱硫弧菌)。所有修饰的CcmE都聚集在一个系统发育树中，来自同一生物体的其他CCM蛋白也是如此。值得注意的是，CcmH在我们所研究的所有完整的古生菌基因组中都不存在，在大多数具有CxxxY型CCME的细菌基因组中也是如此。(C)2006年欧洲生化学会联合会。爱思唯尔出版，版权所有。
C-type cytochromes are characterized by post-translational covalent attachment of heme to thiols that occur in a Cys-Xxx-Xxx-Cys-His motif. Three distinct biogenesis systems are known for this heme attachment. Archaea are now shown to contain a significantly modified form of cytochrome c maturation System I (the Ccm system). The most notable adaptation relative to the well-studied apparatus from proteobacteria and plants is a novel form of the heme chaperone CcmE, lacking the highly conserved histidine that covalently binds heme and is essential for function in Escherichia coli. In most archaeal CcmEs this histidine, normally found in a His-Xxx-Xxx-Xxx-Tyr motif, is replaced by a cysteine residue that occurs in a Cys-Xxx-Xxx-Xxx-Tyr motif. The CcmEs from two halobacteria contain yet another form of CcmE, having HxxxHxxxH approximately corresponding in alignment to the H/CxxxY motif. The CxxxY-type of CcmE is, surprisingly, also found in some bacterial genomes (including Desulfovibrio species). All of the modified CcmEs cluster together in a phylogenetic tree, as do other Ccm proteins from the same organisms. Significantly, CcmH is absent from all of the complete archaeal genomes we have studied, and also from most of the bacterial genomes that have CxxxY-type CcmE. (c) 2006 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.