Verissimo Andreia F, Daldal Fevzi
Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6019, USA.
Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6019, USA.
Biochim Biophys Acta. 2014 Jul;1837(7):989-98. doi: 10.1016/j.bbabio.2014.03.003. Epub 2014 Mar 14.
Cytochromes c are ubiquitous heme proteins that are found in most living organisms and are essential for various energy production pathways as well as other cellular processes. Their biosynthesis relies on a complex post-translational process, called cytochrome c biogenesis, responsible for the formation of stereo-specific thioether bonds between the vinyl groups of heme b (protoporphyrin IX-Fe) and the thiol groups of apocytochromes c heme-binding site (C1XXC2H) cysteine residues. In some organisms this process involves up to nine (CcmABCDEFGHI) membrane proteins working together to achieve heme ligation, designated the Cytochrome c maturation (Ccm)-System I. Here, we review recent findings related to the Ccm-System I found in bacteria, archaea and plant mitochondria, with an emphasis on protein interactions between the Ccm components and their substrates (apocytochrome c and heme). We discuss the possibility that the Ccm proteins may form a multi subunit supercomplex (dubbed "Ccm machine"), and based on the currently available data, we present an updated version of a mechanistic model for Ccm. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference.
细胞色素c是普遍存在的血红素蛋白，存在于大多数生物体中，对各种能量产生途径以及其他细胞过程至关重要。它们的生物合成依赖于一个复杂的翻译后过程，称为细胞色素c生物合成，负责在血红素b（原卟啉IX - 铁）的乙烯基与脱辅基细胞色素c血红素结合位点（C1XXC2H）半胱氨酸残基的巯基之间形成立体特异性硫醚键。在一些生物体中，这个过程涉及多达九种（CcmABCDEFGHI）膜蛋白协同作用以实现血红素连接，称为细胞色素c成熟（Ccm）-系统I。在这里，我们综述了与细菌、古细菌和植物线粒体中发现的Ccm-系统I相关的最新研究结果，重点是Ccm组分与其底物（脱辅基细胞色素c和血红素）之间的蛋白质相互作用。我们讨论了Ccm蛋白可能形成多亚基超复合物（称为“Ccm机器”）的可能性，并基于目前可用的数据，我们提出了一个更新的Ccm机制模型版本。本文是名为：第18届欧洲生物能量学会议的特刊的一部分。
