Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Japan.
FEBS J. 2011 Jul;278(13):2341-8. doi: 10.1111/j.1742-4658.2011.08155.x. Epub 2011 May 25.
Hydrogenophilus thermoluteolus cytochrome c' (PHCP) has typical spectral properties previously observed for other cytochromes c', which comprise Ambler's class II cytochromes c. The PHCP protein sequence (135 amino acids) deduced from the cloned gene is the most homologous (55% identity) to that of cytochrome c' from Allochromatium vinosum (AVCP). These findings indicate that PHCP forms a four-helix bundle structure, similar to AVCP. Strikingly, PHCP with a covalently bound heme was heterologously synthesized in the periplasm of Escherichia coli strains deficient in the DsbD protein, a component of the System I cytochrome c biogenesis machinery. The heterologous synthesis of PHCP by aerobically growing E. coli also occurred without a plasmid carrying the genes for Ccm proteins, other components of the System I machinery. Unlike Ambler's class I general cytochromes c, the synthesis of PHCP is not dependent on the System I machinery and exhibits similarity to that of E. coli periplasmic cytochrome b(562), a 106-residue four-helix bundle.
嗜热氢单胞菌细胞色素 c'（PHCP）具有其他细胞色素 c' 先前观察到的典型光谱特性，这些特性包括安伯勒（Ambler）分类的 II 类细胞色素 c。从克隆基因推导的 PHCP 蛋白序列（135 个氨基酸）与来自变色菌（Allochromatium vinosum）的细胞色素 c'（AVCP）最同源（55%同一性）。这些发现表明 PHCP 形成了类似于 AVCP 的四螺旋束结构。引人注目的是，带有共价结合血红素的 PHCP 在缺乏 DsbD 蛋白（系统 I 细胞色素 c 生物发生机制的组成部分）的大肠杆菌菌株的周质中异源合成。在不携带编码 Ccm 蛋白（系统 I 机制的其他成分）的质粒的情况下，需氧生长的大肠杆菌也能进行 PHCP 的异源合成。与安伯勒分类的 I 类一般细胞色素 c 不同，PHCP 的合成不依赖于系统 I 机制，并且与大肠杆菌周质细胞色素 b（562）的合成相似，后者是一个由 106 个残基组成的四螺旋束。
