Haem-delivery proteins in cytochrome c maturation System II
Haem-delivery proteins in cytochrome c maturation System II
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DOI：
10.1111/j.1365-2958.2009.06833.x
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发表时间：
2009-09-01
影响因子：
3.6
通讯作者：
Hederstedt, Lars
中科院分区：
文献类型：
--
作者：
Ahuja, Umesh;Kjelgaard, Peter;Hederstedt, Lars
C型细胞色素在细菌细胞质膜的外侧起作用，在那里它们也由脱辅基细胞色素多肽和血红素组装而成。在细菌中发现了两种截然不同的细胞色素c成熟系统。大肠杆菌中的系统I有8到9种不同的Ccm蛋白。系统II存在于枯草芽孢杆菌中，包含四种蛋白质：CcdA、ResA、ResB和ResC。ResB和ResC是细胞色素c合成所需的多位膜蛋白，人们对其了解甚少。我们分析了这两个B。枯草芽孢杆菌（E. subtilis）蛋白质。大肠杆菌和原生生物中。ResB显示结合原血红素IX，并且发现血红素共价结合至残基Cys-138。结果是B。subtilis表明ResC也可以结合血红素。我们的研究结果补充了最近的研究结果与螺杆菌CcsBA支持的假设，ResBC作为一个复杂的易位血红素附着到ResB的细胞质侧的膜，然后将其转移到一个细胞质外的位置在ResC，从那里它是提供给脱辅基细胞色素。
P>Cytochromes of the c-type function on the outer side of the cytoplasmic membrane in bacteria where they also are assembled from apo-cytochrome polypeptide and haem. Two distinctly different systems for cytochrome c maturation are found in bacteria. System I present in Escherichia coli has eight to nine different Ccm proteins. System II is found in Bacillus subtilis and comprises four proteins: CcdA, ResA, ResB and ResC. ResB and ResC are poorly understood polytopic membrane proteins required for cytochrome c synthesis. We have analysed these two B. subtilis proteins produced in E. coli and in the native organism. ResB is shown to bind protohaem IX and haem is found covalently bound to residue Cys-138. Results in B. subtilis suggest that also ResC can bind haem. Our results complement recent findings made with Helicobacter CcsBA supporting the hypothesis that ResBC as a complex translocates haem by attaching it to ResB on the cytoplasmic side of the membrane and then transferring it to an extra-cytoplasmic location in ResC, from where it is made available to the apo-cytochromes.