The three mitochondrial encoded CcmF proteins form a complex that interacts with CCMH and c-type apocytochromes in Arabidopsis
The three mitochondrial encoded CcmF proteins form a complex that interacts with CCMH and c-type apocytochromes in Arabidopsis
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DOI：
10.1074/jbc.m802621200
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发表时间：
2008-09-12
影响因子：
4.8
通讯作者：
Giege, Philippe
中科院分区：
文献类型：
--
作者：
Rayapuram, Naganand;Hagenmuller, Jeremie;Giege, Philippe
在拟南芥线粒体基因组中发现了CCMF(N1)、CCmf(N2)和CCmf(C)三个读框。这些序列与参与细胞色素c成熟的细菌基因CCMF的区域相似。CCMF基因通常在动物和真菌基因组中缺失，但在陆地植物和几种进化较远的真核生物的线粒体基因组中发现。在拟南芥中，CCMF(N2)不是一个伪基因，尽管没有经典的起始密码子。拟南芥的3个CCMF基因是在蛋白质水平表达的。它们的产物是线粒体内膜的完整蛋白，总共预测了11到13个跨膜螺旋。CCMF(N2)保守的WWD结构域定位于膜间隙。经Blue Native PAGE检测，3种CCMF蛋白均存在于500 kDa的高分子复合体中。在酵母双杂交裂解泛素体系中，CCMF(N1)与CCMF(N1)和CCMF(C)之间存在直接相互作用，而CCMF(N1)与CcmFC之间没有相互作用。类似地，CCMF(N2)与凋亡素c之间也检测到相互作用，但也与凋亡素c(1)相互作用。最后，CCMF(N1)和CCMF(N2)都与CCMH相互作用，这也被证明与细胞色素c相互作用。这证实了CCMF和CCMH在植物线粒体中形成一个复合体，执行血红素与c型脱细胞色素的组装。
Three reading frames called ccmF(N1), ccmF(N2), and ccmF(c) are found in the mitochondrial genome of Arabidopsis. These sequences are similar to regions of the bacterial gene ccmF involved in cytochrome c maturation. ccmF genes are always absent from animal and fungi genomes but are found in mitochondrial genomes of land plant and several evolutionary distant eukaryotes. In Arabidopsis, ccmF(N2) despite the absence of a classical initiation codon is not a pseudo gene. The 3 ccmF genes of Arabidopsis are expressed at the protein level. Their products are integral proteins of the mitochondrial inner membrane with in total 11 to 13 predicted transmembrane helices. The conserved WWD domain of CcmF(N2) is localized in the inter membrane space. The 3 CcmF proteins are all detected in a high molecular mass complex of 500 kDa by Blue Native PAGE. Direct interaction between CcmF(N2) and both CcmF(N1) and CcmF(C) is shown with the yeast two-hybrid split ubiquitin system, but no interaction is observed between CcmF(N1) and CcmFC. Similarly, interaction is detected between CcmF(N2) and apocytochrome c but also with apocytochrome c(1). Finally, CcmF(N1) and CcmF(N2) both interact with CCMH previously shown to interact as well with cytochrome c. This strengthens the hypothesis that CcmF and CCMH make a complex that performs the assembly of heme with c-type apocytochromes in plant mitochondria.