Tracking molecular evolution of photosynthesis by characterization of a major photosynthesis gene cluster from Heliobacillus mobilis.
Tracking molecular evolution of photosynthesis by characterization of a major photosynthesis gene cluster from Heliobacillus mobilis.
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通过表征运动Heliobacillus mobilis 的主要光合作用基因簇来跟踪光合作用的分子进化。
DOI：
10.1073/pnas.95.25.14851
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发表时间：
1998
影响因子：
11.1
通讯作者：
Bauer,CE
中科院分区：
文献类型：
--
作者：
Xiong,J;Inoue,K;Bauer,CE
已经获得了移动heliobacillus mobilis35.6 kb基因组片段的DNA序列，其中包含一个主要的光合作用基因簇。共鉴定出30个orf，其中20个编码细菌叶绿素和类胡萝卜素生物合成酶、反应中心载脂蛋白（RC）和循环电子传递细胞色素。到RC的供体侧电子转移组分包括一个假设的RC相关的细胞色素553和一个独特的四大亚基细胞色素复合物，由Rieske Fe-S蛋白（编码bypetC）、细胞色素6（petB）、亚基IV （petD）和二血红素细胞色素（petX）组成。对不同光合作用基因产物的系统发育分析表明，富氧谱系是不同于无氧谱系的一致类群。此外,H。mobilis被认为是蓝藻的近亲，蓝藻是基于叶绿体的光合谱系的单系起源。光合作用基因树的共识也表明紫色细菌是最早出现的光合作用谱系。我们的分析还表明，在所有光合作用类群分化之前，一个古老的基因复制事件就产生了副同源基因和双同源基因。此外，我们对光系统I和光系统II核心多肽基因复制的分析支持了一种“异源融合模型”，用于氧气光合作用的起源和进化。
A DNA sequence has been obtained for a 35.6-kb genomic segment fromHeliobacillus mobilisthat contains a major cluster of photosynthesis genes. A total of 30 ORFs were identified, 20 of which encode enzymes for bacteriochlorophyll and carotenoid biosynthesis, reaction-center (RC) apoprotein, and cytochromes for cyclic electron transport. Donor side electron-transfer components to the RC include a putative RC-associated cytochromec553and a unique four-large-subunit cytochromebccomplex consisting of Rieske Fe-S protein (encoded bypetC), cytochromeb6(petB), subunit IV (petD), and a diheme cytochromec(petX). Phylogenetic analysis of various photosynthesis gene products indicates a consistent grouping of oxygenic lineages that are distinct and descendent from anoxygenic lineages. In addition,H. mobiliswas placed as the closest relative to cyanobacteria, which form a monophyletic origin to chloroplast-based photosynthetic lineages. The consensus of the photosynthesis gene trees also indicates that purple bacteria are the earliest emerging photosynthetic lineage. Our analysis also indicates that an ancient gene-duplication event giving rise to the paralogousbchIandbchDgenes predates the divergence of all photosynthetic groups. In addition, our analysis of gene duplication of the photosystem I and photosystem II core polypeptides supports a “heterologous fusion model” for the origin and evolution of oxygenic photosynthesis.