Origin of Bacteriochlorophyll a and the Early Diversification of Photosynthesis.
Origin of Bacteriochlorophyll a and the Early Diversification of Photosynthesis.
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DOI：
10.1371/journal.pone.0151250
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Cardona T
中科院分区：
文献类型：
--
作者：
Cardona T
光合作用起源于数十亿年前的细菌领域;然而，所有光养细菌的最后共同祖先的身份仍然没有确定和推测。在这里，我介绍了BchF或3-乙烯基-细菌叶绿素水合酶的进化，这种酶只存在于能够合成细菌叶绿素a的细菌中。我表明，BchF存在于两种形式起源于早期的分歧，一个发现在门Chlorobi，包括其paradium BchV，和第二种形式，是祖先的酶中发现的剩余的缺氧光合细菌。BchF的共生性与细菌叶绿素a在祖先光养细菌中的进化是一致的，该细菌在辐射事件之前生活，该辐射事件导致了绿球藻门、绿球藻门、酸杆菌门、变形菌门和芽单胞菌门，但仅在I型和II型反应中心的分歧之后。因此，这表明，在许多组现存的细菌缺乏光养是一个衍生的性状。
Photosynthesis originated in the domain Bacteria billions of years ago; however, the identity of the last common ancestor to all phototrophic bacteria remains undetermined and speculative. Here I present the evolution of BchF or 3-vinyl-bacteriochlorophyll hydratase, an enzyme exclusively found in bacteria capable of synthetizing bacteriochlorophyll a. I show that BchF exists in two forms originating from an early divergence, one found in the phylum Chlorobi, including its paralogue BchV, and a second form that was ancestral to the enzyme found in the remaining anoxygenic phototrophic bacteria. The phylogeny of BchF is consistent with bacteriochlorophyll a evolving in an ancestral phototrophic bacterium that lived before the radiation event that gave rise to the phylum Chloroflexi, Chlorobi, Acidobacteria, Proteobacteria, and Gemmatimonadetes, but only after the divergence of Type I and Type II reaction centers. Consequently, it is suggested that the lack of phototrophy in many groups of extant bacteria is a derived trait.