Proteorhodopsin lateral gene transfer between marine planktonic Bacteria and Archaea
Proteorhodopsin lateral gene transfer between marine planktonic Bacteria and Archaea
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DOI：
10.1038/nature04435
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发表时间：
2006-02-16
期刊：
影响因子：
64.8
通讯作者：
DeLong, EF
中科院分区：
文献类型：
--
作者：
Frigaard, NU;Martinez, A;DeLong, EF
浮游细菌、浮游生物和真核生物在光的普遍影响下，在海洋的透光层中生存和竞争。在这种环境中的细菌最近被证明含有称为蛋白视紫红质的发光蛋白，认为其通过催化光驱动的质子跨细胞膜的移位来促进细胞能量代谢（1-7）。到目前为止，变形菌视紫红质基因只在变形菌和少数其他细菌类群中有很好的记载。在这里，我们报告的存在和分布的Proteorhodopsin基因在海洋的上层水柱中，隶属于热浆菌目。古细菌和变形菌的蛋白视紫红质的基因组背景和系统发育关系表明它可能在嗜热菌和嗜热菌之间横向转移。大约10%的广古菌在透光层含有蛋白视紫质基因相邻的小亚基核糖体RNA。古细菌的蛋白视紫红质也被发现在其他基因组区域，在相同或不同的微生物谱系。虽然广古菌分布在整个水体中，但它们的变形视紫红质仅在透光层中被发现。Proteorhodopsins的世界性系统发育分布反映了它们显著的光依赖性适应性贡献，这驱动了光蛋白的横向获取和保留，但限制了其扩散到透光区。
Planktonic Bacteria, Archaea and Eukarya reside and compete in the ocean's photic zone under the pervasive influence of light. Bacteria in this environment were recently shown to contain photoproteins called proteorhodopsins, thought to contribute to cellular energy metabolism by catalysing light-driven proton translocation across the cell membrane(1-7). So far, proteorhodopsin genes have been well documented only in proteobacteria and a few other bacterial groups. Here we report the presence and distribution of proteorhodopsin genes in Archaea affiliated with the order Thermoplasmatales, in the ocean's upper water column. The genomic context and phylogenetic relationships of the archaeal and proteobacterial proteorhodopsins indicate its probable lateral transfer between planktonic Bacteria and Archaea. About 10% of the euryarchaeotes in the photic zone contained the proteorhodopsin gene adjacent to their small-subunit ribosomal RNA. The archaeal proteorhodopsins were also found in other genomic regions, in the same or in different microbial lineages. Although euryarchaeotes were distributed throughout the water column, their proteorhodopsins were found only in the photic zone. The cosmopolitan phylogenetic distribution of proteorhodopsins reflects their significant light-dependent fitness contributions, which drive the photoprotein's lateral acquisition and retention, but constrain its dispersal to the photic zone.