Bacterial rhodopsin:: Evidence for a new type of phototrophy in the sea
Bacterial rhodopsin:: Evidence for a new type of phototrophy in the sea
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DOI：
10.1126/science.289.5486.1902
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发表时间：
2000-09-15
期刊：
影响因子：
56.9
通讯作者：
DeLong, EF
中科院分区：
文献类型：
--
作者：
Béjà, O;Aravind, L;DeLong, EF
极端嗜盐古菌含有视网膜结合的膜蛋白，称为细菌视紫红质，其功能是光驱动的质子泵。到目前为止，细菌视紫红质能够产生化学渗透膜电位响应光已被证明只有在嗜盐古菌。我们在这里描述了一种来自细菌的视紫红质，它是通过对天然海洋浮游细菌的基因组分析发现的。细菌视紫红质编码于未培养的γ-变形菌的基因组中，并且与古细菌视紫红质具有最高的氨基酸序列相似性。该蛋白质在大肠杆菌中功能性表达，并结合视网膜形成活性的光驱动质子泵。新的视紫红质具有古细菌质子泵视紫红质的光化学反应循环和动力学特征。我们的研究结果表明，古细菌样视紫红质广泛分布在不同的类群，包括成员的域细菌。我们的数据还表明，一种以前未被怀疑的细菌介导的光驱动能量产生模式可能经常发生在世界各地的海洋表面沃茨。
Extremely halophilic archaea contain retinal-binding integral membrane proteins called bacteriorhodopsins that function as Light-driven proton pumps. So far, bacteriorhodopsins capable of generating a chemiosmotic membrane potential in response to Light have been demonstrated only in halophilic archaea. We describe here a type of rhodopsin derived from bacteria that was discovered through genomic analyses of naturally occuring marine bacterioplankton. The bacterial rhodopsin was encoded in the genome of an uncultivated gamma-proteobacterium and shared highest amino acid sequence similarity with archaeal rhodopsins. The protein was functionally expressed in Escherichia coli and bound retinal to form an active, Light-driven proton pump. The new rhodopsin exhibited a photochemical reaction cycle with intermediates and kinetics characteristic of archaeal proton-pumping rhodopsins. Our results demonstrate that archaeal-like rhodopsins are broadly distributed among different taxa, including members of the domain Bacteria. Our data also indicate that a previously unsuspected mode of bacterially mediated Light-driven energy generation may commonly occur in oceanic surface waters worldwide.