Structure and mechanisms of sodium-pumping KR2 rhodopsin
Structure and mechanisms of sodium-pumping KR2 rhodopsin
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DOI：
10.1126/sciadv.aav2671
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发表时间：
2019-04-01
期刊：
影响因子：
13.6
通讯作者：
Gordeliy, Valentin
中科院分区：
文献类型：
--
作者：
Kovalev, Kirill;Polovinkin, Vitaly;Gordeliy, Valentin
视紫红质是地球上最普遍的生物光能转换器和最丰富的光合营养机制，具有显著的多样性和生物技术应用潜力。最近，第一个钠泵视紫红质KR2从Krokinakeikastus被发现和表征。然而，KR2的现有结构是矛盾的，并且Na+泵送的机制尚未被理解。在这里，我们提出了一种结构的阳离子（非H+）光驱动泵在生理pH值的五聚体形式。我们还提出了13个原子结构和KR2及其突变体的功能数据，包括钾泵，这表明微生物视紫红质的寡聚化是其生物学功能所必需的。这些研究揭示了KR2在非生理低pH下的结构，其中它充当质子泵。该结构为微生物视紫红质的机制提供了新的见解，并为合理设计用于光遗传学的新型阳离子泵开辟了道路。
Rhodopsins are the most universal biological light-energy transducers and abundant phototrophic mechanisms that evolved on Earth and have a remarkable diversity and potential for biotechnological applications. Recently, the first sodium-pumping rhodopsin KR2 from Krokinobacter eikastus was discovered and characterized. However, the existing structures of KR2 are contradictory, and the mechanism of Na+ pumping is not yet understood. Here, we present a structure of the cationic (non H+) light-driven pump at physiological pH in its pentameric form. We also present 13 atomic structures and functional data on the KR2 and its mutants, including potassium pumps, which show that oligomerization of the microbial rhodopsin is obligatory for its biological function. The studies reveal the structure of KR2 at nonphysiological low pH where it acts as a proton pump. The structure provides new insights into the mechanisms of microbial rhodopsins and opens the way to a rational design of novel cation pumps for optogenetics.