A natural light-driven inward proton pump

• DOI: 10.1038/ncomms13415
• Publication Date: 2016-11-17T09:50:07Z
• Authors: Keiichi Inoue; Shota Ito; Yoshitaka Kato; Yurika Nomura; Mikihiro Shibata; Takayuki Uchihashi; Satoshi P. Tsunoda; Hideki Kandori
• Keywords: Chromophore; Proton Pump; Acceptor

Abstract Light-driven outward H + pumps are widely distributed in nature, converting sunlight energy into proton motive force. Here we report the characterization of an oppositely directed pump with a similar architecture to pumps. A deep-ocean marine bacterium, Parvularcula oceani , contains three rhodopsins, one which functions as light-driven inward when expressed Escherichia coli and mouse neural cells. Detailed mechanistic analyses purified proteins reveal that small differences interactions established at active centre determine direction primary transfer. Outward establish strong electrostatic between donor extracellular acceptor. In these weaker, inducing more relaxed chromophore structure leads long-distance transfer cytoplasmic side. These results demonstrate elaborate molecular design control transfers proteins.