Molecular determinants of proton selectivity and gating in the red-light activated channelrhodopsin Chrimson.

ABSTRACT: Channelrhodopsins are light-gated ion channels of green algae used for the precise temporal and spatial control of transmembrane ion fluxes. The channelrhodopsin Chrimson from Chlamydomonas noctigama allows unprecedented deep tissue penetration due to peak absorption at 590 nm. We demonstrate by electrophysiological recordings and imaging techniques that Chrimson is highly proton selective causing intracellular acidification in HEK cells that is responsible for slow photocurrent decline during prolonged illumination. We localized molecular determinants of both high proton selectivity and red light activation to the extracellular pore. Whereas exchange of Glu143 only drops proton conductance and generates an operational Na-channel with 590 nm activation, exchange of Glu139 in addition incre

SUBMITTER: Vierock J 

PROVIDER: S-EPMC5577340 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature