MerMAIDs: a family of metagenomically discovered marine anion-conducting and intensely desensitizing channelrhodopsins.

ABSTRACT: Channelrhodopsins (ChRs) are algal light-gated ion channels widely used as optogenetic tools for manipulating neuronal activity. ChRs desensitize under continuous bright-light illumination, resulting in a significant decline of photocurrents. Here we describe a metagenomically identified family of phylogenetically distinct anion-conducting ChRs (designated MerMAIDs). MerMAIDs almost completely desensitize during continuous illumination due to accumulation of a late non-conducting photointermediate that disrupts the ion permeation pathway. MerMAID desensitization can be fully explained by a single photocycle in which a long-lived desensitized state follows the short-lived conducting state. A conserved cysteine is the critical factor in desensitization, as its mutation results in recovery of

SUBMITTER: Oppermann J 

PROVIDER: S-EPMC6658528 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature