The Expanding Family of Natural Anion Channelrhodopsins Reveals Large Variations in Kinetics, Conductance, and Spectral Sensitivity.

ABSTRACT: Natural anion channelrhodopsins (ACRs) discovered in the cryptophyte alga Guillardia theta generate large hyperpolarizing currents at membrane potentials above the Nernst equilibrium potential for Cl^- and thus can be used as efficient inhibitory tools for optogenetics. We have identified and characterized new ACR homologs in different cryptophyte species, showing that all of them are anion-selective, and thus expanded this protein family to 20 functionally confirmed members. Sequence comparison of natural ACRs and engineered Cl^--conducting mutants of cation channelrhodopsins (CCRs) showed radical differences in their anion selectivity filters. In particular, the Glu90 residue in channelrhodopsin 2, which needed to be mutated to a neutral or alkaline residue to confer

SUBMITTER: Govorunova EG 

PROVIDER: S-EPMC5335703 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature