Abstract

Protein engineering of microbial rhodopsins has beensuccessful in generating variants with improved properties forapplications in optogenetics. Members of this membraneprotein family can act as both actuators and sensors ofneuronal activity. Chimeragenesis, structure-guidedmutagenesis, and directed evolution have proven effectivestrategies for tuning absorption wavelength, altering ionspecificity and increasing fluorescence. These approachesfacilitate the development of useful optogenetic tools and, insome cases, have yielded insights into rhodopsin structure–function relationships.