Microbial rhodopsins are photoreceptive proteins widely found in microorganisms.These proteins are cat-egorized into two families:type Ⅰ microbial rhodopsins and the recently discovered microbial heliorhodopsin.The two protein families have similar seven transmembrane helices but opposite membrane orientations.These rhodopsins partici-pate in a portfolio of distinct light-driven energy and sensory transduction processes through conformational changes of the shared seven transmembrane helices during the simliar photocycle.In this overview,we discuss the research progress of microbial rhodopsins,including the discovery,classification,structural function,and ecological roles of these two rhodop-sin families.
microbial rhodopsinretinalion pumpphotosensor protein