The regulatory mechanism of ion permeation through a channelrhodopsin derived from Mesostigma viride (MvChR1)

The five glutamate (E) residues of transmembrane (TM)-2 of channelrhodopsin (CrChR)-2 are conserved among several members of the ChR family. A point mutation of one of them, E97, to a nonpolar alanine (E97A) reduced the photocurrent amplitude without influencing other photocurrent properties. The charge at this position is also the determinant of the Gd3+-dependent block of the channel. It has thus been suggested that E97 interacts with hydrated...