A light signal is converted into an electrical one in a single molecule named
channelrhodopsin, one of the archaea-type rhodopsins in unicellular green algae. Although
highly homologous, two molecules of this family, channelrhodopsin-1 (ChR1) and-2 (ChR2),
are distinct in photocurrent properties such as the wavelength sensitivity, desensitization,
and turning-on and-off kinetics. However, the structures regulating these properties have not
been completely identified. Photocurrents were analyzed for several chimera molecules …