Kojima K., Watanabe H.C., Doi S., Miyoshi N., Kato M., Ishikita H., and Sudo Y.
Mutational analysis of the conserved carboxylates of anion channelrhodopsin-2 (ACR2) expressed in Escherichia coli and their roles in anion transport.
BPPB vol. 15 Pages 179-188 (2018)
A transformative leap in neuroscience has been made with optogenetic techniques using algal channelrhodopsin (ChR). Kojima et al. analyzed the molecular mechanism of the light-gated anion channel of Anion channelrhodopsin-2 (ACR2) from the alga Guillardia theta by combining experimental and computational approaches to investigate the roles of conserved carboxylates. They first replaced each of the six conserved carboxylates in ACR2 with a neutral residue (i.e. E9Q, E56Q, E64Q, E159Q, E219Q and D230N), and measured the anion transport activities of the wild-type and those mutant proteins using their own E. coli expression system. Consequently, they observed that E159Q and D230N exhibited significantly lower anion transport activity compared with the wild-type ACR2. Then, they constructed the three-dimensional structural model of ACR2 based on a cation channelrhodopsin, and investigated their roles in anion transport.
This research not only sheds light on the intricate molecular mechanisms of ACR2 by their experimental and theoretical biophysical approaches, but also serves to develop an indispensable tool as an optogenetics toolkit. Thus, this is an outstanding paper giving profound impact on our understanding of optogenetic mechanisms and its potential for future innovation.
June, 2024
Biophysics and Physicobiology Award Selection Committee