Gate-keeper of ion transport—a highly conserved helix-3 tryptophan in a channelrhodopsin chimera, C1C2/ChRWR

摘要

Since the first report of bacteriorhodopsin in 1971, the family of microbial rhodopsins with various light-driven functions has been expanding. The tryptophan homologous to Trp 86 of bacteriorhodopsin is highly conserved among microbial rhodopsins and forms a retinal binding pocket with other amino acids. However, the precise role of this tryptophan in the ion transport function has remained unknown for over 40 years. Nagasaka et al. revealed for the first time that this tryptophan has a role of “gate keeper” of ion transport in a channelrhodopsin. That is, it regulates the structure involved in the gating-on and -off of the cation channel.