Overexpression of Different Types of Microbial Rhodopsins with a Highly Expressible Bacteriorhodopsin from Haloarcula marismortui as a Single Protein in E. coli.

Microbial rhodopsins (M-Rho) are found in Archaea, Bacteria and some species of Eukarya and serve as light-driven ion pumps or mediate phototaxis responses in various biological systems. We previously reported an expression system using a highly expressible mutant, D94N-HmBRI (HEBR) from Haloarcula marismortui, as a leading tag to assist in the expression of membrane proteins that were otherwise difficult to express in E. coli.