Engineering of soluble bacteriorhodopsin

Abstract

Bacteriorhodopsin is a seven-helical light-driven proton pump and a model membrane protein. Here, we report engineering of soluble analogues of bacteriorhodopsin, NeuroBRs, which bind retinal and photocycle under illumination. We also report the crystallographic structure of NeuroBR_A, determined at anisotropic resolution reaching 1.76 Å, that reveals a conserved chromophore binding pocket and tertiary structure. Our results highlight the power of modern protein engineering approaches and pave the way towards wider development of molecular tools derived from membrane proteins.