A Unique Light-Driven Proton Transportation Signal in Halorhodopsin from Natronomonas pharaonis.

ABSTRACT: Halorhodopsin (HR) is a seven-transmembrane retinylidene protein from haloarchaea that is commonly known to function as a light-driven inward chloride pump. However, previous studies have indicated that despite the general characteristics that most HRs share, HRs from distinct species differ in many aspects. We present indium-tin-oxide-based photocurrent measurements that reveal a light-induced signal generated by proton release that is observed solely in NpHR via purified protein-based assays, demonstrating that indeed HRs are not all identical. We conducted mutagenesis studies on several conserved residues that are considered critical for chloride stability among HRs. Intriguingly, the photocurrent signals were eliminated after specific point mutations. We propose an NpHR light-driven, c

SUBMITTER: Chen XR 

PROVIDER: S-EPMC5192691 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature