Crystal structure of Halobacterium salinarum halorhodopsin with a partially depopulated primary chloride-binding site.

ABSTRACT: The transmembrane pump halorhodopsin in halophilic archaea translocates chloride ions from the extracellular to the cytoplasmic side upon illumination. In the ground state a tightly bound chloride ion occupies the primary chloride-binding site (CBS I) close to the protonated Schiff base that links the retinal chromophore to the protein. The light-triggered trans-cis isomerization of retinal causes structural changes in the protein associated with movement of the chloride ion. In reverse, chemical depletion of CBS I in Natronomonas pharaonis halorhodopsin (NpHR) through deprotonation of the Schiff base results in conformational changes of the protein: a state thought to mimic late stages of the photocycle. Here, crystals of Halobacterium salinarum halorhodopsin (HsHR) were soaked at high pH

SUBMITTER: Schreiner M 

PROVIDER: S-EPMC5012209 | biostudies-literature | 2016 Sep

REPOSITORIES: biostudies-literature