Detailed analysis of distorted retinal and its interaction with surrounding residues in the K intermediate of bacteriorhodopsin.

ABSTRACT: The K intermediate of proton pumping bacteriorhodopsin is the first intermediate generated after isomerization of retinal to the 13-cis form. Although various structures have been reported for the K intermediate until now, these differ from each other, especially in terms of the conformation of the retinal chromophore and its interaction with surrounding residues. We report here an accurate X-ray crystallographic analysis of the K structure. The polyene chain of 13-cis retinal is observed to be S-shaped. The side chain of Lys216, which is covalently bound to retinal via the Schiff-base linkage, interacts with residues, Asp85 and Thr89. In addition, the Nζ-H of the protonated Schiff-base linkage interacts with a residue, Asp212 and a water molecule, W402. Based on quantum chemical calculati

SUBMITTER: Taguchi S 

PROVIDER: S-EPMC9938236 | biostudies-literature | 2023 Feb

REPOSITORIES: biostudies-literature