Intramolecular interactions that induce helical rearrangement upon rhodopsin activation: light-induced structural changes in metarhodopsin IIa probed by cysteine S-H stretching vibrations.

ABSTRACT: Rhodopsin undergoes rearrangements of its transmembrane helices after photon absorption to transfer a light signal to the G-protein transducin. To investigate the mechanism by which rhodopsin adopts the transducin-activating conformation, the local environmental changes in the transmembrane region were probed using the cysteine S-H group, whose stretching frequency is well isolated from the other protein vibrational modes. The S-H stretching modes of cysteine residues introduced into Helix III, which contains several key residues for the helical movements, and of native cysteine residues were measured by Fourier transform infrared spectroscopy. This method was applied to metarhodopsin IIa, a precursor of the transducin-activating state in which the intramolecular interactions are likely to

SUBMITTER: Yamazaki Y 

PROVIDER: S-EPMC4022853 | biostudies-literature | 2014 May

REPOSITORIES: biostudies-literature