Rhodopsin activation involves an ensemble of conformational substates

Abstract

G-protein-coupled receptors (GPCRs) are seven transmembrane-helix proteins that participate in transmitting signals across cell membranes to regulate multiple functions of the human body. Rhodopsin is an important prototype for studying class A GPCRs. Here we address aspects of the GPCR activation not available for X-ray crystallography due to cryogenic temperatures and the absence of the membrane environment [1,2]. Our hypothesis was that the activation process involves an allosteric mechanism where a dynamical ensemble of states is affected by protein-membrane interactions [1].