QM/MM Study of the NMR Spectroscopy of the Retinyl Chromophore in Visual Rhodopsin

J Chem Theory Comput. 2005 Jul;1(4):674-85. doi: 10.1021/ct0500850.

Abstract

The (1)H and (13)C nuclear magnetic resonance (NMR) spectra of the retinyl chromophore in rhodopsin are investigated by using quantum mechanics/molecular mechanics (QM/MM) hybrid methods at the density functional theory (DFT) B3LYP/6-31G*:Amber level of theory, in conjunction with the gauge independent atomic orbital (GIAO) method for the ab initio self-consistent-field (SCF) calculation of NMR chemical shifts. The study provides a first-principle interpretation of solid-state NMR experiments based on recently developed QM/MM computational models of rhodopsin and bathorhodopsin [Gascón, J. A.; Batista, V. S. Biophys. J. 2004, 87, 2931-2941]. The reported results are particularly relevant to the development and validation of atomistic models of prototypical G-protein-coupled receptors which regulate signal transduction across plasma membranes.