Biophys. J., 109(October):1652-1662, 2015. Paper abstract bibtex
G-protein-coupled receptors are eukaryotic membrane proteins with broad biological and pharmacological rele- vance. Like all membrane-embedded proteins, their location and orientation are influenced by lipids, which can also impact pro- tein function via specific interactions. Extensive simulations totaling 0.25 ms reveal a process in which phospholipids from the membrane’s cytosolic leaflet enter the empty G-protein binding site of an activated b2 adrenergic receptor and form salt-bridge interactions that inhibit ionic lock formation and prolong active-state residency. Simulations of the receptor embedded in an anionic membrane show increased lipid binding, providing a molecular mechanism for the experimental observation that anionic lipids can enhance receptor activity. Conservation of the arginine component of the ionic lock among Rhodopsin-like G-protein- coupled receptors suggests that intracellular lipid ingression between receptor helices H6 and H7 may be a general mechanism for active-state stabilization.