Abstract
G protein-coupled receptors (GPCRs) represent a vast and critical class of cell surface proteins, making them prime targets for therapeutic intervention. Understanding their structural dynamics, particularly in the context of their native lipid environments, is paramount for deciphering ligand specificity and developing novel drugs. Recent advancements in cryo-electron microscopy (cryo-EM) have revolutionized structural biology, enabling high-resolution determination of membrane proteins, including GPCRs, in near-native states [2, 3, 14, 19]. This review outlines the current state of high-resolution cryo-EM for studying GPCRs, emphasizing the importance of preserving their native lipid milieu. Techniques such as lipid nanodiscs and detergent-free methods are crucial for reconstituting GPCRs in environments that mimic the cell membrane, thereby preserving functional integrity and facilitating high-resolution structure determination [9, 16, 25]. Elucidating the structural basis of ligand binding and subsequent receptor activation requires atomic-level detail, which cryo-EM is increasingly capable of providing [1, 12, 28]. This approach allows for the identification of specific lipid-protein interactions that can influence receptor conformation and ligand affinity, offering new avenues for drug design [11, 30]. By integrating cryo-EM with computational methods like molecular dynamics simulations, a comprehensive understanding of GPCR pharmacology and function can be achieved [22, 27]. This article will explore the methodologies, recent breakthroughs, and future directions in applying high-resolution cryo-EM to unravel GPCR ligand specificity within their native lipid environments.