CRYSTAL STRUCTURES OF THE E 2 -ADRENERGIC RECEPTOR

G protein coupled receptors (GPCRs) constitute the largest family of membrane proteins in the human genome, and are responsible for the majority of signal transduction events involving hormones and neuro- transmitters across the cell membrane. GPCRs that bind to diffusible ligands have low natural abundance, are relatively unstable in detergents, and dis- play basal G protein activation even in the absence of ligands. To overcome these problems two approaches were taken to obtain crystal structures of the ______ * To whom correspondence should be addressed. William Weis, Departments of Structural Biology