Update 1 of: Over One Hundred Peptide-Activated G Protein-Coupled Receptors Recognize Ligands with Turn Structure

Abstract

1. GPCRs: Importance and Occurrence G protein-coupled receptors (GPCRs) are seven transmembrane helical bundle proteins (Figure 1) found on the surface of all cells.1–3 They mediate cellular responses to a diverse range of extracellular stimuli, including both endogenous chemical signals and exogenous environmental agents (e.g., light, amino acids, peptides, proteins, small organic molecules such as amines and lipids, nucleosides, nucleotides, metal ions, and pharmaceuticals). Once activated by an extracellular signal, GPCRs activate heterotrimeric G proteins that interact promiscuously with multiple receptors....