title: A virtual screen for diverse ligands: discovery of selective G protein-coupled receptor antagonists.
abstract: Virtual screening has become a major focus of bioactive small molecule lead identification, and reports of agonists and antagonists discovered via virtual methods are becoming more frequent. G protein-coupled receptors (GPCRs) are the one class of protein targets for which success with this approach has been limited. This is likely due to the paucity of detailed experimental information describing GPCR structure and the intrinsic function-associated structural flexibility of GPCRs which present major challenges in the application of receptor-based virtual screening. Here we describe an in silico methodology that diminishes the effects of structural uncertainty, allowing for more inclusive representation of a potential docking interaction with exogenous ligands. Using this approach, we screened one million compounds from a virtual database, and a diverse subgroup of 100 compounds was selected, leading to experimental identification of five structurally diverse antagonists of the thyrotropin-releasing hormone receptors (TRH-R1 and TRH-R2). The chirality of the most potent chemotype was demonstrated to be important in its binding affinity to TRH receptors; the most potent stereoisomer was noted to have a 13-fold selectivity for TRH-R1 over TRH-R2. A comprehensive mutational analysis of key amino acid residues that form the putative binding pocket of TRH receptors further verified the binding modality of these small molecule antagonists. The described virtual screening approach may prove applicable in the search for novel small molecule agonists and antagonists of other GPCRs.
authors: The Clinical Endocrinology Branch and Laboratory of Biological Modeling, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors: Stanislav
authors: S
authors: Engel
authors: Amanda P
authors: AP
authors: Skoumbourdis
authors: John
authors: J
authors: Childress
authors: Susanne
authors: S
authors: Neumann
authors: Jeffrey R
authors: JR
authors: Deschamps
authors: Craig J
authors: CJ
authors: Thomas
authors: Anny-Odile
authors: AO
authors: Colson
authors: Stefano
authors: S
authors: Costanzi
authors: Marvin C
authors: MC
authors: Gershengorn
mesh_terms: D002460:Cell Line; D004353:Drug Evaluation, Preclinical; D006801:Humans; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D009154:Mutation / Q000235:genetics; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D018025:Receptors, Thyrotropin-Releasing Hormone / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D013972:Thyrotropin / Q000737:chemistry
chemical_list: D008024:Ligands; D043562:Receptors, G-Protein-Coupled; D018025:Receptors, Thyrotropin-Releasing Hormone; D013972:Thyrotropin