A Three-Site Mechanism for Agonist/Antagonist Selective Binding to Vasopressin Receptors

• Published in: Angewandte Chemie (International ed.) Vol. 55; no. 28; pp. 8008 - 8012
• Main Authors: Saleh, Noureldin, Saladino, Giorgio, Gervasio, Francesco L., Haensele, Elke, Banting, Lee, Whitley, David C., Sopkova-de Oliveira Santos, Jana, Bureau, Ronan, Clark, Timothy
• Format: Journal Article
• Language: English
• Published: Germany Blackwell Publishing Ltd 04.07.2016; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Activation; Argipressin; Argipressin receptors; Binding energy; Binding sites; Correlation; Free energy; G-protein coupled receptors; hormones; metadynamics; Molecular dynamics; Mutagenesis; Receptors; Sampling; Selective binding; Selectivity; Simulation; Vasopressin; Vasopressin receptors; Vasopressin V2 receptors; metadynamics; G-protein coupled receptors; receptors; molecular dynamics; hormones
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201602729

Molecular‐dynamics simulations with metadynamics enhanced sampling reveal three distinct binding sites for arginine vasopressin (AVP) within its V2‐receptor (V2R). Two of these, the vestibule and intermediate sites, block (antagonize) the receptor, and the third is the orthosteric activation (agonist) site. The contacts found for the orthosteric site satisfy all the requirements deduced from mutagenesis experiments. Metadynamics simulations for V2R and its V1aR‐analog give an excellent correlation with experimental binding free energies by assuming that the most stable binding site in the simulations corresponds to the experimental binding free energy in each case. The resulting three‐site mechanism separates agonists from antagonists and explains subtype selectivity. Three distinct binding sites are revealed by molecular‐dynamics simulations with metadynamics enhanced sampling for arginine vasopressin (AVP) within its V2 receptor (V2R). Two of these, the vestibule (magenta) and intermediate (green) sites, block (antagonize) the receptor, and the third is the orthosteric activation (agonist) site (blue). The resulting three‐site mechanism separates agonists from antagonists and explains subtype selectivity.