Article

Agonist-bound structures of G protein-coupled receptors

Institut de Génomique Fonctionnelle, UMR 5203 CNRS - U 661 INSERM - Univ. Montpellier I & II, 141, rue de la cardonille, 34094 Montpellier Cedex 05, France.
Current Opinion in Structural Biology (Impact Factor: 8.75). 04/2012; 22(4):482-90. DOI: 10.1016/j.sbi.2012.03.007
Source: PubMed

ABSTRACT G protein-coupled receptors (GPCRs) play a major role in intercellular communication by binding small diffusible ligands (agonists) at the extracellular surface. Agonist-binding induces a conformational change in the receptor, which results in the binding and activation of heterotrimeric G proteins within the cell. Ten agonist-bound structures of non-rhodopsin GPCRs published last year defined for the first time the molecular details of receptor activated states and how inverse agonists, partial agonists and full agonists bind to produce different effects on the receptor. In addition, the structure of the β(2)-adrenoceptor coupled to a heterotrimeric G protein showed how the opening of a cleft in the cytoplasmic face of the receptor as a consequence of agonist binding results in G protein coupling and activation of the G protein.

0 Bookmarks
 · 
181 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Crystal structures of G protein-coupled receptors (GPCRs) have recently revealed the molecular basis of ligand binding and activation, which has provided exciting opportunities for structure-based drug design. The A2A adenosine receptor (A2AAR) is a promising therapeutic target for cardiovascular diseases, but progress in this area is limited by the lack of novel agonist scaffolds. We carried out docking screens of 6.7 million commercially available molecules against active-like conformations of the A2AAR to investigate if these structures could guide the discovery of agonists. Nine out of the 20 predicted agonists were confirmed to be A2AAR ligands, but none of these activated the ARs. The difficulties to discover AR agonists using structure-based methods originated from limited atomic-level understanding of the activation mechanism and a chemical bias towards antagonists in the screened library. In particular, the composition of the screened library was found to strongly reduce the likelihood of identifying AR agonists, which reflected the high ligand complexity required for receptor activation. Extension of this analysis to other pharmaceutically relevant GPCRs suggested that library screening may not be suitable for targets requiring a complex receptor-ligand interaction network. Our results provide specific directions for future development of novel A2AAR agonists and general strategies for structure-based drug discovery.
    Journal of Chemical Information and Modeling 01/2015; DOI:10.1021/ci500639g · 4.30 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Activating and inactivating mutations in numerous human G protein-coupled receptors (GPCRs) are associated with a wide range of disease phenotypes. Here we use several class A GPCRs with a particularly large set of identified disease-associated mutations, many of which were biochemically characterized, along with known GPCR structures and current models of GPCR activation, to understand the molecular mechanisms yielding pathological phenotypes. Based on this mechanistic understanding we also propose different therapeutic approaches, both conventional, using small molecule ligands, and novel, involving gene therapy.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The corticotropin releasing factors receptor-1 and receptor-2 (CRF1R and CRF2R) are therapeutic targets for treating neurological diseases. Antagonists targeting CRF1R have been developed for the potential treatment of anxiety disorders and alcohol addiction. It has been found that antagonists targeting CRF1R always show high selectivity, although CRF1R and CRF2R share a very high rate of sequence identity. This has inspired us to study the origin of the selectivity of the antagonists. We have therefore built a homology model for CRF2R and carried out unbiased molecular dynamics and well-tempered metadynamics simulations for systems with the antagonist CP-376395 in CRF1R or CRF2R to address this issue. We found that the side chain of Tyr(6.63) forms a hydrogen bond with the residue remote from the binding pocket, which allows Tyr(6.63) to adopt different conformations in the two receptors and results in the presence or absence of a bottleneck controlling the antagonist binding to or dissociation from the receptors. The rotameric switch of the side chain of Tyr356(6.63) allows the breaking down of the bottleneck and is a perquisite for the dissociation of CP-376395 from CRF1R.
    Scientific Reports 01/2015; 5. DOI:10.1038/srep08066 · 5.08 Impact Factor