Objectif Upon binding an agonist, the seven transmembrane (TM) helical bundle of a G-protein coupled receptor (GPCR) undergoes conformational changes that catalyze nucleotide exchange within bound G proteins. In rhodopsin, the agonist arises from light-induced isomerization of the retinal ligand, but an active conformation (Ops*) can also be adopted by the opsin apoprotein. We recently solved the structure of Ops* in complex with a peptide from the C-terminal ±-5 helix of the G protein. Considering this structure and previous work, we postulate a mechanism by which the 40 Å gap between the retinal and the nucleotide binding site is bridged. First, TM5 and TM6 engage in new interactions to form a mitt-like structure into which the G-protein ±-5 helix can bind. Second, the bound ±-5 helix switches into a new position, thereby acting as a transmission rod to the nucleotide binding site. In the proposed project, we will test this mechanism and explore the underlying protein dynamics by: - determining the structure of the receptor in complex with longer peptides, and if possible, with the G holoprotein, - measuring conformational changes on the timescale of receptor activation (ms) and expand computational modelling of the respective transitory complexes, - determining the underlying backbone dynamics and fluctuations on the ps-ns time scale by experimentation and molecular dynamics. Some of the necessary methodologies are available, while others must be developed or made available through collaborations. Rhodopsin is the ideal model system for studying signal transduction mechanisms. Our novel multi-prong approach, while risky, will enormously improve our understanding of GPCR signalling mechanisms. The insights gained will be significant for receptor-directed drug development. Champ scientifique medical and health sciencesbasic medicinepharmacology and pharmacydrug discoverynatural sciencesbiological sciencesbiochemistrybiomoleculesproteinsmedical and health sciencesclinical medicineophthalmologynatural sciencesbiological sciencesgeneticsnucleotides Programme(s) FP7-IDEAS-ERC - Specific programme: "Ideas" implementing the Seventh Framework Programme of the European Community for research, technological development and demonstration activities (2007 to 2013) Thème(s) ERC-AG-LS1 - ERC Advanced Grant - Molecular and Structural Biology and Biochemistry Appel à propositions ERC-2009-AdG Voir d’autres projets de cet appel Régime de financement ERC-AG - ERC Advanced Grant Institution d’accueil CHARITE - UNIVERSITAETSMEDIZIN BERLIN Contribution de l’UE € 2 449 840,00 Adresse Chariteplatz 1 10117 Berlin Allemagne Voir sur la carte Région Berlin Berlin Berlin Type d’activité Higher or Secondary Education Establishments Chercheur principal Klaus Peter Hofmann (Prof.) Contact administratif Martina Eickmann (Ms.) Liens Contacter l’organisation Opens in new window Site web Opens in new window Coût total Aucune donnée Bénéficiaires (1) Trier par ordre alphabétique Trier par contribution de l’UE Tout développer Tout réduire CHARITE - UNIVERSITAETSMEDIZIN BERLIN Allemagne Contribution de l’UE € 2 449 840,00 Adresse Chariteplatz 1 10117 Berlin Voir sur la carte Région Berlin Berlin Berlin Type d’activité Higher or Secondary Education Establishments Chercheur principal Klaus Peter Hofmann (Prof.) Contact administratif Martina Eickmann (Ms.) Liens Contacter l’organisation Opens in new window Site web Opens in new window Coût total Aucune donnée