Download MendeleyCrystal structure of opsin in its G-protein-interacting conformation
Scheerer, P., Park, J.H., Hildebrand, P.W., Kim, Y.J., Krauss, N., Choe, H.-W., Hofmann, K.P., Ernst, O.P.(2008) Nature 455: 497-502
- PubMed: 18818650
- DOI: https://doi.org/10.1038/nature07330
- Primary Citation of Related Structures:
3DQB - PubMed Abstract:
Opsin, the ligand-free form of the G-protein-coupled receptor rhodopsin, at low pH adopts a conformationally distinct, active G-protein-binding state known as Ops*. A synthetic peptide derived from the main binding site of the heterotrimeric G protein-the carboxy terminus of the alpha-subunit (GalphaCT)-stabilizes Ops*. Here we present the 3.2 A crystal structure of the bovine Ops*-GalphaCT peptide complex. GalphaCT binds to a site in opsin that is opened by an outward tilt of transmembrane helix (TM) 6, a pairing of TM5 and TM6, and a restructured TM7-helix 8 kink. Contacts along the inner surface of TM5 and TM6 induce an alpha-helical conformation in GalphaCT with a C-terminal reverse turn. Main-chain carbonyl groups in the reverse turn constitute the centre of a hydrogen-bonded network, which links the two receptor regions containing the conserved E(D)RY and NPxxY(x)(5,6)F motifs. On the basis of the Ops*-GalphaCT structure and known conformational changes in Galpha, we discuss signal transfer from the receptor to the G protein nucleotide-binding site.
Organizational Affiliation:
Institut für Medizinische Physik und Biophysik (CC2), Charité - Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany.
