title: Quasi-elastic Neutron Scattering Reveals Ligand-Induced Protein Dynamics of a G-Protein-Coupled Receptor.
abstract: Light activation of the visual G-protein-coupled receptor (GPCR) rhodopsin leads to significant structural fluctuations of the protein embedded within the membrane yielding the activation of cognate G-protein (transducin), which initiates biological signaling. Here, we report a quasi-elastic neutron scattering study of the activation of rhodopsin as a GPCR prototype. Our results reveal a broadly distributed relaxation of hydrogen atom dynamics of rhodopsin on a picosecond-nanosecond time scale, crucial for protein function, as only observed for globular proteins previously. Interestingly, the results suggest significant differences in the intrinsic protein dynamics of the dark-state rhodopsin versus the ligand-free apoprotein, opsin. These differences can be attributed to the influence of the covalently bound retinal ligand. Furthermore, an idea of the generic free-energy landscape is used to explain the GPCR dynamics of ligand-binding and ligand-free protein conformations, which can be further applied to other GPCR systems.
authors.affiliation: Department of Physics and Astronomy, Wayne State University , Detroit, Michigan 48201, United States.
authors.forename: Utsab R
authors.initials: UR
authors.lastname: Shrestha
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721, United States.
authors.forename: Suchithranga M D C
authors.initials: SMDC
authors.lastname: Perera
authors.affiliation: Department of Physics and Astronomy, Wayne State University , Detroit, Michigan 48201, United States.|Computational Science and Engineering Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
authors.forename: Debsindhu
authors.initials: D
authors.lastname: Bhowmik
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721, United States.
authors.forename: Udeep
authors.initials: U
authors.lastname: Chawla
authors.affiliation: Chemical and Engineering Materials Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
authors.forename: Eugene
authors.initials: E
authors.lastname: Mamontov
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona 85721, United States.|Department of Physics, University of Arizona , Tucson, Arizona 85721, United States.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Brown
authors.affiliation: Department of Physics and Astronomy, Wayne State University , Detroit, Michigan 48201, United States.
authors.forename: Xiang-Qiang
authors.initials: XQ
authors.lastname: Chu