title: Site-specific solid-state NMR detection of hydrogen-deuterium exchange reveals conformational changes in a 7-helical transmembrane protein.
abstract: Solid-state NMR spectroscopy is an efficient tool for following conformational dynamics of membrane proteins at atomic resolution. We used this technique for the site-specific detection of light-induced hydrogen-deuterium exchange in the lipid-embedded heptahelical transmembrane photosensor Anabaena sensory rhodopsin to pinpoint the location of its conformational changes upon activation. We show that the light-induced conformational changes result in a dramatic, but localized, increase in the exchange in the transmembrane regions. Most notably, the cytoplasmic half of helix G and the cytoplasmic ends of helices B and C exchange more extensively, probably as a result of their relative displacement in the activated state, allowing water to penetrate into the core of the protein. These light-induced rearrangements must provide the structural basis for the photosensory function of Anabaena sensory rhodopsin.
authors.affiliation: Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Shenlin
authors.initials: S
authors.lastname: Wang
authors.forename: Lichi
authors.initials: L
authors.lastname: Shi
authors.forename: Izuru
authors.initials: I
authors.lastname: Kawamura
authors.forename: Leonid S
authors.initials: LS
authors.lastname: Brown
authors.forename: Vladimir
authors.initials: V
authors.lastname: Ladizhansky
mesh_terms: D017033:Anabaena; D001426:Bacterial Proteins / Q000737:chemistry*; D041961:Deuterium Exchange Measurement; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D017433:Protein Structure, Secondary; D012243:Rhodopsin / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D012243:Rhodopsin