title: Determination of a molecular torsional angle in the metarhodopsin-I photointermediate of rhodopsin by double-quantum solid-state NMR.
abstract: We present a solid-state NMR study of metarhodopsin-1, the pre-discharge intermediate of the photochemical signal transduction cascade of rhodopsin, which is the 41 kDa integral membrane protein that triggers phototransduction in vertebrate rod cells. The H-C10-C11-H torsional angles of the retinylidene chromophore in bovine rhodopsin and metarhodopsin-I were determined simultaneously in the photo-activated membrane-bound state, using double-quantum heteronuclear local field spectroscopy. The torsional angles were estimated to be [phi] = 160+/-10 degrees for rhodopsin and phi = 180+/-25 degrees for metarhodopsin-I. The result is consistent with current models of the photo-induced conformational transitions in the chromophore, in which the 11-Z retinal ground state is twisted, while the later photointermediates have a planar all-E conformation.
authors.affiliation: Physical Chemistry Division, Arrhenlius Laboratory, Stockholm University, Sweden.
authors.forename: X
authors.initials: X
authors.lastname: Feng
authors.forename: P J
authors.initials: PJ
authors.lastname: Verdegem
authors.forename: M
authors.initials: M
authors.lastname: Edén
authors.forename: D
authors.initials: D
authors.lastname: Sandström
authors.forename: Y K
authors.initials: YK
authors.lastname: Lee
authors.forename: P H
authors.initials: PH
authors.lastname: Bovee-Geurts
authors.forename: W J
authors.initials: WJ
authors.lastname: de Grip
authors.forename: J
authors.initials: J
authors.lastname: Lugtenburg
authors.forename: H J
authors.initials: HJ
authors.lastname: de Groot
authors.forename: M H
authors.initials: MH
authors.lastname: Levitt
mesh_terms: D000818:Animals; D002417:Cattle; D008027:Light; D008956:Models, Chemical; D008968:Molecular Conformation; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D012176:Retinoids / Q000737:chemistry / Q000528:radiation effects; D012243:Rhodopsin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000528:radiation effects; D015398:Signal Transduction
chemical_list: D012176:Retinoids; C121835:retinylidene chromophore; C013110:metarhodopsins; D012243:Rhodopsin