title: Sensory rhodopsin I photocycle intermediate SRI380 contains 13-cis retinal bound via an unprotonated Schiff base.
abstract: Sensory rhodopsin I (SRI), the mutated derivative SRI-D76N and the complex of SRI with its transducer HtrI were overexpressed in Halobacterium salinarium and analyzed by resonance Raman spectroscopy. In the initial state SRI contains all-trans retinal bound via a protonated Schiff base as confirmed by retinal extraction which yields 95 +/- 3% all-trans retinal. The photocycle intermediate absorbing maximally at 380 nm (SRI380) contains a Schiff base linkage between the protein and 13-cis retinal. Extraction of illuminated SRI yields up to 93% 13-cis retinal. Neither the mutation D76N nor HtrI changed the vibrational pattern of the chromophore.
authors.affiliation: Max-Planck Institut für Biochemie, Martinsried, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Haupts
authors.forename: W
authors.initials: W
authors.lastname: Eisfeld
authors.forename: M
authors.initials: M
authors.lastname: Stockburger
authors.forename: D
authors.initials: D
authors.lastname: Oesterhelt
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry*; D006217:Halobacterium; D025602:Halorhodopsins; D012172:Retinaldehyde / Q000737:chemistry*; D012545:Schiff Bases / Q000737:chemistry; D025603:Sensory Rhodopsins; D013059:Spectrum Analysis, Raman
chemical_list: D025602:Halorhodopsins; C061497:SRI protein, Halobacterium; D012545:Schiff Bases; D025603:Sensory Rhodopsins; D001436:Bacteriorhodopsins; D012172:Retinaldehyde