title: The chromophore structure of the long-lived intermediate of the C128T channelrhodopsin-2 variant.
abstract: The photocycle of the light-activated channel, channelrhodopsin-2 C128T, has been studied by resonance Raman (RR) spectroscopy focussing on the intermediates P380 and P353 that constitute a side pathway in the recovery of the parent state. The P353 species displays a UV-vis absorption spectrum with a fine-structure reminiscent of the reduced-retro form of bacteriorhodopsin, whereas the respective RR spectra differ substantially. Instead, the RR spectra of the P380/P353 intermediate couple are closely related to that of a free retinal in the all-trans configuration. These findings imply that the parent state recovery via P380/P353 involves the transient hydrolysis and re-formation of the retinal-protein linkage.
authors.affiliation: Technische Universität Berlin, Institut für Chemie, Berlin, Germany.
authors.forename: Sara
authors.initials: S
authors.lastname: Bruun
authors.forename: Hendrik
authors.initials: H
authors.lastname: Naumann
authors.forename: Uwe
authors.initials: U
authors.lastname: Kuhlmann
authors.forename: Claudia
authors.initials: C
authors.lastname: Schulz
authors.forename: Katja
authors.initials: K
authors.lastname: Stehfest
authors.forename: Peter
authors.initials: P
authors.lastname: Hegemann
authors.forename: Peter
authors.initials: P
authors.lastname: Hildebrandt
mesh_terms: D000075402:Channelrhodopsins; D003116:Color; D006801:Humans; D006863:Hydrogen-Ion Concentration; D050505:Mutant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D013059:Spectrum Analysis, Raman
chemical_list: D000075402:Channelrhodopsins; D050505:Mutant Proteins; D009419:Nerve Tissue Proteins