title: Vibronic Dynamics of the Ultrafast all-trans to 13-cis Photoisomerization of Retinal in Channelrhodopsin-1.
abstract: Channelrhodopsins are light-gated ion channels with extensive applications in optogenetics. Channelrhodopsin-1 from Chlamydomonas augustae (CaChR1) exhibits a red-shifted absorption spectrum as compared to Channelrhodopsin-2, which is highly beneficial for optogenetic application. The primary event in the photocycle of CaChR1 involves an isomerization of the protein-bound retinal chromophore. Here, we apply highly time-resolved vibronic spectroscopy to reveal the electronic and structural dynamics associated with the first step of the photocycle of CaChR1. We observe vibrationally coherent formation of the P1 intermediate exhibiting a twisted 13-cis retinal with a 110 ± 7 fs time constant. Comparison with low-temperature resonance Raman spectroscopy of the corresponding trapped photoproduct demonstrates that this rapidly formed P1 intermediate is stable for several hundreds of nanoseconds.
authors.affiliation: Physical and Theoretical Chemistry Laboratory, University of Oxford , South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors.forename: Christoph
authors.initials: C
authors.lastname: Schnedermann
authors.forename: Vera
authors.initials: V
authors.lastname: Muders
authors.forename: David
authors.initials: D
authors.lastname: Ehrenberg
authors.forename: Ramona
authors.initials: R
authors.lastname: Schlesinger
authors.affiliation: Physical and Theoretical Chemistry Laboratory, University of Oxford , South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors.forename: Philipp
authors.initials: P
authors.lastname: Kukura
authors.forename: Joachim
authors.initials: J
authors.lastname: Heberle
mesh_terms: D002696:Chlamydomonas / Q000737:chemistry; D007536:Isomerism; D055668:Photochemical Processes; D010940:Plant Proteins / Q000737:chemistry; D012172:Retinaldehyde / Q000737:chemistry*; D012243:Rhodopsin / Q000737:chemistry*; D013059:Spectrum Analysis, Raman
chemical_list: D010940:Plant Proteins; D012243:Rhodopsin; D012172:Retinaldehyde