title: Barrierless Photoisomerization of 11-cis Retinal Protonated Schiff Base in Solution.
abstract: A hallmark of the primary visual event is the barrierless, ultrafast, and efficient 11-cis to all-trans photoisomerization of the retinal protonated Schiff base (RPSB) chromophore. The remarkable reactivity of RPSB in the visual pigment rhodopsin has been attributed to potential energy surface modifications enabled by evolution-optimized chromophore-protein interactions. Here, we use a combined synthetic and ultrafast spectroscopic approach to show that barrierless photoisomerization is an intrinsic property of 11-cis RPSB, suggesting that the protein may merely adjust the ratio between fast reactive and slow unreactive decay channels. These results call for a re-evaluation of our understanding and theoretical description of RPSB photochemistry.
authors.affiliation: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford , South Parks Road, Oxford OX1 3QZ, U.K.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Bassolino
authors.affiliation: Department of Chemistry, Chemistry Research Laboratory, University of Oxford , Mansfield Road, Oxford OX1 3TA, U.K.
authors.forename: Tina
authors.initials: T
authors.lastname: Sovdat
authors.affiliation: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford , South Parks Road, Oxford OX1 3QZ, U.K.
authors.forename: Alex
authors.initials: A
authors.lastname: Soares Duarte
authors.affiliation: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford , South Parks Road, Oxford OX1 3QZ, U.K.
authors.forename: Jong Min
authors.initials: JM
authors.lastname: Lim
authors.affiliation: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford , South Parks Road, Oxford OX1 3QZ, U.K.
authors.forename: Christoph
authors.initials: C
authors.lastname: Schnedermann
authors.affiliation: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford , South Parks Road, Oxford OX1 3QZ, U.K.
authors.forename: Matz
authors.initials: M
authors.lastname: Liebel
authors.affiliation: Department of Chemistry, Chemistry Research Laboratory, University of Oxford , Mansfield Road, Oxford OX1 3TA, U.K.
authors.forename: Barbara
authors.initials: B
authors.lastname: Odell
authors.affiliation: Department of Chemistry, Chemistry Research Laboratory, University of Oxford , Mansfield Road, Oxford OX1 3TA, U.K.
authors.forename: Timothy D W
authors.initials: TD
authors.lastname: Claridge
authors.affiliation: Department of Chemistry, Chemistry Research Laboratory, University of Oxford , Mansfield Road, Oxford OX1 3TA, U.K.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Fletcher
authors.affiliation: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford , South Parks Road, Oxford OX1 3QZ, U.K.
authors.forename: Philipp
authors.initials: P
authors.lastname: Kukura
mesh_terms: D007536:Isomerism; D015394:Molecular Structure; D010777:Photochemistry; D012172:Retinaldehyde / Q000737:chemistry* / Q000378:metabolism*; D012545:Schiff Bases / Q000737:chemistry*; D012996:Solutions
chemical_list: D012545:Schiff Bases; D012996:Solutions; D012172:Retinaldehyde