title: Origin of Fluorescence in 11-cis Locked Bovine Rhodopsin.
abstract: The excited state lifetime of bovine rhodopsin (Rh) increases from ca. 100 fs to 85 ps when the C11═C12 bond of its chromophore is locked by a cyclopentene moiety (Rh5). To explain such an increase, we employed ab initio multiconfigurational quantum chemistry to construct computer models of Rh and Rh5 and to investigate the shape of their excited state potential energy surfaces in a comparative way. Our results show that the observed Rh5 fluorescence (λmax(f) = 620 nm) is due to a previously unreported locally excited intermediate whose lifetime is controlled by a small energy barrier. The analysis of the properties and decay path of such an intermediate provides useful information for engineering rhodopsin variants with augmented fluorescence efficiencies.
authors.affiliation: Department of Chemistry, Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States.
authors.forename: Elena N
authors.initials: EN
authors.lastname: Laricheva
authors.affiliation: Department of Chemistry, Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States.
authors.forename: Samer
authors.initials: S
authors.lastname: Gozem
authors.affiliation: Dipartimento di Chimica, Università di Siena, via De Gasperi 2, I-53100 Siena, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Rinaldi
authors.affiliation: Dipartimento di Chimica, Università di Siena, via De Gasperi 2, I-53100 Siena, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Melaccio
authors.affiliation: Dipartimento di Chimica, Università di Siena, via De Gasperi 2, I-53100 Siena, Italy.
authors.forename: Alessio
authors.initials: A
authors.lastname: Valentini
authors.affiliation: Department of Chemistry, Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States.|Dipartimento di Chimica, Università di Siena, via De Gasperi 2, I-53100 Siena, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Olivucci