Divergent pathways in photobleaching of 7,9-dicis-rhodopsin and 9,11-dicis-12-fluororhodopsin: one-photon-two-bond and one-photon-one-bond isomerization.
Through low-temperature photochemistry, UV/vis spectroscopy, and chromophore extraction experiments, we have established that 7,9-dicis-rhodopsin undergoes one-photon-two-bond photoisomerization to a batho intermediate (its absorption maximum is slightly blue shifted from that of bathorhodopsin) containing the all-trans geometry, while 9,11-dicis-12-fluororhodopsin undergoes one-photon-one-bond isomerization to the corresponding 9-cis isomer and then the all-trans batho intermediate. The difference in the photochemical properties of the two dicis pigment analogs was rationalized by possible local protein perturbation, lability of the 11-cis geometry, and photochemical properties of the chromophores.
Zhu
Y
Y
Department of Chemistry, University of Hawaii, Honolulu 96822.
Liu
R S
RS
D000818:Animals; D002417:Cattle; D003198:Computer Simulation; D007536:Isomerism; D008968:Molecular Conformation; D010777:Photochemistry; D017785:Photons; D012243:Rhodopsin / Q000031:analogs & derivatives* / Q000737:chemistry*; D012374:Rod Cell Outer Segment / Q000378:metabolism; D013053:Spectrophotometry
C083505:9,11-dicis-12-fluororhodopsin; D012243:Rhodopsin