title: An investigation of the electrochemical cycle of bacteriorhodopsin analogs with the modified ring.
abstract: 5,6-Epoxy-, 4-methoxy-, 4-hydroxy-, and 3,4-dehydrobacteriorhodopsins can generate delta psi coupled to a photochemical cycle with intermediate M. The kinetics of delta psi comprises three main electrogenic phases: the fast small negative, the microsecond, and the millisecond positive phases. The photocycle efficiency is lower in all the analogs. The photocycle is modified insignificantly only in 3,4-dehydrobacteriorhodopsin. In the other pigments the decay of the flash-induced bleaching in the chromophore main absorption band is slower than the decay of M or long-wave intermediates, especially in the 4-hydroxy analog. In the latter analog, such distinctions, according to delta pH measurements, are partly due to deceleration of the decay of the novel intermediate (P). In 5,6-epoxybacteriorhodopsin, at all wavelengths, the decay of the intermediates takes seconds upon M formation. According to our and literature data, no bacteriorhodopsin analogs are known to have a cycle which preserves the M-intermediate and does not transport a proton.
authors.affiliation: A.N. Belozersky Laboratory of Molecular Biology and Bioorganic Chemistry, Moscow State University, USSR.
authors.forename: L A
authors.initials: LA
authors.lastname: Drachev
authors.forename: A L
authors.initials: AL
authors.lastname: Drachev
authors.forename: L N
authors.initials: LN
authors.lastname: Chekulaeva
authors.forename: R P
authors.initials: RP
authors.lastname: Evstigneeva
authors.forename: A D
authors.initials: AD
authors.lastname: Kaulen
authors.forename: L V
authors.initials: LV
authors.lastname: Khitrina
authors.forename: A A
authors.initials: AA
authors.lastname: Khodonov
authors.forename: Z R
authors.initials: ZR
authors.lastname: Lazarova
authors.forename: B I
authors.initials: BI
authors.lastname: Mitsner
mesh_terms: D001436:Bacteriorhodopsins / Q000031:analogs & derivatives / Q000032:analysis / Q000528:radiation effects*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007834:Lasers; D010777:Photochemistry; D011522:Protons; D012172:Retinaldehyde / Q000031:analogs & derivatives / Q000032:analysis / Q000528:radiation effects*; D012176:Retinoids / Q000528:radiation effects*
chemical_list: D011522:Protons; D012176:Retinoids; D001436:Bacteriorhodopsins; C017184:dehydroretinal; D012172:Retinaldehyde