An investigation of the electrochemical cycle of bacteriorhodopsin analogs with the modified ring.
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.
Drachev
L A
LA
A.N. Belozersky Laboratory of Molecular Biology and Bioorganic Chemistry, Moscow State University, USSR.
Drachev
A L
AL
Chekulaeva
L N
LN
Evstigneeva
R P
RP
Kaulen
A D
AD
Khitrina
L V
LV
Khodonov
A A
AA
Lazarova
Z R
ZR
Mitsner
B I
BI
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*
D011522:Protons; D012176:Retinoids; D001436:Bacteriorhodopsins; C017184:dehydroretinal; D012172:Retinaldehyde