S. Moltke et al., KINETICS OF LIGHT-INDUCED INTRAMOLECULAR CHARGE-TRANSFER AND PROTON RELEASE IN BACTERIORHODOPSIN, Israel Journal of Chemistry, 35(3-4), 1995, pp. 401-414
Recent advances in understanding the intramolecular charge transfer an
d proton release by the light-driven proton pump bacteriorhodopsin (bR
) are critically reviewed. The focus is on the time-resolved electrica
l methods, i.e., photocurrent and photovoltage measurements, and on tr
ansient absorption experiments with pH-sensitive dyes. Particular atte
ntion is paid to the following topics: charge translocation in the low
-pH forms of bR (acid-blue and acid-purple); electrogenicity of the 13
-cis cycle; results with bR mutants; surface-bound dyes to detect the
proton release at specific sites on either side of the protein; the qu
estion of kinetic coupling between the deprotonation of the Schiff bas
e and proton release: and rapid long-range migration of protons along
the surface of the purple membrane.