DC photoelectric signals from bacteriorhodopsin adsorbed on lipid monolayers and thiol/lipid bilayers supported by mercury.
Purple membrane (PM) fragments were adsorbed on a dioleoylphosphatidylcholine (DOPC) monolayer and on a mixed alkanethiol/DOPC bilayer supported by mercury to investigate the kinetics of light-driven proton transport by bacteriorhodopsin (bR). The light-on and light-off capacitive currents on an alkanethiol/DOPC bilayer at pH 6.4 were interpreted on the basis of a simple equivalent circuit. The pH dependence of the biphasic decay kinetics of the light-on currents was analyzed to estimate the pK(a) values for the transitions releasing protons to, and taking up protons from, the solution. The linear dependence of the stationary light-on current of bR on a DOPC monolayer self-assembled on mercury upon the applied potential was interpreted on the basis of an equivalent circuit.
Dolfi
Andrea
A
Department of Chemistry, University of Florence, Via della Lastruccio 3, 50019 Sesto Fiorentino, Florence, Italy.
Tadini Buoninsegni
Francesco
F
Moncelli
Maria Rosa
MR
Guidelli
Rolando
R
D000327:Adsorption; D001436:Bacteriorhodopsins / Q000737:chemistry*; D008051:Lipid Bilayers; D008628:Mercury / Q000737:chemistry*; D010713:Phosphatidylcholines / Q000737:chemistry*
D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D001436:Bacteriorhodopsins; C017251:1,2-oleoylphosphatidylcholine; D008628:Mercury