title: Transient absorption and photovoltage study of' self-assembled bacteriorhodopsin/polycation multilayer films.
abstract: A series of organized (PDAC/PM)(n) (poly(diallyldimethylammonium chloride)/purple membrane) multilayer films were prepared by alternate adsorptions of positively charged PDAC polyelectrolyte and negatively charged purple membrane (PM). The kinetics of the photocycle of bacteriorhodopsin (bR) in PM was studied by flash photolysis and transient photovoltage methods. Although the orientation of the adsorbed bR depends on the pH of the PM suspension, the kinetics of the photo-induced reaction cycle in dehydrated films is independent of the deposition pH. In dry (PDAC/PM)(n) films the decay of the M intermediate to the initial bR state is multiexponential and delayed to several minutes for both orientations. A simultaneous two-exponential decay in millisecond time domain was observed at red wavelengths. The source of the red-shifted absorption is suggested to be the C(610) intermediate of the cis photocycle of bR.
authors.affiliation: Institute of Materials Chemistry, Tampere University of Technology, PO Box 541, 33101, Tampere, Finland. tapio.jussila@tut.fi
authors.forename: Tapio
authors.initials: T
authors.lastname: Jussila
authors.forename: Meiling
authors.initials: M
authors.lastname: Li
authors.forename: Nikolai V
authors.initials: NV
authors.lastname: Tkachenko
authors.forename: Sinikka
authors.initials: S
authors.lastname: Parkkinen
authors.forename: Baofang
authors.initials: B
authors.lastname: Li
authors.forename: Long
authors.initials: L
authors.lastname: Jiang
authors.forename: Helge
authors.initials: H
authors.lastname: Lemmetyinen
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D025802:Electric Capacitance; D004563:Electrochemistry; D004574:Electromagnetic Fields; D006863:Hydrogen-Ion Concentration; D008027:Light; D008422:Materials Testing / Q000379:methods*; D008567:Membranes, Artificial; D008956:Models, Chemical; D010777:Photochemistry / Q000379:methods*; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D020099:Coated Materials, Biocompatible; D008567:Membranes, Artificial; D001436:Bacteriorhodopsins