title: pH-sensitive fluorescent dye as probe for proton uptake in photosynthetic reaction centers.
abstract: Isolated and purified reaction centers (RC) from Rhodobacter sphaeroides R-26.1 were solubilised in detergent with excess quinone and external electron donors and illuminated in the presence of pyranine. The pH change accompanying the reaction center photocycle was monitored by recording the variation of the pyranine fluorescence intensity. Using Q(B)-depleted reaction centers or blocking the photocycle with terbutryne strongly reduced the pH change. The usefulness and limits of this technique in monitoring the pH changes during the RC photocycle are also discussed.
authors.affiliation: Istituto per i Processi Chimico-Fisici, Sezione di Bari, I-70126 Bari, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Agostiano
authors.forename: F
authors.initials: F
authors.lastname: Mavelli
authors.forename: F
authors.initials: F
authors.lastname: Milano
authors.forename: L
authors.initials: L
authors.lastname: Giotta
authors.forename: M
authors.initials: M
authors.lastname: Trotta
authors.forename: L
authors.initials: L
authors.lastname: Nagy
authors.forename: P
authors.initials: P
authors.lastname: Maroti
mesh_terms: D001190:Arylsulfonates; D004307:Dose-Response Relationship, Radiation; D005456:Fluorescent Dyes; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008027:Light; D010777:Photochemistry / Q000379:methods*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000032:analysis / Q000737:chemistry* / Q000528:radiation effects*; D011522:Protons; D011874:Radiometry / Q000379:methods; D012242:Rhodobacter sphaeroides / Q000378:metabolism*; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D001190:Arylsulfonates; D005456:Fluorescent Dyes; D045322:Photosynthetic Reaction Center Complex Proteins; D011522:Protons; C005047:pyranine