Charge recombination kinetics as a probe of protonation of the primary acceptor in photosynthetic reaction centers.
The kinetics of the charge recombination D+QA-----DQA was used to probe the protonation of the primary acceptor in reaction centers from Rhodopseudomonas sphaeroides, in which the native ubiquinone was replaced by anthraquinone. We found that QA- is stabilized by the rapid (t less than 10(-2) s) binding of a proton, with a pK of 9.8. The distance between QA- and the proton binding site was estimated to be larger than approximately 5 A.
D001426:Bacterial Proteins / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008433:Mathematics; D008954:Models, Biological; D045322:Photosynthetic Reaction Center Complex Proteins; D012242:Rhodobacter sphaeroides / Q000378:metabolism*
D001426:Bacterial Proteins; D045322:Photosynthetic Reaction Center Complex Proteins