Time constant for recombination of (P(Primary electron donor))+ and QuinoneB-

Value 0.3 sec^-1
Organism Bacteria Rhodobacter sphaeroides
Reference Francia F, Dezi M, Rebecchi A, Mallardi A, Palazzo G, Melandri BA, Venturoli G. Light-harvesting complex 1 stabilizes P+QB- charge separation in reaction centers of Rhodobacter sphaeroides. Biochemistry. 2004 Nov 943(44):14199-210PubMed ID15518570
Method The kinetics of charge recombination following photoexcitation by a laser pulse have been analyzed in the reaction center-light harvesting complex 1 (RC-LH1) purified from the photosynthetic bacterium Rhodobacter sphaeroides.
Comments Within the RC complex, direct photon absorption or energy transfer from LH1 promotes the primary electron donor P (a special pair of bacteriochloropylls) to the first excited singlet state P*. In RC-LH1 core complexes isolated from photosynthetically grown cells P(+)Q(B)(-) recombines with an average rate constant, k approximately 0.3 s(-1), more than three times smaller than that measured in RC deprived of the LH1 (k approximately 1 s(-1)).
Entered by Uri M
ID 104477