Ubiquinol Formation and Re-Reduction of

With ubiquinone (UQ,q) located at the Qg site, electron transfer occurs from Qa to Qg with a lifetime of approximately 100 mieroseconds (ps) (Okamura and Feher, 1992). Also on a ps time-seale, the P eation is re-redueed by an eleetron donated by the heme of a eytochrome (Mathis, 1994 Wang et al., 1994 Dutton et al 1975 Prince et ah, 1974). In the case of the 

sphaeroides reaction centre, the electron is provided by a cytochrome C2 that docks to the periplasmic face of the reaction centre. In the absence of this reduction of P, the radical pair state recombines to the ground 

Light-Driven Cyciic Eiectron Transfer Coupled to Proton Translocation 

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