Kinetics and mechanism of electron transfer in intact photosystem II and in the isolated reaction center: pheophytin is the primary electron acceptor.

ABSTRACT: The mechanism and kinetics of electron transfer in isolated D1/D2-cyt(b559) photosystem (PS) II reaction centers (RCs) and in intact PSII cores have been studied by femtosecond transient absorption and kinetic compartment modeling. For intact PSII, a component of approximately 1.5 ps reflects the dominant energy-trapping kinetics from the antenna by the RC. A 5.5-ps component reflects the apparent lifetime of primary charge separation, which is faster by a factor of 8-12 than assumed so far. The 35-ps component represents the apparent lifetime of formation of a secondary radical pair, and the approximately 200-ps component represents the electron transfer to the Q(A) acceptor. In isolated RCs, the apparent lifetimes of primary and secondary charge separation are approximately 3 and 11 ps,

SUBMITTER: Holzwarth AR 

PROVIDER: S-EPMC1458990 | biostudies-literature | 2006 May

REPOSITORIES: biostudies-literature