The position of QB in the photosynthetic reaction center depends on pH: a theoretical analysis of the proton uptake upon QB reduction.

ABSTRACT: Electrostatics-based calculations have been performed to examine the proton uptake upon reduction of the terminal electron acceptor Q(B) in the photosynthetic reaction center of Rhodobacter sphaeroides as a function of pH and the associated conformational equilibrium. Two crystal structures of the reaction center were considered: one structure was determined in the dark and the other under illumination. In the two structures, the Q(B) was found in two different positions, proximal or distal to the nonheme iron. Because Q(B) was found mainly in the distal position in the dark and only in the proximal position under illumination, the two positions have been attributed mostly to the oxidized and the reduced forms of Q(B), respectively. We calculated the proton uptake upon Q(B) reduction by fo

SUBMITTER: Taly A 

PROVIDER: S-EPMC1302777 | biostudies-literature | 2003 Mar

REPOSITORIES: biostudies-literature