Site-directed mutagenesis of photosynthetic reaction centers

Recent progress in the isolation and characterization of site-directed mutants of several points the reaction centers of the purple non-sulfur photosynthetic bacteria and of photosystem II has led to an improved understanding of several points: the reasons for the unidirectionality of electron transfer along only one of two branches of reaction-center cofactors; the mechanism by which proton and electron transfers are coupled during reduction of the secondary quinone electron acceptor to the quinol; and, the location and role of amino acid residues involved in donor-side electron-transfer reactions in photosystem II.