Three Dimensional Structure-Based Genetic Modifications of A Bacterial Cytochrome bc1 Complex

Abstract

The ubihydroquinone: cytochromec oxidoreductase (cyt bc1 complex) is a major membrane protein complex present in many organisms including bacteria, mitochondria, and chloroplast (called plastohydroquinone: plastocyanin oxidoreductase or cyt b6f complex). This energy transducing complex is part of respiratory and photosynthetic electron transfer chains, and contribute to the formation of membrane potential and proton gradient, subsequently coupled to ATP synthesis (1–3). In phototrophic bacteria, the cyt bc1 complex oxidizes ubihydroquinone (UQH2) and reduces the soluble cyt c 2 and the membrane-attached c y acting as electron carriers to the reaction center in photosynthesis, or to the cyt c oxidase during respiration. The chloroplast cyt b6f complex on the other hand, transfers electrons between the photosystem II and I Using plastoquinone and plastocyanine as electron donor and acceptor, respectivley. Recently, a third kind of cyt bc complex somewhat similar to the cyt b6f complex was discovered in Gram+ bacteria (4).