Energy transduction and electron carrier protein in Rhodobacter capsulatus

Living organisms are required to convert various forms of energies for their survival. A variety of bacteria and mitochondria contain enzymes that catalyze respiration by using molecular oxygen as the terminal electron acceptor. These oligomeric, cytochrome (cyt) containing enzyme complexes are embedded into the inner mitochondrial membrane or bacterial plasma membrane. Electron Transfer (ET) pathways contain several membrane associated multi subunit pigment proteins that are connected to each other by electron carrier proteins. Rhodobacter species are universally accepted model organisms for studies on energy transduction. Among them, R. capsulatus has various energy transduction modes including anoxygenic photosynthesis and several types of respiration. Although these have been studied over fifty years a complete knowledge of their ET pathways still lacks and many outstanding questions related especially to cytochromes their structure function and assembly remain unanswered. Towards this aim R. capsulatus cyt cbb(3) oxidase and cyt c(y) formed the focus of recent research expected to help us to understand their importance during evolution.