title: C-type cytochromes in the photosynthetic electron transfer pathways in green sulfur bacteria and heliobacteria.
abstract: Green sulfur bacteria and heliobacteria are strictly anaerobic phototrophs that have homodimeric type 1 reaction center complexes. Within these complexes, highly reducing substances are produced through an initial charge separation followed by electron transfer reactions driven by light energy absorption. In order to attain efficient energy conversion, it is important for the photooxidized reaction center to be rapidly rereduced. Green sulfur bacteria utilize reduced inorganic sulfur compounds (sulfide, thiosulfate, and/or sulfur) as electron sources for their anoxygenic photosynthetic growth. Membrane-bound and soluble cytochromes c play essential roles in the supply of electrons from sulfur oxidation pathways to the P840 reaction center. In the case of gram-positive heliobacteria, the photooxidized P800 reaction center is rereduced by cytochrome c-553 (PetJ) whose N-terminal cysteine residue is modified with fatty acid chains anchored to the cytoplasmic membrane.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Azai
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Tsukatani
authors.forename: Shigeru
authors.initials: S
authors.lastname: Itoh
authors.forename: Hirozo
authors.initials: H
authors.lastname: Oh-oka
mesh_terms: D000595:Amino Acid Sequence; D019414:Chlorobi / Q000378:metabolism*; D003574:Cytochrome c Group / Q000737:chemistry / Q000378:metabolism*; D004579:Electron Transport; D006094:Gram-Positive Bacteria / Q000378:metabolism*; D008969:Molecular Sequence Data; D010788:Photosynthesis
chemical_list: D003574:Cytochrome c Group