title: Cytochrome c6-like protein as a putative donor of electrons to photosystem I in the cyanobacterium Nostoc sp. PCC 7119.
abstract: Most organisms performing oxygenic photosynthesis contain either cytochrome c(6) or plastocyanin, or both, to transfer electrons from cytochrome b(6)-f to photosystem I. Even though plastocyanin has superseded cytochrome c(6) along evolution, plants contain a modified cytochrome c(6), the so called cytochrome c(6A), whose function still remains unknown. In this article, we describe a second cytochrome c(6) (the so called cytochrome c(6)-like protein), which is found in some cyanobacteria but is phylogenetically more related to plant cytochrome c(6A) than to cyanobacterial cytochrome c(6). In this article, we conclude that the cytochrome c(6)-like protein is a putative electron donor to photosystem I, but does play a role different to that of cytochrome c(6) and plastocyanin as it cannot accept electrons from cytochrome f. The existence of this third electron donor to PSI could explain why some cyanobacteria are able to grow photoautotrophically in the absence of both cytochrome c(6) and plastocyanin. In any way, the Cyt c(6)-like protein from Nostoc sp. PCC 7119 would be potentially utilized for the biohydrogen production, using cell-free photosystem I catalytic nanoparticles.
authors: Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla y CSIC, Américo Vespucio 49, 41092 Sevilla, Spain.
authors: Francisco M
authors: FM
authors: Reyes-Sosa
authors: Jorge
authors: J
authors: Gil-Martínez
authors: Fernando P
authors: FP
authors: Molina-Heredia
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003001:Cloning, Molecular; D045365:Cytochromes c6 / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004269:DNA, Bacterial / Q000737:chemistry; D004579:Electron Transport; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008027:Light; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046937:Nostoc / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D010084:Oxidation-Reduction; D010788:Photosynthesis / Q000502:physiology; D045331:Photosystem I Protein Complex / Q000378:metabolism*; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D045365:Cytochromes c6; D004269:DNA, Bacterial; D045331:Photosystem I Protein Complex