title: [A model of the quinone-binding site of photosystem I: investigation of charge transfer complexes of phylloquinone and its derivatives with tryptophan].
abstract: Phylloquinone (vitamin K1; 2-methyl-3-phytyl-1,4-naphthoquinone), the secondary electron acceptor A1 in photosystem I of plants, algae, and cyanobacteria, mediates the electron transfer between A0 (a monomeric chlorophyll a) and the iron-sulfur cluster Fx. In order to investigate the interaction of vitamin K1 with the A1-binding site, their models on the non-covalent complexes were obtained and studied. The fluorescent properties of vitamin K1, its derivatives, and their complexes with Trp showed a possible role of amino acid components in the formation of a stable energy state, which provides the energy redistribution between oxidized and reduced forms of vitamin K1. The formation of the charge-transfer complex and the influence of the ratio of the components on fluorescence derived from the tryptophan-vitamin K1, tryptophan-dihydrovitamin K1 , tryptophan-quinhydrone K1, and tryptophan-naphthochromanol complexes are described. The data obtained allow us to suggest that naphthochromanol is involved in the energy transfer reaction in PS I as an intermediate form of the secondary electron acceptor.
authors.forename: N M
authors.initials: NM
authors.lastname: Leonova
authors.forename: E E
authors.initials: EE
authors.lastname: Zhukova
authors.forename: R P
authors.initials: RP
authors.lastname: Evstigneeva
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D004579:Electron Transport; D008958:Models, Molecular; D008969:Molecular Sequence Data; D045331:Photosystem I Protein Complex / Q000737:chemistry*; D010944:Plants / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000737:chemistry*; D010837:Vitamin K 1 / Q000737:chemistry*
chemical_list: D045331:Photosystem I Protein Complex; D010837:Vitamin K 1; D014364:Tryptophan