title: DNA-fiber EPR study of the orientation of Cu(II) complexes of 1,10-phenanthroline and its derivatives bound to DNA: mono(phenanthroline)-copper(II) and its ternary complexes with amino acids.
abstract: The orientation of mono(1,10-phenanthroline)copper(II), [Cu(phen)]2+, and the ternary complexes with amino acids, [Cu(phen)X(aa)]n+, where X(aa) stands for an alpha-amino acid, has been investigated by electron paramagnetic resonance (EPR) spectra of the complexes on DNA fibers. It has been revealed that these complexes bind to DNA with several different binding modes. The observation of a species whose g axis is almost parallel to the DNA double helical axis has suggested that the phenanthroline moiety intercalates to DNA. An absence of the intercalated species for the corresponding 2,2'-bipyridine complex has shown that the three-fused aromatic rings in phenanthroline are critical for the intercalative binding of the complexes. The intercalative binding was promoted by 5,6-dimethyl groups on the phenanthroline ring, whereas it was disturbed by 2,9-dimethyl groups, indicating that the planarity of the coordination sphere is important for the intercalative binding. In all cases, the amount of the non-intercalated species was larger than that of the intercalated one. The amino acids in the ternary complexes of glycine, leucine, serine, threonine, cysteine, methionine, and asparagine were partly substituted with some coordinating groups in DNA, whereas the ternary complexes of lysine, arginine, and glutamine remained intact on DNA.
authors.affiliation: Department of Applied Chemistry, Chuo University, Kasuga 1-13-27, Bunkyo-ku, Tokyo 112-8551, Japan. chikira@chem.chuo-u.ac.jp
authors.forename: Makoto
authors.initials: M
authors.lastname: Chikira
authors.forename: Yuji
authors.initials: Y
authors.lastname: Tomizawa
authors.forename: Dai
authors.initials: D
authors.lastname: Fukita
authors.forename: Takashi
authors.initials: T
authors.lastname: Sugizaki
authors.forename: Norikazu
authors.initials: N
authors.lastname: Sugawara
authors.forename: Toru
authors.initials: T
authors.lastname: Yamazaki
authors.forename: Arihiko
authors.initials: A
authors.lastname: Sasano
authors.forename: Heisaburo
authors.initials: H
authors.lastname: Shindo
authors.forename: Mallayan
authors.initials: M
authors.lastname: Palaniandavar
authors.forename: William E
authors.initials: WE
authors.lastname: Antholine
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D003300:Copper / Q000378:metabolism*; D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D010618:Phenanthrolines / Q000737:chemistry* / Q000378:metabolism*; D012474:Salmon; D013696:Temperature
chemical_list: D000596:Amino Acids; D010618:Phenanthrolines; D003300:Copper; D004247:DNA; C025205:1,10-phenanthroline