How amino acids control the binding of Cu(II) ions to DNA (II): effect of basic amino acid residues and the chirality on the orientation of the complexes.
The binding structures of bis-lysine and bis-arginine complexes of copper(II) on highly oriented DNA fibers have been investigated by ESR spectroscopy. These complexes bind to DNA in two different modes; species A in one mode has a planar coordination structure as in solution, and species B in the other mode has a distorted planar structure on the DNA. The relative amount of A and B changes with the conformation of the DNA, as well as with the type and chirality of the amino acids. Arginine forms A more than lysine. On A-form DNA fibers, A for L-lysine and L-arginine complexes are bound with the angle theta = 45 degrees between the g// axis and the DNA helical axis, while A and B for the D-isomers are almost randomly oriented. L-arginine fixes the orientation of A on A-form DNA fibers more firmly than L-lysine. On B-form DNA fibers, the orientation of the complexes is modulated dynamically, and the g// axes have a tendency to be reoriented along the fiber axis by the conformational change of the DNA from A- to B-form at room temperature. The D-arginine complex on B-form DNA is peculiar in that it rotates ore freely than the other complexes at room temperature and shows only the A at low temperature.
Chikira
M
M
Department of Applied Chemistry, Chuo University, Tokyo, Japan.
Inoue
M
M
Nagane
R
R
Harada
W
W
Shindo
H
H
D000818:Animals; D001120:Arginine / Q000737:chemistry* / Q000494:pharmacology; D003300:Copper / Q000737:chemistry* / Q000378:metabolism; D004247:DNA / Q000737:chemistry* / Q000187:drug effects; D004578:Electron Spin Resonance Spectroscopy; D006860:Hydrogen Bonding; D008239:Lysine / Q000737:chemistry* / Q000494:pharmacology; D008297:Male; D008961:Models, Structural; D009690:Nucleic Acid Conformation; D012474:Salmon; D013237:Stereoisomerism; D013737:Testis
D003300:Copper; D004247:DNA; D001120:Arginine; D008239:Lysine