Synthesis, characterization, and DNA binding and cleavage properties of copper(II)-tryptophanphenyl-alanine-1,10-phenanthroline/2,2'-bipyridine complexes.
The mononuclear dipeptide-based Cu(II) complexes [Cu(II) (trp-phe)(phen)(H₂O)] ⋅ ClO₄ (1) and [Cu(II) (trp-phe)(bpy)(H₂O)] ⋅ ClO₄ (2) (trp-phe=tryptophanphenylalanine, phen=1,10-phenanthroline, bpy=2,2'-bipyridine) were isolated, and their interaction with DNA was studied. They exhibit intercalative mode of interaction with DNA. The intercalative interaction was quantified by Stern-Volmer quenching constant (K(sq) =0.14 for 1 and 0.08 for 2). The Cu(II) complexes convert supercoiled plasmid DNA into its nicked circular form hydrolytically at physiological conditions at a concentration as low as 5 μM (for 1) and 10 μM (for 2). The DNA hydrolysis rates at a complex concentration of 50 μM were determined as 1.74 h(-1) (R=0.985) for 1 and 0.65 h(-1) (R=0.965) for 2. The rate enhancement in the range of 2.40-4.10×10⁷-fold compared to non-catalyzed double-stranded DNA is significant. This was attributed to the presence of a H(2) O molecule in the axial position of the Cu complexes.
Department of Chemistry, Osmania University, Hyderabad, India. rabi_pr@rediffmail.com
Pulimamidi R
PR
Reddy
Nomula
N
Raju
Battu
B
Satyanarayana
D015082:2,2'-Dipyridyl / Q000737:chemistry*; D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D003300:Copper / Q000737:chemistry*; D004247:DNA / Q000378:metabolism*; D053837:DNA Cleavage; D004578:Electron Spin Resonance Spectroscopy; D010618:Phenanthrolines / Q000737:chemistry*; D010957:Plasmids / Q000737:chemistry; D013055:Spectrophotometry, Infrared
D056831:Coordination Complexes; D010618:Phenanthrolines; D015082:2,2'-Dipyridyl; D003300:Copper; D004247:DNA; C025205:1,10-phenanthroline