Synthesis, characterization, and DNA-binding studies of ruthenium complexes [Ru(tpy)(ptn)]2+ and Ru(dmtpy)(ptn)]2+.
Two ruthenium(II) polypyridyl complexes [Ru(tpy)(ptn)](2+) (1) and Ru(dmtpy)(ptn)](2+) (2) (ptn=3-(1,10-phenanthrolin-2-yl)-as-triazino[5,6-f]naphthalene, tpy=2,2':6',2"-terpyridine, dmtpy=5,5'-dimethyl-2,2':6',2"-terpyridine) have been synthesized and characterized by elemental analysis, (1)H NMR, mass spectrometry and crystal structure analysis. Spectroscopic studies together with isothermal titration calorimetry (ITC) and viscosity measurements prove that two complexes bind to DNA in an intercalative mode. ITC experiments show that the binding mode for complex 2 is entropically driven, while an entropy-driven initial binding of complex 1 is followed by an entropically and enthalpically favorable process. This difference may be attributed to the ancillary ligand effects on the DNA binding of Ru(II) complexes. Circular dichroism titrations of calf thymus DNA (CT-DNA) with Ru(II) complexes show that complexes 1 and 2 induce B to Z conformational transition of calf thymus DNA at low ionic strength (0.05 M NaCl). The induced Z-DNA conformation can revert to B form when Ru(II) complexes are displaced by ethidium bromide or at high ionic strengths ([NaCl]=0.4 M), but keeps intact with temperature ranged from 25 to 90 °C. The unique structure and characteristics of Ru(II) complexes designed in this investigation will be useful for the study of Z-DNA.
MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China.
Lü-Ying
LY
Li
Hai-Na
HN
Jia
Hui-Juan
HJ
Yu
Ke-Jie
KJ
Du
Qi-Tian
QT
Lin
Kang-Qiang
KQ
Qiu
Hui
H
Chao
Liang-Nian
LN
Ji
D000818:Animals; D001665:Binding Sites; D002151:Calorimetry; D002417:Cattle; D002942:Circular Dichroism; D056831:Coordination Complexes / Q000138:chemical synthesis*; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D059371:DNA, B-Form / Q000737:chemistry*; D043542:DNA, Z-Form / Q000737:chemistry*; D004996:Ethidium / Q000737:chemistry; D007364:Intercalating Agents / Q000138:chemical synthesis*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D009994:Osmolar Concentration; D012428:Ruthenium / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D013696:Temperature; D013816:Thermodynamics; D014783:Viscosity
D056831:Coordination Complexes; D059371:DNA, B-Form; D043542:DNA, Z-Form; D007364:Intercalating Agents; D012965:Sodium Chloride; D012428:Ruthenium; D004247:DNA; C427203:calf thymus DNA; D004996:Ethidium