Intercalation of bulky Delta,Delta- and Lambda,Lambda-bis-Ru(II) complex between DNA base pairs.
Interaction of Delta,Delta- and Lambda,Lambda-bis-Ru(II) complexes with native DNA was investigated by isotropic absorption and polarized spectroscopy including circular and linear dichroism (CD and LD). Despite the steric hindrance originating from its four bulky phenanthroline ligands at both ends of the molecule, this molecule rapidly intercalates between DNA base pairs. Intercalation was judged by large hypochromism and red shift in the UV-visible absorption spectra in the absorption region of the bridging moiety as well as in the metal-to-ligand-charge transfer absorption region. Further support for the intercalation is found in the fact that the magnitude of negative reduced LD signal in the absorption region of the bridging moiety was comparable to that of the DNA absorption region, indicating that the bridge connecting the two Ru(II) complexes is nearly parallel to the DNA base planes. No difference in the binding mode between the two enantiomers was observed. In the presence of either bis-Ru(II) complex, ethidium bromide, a classical intercalator, can intercalate into the empty sites but was not able to replace the Ru(II) complexes. Near the saturation, ground state interaction between ethidium and bis-Ru(II) complex was evident by LD.
Jang
Yoon Jung
YJ
Department of Chemistry, Yeungnam University, Gyeongsan City, Gyeong-buk 712-749, Republic of Korea.
Kwon
Byung-Hyang
BH
Choi
Byung-Hoon
BH
Bae
Chang Hwan
CH
Seo
Mi Sook
MS
Nam
Wonwoo
W
Kim
Seog K
SK
D020029:Base Pairing; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D007364:Intercalating Agents / Q000138:chemical synthesis / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D017975:Ruthenium Compounds / Q000737:chemistry*; D013057:Spectrum Analysis; D014783:Viscosity
D007364:Intercalating Agents; D009942:Organometallic Compounds; D017975:Ruthenium Compounds; D004247:DNA