title: Binding and photocleavage of cationic porphyrin-phenylpiperazine hybrids to DNA.
abstract: The binding properties of cationic porphyrin-phenylpiperazine hybrids to calf thymus (CT) DNA were investigated by using absorption, fluorescence and circular dichroism (CD) spectra, and the apparent affinity binding constants (K(app)) of the porphyrins for CT DNA were determined by using a competition method with ethidium bromide (EB). Intercalation of porphyrin into CT DNA occurred when two phenylpiperazines were introduced at cis position onto the periphery of cationic porphyrin. The photocleavages of pBR322 plasmid DNA by the porphyrins were consistent with the values of K(app). With [porphyrin]/[DNA base pairs] ratio increased, the binding mode tended to be outside binding, and the cleavage abilities of the porphyrins varied. In the presence of sodium azide, a quencher of 1O2, the cleavage of DNA by the porphyrin of intercalation was less inhibited.
authors.affiliation: College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, Hubei, PR China.
authors.forename: Tao
authors.initials: T
authors.lastname: Jia
authors.forename: Zhong-Xing
authors.initials: ZX
authors.lastname: Jiang
authors.forename: Kai
authors.initials: K
authors.lastname: Wang
authors.forename: Zao-Ying
authors.initials: ZY
authors.lastname: Li
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002412:Cations / Q000737:chemistry*; D002417:Cattle; D002678:Chimera; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects; D004996:Ethidium / Q000494:pharmacology; D005453:Fluorescence; D007202:Indicators and Reagents / Q000378:metabolism; D007364:Intercalating Agents / Q000494:pharmacology; D007700:Kinetics; D008027:Light; D015394:Molecular Structure; D010879:Piperazines / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects; D010957:Plasmids; D011166:Porphyrins / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects; D019810:Sodium Azide / Q000494:pharmacology; D013050:Spectrometry, Fluorescence; D014466:Ultraviolet Rays
chemical_list: D002412:Cations; D007202:Indicators and Reagents; D007364:Intercalating Agents; D010879:Piperazines; D011166:Porphyrins; D004247:DNA; C427203:calf thymus DNA; D019810:Sodium Azide; D004996:Ethidium; C031503:phenylpiperazine