title: Tricationic pyridium porphyrins appending different peripheral substituents: experimental and DFT studies on their interactions with DNA.
abstract: Four tricationic pyridium porphyrins appending hydroxyphenyl, methoxyphenyl, propionoxyphenyl or carboxyphenyl group at meso-20-position of porphyrin core have been synthesized and their abilities to bind and cleave DNA have been investigated. Using a combination of absorption, fluorescence, circular dichroism (CD) spectra, thermal DNA denaturation as well as viscosity measurements, their binding modes and intrinsic binding constants (K(b)) to calf DNA (CT DNA) were comparatively studied and also compared with those of 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin (TMPyP). The results suggest that the K(b) values of these porphyrins are greatly influenced by the number of positive charges and steric hindrance. Theoretical calculations applying the density functional theory (DFT) have been carried out and explain their DNA-binding properties reasonably. The efficiency of DNA photocleavage by these porphyrins shows high dependence on the values of K(b).
authors.affiliation: MOE Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou, PR China.
authors.forename: Ping
authors.initials: P
authors.lastname: Zhao
authors.forename: Lian-Cai
authors.initials: LC
authors.lastname: Xu
authors.forename: Jin-Wang
authors.initials: JW
authors.lastname: Huang
authors.forename: Kang-Cheng
authors.initials: KC
authors.lastname: Zheng
authors.forename: Bo
authors.initials: B
authors.lastname: Fu
authors.forename: Han-Cheng
authors.initials: HC
authors.lastname: Yu
authors.forename: Liang-Nian
authors.initials: LN
authors.lastname: Ji
mesh_terms: D001667:Binding, Competitive; D002942:Circular Dichroism; D003198:Computer Simulation; D004247:DNA / Q000737:chemistry*; D015394:Molecular Structure; D009691:Nucleic Acid Denaturation; D010782:Photolysis; D011166:Porphyrins / Q000138:chemical synthesis / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D011789:Quantum Theory; D013050:Spectrometry, Fluorescence; D013696:Temperature; D014783:Viscosity
chemical_list: D011166:Porphyrins; D011725:Pyridines; D004247:DNA