A comparative study of the interaction of 5,10,15,20-tetrakis (N-methylpyridinium-4-yl)porphyrin and its zinc complex with DNA using fluorescence spectroscopy and topoisomerisation

作者：John M. Kelly, Martin J. Murphy, David J. McConnell, Cohn OhUigin · 发表于：Nucleic Acids Research · 年份：1985 · DOI：10.1093/nar/13.1.167 · 被引用次数：225 · 研究领域：Porphyrin and Phthalocyanine Chemistry、Porphyrin Metabolism and Disorders、Metal complexes synthesis and properties

Binding of 5,10,15,20-tetrakis (N-methylpyridinium-4-yl)porphyrin (H2TMPyP4+) and its zinc complex (ZnTMPyP4+) to DNA is demonstrated by their coelectrophoresis and by absorption and fluorescence spectroscopic methods. Topoisomerisation of pBR322 DNA shows that H2TMPyP4+ unwinds DNA as efficiently as ethidium bromide showing that it intercalates at many sites. ZnTMPyP4+ may cause limited unwinding. Marked changes in the fluorescence spectra of the porphyrins are found in the presence of DNA. The fluorescence intensity of either H2TMPyP4+ or ZnTMPyP4+ is enhanced in the presence of poly (d(A-T)), whereas in the presence of poly (d(G-C] the fluorescence intensity of ZnTMPyP4+ is only slightly affected and that of H2TMPyP4+ markedly reduced. Both the porphyrins photosensitize the cleavage of DNA in aerated solution upon visible light irradiation.