title: DNA intercalation and photosensitization by cationic meso substituted porphyrins.
abstract: Several cationic porphyrins are known to bind to DNA by intercalative and outside binding modes. This study identifies the cis and trans isomers of bis(N-methyl-4-phridiniumyl)diphenyl porphyrin as DNA intercalators based on evidence from a DNA topoisomerase I assay. Moreover, both isomers are shown to be potent photosensitizers of DNA, inducing multiple S1 nuclease sensitive breaks in the phosphodiester backbone. Porphyrin-induced photodamage in DNA was also shown to be quantitatively dependent upon ionic strength and to inhibit the action of restriction endonucleases. The results indicate that these porphyrins can be useful probes of DNA structure and have potential as DNA-targeted photosensitizers.
authors.affiliation: Experimental Biology, Roswell Park Cancer Institute, Buffalo, NY 14263.
authors.forename: B R
authors.initials: BR
authors.lastname: Munson
authors.forename: R J
authors.initials: RJ
authors.lastname: Fiel
mesh_terms: D002412:Cations; D004247:DNA / Q000187:drug effects*; D004249:DNA Damage; D004587:Electrophoresis, Agar Gel; D006358:Hot Temperature; D007364:Intercalating Agents / Q000737:chemistry / Q000494:pharmacology*; D015394:Molecular Structure; D009691:Nucleic Acid Denaturation; D010777:Photochemistry; D010957:Plasmids; D011166:Porphyrins / Q000737:chemistry / Q000494:pharmacology*; D015719:Single-Strand Specific DNA and RNA Endonucleases / Q000378:metabolism
chemical_list: D002412:Cations; D007364:Intercalating Agents; D011166:Porphyrins; D004247:DNA; D015719:Single-Strand Specific DNA and RNA Endonucleases