Mechanism of DNA Damage Photosensitized by Trisbipyrazyl Ruthenium Complex. Unusual Role of Cu/Zn Superoxide Dismutase¶
| Autor: | Nicole Paillous, Etienne Gicquel, Patricia Vicendo |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Photolysis
Photosensitizing Agents Base Sequence Superoxide Dismutase Chemistry DNA damage Oligonucleotide chemistry.chemical_element General Medicine In Vitro Techniques Photochemistry Biochemistry Ruthenium Electron transfer chemistry.chemical_compound Oligodeoxyribonucleotides Organometallic Compounds Nucleic acid Photosensitizer Physical and Theoretical Chemistry Oxidation-Reduction Polyacrylamide gel electrophoresis DNA DNA Damage |
| Zdroj: | Photochemistry and Photobiology. 72:583-589 |
| ISSN: | 0031-8655 |
| DOI: | 10.1562/0031-8655(2000)0720583moddpb2.0.co2 |
| Popis: | Trisbipyrazyl ruthenium(II) (Ru[bpz]3(2+)) was examined as DNA photosensitizer. Damage resulting from the photolysis of synthetic oligonucleotides has been monitored by polyacrylamide gel electrophoresis. Photoadduct formation is found on both single- and double-stranded oligonucleotides. On oligonucleotide duplex, oxidative damage occurs selectively at the 5'G of the 5'GG3' site and to a lesser extent at the 5'G of a GA sequence. These findings suggest the involvement of electron transfer and show that this mechanism is the main DNA damaging process involved in Ru(bpz)3(2+) photosensitization. In addition, photoadducts and oxidative damage are both highly affected by an increase of salt concentration in the reaction medium, stressing the importance of direct interactions between nucleic acid bases and the excited ruthenium complex for efficient electron transfer. On single-stranded oligonucleotides, all the guanines are oxidized to the same extent. In this case, oxidative damage, which is not affected by an increase of salt in the solution, has been attributed, in part, to singlet oxygen. More importantly, Cu/Zn superoxide dismutase (SOD) strongly enhances the yield of all damage, correlated to an increase of both electron transfer and singlet oxygen production. This original activity of SOD is the first example of bioactivation of a polyazaaromatic ruthenium complex. |
| Databáze: | OpenAIRE |
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