title: Effects of the interaction between beta-carboline-3-carboxylic acid N-methylamide and polynucleotides on singlet oxygen quantum yield and DNA oxidative damage.
abstract: The complexation of beta-carboline-3-carboxylic acid N-methylamide (betaCMAM) with the sodium salts of the nucleotides polyadenylic (Poly A), polycytidylic (Poly C), polyguanylic (Poly G), polythymidylic (Poly T) and polyuridylic (Poly U) acids, and with double stranded (dsDNA) and single stranded deoxyribonucleic acids (ssDNA) was studied at pH 4, 6 and 9. Predominant 1:1 complex formation is indicated from Job plots. Association constants were determined using the Benesi-Hildebrand equation. BetaCMAM-sensitized singlet oxygen quantum yields were determined at pH 4, 6 and 9, and the effects on this of adding oligonucleotides, dsDNA and ssDNA were studied at the three pH values. With dsDNA, the effect on betaCMAM triplet state formation was also determined through triplet-triplet transient absorption spectra. To evaluate possible oxidative damage of DNA following singlet oxygen betaCMAM photosensitization, we used thiobarbituric acid-reactivity assays and electrophoretic separation of DNA assays. The results showed no oxidative damage at the level of DNA degradation or strand break.
authors.affiliation: Departamento de Química, Universidad de Burgos, Burgos, Spain.
authors.forename: Iñigo X
authors.initials: IX
authors.lastname: García-Zubiri
authors.forename: Hugh D
authors.initials: HD
authors.lastname: Burrows
authors.forename: J Sérgio
authors.initials: JS
authors.lastname: Seixas de Melo
authors.forename: Joao
authors.initials: J
authors.lastname: Pina
authors.forename: María
authors.initials: M
authors.lastname: Monteserín
authors.forename: María J
authors.initials: MJ
authors.lastname: Tapia
mesh_terms: D002243:Carbolines / Q000737:chemistry*; D004249:DNA Damage / Q000235:genetics*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D011119:Polynucleotides / Q000737:chemistry* / Q000235:genetics*; D026082:Singlet Oxygen / Q000737:chemistry*; D013053:Spectrophotometry
chemical_list: D002243:Carbolines; D011119:Polynucleotides; C526324:beta-carboline-3-carboxylic acid N-methylamide; D026082:Singlet Oxygen