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Effects of the Interaction Between β ‐Carboline‐3‐carboxylic acid N ‐Methylamide and Polynucleotides on Singlet Oxygen Quantum Yield and DNA Oxidative Damage
Author(s) -
GarcíaZubiri Iñigo X.,
Burrows Hugh D.,
Sérgio Seixas de Melo J.,
Pina Joao,
Monteserín María,
Tapia María J.
Publication year - 2007
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.2007.00187.x
Subject(s) - singlet oxygen , chemistry , polynucleotide , dna , singlet state , quantum yield , photochemistry , oxygen , biochemistry , fluorescence , organic chemistry , excited state , physics , quantum mechanics , nuclear physics
The complexation of β ‐carboline‐3‐carboxylic acid N ‐methylamide ( β CMAM) 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. β CMAM‐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 β CMAM triplet state formation was also determined through triplet–triplet transient absorption spectra. To evaluate possible oxidative damage of DNA following singlet oxygen β CMAM 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.