The influence of GC/AT composition on intercalating and semi-intercalating binding of ethidium bromide to DNA

Journal of the Brazilian Chemical Society

Poghos O. Vardevanyan²  Ara P. Antonyan²  Marine A. Parsadanyan²  Mariam A. Shahinyan²  Lilit A. Hambardzumyan²  Margarita A. Torosyan¹  Armen T. Karapetian¹ 

[1] ,Yerevan State University Biophysics Department Yerevan,Armenia

关键词: DNA;    ethidium bromide;    adsorption isotherms;    spectrophotometry;    spectrofluorometry;   

DOI  :  10.1590/S0103-50532012005000076

来源: SciELO

【 摘 要 】

The binding parameters of ethidium bromide (EtBr) with DNA of various GC/AT ratios were determined using absorption and fluorescence spectroscopy. Our experimental data clearly demonstrate the co-existence of fluorescing and non-fluorescing types of "strong" binding at low concentration of EtBr. The fluorescent complex corresponds to the ordinary intercalative model. The non-fluorescent complex is referred to semi-intercalative binding of EtBr. The binding constant (K) and the number of base pairs corresponding to a binding site (n) of the fluorescent (Kf and n f) and non-fluorescent (Knf, n nf) types of interactions were determined. The average size of binding site (n) is equal to 1.5 bp (absorption spectroscopy), and n f ca. 2 bp (fluorescence spectroscopy). It was shown that n nf is dependent on GC-content and total n is independent of it.

【 授权许可】

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