title: Joint interaction of ethidium bromide and methylene blue with DNA. The effect of ionic strength on binding thermodynamic parameters.
abstract: Large amount of data of experimental and theoretical studies have shown that ethidium bromide (EtBr) and methylene blue (MB) may bind to nucleic acids via three modes: intercalation between two adjacent base pairs, insertion into the plane between neighboring bases in the same strand (semi-intercalation), and outside binding with negatively charged backbone phosphate groups. The aim of the given research is to examine the behavior of these two ligands at both separate and joint DNA binding. The obtained experimental data show that the effect of simultaneous binding of EtBr and MB on double-stranded DNA has a non-additive effect of separate binding. The analyses of the melting thermodynamic parameters of DNA complexes with two bound ligands suggest competitive mechanism of interaction.
authors.affiliation: a Department of Biophysics , Yerevan State University , Alex Manoogian 1, 0025 Yerevan , Armenia.
authors.forename: Poghos O
authors.initials: PO
authors.lastname: Vardevanyan
authors.affiliation: a Department of Biophysics , Yerevan State University , Alex Manoogian 1, 0025 Yerevan , Armenia.
authors.forename: Ara P
authors.initials: AP
authors.lastname: Antonyan
authors.affiliation: a Department of Biophysics , Yerevan State University , Alex Manoogian 1, 0025 Yerevan , Armenia.
authors.forename: Marine A
authors.initials: MA
authors.lastname: Parsadanyan
authors.affiliation: b Department of Physics and Electric Engineering , National University of Architecture and Construction , Yerevan 0009 , Armenia.
authors.forename: Margarita A
authors.initials: MA
authors.lastname: Torosyan
authors.affiliation: b Department of Physics and Electric Engineering , National University of Architecture and Construction , Yerevan 0009 , Armenia.
authors.forename: Armen T
authors.initials: AT
authors.lastname: Karapetian
mesh_terms: D000818:Animals; D002417:Cattle; D004247:DNA / Q000737:chemistry*; D004996:Ethidium / Q000737:chemistry*; D008751:Methylene Blue / Q000737:chemistry*; D009994:Osmolar Concentration; D013816:Thermodynamics
chemical_list: D004247:DNA; D004996:Ethidium; D008751:Methylene Blue
keywords: DNA; competitive mechanism; ethidium bromide; melting thermodynamic parameters; methylene blue