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Albany 2019: 20th Conversation - Abstracts

category image Albany 2019
Conversation 20
June 11-15 2019
Adenine Press (2019)

Interaction of ethidium bromide and mitoxantrone with double-stranded poly(rA)-poly(rU)

The study of binding of the ligands ethidium bromide (EtBr) and mitoxantrone (MTX) with double-stranded (ds-) DNA (B-form) and ds-poly(rA)-poly(rU) (ds-RNA, A-form) has been carried out. The obtained results reveal that EtBr forms several types of complexes with both ds-DNA and ds-poly(rA)-poly(rU) structures: by intercalation, semi-intercalation and electrostatic modes simultaneously. Though, it was revealed that EtBr shows practically the same affinity to ds-DNA and ds-poly(rA)-poly(rU). MTX binds to ds-DNA and ds-RNA by semi-intercalation and electrostatic modes and performs some preference to DNA (to B-form). Our obtained data also indicate that MTX binds to DNA by analogous mechanism with methylene blue (MB): – at relatively high ionic strengths and low concentrations it semi-intercalates into ds-structure of nucleic acid (NA), at high concentrations of the ligands – binds to helix electrostatically from the outer side (Vardevanyan et al, 2016). It was also revealed that at the joint binding of both ligands to NA and their low concentrations a competition between bound EtBr molecules and MTX does not emerge, meanwhile their general effect on stabilization of DNA ds-structures is less, than at separate impacts. At high concentrations of both ligands in the case of ds-DNA a competition between them emerges, though, the EtBr effect becomes prevailing. At the same time in the case of the joint interaction of both ligands with poly(rA)-poly(rU) the main part of stabilization of ds-structures corresponds to EtBr, which may be the result of MTX weak affinity to ds-poly(rA)-poly(rU).

Thus, the experimental data indicate that despite the versatility of the main (semi-intercalation) binding mode, MTX interacts with RNA much weaker, than with DNA. From this point of view, in the case of EtBr it was not revealed a preference to DNA or RNA. It was shown that the EtBr binding modes to the NA does not depend on absence or presence of MTX.

Reference

Vardevanyan, P.O., Antonyan, A.P., Parsadanyan, M.A., Torosyan, M.A. & Karapetian A.T.(2016). Joint interaction of ethidium bromide and methylene blue with DNA. The effect of ionic strength on binding thermodynamic parameters. J. Biomol. Struct. Dyn.34, 1377-1382, DOI: http://dx.doi.org/10.1080/07391102.2015.1079557.

Armen T. Karapetyan1*
Margarita A. Torosyan1*
Mariam A. Shahinyan2

1* Department of Physics and Electrotechnics
Natioanl University of Architecture and Construction of Armenia
Yerevan, Armenia 0009
2 Department of Biophysics
Yerevan State University
Yerevan, Armenia 0025

Ph:(+37410) 550406
Email:karapetyanat@gmail.com