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Albany 2019: 20th Conversation - Abstracts

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

Comparative study of binding of some intercalating compounds with DNA

The comparative study of DNA-acridine orange (AO), DNA-ethidium bromide (EtBr) and DNA-methylene blue (MB) complexes has been carried out using UV melting method at the solution ionic strength 0.02 M, in the interval of ligand/DNA concentration ratio change – 0 < r ≤ 0.33. Changes of the melting parameter values (δ(1/Tm) and δ(ΔT/Tm2)) of these complexes were obtained. The obtained data indicate that MB, AO and EtBr, being intercalators, stabilize DNA ds-structure. In the case of AO this effect is conditioned both by intercalator and by electrostatic binding modes (Sarkar et al, 2008), in the case of MB this effect is conditioned by semi-intercalation and electrostatic modes. Meanwhile, the stabilizing effect of MB on DNA ds-structure is higher than that of AO. This fact indicates that in the case of AO the contribution of the electrostatic mode to ds-DNA stabilization is much weaker, than in the case of MB. In the case of EtBr a weakening of DNA ds-structure stabilization is found out, which is conditioned by the fact that EtBr shows a semi-intercalation type of the binding to ss-structures of DNA as well, which becomes significant and invokes a destabilization of its native structure.

The interaction of EtBr, MB and AO with DNA at the solution ionic strength 0.02 M has been studied by differential spectroscopy method as well. The results of these studies also indicate that EtBr binds to DNA by intercalation, semi-intercalation and electrostatic modes; MB – by semi-intercalation and electrostatic modes and AO – by intercalation and electrostatic modes, as in case of interaction of these ligands with poly(rA)-poly(rU) (Vardevanyan et al, 2017). It was shown that the simultaneous performance of intercalation and semi-intercalation modes conditions the formation of a real isosbestic point (IP) in the absorption spectra of EtBr-DNA complexes. In the absence of intercalation at MB interaction with DNA a pseudo-IP in differential absorption spectra of these complexes is formed. In the spectra of AO-DNA complexes both IP and pseudo-IP are not formed, despite the fact that this ligand binds to DNA by intercalation mode.

References

    Sarkar, D., Das, P., Basak, S., & Chattopadhyay, N. (2008). Binding interaction of cationic phenazinium dyes with calf thymus DNA: a comparative study. The Journal of Physical Chemistry B 112, 9243-9249.

    Vardevanyan, P.O., Antonyan, A.P., Parsadanyan, M.A., Shahinyan, M.A. & Sahakyan V.G. (2017). Peculiarities of interaction of synthetic polyribonucleotide poly(rA)-poly(rU) with some intercalators. J. of Biomol. Struct. & Dyn.35.1-7. DOI: 10.1080/07391102.2017.1402708.

Poghos O. Vardevanyan1*
Ara P. Antonyan1
Marine A. Parsadanyan1,
Mariam A. Shahinyan1
Victoria G. Sahakyan2

1 Department of Biophysics
Yerevan State University
Yerevan, Armenia
2 Department of Clinical Pathology
Yerevan State Medical University after M.Heratsi
Yerevan, Armenia

Ph: (+37460) 710522
Email: p.vardevanyan@ysu.am