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Albany 2019: 20th Conversation - Abstracts

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

The Molecular alterations in DNA under UV-irradiation

The ionizing radiation of matter produces a large number of ions, radicals, which can subsequently cause both physical and chemical modification in the biological media. Moreover the irradiation can induce strand break formation in double-stranded supercoiled DNA.

In present work the influence of UV-irradiation on the structural transformations of DNA in buffer solutions was studied using UV- absorption spectroscopy and viscometry. Detection of DNA structural changes such as single stranded and double stranded breaks under UV-irradiation were characterized by their melting curves, in which temperature-dependent spectral measurements were carried out in buffered solutions for different exposure time/dose of irradiation. The changes of melting temperature (Tm) and interval of helix-coil transition (ΔT) at different exposure times indicate damages to the secondary structure of DNA (Karapetyan & all, 2015). The decreasing of melting temperature testifies to DNA destabilization, which could occur due to base modifications, strand breaks or breaks of hydrogen bonds between the DNA strands during irradiation. The increases of damaged sites create favorable conditions for helix-coil transition. Moreover, an increase in ΔT (degree of heterogeneity) also indicates the presence of defective sites. The relative viscosity of the UV-irradiated DNA solution decreased with increasing irradiation time, which indicates a reduction of macromolecules size.

Studies have demonstrated that viscometry and spectrophotometric measurements are in good agreement.

References

N.H. Karapetyan, A.L. Torosyan, M.H. Malakyan, S.A. Bajinyan, S.G. Haroutiunian (2015). Investigation of irradiated rats DNA in the presence of Cu(II) chelates of amino acids Schiff bases. Journal of Biomolecular Structure and Dynamics. 34(1):177-183.

Gayane V. Ananyan*
Nelli H. Karapetyan
Vigen G. Barkhudaryan

Department of Molecular Physics
Yerevan State University
1 Alex Manoogian St. 0025
Yerevan, Armenia

angay@ysu.am