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Book of Abstracts: Albany 2007

category image Albany 2007
Conversation 15
June 19-23 2007

Formation of Pseudo-ring Structures in DNA Bound with cis-platinum

cis-diamminedichloroplatinum(II) (cis-DDP) form covalent adduct with DNA both in vivo and in vitro. In the present study, the UV-spectroscopic helix-coil transition method is used to analyze the changes of the high-molecular DNA double helix occurring due to the formation of complexes with cis-DDP at the concentrations of cis-DDP 0.00003 < rb < 0.003, where rb is the number of moles of bound DDP per mole of nucleotide.

The characteristic behavior of the high molecular DNA melting temperature Tm on concentration of cis-DDP shows that there exist three precisely expressed areas of concentration of ligand on efficiency of influence of cis-DDP on DNA:
  1. the area of monotonous increase of DNA melting temperature at 4-5 degrees (10-5 < rb < 10-4)
  2. the area of monotonous downturn of DNA melting temperature (10-4 < rb < 10-3)
  3. the area of sharp fall of DNA melting temperature of (10-3 < rb).
The character of Tm changes in the first area of cis-DDP concentration seems rather strange. The observed changes of parameters of helix-coil transition cannot be explained in terms of local alterations of the double helix caused by local, kinetically inert, bidentate and monodentate platinum binding to DNA sequences. It is obvious good agreement of experimental data for ring structures formation with appropriate theoretical calculations.

Samvel G. Haroutiunyan1, *
Dmitrii Yu. Lando2
Tigran S. Haroutiunyan3
Ara P. Antonyan3
Shushanik A. Sargsyan4
Poghos O.Vardevanyan3

1Departments of Molecular Physics
3Biophysics Yerevan State University
0025 Yerevan
Alek Manoogian 1, Armenia
2Institute of Bioorganic Chemistry
220141 Minsk
Ziodinskaia 5, Byelorus
4Department of Medicinal and Biological Physics Yerevan State Medical University
Yerevan, 0025
Koryun 2, Armenia

*Email: sharout@ysu.am