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Bulletin of Experimental Biology and Medicine, Vol. 150, No. 3, January, 2011
375
BIOGERONTOLOGYEffect of the Peptide Bronchogen (Ala-Asp-Glu-Leu)
on DNA Thermostability
J. R. Monaselidze, V. Kh. Khavinson*, M. Z. Gorgoshidze, D. G. Khachidze, E. M. Lomidze, T. A. Jokhadze**, and T. A. Lezhava**
Translated from Byulleten Eksperimentalnoi Biologii i Meditsiny, Vol. 150, No. 9, pp. 344-346, September, 2010 Original article submitted April 15, 2009
Thermodynamic parameters of DNA melting in the presence of a peptide bronchogen in various concentrations were estimated on a differential scanning microcalorimeter. Bronchogen was shown to serve as a DNA-stabilizing agent. Bronchogen increased the melting temperature of DNA from calf thymus and mouse liver by 3.1oC in a narrow range of r (molar ratio of bronchogen/DNA b.p., 0.01-0.055). A further increase in r was not accompanied by changes in the melting temperature. The complex melting enthalpy (Hmelt) remained unchanged in this range of r (0.01-1.0). Hmelt for DNA from the thymus and mouse liver was 11.4 and 12.7 cal/g, respectively. Our results indicate that bronchogen is not an adeninethymine-specic or guaninecytosine-specic ligand. The type of binding is considered as strong and occasional. The binding occurs with both strands of DNA (mainly with nitrogen bases).
Key Words: microcalorimeter; thermostability; DNA; peptide
Studying the interaction of low-molecular-weight bio-active compounds exhibiting sequence-specic binding with DNA sites is an important pharmacological problem. These investigations involve a variety of physical, chemical, and biological methods [1,8].
Biological activity and mechanisms of binding of these ligands with DNA can be evaluated by studying the thermodynamic parameters for melting of complexes that consist of the test compounds and DNA (in solutions) [3,6].
New water-soluble low-molecular-weight peptide compounds were recently synthesized. They are extensively used in genomics and in medical practice
[1,2,4]. A new peptide bronchogen (Ala-Asp-Glu-Leu) stimulates proliferation ad functional activity of major cell structures in tissue culture. This agent produces a trophic and stabilizing effect on morphological characteristics and regeneration of the differentiated tissue. A clinical study showed that bronchogen is efcient in combination therapy of patients with respiratory diseases. Moreover, bronchogen is successively used for prevention...