Volume 9, Number 3, p.p. 113–118
The influence of hexamminecobalt(III) on DNA melting thermodynamic parameters and condensed DNA melting
Giorgi Gogoladze,1 Ketevan Tsakadze,2 and George Mrevlishvili1
1
Department of Exact Sciences, Tbilisi State University, 3 Chavchavadze Ave, 0128 Tbilisi, Georgia
2
Department of Biological Systems, Andronikashvili Institute of Physics, 6 Tamarashvili St, 0177 Tbilisi, Georgia
We report the results of measurements using differential scanning calorimetry (DSC) of the thermodynamic parameters of DNA melting in diluted solution at different concentrations of hexamminecobalt(III), including the critical concentration at which DNA condensation takes place. The [Co]/[P] ratios varied from 0 to 0.35; DNA thermostability increased with increase of hexamminecobalt(III) concentration. DNA denaturation enthalpy did not change when [Co]/[P] varied from 0 to 0.3 (56 J/g) and then rapidly dropped to 30–31 J/g at [Co]/[P] = 0.35. The change of DNA melting range with increase of hexamminecobalt(III) concentration was not monotonic. The initial increase was followed by a subsequent decrease and finally, at [Co]/[P] = 0.35, they were 8–9 times less than those of solutions devoid of hexamminecobalt(III).
Keywords:
DNA condensation; DNA melting; DNA melting range, DNA transition temperature, hexamminecobalt(III)