A circular dichroism study of the stability of guanine quadruplexes of thrombin DNA aptamers at presence of K+ and Na+ ions

作者：Ponikova Slavomira; Antalik Marian; Hianik Tibor^*

来源：General Physiology and Biophysics, 2008, 27(4): 271-277.

• DNA aptamers
• Circular dichroism
• Guanine quadruplex
• Potassium
• Sodium

The effect of K+ and Na+ on the properties of DNA aptamers that selective binds to fibrinogen (FIBRI) and heparin (HEPA) exosites of human a-thrombin was studied by circular dichroism (CD). The complexes of FIBRI-K+ were slightly more stable than HEPA-K+. However, lower stability was observed for HEPA-K+ at presence of Na+ in comparison with FIBRI-K+. The analysis of CD melting curves suggests differences in thermal stability of both aptamers at presence of K+. The melting temperatures (T-m) and changes in van't Hoff enthalpy for HEPA-K+ complexes were lower in comparison with those for FIBRI-K+. With increasing HEPA concentration the T-m value increased, but T-m did not change with increasing FIBRI concentration. This suggests formation of HEPA aggregates, while FIBRI aptamers are in monomeric form.

• 出版日期2008-12