Mg2+ ion effect on stability of double-stranded polynucleotide formed by polyriboinosinic and polyribocytidilic chains

Authors

  • V.A. Sorokin Institute for Low Temperature Physics and Engineering, NASU Author
  • V.A. Valeev Institute for Low Temperature Physics and Engineering, NASU Author
  • E.L. Usenko Institute for Low Temperature Physics and Engineering, NASU Author
  • V.A. Karachevtsev Institute for Low Temperature Physics and Engineering, NASU Author

Keywords:

polynucleotides, thermal stability, metal ions

Abstract

Mg2+ effect on the thermal stability of the double-stranded polynucleotide Poly I •Poly C (IC) under conditions close to physiological ones (0.1 M Na+, pH 7) was studied by the differential UV spectroscopy method. The initial increase of the ion concentration ([Mg2+]) leads to the rise of the melting temperature Tm and to the decrease of the absorption hyperchromicity value, conditioned by the heating-induced helix-coil transition (hmax). The last effect is supposed to be a result of the Mg2+ interaction with π-electrons of hypoxanthine or cytosine rings (cation-π-interaction). When [Mg2+] reaches its critical value ([Mg2+]cr  ∼ 10-4M), Tm decreases cooperatively and hmax rises up to values close to those observed in the absence of magnesium. It is supposed that at [Mg2+] = [Mg2+]cr IC transits into a new structural state. With [Mg2+]>[Mg2+]cr Tm of the polynucleotide increases again and hmax lowers slightly.

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Author Biographies

  • V.A. Sorokin, Institute for Low Temperature Physics and Engineering, NASU

    47 Lenin Ave., Kharkov, 61103, Ukraine

  • V.A. Valeev, Institute for Low Temperature Physics and Engineering, NASU

    47 Lenin Ave., Kharkov, 61103, Ukraine

  • E.L. Usenko, Institute for Low Temperature Physics and Engineering, NASU

    47 Lenin Ave., Kharkov, 61103, Ukraine

  • V.A. Karachevtsev, Institute for Low Temperature Physics and Engineering, NASU

    47 Lenin Ave., Kharkov, 61103, Ukraine

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Published

2005-06-06

Issue

Vol. 1 No. 15 (2005): Біофізичний вісник

Section

Molecular biophysics

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How to Cite

Mg2+ ion effect on stability of double-stranded polynucleotide formed by polyriboinosinic and polyribocytidilic chains. (2005). Biophysical Bulletin, 1(15), 57-61. https://periodicals.karazin.ua/biophysvisnyk/article/view/18096

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