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Journal of Spectroscopy
Volume 2015, Article ID 842810, 8 pages
http://dx.doi.org/10.1155/2015/842810
Research Article

Spectroscopic Study of Cytosine Methylation Effect on Thermodynamics of DNA Duplex Containing CpG Motif

Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 3, 12116 Prague 2, Czech Republic

Received 6 February 2015; Revised 10 August 2015; Accepted 11 August 2015

Academic Editor: Eugen Culea

Copyright © 2015 Václav Římal et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Effect of cytosine methylation on DNA duplexes was studied by using a model system of three self-complementary DNA octamers containing central CpG motif surrounded by a couple of AT base pairs, CAACGTTG, CATCGATG, and CTTCGAAG, and their analogues with the central cytosine methylated at C5 position. Temperature dependences of 1H NMR, UV absorption, and Raman scattering spectra measured for aqueous solutions at concentrations of different orders of magnitude were subjected to a joint analysis that allowed an accurate determination of the enthalpy and entropy of duplex formation. It was revealed that the changes of the enthalpy and entropy contributions are strongly dependent on the base composition in the vicinity of the CpG motif.