Structural Analysis of DNA Interactions with Magnesium Ion Studied by Raman Spectroscopy
S. Ponkumar, P. Duraisamy and N. Iyandurai
DOI : 10.3844/ajbbsp.2011.135.140
American Journal of Biochemistry and Biotechnology
Volume 7, Issue 3
Problem statement: In the present study, FT Raman spectroscopy had been used to extend our knowledge about Magnesium ion - DNA interactions at various volume ratios (1:50, 1:20, 1:10 and 1:5). Approach: The analysis of FT Raman data supported the existence of structural specificities in the interaction and also the stability of DNA secondary structure. Results: Results from the Raman spectra clearly indicate that the interaction of Magnesium ion with DNA is mainly through the phosphate groups of DNA with negligible change of the B-conformation of DNA at all the volume ratios studied. For example, band at 1079 cm-1 is assigned to the symmetrical stretching vibration of the nucleic acid phosphodioxy (PO-2) group. This band in the order 1079→ 1075→ 1070→ 1066→ 1063 cm-1 at all Magnesium ion DNA concentrations studied. Similarly, Raman band at 845 cm-1 due to antisymmetrical phosphodiester (O-P-O) stretching of DNA. Conclusion: Magnesium ion interaction with the DNA phosphate is weak in comparison to interactions with the bases. On the other hand, the Raman signature of B-DNA is largely unperturbed by magnesium ion, suggesting much weaker interactions.
© 2011 S. Ponkumar, P. Duraisamy and N. Iyandurai. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.