Raman study of magnesium induced conversion of polyU·polyA duplexes to polyU·polyA·polyU triplexes
Issue title: From Molecule to Tissue: XIII European Conference on the Spectroscopy of Biological Molecules, Palermo, Italy, August 28–September 2, 2009, Part 2 of 2
Affiliations: Faculty of Mathematics and Physics, Institute of Physics, Charles University, Prague 2, Czech Republic
Note: [] Corresponding author: S.J. Espinoza Herrera, Faculty of Mathematics and Physics, Institute of Physics, Charles University, Ke Karlovu 5, Prague 2, CZ-121 16, Czech Republic. Tel.: +420 221 911 472; Fax: +420 224 922 797; E-mail: espinoza@karlov.mff.cuni.cz.
Abstract: Raman titration experiment with magnesium salt added gradually to aqueous solution of duplexes formed by RNA homopolynucleotides polyU and polyA was performed to reveal its effect on homopolynucleotide complexes. Statistical analysis of obtained spectral set has confirmed the effect already found by less structurally sensitive methods [Nucleic Acids Res. 31(17) (2003), 5101–5107] that at sufficiently high concentrations magnesium causes transformation of polyU·polyA duplexes to polyU·polyA·polyU triplexes and single polyA strands. It was found that at relatively high polynucleotide concentrations used in Raman experiment, the threshold magnesium concentration for this effect is above the concentration of duplex basepairs in solution. Due to the strong spectral changes attributed to the varied percentages of duplexes, triplexes and single strands, it was not possible to register weaker direct Raman signs of the magnesium binding to polynucleotide strand.
