Raman scattering of light in oligonucleotides

Biophysics and medical physics

The purpose of our investigation was to develop a highly sensitive technique of the Raman light scattering spectroscopy with high spectral resolution for later use as an experimental procedure for closer examination of molecular structure and clarification of the chemical nature of intermolecular and intramolecular interactions in synthetic oligonucleotides.  This task has been accomplished with optimal results. High spectral resolution spectra being sensitive to secondary, tertiary, and quaternary structures were obtained by a highly sensitive method of non-resonant Raman scattering of light in biomacromolecules through the example of single-stranded short oligonucleotides (20G, 20T), where d – deoxynucleotide, G – guanine, T – thymine.  The high-quality compounds involved were synthesized using the solid-phase phosphoroamidite method. The detection of narrow spectral lines allowed to determine the characteristic scale of times and gave new opportunities for studying the dynamics of fast relaxation processes of vibrational motions of atoms in biomacromolecules.  The full width at its half-height for one of the narrowest lines (1355.4 cm–1) was found to be 14.6 cm–1; this line belongs to the vibrations of methyl group of dT. The corresponding lifetime was equal to 0.38 ps.