Raman scattering in dried DNA and crystalline amino acids

Abstract

Raman spectrum characteristics of dried deoxyribonucleic acid (DNA) and two types of crystalline amino acids (L-lysine, D-asparagine) are compared in a wide range of frequencies, including the regions of lattice (7 to 200 cm⁻¹) and intramolecular (200 to 4000 cm⁻¹) vibrations. It is found that the spectral position of the low-frequency band in the Raman spectrum of DNA with a peak near 26 cm⁻¹ correlates with the Raman spectrum of high-Q low-frequency modes that manifest themselves in the crystalline amino acids under investigation. The low-frequency band of DNA refers to a twist-like vibrational mode of nucleobases. The intensities of this DNA mode and the high-Q lattice modes of the crystalline amino acids L-lysine and D-asparagine are several times as high as those of the Raman lines corresponding to the intramolecular modes. Resonant coupling of low-frequency modes of DNA and amino acid molecular chains is analyzed.