DNA Low-Frequency Internal Vibrations

摘要

We performed a series of FTIR measurements of DNA absorption spectra in THz range and confirmed that these spectra of nucleaic acids can serve as a signature of their structure. We also have suggested a method for the prediction of far infrared absorption spectra in THz region for biomolecules. This theoretical method includes I) energy minimization, 2) calculation of normal modes, 3) calculation of dipole oscillations, 4) calculations of IR absorption. We have calculated normal modes and their oscillator strengths for a number of synthetic DNA and RNA molecules with known base pair sequence. The calculated positions of the resonance peaks in absorption spectra were found to be in a good agreement with those obtained experimentally, which validates both the predictive power of our theoretical methods and accuracy of experimatal measurements.