Raman Optical Activity as a Tool to Monitor Polynucleotide Conformation in Solutions

Area of Science:

• Biophysics
• Spectroscopy
• Computational Chemistry

Background:

• Biopolymer structure and flexibility dictate function, but solution studies are limited.
• Raman optical activity (ROA) offers high sensitivity to conformational changes in biomolecules.
• ROA studies on nucleic acids are infrequent due to molecular complexity and spectral interpretation challenges.

Purpose of the Study:

• To investigate the relationship between spectral features and nucleic acid structure.
• To enhance experimental and computational techniques for studying nucleic acids.
• To analyze the spectra of four key oligonucleotides (polyA, polyC, polyG, polyU).

Main Methods:

• Measurement of Raman and ROA spectra across a broad wavenumber range.
• Molecular dynamics (MD) and density functional theory (DFT) for spectral simulations.
• Comparison of temperature-dependent spectral changes with electronic circular dichroism (ECD) melting curves.

Main Results:

• Spectra accurately reflect molecular geometry and temperature-induced structural variations.
• Temperature-dependent spectral changes correlate with ECD-derived melting curves.
• The RNA.Shaw force field demonstrated superior performance over RNA.OL3 in MD simulations.

Conclusions:

• Combined spectroscopic and computational approaches provide powerful insights into nucleic acid solution properties.
• ROA and MD simulations are valuable for validating and refining force fields.
• This methodology advances the study of nucleic acid structure and dynamics.