Base-specific pre-melting and melting transitions of DNA in presence of ionic liquids probed by synchrotron-based UV resonance Raman scattering

Hydrated ionic liquids (ILs) have been identified as solvent media able to enhance the structural stability of deoxyribonucleic acid (DNA). In this work, we investigate molecular interaction between imidazolium-based ILs and DNA during its thermal unfolding pathway, by exploiting synchrotron-based UV Resonance Raman scattering (UVRR) experiments. This technique gives a selective focus on responses specific nucleobases in structure DNA, providing experimental sensitivity both cooperative local changes occurring along complex process DNA. UVRR measurements probe two distinct temperature-dependent phenomena double-helix, i.e. non-cooperative pre-melting mainly involving adenine bases melting transition primarily localized guanine tracts. The analysis spectra reveals that cation anion strongly interact with thus affecting but not perturbing precedes complete separation strands Overall these results suggest dominant occurs imidazolium thymine agreement previous dynamics simulations.