The structure and function of biological macromolecules change due to intermolecular deuterium bond formation or deuterium substitution with environmental D2O. In this study, surface-enhanced Raman spectroscopy (SERS) was used to detect interaction sites between D2O and ssDNA and their action mechanisms. SERS peaks of ssDNA changed with increasing D2O proportions, and the site of action mainly involved A and G bases, whose number strengthened the interaction between sequences and D2O and hence the SERS peak intensities. Fixing the number of A and G bases prevented changes in their positions from significantly altering the map. We also identified the interaction between ssDNA sequences that easily formed a G-quadruplex structure and D2O. The amplitude of the SERS peak intensity change reflected the ssDNA structural stability and number of active sites. These findings are highly significant for exploring genetic exchanges and mutations and could be used to determine the stability and structural changes of biological macromolecules.
Keywords: DNA structures; Raman spectroscopy; deuterium; hydrogen bonds; nucleobases.