Probing in vitro ribose induced DNA-glycation using Raman microspectroscopy.

To identify and characterize glycation, induced modifications of DNA are crucial toward understanding their functional significance due to their significant role in the long term control of aging and age-related diseases. In this study, we present the ability of Raman microspectroscopy as a novel analytical technique for a rapid and reliable identification of glycated DNA in a reagent-free manner. We have demonstrated that this technique has potential to provide very small conformational modifications. The combination of principal component analysis (PCA) and two-dimensional (2D) correlation spectroscopy has assisted us to explore in vitro DNA-glycation and provide more insights into the dynamics of the DNA-glycation process in an easier fashion. PCA analysis of Raman spectra shows a clear discrimination between native and glycated DNA samples. On the other hand, 2D correlation Raman analysis provides sequential order of the mechanism of the DNA-glycation process, and most likely, it occurs in the following sequence: Structural modifications of individual nucleobases (G > A > C) → DNA backbone modifications → partial transition of DNA conformations (A to B form). Our observations clearly suggest that the structure of DNA is altered, i.e., a partial transition of DNA backbone conformation from A to B form when glycated, but does not induce any final transition in DNA double helix conformation, and eventually, DNA presents in an intermediate A-B form, more toward the B form.