Z-DNA Dynamic Structure: A Hydrogen Exchange Study

Abstract

Among the various thermally-driven structural fluctuations taking place in double-stranded nucleic acids, it is now aknowledged that the motions of the base pairs leading to the hydrogen exchange of these protons (amino and imino protons can exchange with water protons) are an essential aspect of the dynamic structure of these molecules (1). To study this type of fluctuations in Z-DNA, we have measured, as a function of temperature, the hydrogen exchange kinetics of the protons involved in hydrogen bonds between the base pairs of poly(dG-dC).poly(dG-dC). Altogether these results suggest that the guanine residue is much more likely to be in contact with the solvent than the cytosine residue (2).