DETERMINATION OF THE NUCLEOSIDIC STRUCTURAL PARAMETERS BY MEANS OF DNA VIBRATIONAL MARKERS

Normal mode calculations based on the GF-Wilson method and a reliable force field allow the vibrational markers arising from the deoxyadenosine (dA) and deoxyguanosine (dG) residues in DNA double helical chains (right- and left-handed conformations) to be reproduced. To do this, a fast, optimized code running on a CRAY-2 computer has been performed. The normal modes of these nucleosides have been calculated as a function of their structural parameters, on the basis of a non-redundant set of internal coordinates. This study permits a better understanding of the behaviour of the main nucleosidic markers used experimentally to determine the conformation of an oligonucleotide or polynucleotide in the crystalline phase and in solution. Taking account of the calculated data, we propose a reliable set of values for the nucleosidic structural parameters which are in good agreement with those estimated by other techniques such as X-ray diffraction or nuclear magnetic resonance (NMR) spectroscopy. We have extended this study to follow the evolution of the nucleosidic vibrational markers as a function of the sugar conformation and the glycosidic torsion angle. © 1990.