NMR-STUDY OF AZIDO-2',3'-DIDEOXYRIBOSYLTHYMINE-5'-MONOPHOSPHATE AND 2',3'-DIDEOXYRIBOSYLADENINE-5'-MONOPHOSPHATE

The molecular conformation of azido-2',3'-dideoxyribosylthymine-5'-mon ophosphate (AZTMP) and 2',3'-dideoxyribospladenine-5'-monophosphate (d dAMP) has been investigated by NMR spectroscopy. AZTMP shows significa nt variations in conformational behaviour compared to 3'-azido-2',3'-d ideoxyribosylthymine (AZT). Preponderance of unique conformations is f ound, implying a more rigid structure for the nucleotide. The sugar ri ng displays equilibrium between C2'-endo (74%)- and C2'-exo (26%) conf ormers. The major conformers around C5'-O5', C4'-C5' and the glycosidi c bonds are beta(t), gamma(+) and anti. ddAMP, however, shows a confor mation similar to its nucleoside analogue, with the sugar ring pucker between C2'-exo/C3'-endo (75%) and C2'-endo (25%). The major conformer s around C5'-O5', C4'-C5' and the glycosidic bonds are beta(t), gamma( +) and anti.