Abstract: | The deoxyoligonucleotide d(TGCA)3 is a candidate for exhibiting unusual conformations. Its 1H NMR spectrum under low salt conditions has been obtained at 400 MHz and assigned using two-dimensional NMR techniques. The sugar puckers and glycosidic torsions have been determined by inspecting the relative intensities of the intranucleotide NOEs and COSY crosspeaks. At low electrolyte concentration (100 mM NaCl) the molecule exists as a right-handed duplex with twelve Watson-Crick base-pairs and deoxyribose moieties assuming the O1'-endo to C1'-exo pucker. |