H-1 AND P-31 RESONANCE ASSIGNMENTS AND SECONDARY STRUCTURE OF HAIRPINCONFORMER OF IA MISMATCHED OLIGONUCLEOTIDE D-GGTACIAGTACC

Almost complete H-1 and P-31 resonance assignments of two coexisting c onformers (duplex and an hairpin) of d-GGTACIAGTACC at 1.25 mM concent ration and 305 K have been achieved. The results demonstrate that the hairpin conformer has a structure with two purines I6 and A7 forming a two-base loop on a B-DNA stem. Stacking is continued on the 5'-side o f the loop, with the 16 stacked upon C5. The base A7, on the 3'-side o f the loop stacks partially with I6. The glycosidic angle for G8 is in the anti domain and it maintains normal Watson-Crick base-pairing wit h the opposite C5.