Y. Boulard et al., Solution structures of oligonucleotides containing either a guanine or a cytosine in front of a gap of one nucleotide, J CHIM PHYS, 96(9-10), 1999, pp. 1566-1572
We report NMR and molecular modelling studies on two DNA duplexes containin
g a gap of one nucleotides. The difference between the two oligonucleotides
lies in the central base face to the gap, a guanine or a cytosine. For the
gapG, we observed in solution a B-form conformation where the guanine stac
ks in the helix. For the gapC, we reveal the existence of two species, one
majority where the cytosine is inside the helix and a second for which the
cytosine is extrahelical.