Crystal structure and stability of a DNA duplex containing A(anti).G(syn) base-pairs.
Brown, T., Leonard, G.A., Booth, E.D., Chambers, J.(1989) J Mol Biol 207: 455-457
- PubMed: 2754734
- DOI: https://doi.org/10.1016/0022-2836(89)90268-4
- Primary Citation of Related Structures:
111D - PubMed Abstract:
The synthetic dodecanucleotide d(CGCAAATTGGCG) has been analysed by single-crystal X-ray diffraction techniques and the structure refined to R = 0.16 and 2.25 A resolution, with the location of 94 solvent molecules. The sequence crystallizes as a full turn of a B-DNA helix with ten Watson-Crick base-pairs and two adenine-guanine mispairs. The analysis clearly shows that the mismatches are of the form A(anti).G(syn). Thermal denaturation studies indicate that the stability of the duplex is strongly pH dependent, with a maximum at pH 5.0, suggesting that the base-pair is stabilized by protonation. Three different arrangements have been observed for base-pairs between guanine and adenine and it is likely that A.G mismatch conformation is strongly influenced by dipole-dipole interactions with adjacent base-pairs.
Organizational Affiliation:
Department of Chemistry, University of Edinburgh, U.K.