Insights into the DNA stabilizing contributions of a bicyclic cytosine analogue: crystal structures of DNA duplexes containing 7,8-dihydropyrido [2,3-d]pyrimidin-2-one.
Juan, E.C.M., Shimizu, S., Ma, X., Kurose, T., Haraguchi, T., Zhang, F., Tsunoda, M., Ohkubo, A., Sekine, M., Shibata, T., Millington, C.L., Williams, D.M., Takenaka, A.(2010) Nucleic Acids Res
- PubMed: 20554855
- DOI: https://doi.org/10.1093/nar/gkq519
- Primary Citation of Related Structures:
3N4N, 3N4O - PubMed Abstract:
The incorporation of the bicyclic cytosine analogue 7,8-dihydropyrido[2,3-d]pyrimidin-2-one (X) into DNA duplexes results in a significant enhancement of their stability (3-4 K per modification). To establish the effects of X on the local hydrogen-bonding and base stacking interactions and the overall DNA conformation, and to obtain insights into the correlation between the structure and stability of X-containing DNA duplexes, the crystal structures of [d(CGCGAATT-X-GCG)](2) and [d(CGCGAAT-X-CGCG)](2) have been determined at 1.9-2.9 Å resolutions. In all of the structures, the analogue X base pairs with the purine bases on the opposite strands through Watson-Crick and/or wobble type hydrogen bonds. The additional ring of the X base is stacked on the thymine bases at the 5'-side and overall exhibits greatly enhanced stacking interactions suggesting that this is a major contribution to duplex stabilization.
Organizational Affiliation:
Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.