DNA triads are composed of three bases interacting in plane, bearing 2-strand connectivity scheme (1).

In the context of DNA quadruplexes, they exist in lateral or apical configurations. Laterally arranged, GAG triads expand G-tetrads into DNA pentads, hexads or heptads (2-4). In the apical configuration DNA triads form structured loops leading to diamond-shaped quadruplexes.

These two distinct topologies are represented in two novel DNA architectures [5, 6, in preparation] found to be affecting the processes of HIV integration and c-myc gene regulation.

References and Footnotes

1. V. V. Kuryavyi and T. M. Jovin. Nature genet. 9, 339-341 (1995).
2. A. Kettani, A. Gorin, A. Majumdar, T. Hermann, E. Skripkin, H. Zhao, R.Jones, and D. J. Patel. J. Mol. Biol. 297, 627-624 (2000).
3. N. Zhang, A. Gorin, A. Majumdar, A. Kettani, N. Chernichenko, E. Skripkin, and D. J. Patel. J. Mol. Biol. 311, 1063-1079 (2001).
4. A. Matsugami, K. Ouhashi, M. Kanagawa, H. Liu, S. Kanagawa, S. Uesugi, and M. Katahira. J. Mol. Biol. 313, 255-269 (2001).
5. A. T. Phan, Y. S. Modi, and D. J. Patel. J. Am. Chem. Soc. 126, 8710-8716 (2004).
6. A. T. Phan, V. Kuryavyi, J.-B. Ma, A. Faure, M.-L. Andreola, and D. J. Patel. Proc. Natl. Acad. Sci. USA 102, 571-576 (2005).