Crystal structure of an RNA quadruplex containing inosine tetrad: implications for the roles of NH2 group in purine tetrads.

@article{Pan2006CrystalSO,
  title={Crystal structure of an RNA quadruplex containing inosine tetrad: implications for the roles of NH2 group in purine tetrads.},
  author={Baocheng Pan and K T Shi and Muttaiya Sundaralingam},
  journal={Journal of molecular biology},
  year={2006},
  volume={363 2},
  pages={451-9}
}
Polyinosinic acid has been known to adopt the four-stranded helical structure but its basic unit, inosine tetrad (I tetrad), has not been determined at the atomic level. Here we report the crystal structure of an RNA quadruplex containing an I tetrad at 1.4 A resolution. The I tetrad has one cyclic hydrogen bond N1...O6 with the bond length of 2.7 A. A water bridge is observed in the minor groove side of the base tetrad. Even though it is sandwiched by guanine tetrads (G tetrads), the I tetrad… CONTINUE READING