The transition from a neutral-pH double helix to a low-pH triple helix induces a conformational switch in the CCCG tetraloop closing a Watson-Crick stem.

@article{Dongen1996TheTF,
  title={The transition from a neutral-pH double helix to a low-pH triple helix induces a conformational switch in the CCCG tetraloop closing a Watson-Crick stem.},
  author={Martien C. J. M. van Dongen and Sybren S. Wijmenga and Gijsbert A. van der Marel and Jacques H. van Boom and Cornelis W. Hilbers},
  journal={Journal of molecular biology},
  year={1996},
  volume={263 5},
  pages={715-29}
}
The CCCG-loop in a DNA fragment, which is capable of forming an intramolecular triple helix as well as a hairpin structure, was investigated by NMR and molecular modeling studies. The structure of this loop is found as a type II conformation, one of the three commonly observed folding patterns of tetraloops, irrespective of the geometry of the underlying helix. In each situation, the loop exhibits a base-pair between the first cytosine and the guanine residue of the loop. The geometry of this… CONTINUE READING