A transition-state interaction shifts nucleobase ionization toward neutrality to facilitate small ribozyme catalysis.

@article{Liberman2012ATI,
  title={A transition-state interaction shifts nucleobase ionization toward neutrality to facilitate small ribozyme catalysis.},
  author={Joseph A. Liberman and Man Guo and Jermaine L. Jenkins and Jolanta Krucinska and Yuanyuan Chen and Paul R Carey and Joseph E Wedekind},
  journal={Journal of the American Chemical Society},
  year={2012},
  volume={134 41},
  pages={16933-6}
}
One mechanism by which ribozymes can accelerate biological reactions is by adopting folds that favorably perturb nucleobase ionization. Herein we used Raman crystallography to directly measure pK(a) values for the Ade38 N1 imino group of a hairpin ribozyme in distinct conformational states. A transition-state analogue gave a pK(a) value of 6.27 ± 0.05, which agrees strikingly well with values measured by pH-rate analyses. To identify the chemical attributes that contribute to the shifted pK(a… CONTINUE READING