Shared traits on the reaction coordinates of ribonuclease and an RNA enzyme

Biochem Biophys Res Commun. 2008 Jun 20;371(1):154-8. doi: 10.1016/j.bbrc.2008.04.036. Epub 2008 Apr 16.

Abstract

Reaction-intermediate analogs have been used to understand how phosphoryl transfer enzymes promote catalysis. Herein we report the first structure of a small ribozyme crystallized with a 3'-OH, 2',5'-linkage in lieu of the normal phosphodiester substrate. The new structure shares features of the reaction coordinate exhibited in prior ribozyme structures including a vanadate complex that mimicked the oxyphosphorane transition state. As such, the structure exhibits reaction-intermediate traits that allow direct comparison of stabilizing interactions to the 3'-OH, 2',5'-linkage contributed by the RNA enzyme and its protein counterpart, ribonuclease. Clear similarities are observed between the respective structures including hydrogen bonds to the non-bridging oxygens of the scissile phosphate. Other commonalities include carefully poised water molecules that may alleviate charge build-up in the transition state and placement of a positive charge near the leaving group. The advantages of 2',5'-linkages to investigate phosphoryl-transfer reactions are discussed, and argue for their expanded use in structural studies.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Catalysis
  • Crystallization
  • Nucleic Acid Conformation
  • Protein Conformation
  • RNA, Catalytic / chemistry*
  • Ribonucleases / chemistry*
  • X-Ray Diffraction

Substances

  • RNA, Catalytic
  • Ribonucleases