Imidazole rescue of a cytosine mutation in a self-cleaving ribozyme.

Journal Article (Journal Article)

Ribozymes use a number of the same catalytic strategies as protein enzymes. However, general base catalysis by a ribozyme has not been demonstrated. In the hepatitis delta virus antigenomic ribozyme, imidazole buffer rescued activity of a mutant with a cytosine-76 (C76) to uracil substitution. In addition, a C76 to adenine substitution reduced the apparent pKa (where Ka is the acid constant) of the self-cleavage reaction by an amount consistent with differences in the pKa values of these two side chains. These results suggest that, in the wild-type ribozyme, C76 acts as a general base. This finding has implications for potential catalytic functions of conserved cytosines and adenines in other ribozymes and in ribonuclear proteins with enzymatic activity.

Full Text

Duke Authors

Cited Authors

  • Perrotta, AT; Shih, I; Been, MD

Published Date

  • October 1, 1999

Published In

Volume / Issue

  • 286 / 5437

Start / End Page

  • 123 - 126

PubMed ID

  • 10506560

International Standard Serial Number (ISSN)

  • 0036-8075

Digital Object Identifier (DOI)

  • 10.1126/science.286.5437.123


  • eng

Conference Location

  • United States