HDV ribozyme activity in monovalent cations.
Published
Journal Article
Activity of the two ribozymes from hepatitis delta virus in monovalent salts was examined and compared to activity in Mg2+. Both ribozymes self-cleaved in high concentrations of monovalent cations, and an active site cytosine was required for cleavage activity under those conditions. Cleavage rates were 30-50-fold higher for reactions in LiCl than for reactions in NaCl or NH4Cl, and a thio effect indicated that chemistry was rate-determining for cleavage of the HDV genomic ribozyme in LiCl. Still, in LiCl, there was a more than 100-fold increase in the rate when MgCl2 was included in the reaction. However, the pH-rate profiles for the reactions in LiCl with and without MgCl2 were both bell-shaped with the pH optima in the neutral range. These findings support the idea that monovalent cations can partially substitute for divalent metal ions in the HDV ribozymes, although a divalent metal ion is more effective in supporting catalysis. The absence of a dramatic change in the general shape of pH-rate profiles in LiCl, relative to the profile for reactions including Mg2+, is in contrast to earlier data for the reactions in NaCl and limits our interpretation of the specific role played by the divalent metal ion in the catalytic mechanism.
Full Text
Duke Authors
Cited Authors
- Perrotta, AT; Been, MD
Published Date
- September 26, 2006
Published In
Volume / Issue
- 45 / 38
Start / End Page
- 11357 - 11365
PubMed ID
- 16981696
Pubmed Central ID
- 16981696
International Standard Serial Number (ISSN)
- 0006-2960
Digital Object Identifier (DOI)
- 10.1021/bi061215+
Language
- eng
Conference Location
- United States