Hammerhead ribozymes: importance of stem-loop II for activity.
AUTOR(ES)
Tuschl, T
RESUMO
The activity of several hammerhead ribozyme constructs with constant lengths of stems I and III of 5 nt each but with variously shortened stems II is reported. Stems with 2 bp rather than the conventional 4 bp show essentially unaltered catalytic activity, independent of the composition of the tetraloop. Further reduction in size to 1 bp or 0 bp decreases activity drastically. Inversion of the G10.1.C11.1 bp next to the invariant core leads to a loss in activity, even when the stem consists of 4 bp. Thus, the minimal structural requirement for stem-loop II is a 2-bp stem with a conserved G.C bp. The reduction in catalytic activity is predominantly a result of a decrease of catalytic constant kcat, whereas Km is only slightly affected. Thus, the structural requirement for optimal activity in these constructs where the chemical-cleavage step is rate limiting is determined by the stabilization of the transition state.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=47061Documentos Relacionados
- Importance of a 5′ Stem-Loop for Longevity of papA mRNA in Escherichia coli
- RNA Destabilization by the Granulocyte Colony-Stimulating Factor Stem-Loop Destabilizing Element Involves a Single Stem-Loop That Promotes Deadenylation
- DNA stem-loop structures in oligopurine-oligopyrimidine triplexes.
- Discovering common stem–loop motifs in unaligned RNA sequences
- RNA stem–loop enhanced expression of previously non-expressible genes