English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Endonucleolytic processing of precursor tRNAs (ptRNAs) by RNase P yields 3'-OH and 5'-phosphate termini, and at least two metal ions are thought to be essential for catalysis. To determine if the hydrolysis reaction catalyzed by bacterial RNase P (RNAs) involves stabilization of the 3'-oxyanion leaving group by direct coordination to one of the catalytic metal ions, ptRNA substrates with single 3'- S -phosphorothiolate linkages at the RNase P cleavage site were synthesized. With a 3'- S -phosphorothiolate-modified ptRNA carrying a 7 nt 5'-flank, a complete shift of the cleavage site to the next unmodified phosphodiester in the 5'-direction was observed. Cleavage at the modified linkage was not restored in the presence of thiophilic metal ions, such as Mn(2+)or Cd(2+). To suppress aberrant cleavage, we also constructed a 3'- S -phosphorothiolate-modified ptRNA with a 1 nt 5'-flank. No detectable cleavage of this substrate was seen in reactions catalyzed by RNase P RNAs from Escherichia coli and Bacillus subtilis, independent of the presence of thiophilic metal ions. Ground state binding of modified ptRNAs was not impaired, suggesting that the 3'- S -phosphorothiolate modification specifically prevents formation of the transition state, possibly by excluding catalytic metal ions from the active site.

nucleic acids research

Active site constraints in the hydrolysis reaction catalyzed by bacterial RNase P: analysis of precursor tRNAs with a single 3'-S-phosphorothiolate internucleotide linkage