Rp-phosphorothioate modifications in RNase P RNA that interfere with tRNA binding.
AUTOR(ES)
Hardt, W D
RESUMO
We have used Rp-phosphorothioate modifications and a binding interference assay to analyse the role of phosphate oxygens in tRNA recognition by Escherichia coli ribonuclease P (RNase P) RNA. Total (100%) Rp-phosphorothioate modification at A, C or G positions of RNase P RNA strongly impaired tRNA binding and pre-tRNA processing, while effects were less pronounced at U positions. Partially modified E. coli RNase P RNAs were separated into tRNA binding and non-binding fractions by gel retardation. Rp-phosphorothioate modifications that interfered with tRNA binding were found 5' of nucleotides A67, G68, U69, C70, C71, G72, A130, A132, A248, A249, G300, A317, A330, A352, C353 and C354. Manganese rescue at positions U69, C70, A130 and A132 identified, for the first time, sites of direct metal ion coordination in RNase P RNA. Most sites of interference are at strongly conserved nucleotides and nine reside within a long-range base-pairing interaction present in all known RNase P RNAs. In contrast to RNase P RNA, 100% Rp-phosphorothioate substitutions in tRNA showed only moderate effects on binding to RNase P RNAs from E. coli, Bacillus subtilis and Chromatium vinosum, suggesting that pro-Rp phosphate oxygens of mature tRNA contribute relatively little to the formation of the tRNA-RNase P RNA complex.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=398413Documentos Relacionados
- Ribonuclease P (RNase P) RNA is converted to a Cd(2+)-ribozyme by a single Rp-phosphorothioate modification in the precursor tRNA at the RNase P cleavage site.
- Identification of specific Rp-phosphate oxygens in the tRNA anticodon loop required for ribosomal P-site binding
- Structural features of yeast tRNA genes which affect transcription factor binding.
- Structural similarities in glutaminyl- and methionyl-tRNA synthetases suggest a common overall orientation of tRNA binding.
- Cleavage of tRNA within the mature tRNA sequence by the catalytic RNA of RNase P: implication for the formation of the primer tRNA fragment for reverse transcription in copia retrovirus-like particles.
