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Rp-phosphorothioate modifications in RNase P RNA that interfere with tRNA binding
W D Hardt1, J M Warnecke, V A Erdmann
1Institut für Biochemie, Freie Universität Berlin, Germany.
The EMBO Journal
|June 15, 1995
Summary
Phosphate oxygens in ribonuclease P (RNAP) RNA are crucial for tRNA binding and processing. Modifications to these sites, particularly at conserved nucleotides, significantly disrupt this interaction, revealing key coordination sites.
Area of Science:
- Molecular Biology
- Biochemistry
- RNA Biology
Background:
- Ribonuclease P (RNase P) is essential for tRNA maturation.
- The role of specific phosphate oxygens in the RNase P RNA-tRNA interaction remains incompletely understood.
Purpose of the Study:
- To investigate the contribution of phosphate oxygens in RNase P RNA to tRNA recognition.
- To identify specific sites of metal ion coordination involved in the RNase P RNA-tRNA complex.
Main Methods:
- Rp-phosphorothioate modifications were introduced into RNase P RNA.
- Binding interference assays and gel retardation were employed to assess tRNA binding.
- Manganese rescue experiments were performed to identify metal ion coordination sites.
Main Results:
- Extensive Rp-phosphorothioate modification of RNase P RNA significantly impaired tRNA binding and pre-tRNA processing.
- Specific nucleotide positions (e.g., A67, G68, U69, C70, C71, G72, A130, A132) were identified as critical for tRNA binding.
- Manganese rescue confirmed direct metal ion coordination at U69, C70, A130, and A132.
- Modifications in tRNA showed minimal impact on binding to RNase P RNAs, indicating a greater role for RNase P RNA phosphates.
Conclusions:
- Phosphate oxygens of RNase P RNA play a critical role in tRNA recognition and binding.
- Specific sites within conserved nucleotides and a long-range base-pairing interaction are vital for complex formation.
- The phosphate oxygens of mature tRNA contribute less significantly to the stability of the RNase P RNA-tRNA complex.