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Base pairing between Escherichia coli RNase P RNA and its substrate
1Department of Microbiology, Biomedical Center, S-751 23 Uppsala, Sweden.
The EMBO Journal
|October 17, 1994
Summary
Compensatory mutations reveal specific base pairing in E. coli RNase P RNA (M1 RNA) and its substrate. This interaction anchors the substrate, facilitating precise cleavage and exposing the catalytic site.
Area of Science:
- Molecular Biology
- Biochemistry
- RNA Catalysis
Background:
- Catalytic activity of most ribozymes depends on substrate-ribozyme base pairing.
- RNase P RNA is an exception where this interaction's necessity is debated.
Purpose of the Study:
- To investigate the role of specific base pairing between E. coli RNase P RNA (M1 RNA) and its substrate.
- To elucidate the mechanism of substrate anchoring and cleavage site exposure.
Main Methods:
- Utilized compensatory mutations in M1 RNA and the substrate.
- Analyzed Watson-Crick complementarity between conserved residues.
Main Results:
- Demonstrated essential Watson-Crick base pairing between M1 RNA residues (G292, G293) and substrate residues (+74C, +75C).
- Showed this pairing partially unfolds the substrate's amino acid acceptor stem.
- Suggested potential base pairing between U294 (M1 RNA) and the +73 discriminator base.
Conclusions:
- M1 RNA anchors the substrate via specific base pairing, ensuring accurate cleavage site positioning.
- This mechanism is crucial for the catalytic function of RNase P RNA.
- Findings offer insights into the evolutionary context of ribozyme function.