Recombinant Escherichia coli O7:K1 Ribonuclease 3 (rnc)
Description
Molecular Structure and Catalytic Mechanism
Core Functions
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Ribosomal RNA maturation: Processes precursor rRNA into 16S and 23S rRNAs, though not strictly essential (alternative ribonucleases compensate in rnc mutants) .
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Gene expression regulation:
Global Regulatory Impact
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Modulates ~12% of E. coli mRNAs, with 9% upregulated and 3% downregulated in rnc mutants .
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Fitness studies show a bimodal distribution of mutational effects: most mutations are neutral or deleterious, underscoring its optimized activity .
Autoregulation
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Cleaves a stem-loop in its own 5′ UTR, reducing mRNA stability and limiting protein levels by ~5-fold .
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Titrated by rRNA under high-growth conditions, linking enzyme activity to cellular metabolic states .
Post-Translational Modifications
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Phosphorylation: Bacteriophage T7 kinase enhances activity 4-fold during infection to promote viral transcript processing .
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Growth-phase dependence: Activity declines in stationary phase, though regulatory mechanisms remain unclear .
Key Research Findings
Biotechnological and Biomedical Applications
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Antiviral systems: Exploited in CRISPR-Cas9 adaptations for guide RNA processing .
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Gene expression tuning: Used to engineer synthetic circuits by modulating mRNA stability .
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Antimicrobial targets: rnc deletion attenuates pathogens like Salmonella, suggesting therapeutic potential .
Open Questions and Future Directions
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Structural dynamics: How do post-translational modifications alter RNase III substrate specificity?
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Host-pathogen interplay: Can RNase III inhibitors mitigate bacterial virulence without harming host RNA metabolism?
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Synthetic biology: Can engineered RNase III variants achieve orthogonal RNA processing in heterologous systems?
Product Specs
Target Background
KEGG: ect:ECIAI39_2772
