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Updated: Aug 30, 2026

Recombinant Protein Expression, Crystallization, and Biophysical Studies of a Bacillus-conserved Nucleotide Pyrophosphorylase, BcMazG
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MazF cleaves cellular mRNAs specifically at ACA to block protein synthesis in Escherichia coli

Yonglong Zhang1, Junjie Zhang, Klaus P Hoeflich

  • 1Department of Biochemistry, Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA.

Molecular Cell
|October 29, 2003
PubMed

Insights

The MazF toxin from Escherichia coli is a sequence-specific ribonuclease that halts protein synthesis by cleaving cellular mRNAs, leading to cell death. Its antitoxin, MazE, can reverse this effect.

Area of Science:

  • Molecular Biology
  • Bacteriology
  • Genetics

Background:

  • Escherichia coli possesses addiction modules encoding toxin-antitoxin pairs.
  • These modules regulate bacterial growth arrest and cell death.

Purpose of the Study:

  • To characterize the MazF toxin from the mazEF addiction module.
  • To elucidate its mechanism of action as an endoribonuclease.

Main Methods:

  • Investigated MazF's enzymatic activity on single-stranded RNA.
  • Assessed MazF's function independently of ribosomes.
  • Tested MazF's effect on protein synthesis in cell-free systems.
  • Examined the role of the antitoxin MazE.

Main Results:

  • MazF is a sequence-specific (ACA) endoribonuclease acting on single-stranded RNA.
  • MazF efficiently inhibits protein synthesis by cleaving cellular mRNAs.
  • MazF functions independently of ribosomes, distinguishing it from RelE.
  • Purified MazF inhibits both prokaryotic and eukaryotic cell-free protein synthesis.
  • The antitoxin MazE neutralizes MazF's inhibitory activity.

Conclusions:

  • MazF acts as a toxic endoribonuclease, arresting cell growth and causing death by degrading cellular mRNAs.
  • MazF's mechanism involves specific RNA cleavage, distinct from ribosome-associated toxins.
  • This finding has implications for understanding cell physiology under stress.

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