Recombinant Escherichia coli Microcin J25 (mcjA)

Function

Peptide antibiotic that functions through inhibition of the bacterial DNA-dependent RNA polymerase (RNAP) (PubMed:11443089, PubMed:12401787). Inhibits transcription by binding deep within RNAP secondary channel, where it sterically blocks the folding of the trigger loop, which is essential for efficient catalysis (PubMed:15200952, PubMed:30626643). In addition, it also seems to restrict access of nucleotide substrates to the catalytic center, and shows a partially competitive mode of inhibition with them (PubMed:15200952, PubMed:30626643). Exhibits potent bacteriocidal activity against a range of Enterobacteriaceae, including several pathogenic E.coli, Salmonella and Shigella strains (PubMed:1429464). Also acts on the cytoplasmic membrane of Salmonella newport, producing alteration of membrane permeability and disruption of the subsequent gradient dissipation, which inhibits several processes essential for cell viability, such as oxygen consumption (PubMed:11731133). Induces bacterial filamentation in susceptible cells in a non-SOS-dependent way, but this phenotype may result from impaired transcription of genes coding for cell division proteins (PubMed:1429464)

Subcellular Location

Secreted

• Solbiati J.O. et al. Sequence analysis of the four plasmid genes required to produce the circular peptide antibiotic microcin J25. — J. Bacteriol. (1999)
• Blond A. et al. The cyclic structure of microcin J25, a 21-residue peptide antibiotic from Escherichia coli. — Eur. J. Biochem. (1999)
• Salomon R.A. et al. Microcin 25, a novel antimicrobial peptide produced by Escherichia coli. — J. Bacteriol. (1992)
• Rintoul M.R. et al. The antibacterial action of microcin J25: evidence for disruption of cytoplasmic membrane energization in Salmonella newport. — FEMS Microbiol. Lett. (2001)
• Delgado M.A. et al. Escherichia coli RNA polymerase is the target of the cyclopeptide antibiotic microcin J25. — J. Bacteriol. (2001)
• Yuzenkova J. et al. Mutations of bacterial RNA polymerase leading to resistance to microcin J25. — J. Biol. Chem. (2002)
• Mukhopadhyay J. et al. Antibacterial peptide microcin J25 inhibits transcription by binding within and obstructing the RNA polymerase secondary channel. — Mol. Cell (2004)
• Pavlova O. et al. Systematic structure-activity analysis of microcin J25. — J. Biol. Chem. (2008)