Related Experiment Video

Updated: Jul 11, 2026

High Resolution Electron Microscopy of the Helicobacter pylori Cag Type IV Secretion System Pili Produced in Varying Conditions of Iron Availability
09:05

High Resolution Electron Microscopy of the Helicobacter pylori Cag Type IV Secretion System Pili Produced in Varying Conditions of Iron Availability

Published on: November 21, 2014

The colicin G, H and X determinants encode microcins M and H47, which might utilize the catecholate siderophore

S I Patzer1, M R Baquero2, D Bravo2

  • 1Mikrobiologie/Membranphysiologie, Universität Tübingen, Auf der Morgenstelle 28, Tübingen, Germany.

Microbiology (Reading, England)
|September 2, 2003
PubMed

Insights

Escherichia coli produces microcins H47 and M, utilizing RND-type export systems and specific receptors for iron uptake. These microcins enhance competitive advantages against other enterobacteria.

Area of Science:

  • Microbiology
  • Bacteriology
  • Molecular Biology

Background:

  • Escherichia coli strains produce various colicins and microcins, which are proteinaceous toxins involved in interbacterial competition.
  • The export mechanisms and receptor interactions of these bacteriocins are crucial for their function and host range.

Purpose of the Study:

  • To characterize the production, export, and receptor usage of newly identified microcins H47 and M from Escherichia coli.
  • To elucidate the genetic basis and regulation of microcin H47 and M production.

Main Methods:

  • Comparative genomic analysis of microcin gene clusters.
  • Identification of export systems and outer membrane receptors through genetic and biochemical approaches.
  • Investigation of iron-dependent regulation using Fur box analysis.

Main Results:

  • Escherichia coli strains CA46, CA58, and Nissle 1917 produce microcins H47 and M, exported via an RND-type system including TolC.
  • The gene clusters for microcins H47 and M share significant homology, with variations in gene content.
  • Iron regulation of microcin production is mediated by a Fur box.
  • Catecholate siderophore receptors (Fiu, Cir, FepA, IroN) were identified as receptors for microcins M, H47, and E492.
  • The iroB gene, involved in salmochelin synthesis, is present in microcin gene clusters.

Conclusions:

  • Microcins H47 and M are exported through a TolC-dependent RND system.
  • The presence of the iroB gene suggests a link between microcin production and catecholate siderophore utilization.
  • These microcins likely confer a competitive advantage to producing strains against enterobacteria employing catecholate siderophores.

More Related Videos

Essential Metal Uptake in Gram-negative Bacteria: X-ray Fluorescence, Radioisotopes, and Cell Fractionation10:34

Essential Metal Uptake in Gram-negative Bacteria: X-ray Fluorescence, Radioisotopes, and Cell Fractionation

Published on: February 1, 2018

Identification of Antibacterial Immunity Proteins in Escherichia coli using MALDI-TOF-TOF-MS/MS and Top-Down Proteomic Analysis09:26

Identification of Antibacterial Immunity Proteins in Escherichia coli using MALDI-TOF-TOF-MS/MS and Top-Down Proteomic Analysis

Published on: May 23, 2021

Related Concept Videos

Cytoskeletal Proteins in Bacteria01:29

Cytoskeletal Proteins in Bacteria

Bacterial cells were initially considered simple, randomly organized structures lacking a cytoskeleton. However, the discovery of cytoskeleton homologs in bacteria led to the change of this opinion. Bacterial cytoskeletal filaments regulate the cell shape, cell polarity, cell division, and partitioning of plasmids during cell division. It was later discovered that bacterial cytoskeletal proteins, mainly actin and tubulin homologs, are diverse compared to their eukaryotic counterparts. On the...
Protein Import into the Peroxisomes01:27

Protein Import into the Peroxisomes

Cells contain membrane-bound organelles called peroxisomes that oxidize organic molecules by transferring hydrogen atoms to oxygen, producing hydrogen peroxide. Peroxisomes enzymatically convert the released hydrogen peroxide into water and oxygen.
Peroxisomal Protein Import:
Peroxisomes lack the genetic machinery required to code for their own proteins. Hence, most peroxisomal membrane, lumenal and transmembrane proteins are synthesized in the cytoplasm or ER and transported to the peroxisome...
Antimicrobial Proteins01:23

Antimicrobial Proteins

Antimicrobial proteins are important components of the immune system. They aid the body in combating pathogens by either killing them directly or hindering their replication processes. Four main types of antimicrobial substances are interferons, the complement system, iron-binding proteins, and antimicrobial proteins.
Interferons
Interferons (IFNs) are proteins produced by lymphocytes, macrophages, and fibroblasts infected with viruses. While IFNs cannot prevent viruses from entering and...
Fimbriae, Pili, and Axial Filaments01:28

Fimbriae, Pili, and Axial Filaments

Fimbriae and pili are specialized bacterial surface structures that play pivotal roles in adhesion, genetic exchange, and motility. Composed primarily of pilin protein, these hairlike appendages are crucial for bacterial survival and pathogenicity in various environments.Fimbriae: Adhesion and PathogenicityFimbriae are fine, filamentous structures measuring 2–10 nanometers in diameter and are densely distributed on the bacterial cell surface. They facilitate bacterial adhesion to abiotic...
Chemotaxis in E. coli01:27

Chemotaxis in E. coli

Chemotaxis in Escherichia coli is a sensory-driven motility mechanism that enables bacteria to navigate chemical gradients, moving toward beneficial environments while avoiding harmful conditions. This process relies on a signal transduction system integrating external chemical cues with flagellar motor control.Chemoreceptors and Signal DetectionE. coli detects chemical gradients through methyl-accepting chemotaxis proteins (MCPs), which are membrane-bound chemoreceptors that sense attractants...
Bacterial Gastroenteritis01:18

Bacterial Gastroenteritis

Bacterial gastroenteritis, characterized by diarrhea, abdominal cramps, and vomiting, is often caused by ingestion of contaminated food or water and is frequently associated with pathogenic Escherichia coli strains. These microbes exploit two principal mechanisms to inflict disease.Shiga toxin–producing E. coli, also referred to as STEC—notably O157:H7—release Shiga toxins that target ribosomes, blocking protein synthesis. The B subunit of the toxin binds the host glycolipid receptor...