AI Article Synopsis
- Colicins are bacterial toxins that exploit outer membrane receptors to enter and kill target cells, with two main groups using different import systems (Tol system for group A and ExbB-ExbD-TonB system for group B).
- Genetic studies suggest that some components of these systems can compensate for each other, but not all parts are interchangeable, highlighting the complexity of colicin entry mechanisms.
- The paper explores how mutations in tolQ and exbB impact colicin sensitivity, emphasizing the energy requirements for the uptake processes and interactions with immunity proteins in group A and B colicins.
Article Abstract
Colicins are bacterial toxins that parasitize OM (outer membrane) receptors to bind to the target cells, use an import system to translocate through the cell envelope and then kill sensitive cells. Colicins classified as group A (colicins A, E1-E9, K and N) use the Tol system (TolA, TolB, TolQ and TolR), whereas group B colicins (colicins B, D, Ia, M and 5) use the ExbB-ExbD-TonB system. Genetic evidence has suggested that TolQ and ExbB, as well as TolR and ExbD, are interchangeable, whereas this is not possible with TolA and TonB. Early reports indicated that group B colicin uptake requires energy input, whereas no energy was necessary for the uptake of the pore-forming colicin A. Furthermore, energy is required to dissociate the complex formed with colicin E9 and its cognate immunity protein during the import process. In the present paper, we detail the functional phenotypes and colicin-sensitivity results obtained in tolQ and exbB mutants and cross-complementation data of amino acid substitutions that lie within ExbB or TolQ TMHs (transmembrane helices). We also discuss on a specific phenotype that corresponds to group A colicin-sensitivity associated with a non-functional Tol system.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1042/BST20120181 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
A Conjugated Oligomer with Drug Efflux Pump Inhibition and Photodynamic Therapy for Synergistically Combating Resistant Bacteria.
ACS Appl Mater Interfaces
January 2025
Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Shaanxi Normal University, Xi'an 710119, P. R. China.
High expression of drug efflux pump makes antibiotics ineffective against bacteria, leading to drug-resistant strains and even the emergence of "superbugs". Herein, we design and synthesize a dual functional o-nitrobenzene (NB)-modified conjugated oligo-polyfluorene vinylene (OPFV) photosensitizer, OPFV-NB, which can depress efflux pump activity and also possesses photodynamic therapy (PDT) for synergistically overcoming drug-resistant bacteria. Upon light irradiation, the OPFV-NB can produce aldehyde active groups to covalently bind outer membrane proteins, such as tolerant colicin (TolC), blocking drug efflux of bacteria.
View Article and Find Full Text PDFGenomic and phenotypic characterization of multidrug-resistant serovar Reading isolates involved in a turkey-associated foodborne outbreak.
Front Microbiol
January 2024
USDA, ARS, National Animal Disease Center, Food Safety and Enteric Pathogens, Ames, IA, United States.
is a global bacterial foodborne pathogen associated with a variety of contaminated food products. Poultry products are a common source of -associated foodborne illness, and an estimated 7% of human illnesses in the United States are attributed to turkey products. From November 2017 to March 2019, the Centers for Disease Control and Prevention reported a turkey-associated outbreak of multidrug-resistant (MDR; resistant to ≥3 antimicrobial classes) serovar Reading (.
View Article and Find Full Text PDFUnusual modifications of protein biomarkers expressed by plasmid, prophage, and bacterial host of pathogenic Escherichia coli identified using top-down proteomic analysis.
Rapid Commun Mass Spectrom
January 2024
Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, California, USA.
Rationale: Pathogenic bacteria often carry prophage (bacterial viruses) and plasmids (small circular pieces of DNA) that may harbor toxin, antibacterial, and antibiotic resistance genes. Proteomic characterization of pathogenic bacteria should include the identification of host proteins and proteins produced by prophage and plasmid genomes.
Methods: Protein biomarkers of two strains of Shiga toxin-producing Escherichia coli (STEC) were identified using antibiotic induction, matrix-assisted laser desorption/ionization tandem time-of-flight (MALDI-TOF-TOF) tandem mass spectrometry (MS/MS) with post-source decay (PSD), top-down proteomic (TDP) analysis, and plasmid sequencing.
Analysis of In-Patient Evolution of Escherichia coli Reveals Potential Links to Relapse of Bone and Joint Infections.
J Infect Dis
May 2024
Genetics of Biofilms Laboratory, Institut Pasteur, Université de Paris-Cité, Paris, France.
Bone and joint infections (BJIs) are difficult to treat and affect a growing number of patients, in which relapses are observed in 10-20% of case. These relapses, which call for prolonged antibiotic treatment and increase resistance emergence risk, may originate from ill-understood adaptation of the pathogen to the host. Here, we investigated 3 pairs of Escherichia coli strains from BJI cases and their relapses to unravel adaptations within patients.
View Article and Find Full Text PDFNew insights into the antimicrobial action and protective therapeutic effect of tirapazamine towards Escherichia coli-infected mice.
Int J Antimicrob Agents
September 2023
Beijing Key Laboratory of Traditional Chinese Veterinary Medicine, Animal Science and Technology College, Beijing University of Agriculture, Beijing, China. Electronic address:
Objectives: Escherichia coli is an important pathogen responsible for numerous cases of diarrhoea worldwide. The bioreductive agent tirapazamine (TPZ), which was clinically used to treat various types of cancers, has obvious antibacterial activity against E. coli strains.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!