Related Experiment Video

Updated: Jun 14, 2026

Fluorescent Immunolocalization of Arabinogalactan Proteins and Pectins in the Cell Wall of Plant Tissues
10:14

Fluorescent Immunolocalization of Arabinogalactan Proteins and Pectins in the Cell Wall of Plant Tissues

Published on: February 27, 2021

A deficiency in arabinogalactan biosynthesis affects Corynebacterium glutamicum mycolate outer membrane stability

Roland Bou Raad1, Xavier Méniche, Celia de Sousa-d'Auria

  • 1Laboratoire de Microbiologie Moléculaire et Cellulaire, Institut de Biochimie et de Biophysique Moléculaire et Cellulaire (IBBMC), UMR 8619, Université de Paris Sud XI et Centre National de la Recherche Scientifique (CNRS), F-91405 Orsay Cedex, France.

Journal of Bacteriology
|April 6, 2010
PubMed

Insights

Altering arabinogalactan biosynthesis in Corynebacterineae bacteria disrupts the cell envelope, causing outer membrane fragments to be released. This highlights the importance of the mycolate outer membrane

Area of Science:

  • Bacteriology
  • Cell Biology
  • Biochemistry

Background:

  • Corynebacterineae, including Mycobacterium tuberculosis and Corynebacterium glutamicum, possess a unique Gram-positive cell envelope structure.
  • This envelope features a heteropolymer of peptidoglycan and arabinogalactan (AG) covalently linked to an outer membrane.
  • Arabinogalactan biosynthesis involves multiple arabinosyltransferases, with AftB specifically adding arabinofuranosyl (Araf) residues.

Purpose of the Study:

  • To investigate the role of AftB in arabinogalactan biosynthesis and its impact on cell envelope integrity in C. glutamicum.
  • To characterize the cell envelope defects and outer membrane shedding in a Delta aftB mutant.
  • To explore the potential of outer membrane-derived fragments (OMFs) for characterizing the Corynebacterineae outer membrane.

Main Methods:

  • Generating and analyzing a Delta aftB mutant of Corynebacterium glutamicum.
  • Assessing arabinogalactan mycoloylation sites in the mutant.
  • Analyzing the composition of shed membrane fragments using techniques like protein fingerprinting.
  • Investigating cell envelope structure and integrity.

Main Results:

  • Delta aftB cells exhibit reduced arabinogalactan mycoloylation but can still form an outer membrane.
  • Mutant cells grown in rich medium show a perturbed cell envelope and release significant amounts of membrane fragments.
  • These OMFs contain trehalose mycolates and the porin PorA/H, but lack typical plasma membrane phospholipids.
  • This is the first report of outer membrane destabilization in Corynebacterineae, indicating the necessity of strong outer membrane-polymer interactions for integrity.

Conclusions:

  • The study demonstrates that AftB-mediated AG biosynthesis is crucial for maintaining the integrity of the atypical mycolate outer membrane in Corynebacterineae.
  • The release of OMFs from the Delta aftB mutant provides a valuable resource for studying the composition and structure of this unique outer membrane.
  • Further analysis of OMFs led to the identification of novel proteins involved in outer membrane biogenesis, including mycoloyltransferases and a potential S-layer protein homolog.

More Related Videos

Separation of the Cell Envelope for Gram-negative Bacteria into Inner and Outer Membrane Fractions with Technical Adjustments for Acinetobacter baumannii10:24

Separation of the Cell Envelope for Gram-negative Bacteria into Inner and Outer Membrane Fractions with Technical Adjustments for Acinetobacter baumannii

Published on: April 10, 2020

Functional Complementation Analysis (FCA): A Laboratory Exercise Designed and Implemented to Supplement the Teaching of Biochemical Pathways09:27

Functional Complementation Analysis (FCA): A Laboratory Exercise Designed and Implemented to Supplement the Teaching of Biochemical Pathways

Published on: June 24, 2016

Related Concept Videos

Bacterial Phylum Actinobacteria01:30

Bacterial Phylum Actinobacteria

Coryneform bacteria are gram-positive, aerobic, nonmotile rods that exhibit irregular, club-shaped, or V-shaped arrangements. Their V-shape results from snapping division, where the inner cell wall layer forms the cross-wall, while the outer layer remains intact until it ruptures on one side, causing the daughter cells to bend away.The primary genera are Corynebacterium and Arthrobacter. Corynebacterium includes diverse species, ranging from saprophytes to pathogens like Corynebacterium...
Archaeal Cell Wall01:29

Archaeal Cell Wall

Archaeal cell walls are structurally and compositionally distinct from their bacterial counterparts, lacking the characteristic peptidoglycan layer found in most bacteria. Instead, archaeal cell walls exhibit remarkable diversity, utilizing materials such as pseudomurein, polysaccharides, and proteins to construct their protective outer layers. This structural flexibility is closely tied to archaea's ecological adaptability.S-Layers: The Common Archaeal Cell WallThe S-layer is the most...
Inhibitors of Gram-positive Cell Wall Synthesis01:23

Inhibitors of Gram-positive Cell Wall Synthesis

Bacterial cell walls are typically rigid structures composed mainly of peptidoglycan, a mesh-like polymer that provides mechanical strength and maintains cell shape. The synthesis of peptidoglycan is a crucial process in bacterial growth and serves as a primary target for many antibiotics.Mechanism of Action of Beta-Lactam AntibioticsBeta-lactam antibiotics, such as penicillin, inhibit peptidoglycan synthesis in actively growing cells. These antibiotics share a characteristic four-membered...
Bacterial Cell Wall01:22

Bacterial Cell Wall

The bacterial cell wall is an essential structural component that encases the plasma membrane, preserving cellular integrity, determining shape, and protecting against osmotic stress. This rigid yet flexible structure primarily comprises peptidoglycan, a polymer that forms a mesh-like matrix conferring mechanical strength and flexibility.Peptidoglycan Composition and StructurePeptidoglycan, the core of the bacterial cell wall, comprises alternating units of N-acetylglucosamine (NAG) and...
Peptidoglycan Synthesis01:28

Peptidoglycan Synthesis

Structure of PeptidoglycanPeptidoglycan is a vital structural component of the bacterial cell wall, providing mechanical strength and shape to the cell. It consists of repeating units of two sugars—N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)—linked by β-1,4 glycosidic bonds. These sugar chains are cross-linked by short peptide chains, forming a mesh-like polymer that surrounds the bacterial plasma membrane.Cytoplasmic Phase – Precursor SynthesisPeptidoglycan biosynthesis begins in...
Gene Regulation During Sporulation01:17

Gene Regulation During Sporulation

Sporulation is a complex developmental process that allows certain Gram-positive bacteria, such as Bacillus subtilis and Clostridium species, to survive extreme environmental conditions. This process is tightly regulated by a series of signaling cascades and transcriptional controls, ensuring the formation of a highly resistant endospore.Sporulation is triggered by unfavorable conditions, such as nutrient depletion, and is governed by a phosphorelay system. One of the sensor kinases, such as...