Related Experiment Video

Updated: Jul 1, 2025

Using Microtiter Dish Radiolabeling for Multiple In Vivo Measurements Of Escherichia coli pppGpp Followed by Thin Layer Chromatography
06:30

Using Microtiter Dish Radiolabeling for Multiple In Vivo Measurements Of Escherichia coli pppGpp Followed by Thin Layer Chromatography

Published on: June 4, 2019

6.0K

(p)ppGpp modifies RNAP function to confer β-lactam resistance in a peptidoglycan-independent manner

Henri Voedts1, Constantin Anoyatis-Pelé1, Olivier Langella2

  • 1Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université Paris Cité, Paris, France.

Nature Microbiology
|March 5, 2024
PubMed

Insights

Elevated (p)ppGpp levels confer beta-lactam resistance without altering peptidoglycan metabolism. Modifications in RNA polymerase and ribosome function are key to preventing beta-lactam inactivation of essential enzymes.

Area of Science:

  • Bacterial Physiology
  • Molecular Biology
  • Antimicrobial Resistance

Background:

  • The alarmone (p)ppGpp regulates bacterial responses to nutrient stress.
  • Elevated (p)ppGpp levels are linked to mecillinam and broad-spectrum beta-lactam resistance, particularly via the beta-lactam-insensitive transpeptidase YcbB (LdtD).

Purpose of the Study:

  • To investigate the potential role of (p)ppGpp in modulating bacterial cell wall peptidoglycan metabolism concerning beta-lactam resistance.
  • To elucidate the mechanisms underlying (p)ppGpp-mediated beta-lactam resistance.

Main Methods:

  • Analysis of Escherichia coli peptidoglycan structure using high-resolution mass spectrometry.
  • Genetic manipulation including amino acid substitutions in RNA polymerase (RNAP) subunits and CRISPR interference (CRISPRi) for ribosomal RNA operon downregulation.

Main Results:

  • (p)ppGpp-dependent beta-lactam resistance was confirmed not to involve alterations in peptidoglycan metabolism.
  • Specific amino acid substitutions in RNAP subunits, with or without ribosomal RNA operon downregulation, conferred resistance.
  • Beta-lactams were found to have no direct impact on RNAP or ribosomes.

Conclusions:

  • Beta-lactam resistance mediated by (p)ppGpp is independent of changes in peptidoglycan metabolism.
  • Modifications in RNA polymerase and ribosome function are crucial for preventing the detrimental effects of beta-lactams on peptidoglycan transpeptidases.

More Related Videos

Identifying the Binding Proteins of Small Ligands with the Differential Radial Capillary Action of Ligand Assay DRaCALA09:26

Identifying the Binding Proteins of Small Ligands with the Differential Radial Capillary Action of Ligand Assay DRaCALA

Published on: March 19, 2021

3.5K
A Purification and In Vitro Activity Assay for a pppGpp Synthetase from Clostridium difficile09:53

A Purification and In Vitro Activity Assay for a pppGpp Synthetase from Clostridium difficile

Published on: November 3, 2018

8.4K

Related Concept Videos

Bacterial RNA Polymerase00:43

Bacterial RNA Polymerase

Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
29.5K
Types of RNA01:23

Types of RNA

Overview
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse functions and can be broadly classified as protein-coding or non-coding RNA. Non-coding RNAs play important roles in the regulation of gene expression in response to developmental and environmental changes. Non-coding RNAs in prokaryotes can be manipulated to develop more effective antibacterial drugs for human or animal use.
RNA...
63.7K
Transcription Attenuation in Prokaryotes02:42

Transcription Attenuation in Prokaryotes

Transcriptional attenuation occurs when RNA transcription is prematurely terminated due to the formation of a terminator mRNA hairpin structure.  Bacteria use these hairpins to regulate the transcription process and control the synthesis of several amino acids including histidine, lysine, threonine, and phenylalanine. Transcription attenuation takes place in the non-coding regions of mRNA.
There are several different mechanisms used to attenuate transcription. In ribosome mediated...
15.3K
Prokaryotic Transcriptional Activators and Repressors01:58

Prokaryotic Transcriptional Activators and Repressors

The organization of prokaryotic genes in their genome is notably different from that of eukaryotes. Prokaryotic genes are organized, such that the genes for proteins involved in the same biochemical process or function are located together in groups. This group of genes, along with their regulatory elements, are collectively known as an operon. The functional genes in an operon are transcribed together to give a single strand of mRNA known as polycistronic mRNA.
Transcription of prokaryotic...
21.0K
Eukaryotic RNA Polymerases00:58

Eukaryotic RNA Polymerases

RNA Polymerase (RNAP) is conserved in all animals, with bacterial, archaeal, and eukaryotic RNAPs sharing significant sequence, structural, and functional similarities. Among the three eukaryotic RNAPs, RNA Polymerase II is most similar to bacterial RNAP in terms of both structural organization and folding topologies of the enzyme subunits. However, these similarities are not reflected in their mechanism of action.
All three eukaryotic RNAPs require specific transcription factors, of which the...
24.2K
Antibiotic Selection00:57

Antibiotic Selection

Overview
53.5K