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Semi-Quantitative Analysis of Peptidoglycan by Liquid Chromatography Mass Spectrometry and Bioinformatics
09:09

Semi-Quantitative Analysis of Peptidoglycan by Liquid Chromatography Mass Spectrometry and Bioinformatics

Published on: October 13, 2020

Structure-function analysis of MurJ reveals a solvent-exposed cavity containing residues essential for peptidoglycan

Emily K Butler1, Rebecca M Davis, Vase Bari

  • 1Department of Microbiology, The Ohio State University, Columbus, Ohio, USA.

Journal of Bacteriology
|August 13, 2013
PubMed

Insights

The essential bacterial cell wall protein MurJ, a proposed lipid II flippase, has a 3D structure revealing a central cavity. Specific charged residues within this cavity are crucial for MurJ

Area of Science:

  • Microbiology
  • Structural Biology
  • Biochemistry

Background:

  • Gram-negative bacteria like E. coli require peptidoglycan (PG) for cell wall integrity.
  • Lipid II is a crucial precursor for PG synthesis, requiring translocation across the inner membrane.
  • MurJ, an inner membrane protein, is essential for PG biogenesis and homologous to MOP exporter superfamily flippases.

Purpose of the Study:

  • To determine the structure and function of the essential E. coli inner membrane protein MurJ.
  • To investigate MurJ's role as a potential lipid II flippase in peptidoglycan biosynthesis.

Main Methods:

  • Generated a 3D structural model of MurJ using the I-TASSER server.
  • Performed in vivo topological studies to determine transmembrane domains.
  • Conducted functional studies on charged residues within MurJ's central cavity.

Main Results:

  • A 3D model of MurJ revealed a solvent-exposed cavity within the membrane plane.
  • MurJ possesses 14 transmembrane domains, validating structural model features.
  • Specific charged residues in the central cavity are essential for MurJ function.

Conclusions:

  • MurJ's structure is homologous to MOP exporter proteins.
  • The findings support MurJ's proposed function as an essential transporter in peptidoglycan biosynthesis.
  • MurJ likely functions as the lipid II flippase in E. coli.

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