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Dual roles of FmtA in Staphylococcus aureus cell wall biosynthesis and autolysis

Aneela Qamar1, Dasantila Golemi-Kotra

  • 1Department of Biology, York University, Toronto, Ontario, Canada.

Antimicrobial Agents and Chemotherapy
|May 9, 2012
PubMed

Insights

The Staphylococcus aureus FmtA protein has dual roles in bacterial growth. Low FmtA concentrations promote autolysis and biofilm production, while high concentrations enhance growth by aiding peptidoglycan synthesis.

Area of Science:

  • Microbiology
  • Bacterial Cell Wall Biology

Background:

  • The fmtA gene is part of the Staphylococcus aureus core cell wall stimulon.
  • The FmtA protein is known to interact with beta-lactams, forming covalent adducts.

Purpose of the Study:

  • To elucidate the enzymatic activity and cellular localization of the FmtA protein.
  • To investigate the role of FmtA in Staphylococcus aureus growth, autolysis, and biofilm production.
  • To determine the interaction between FmtA and wall teichoic acids.

Main Methods:

  • Enzymatic assays to determine D-Ala-D-Ala-carboxypeptidase activity.
  • Covalent incorporation assays using C14-Gly.
  • Fluorescence microscopy for protein localization.
  • Studies on S. aureus subjected to varying FmtA concentrations.

Main Results:

  • FmtA exhibits weak D-Ala-D-Ala-carboxypeptidase activity and incorporates C14-Gly into cell walls.
  • FmtA localizes to the cell division septum and specifically interacts with wall teichoic acids.
  • Low FmtA concentrations (≤0.1 μM) induce autolysis and biofilm production, dependent on wall teichoic acids.
  • High FmtA concentrations (>0.2 μM) repress autolysis and biofilm formation, enhancing bacterial growth.

Conclusions:

  • FmtA plays dual roles in S. aureus growth, potentially modulating autolysin AtlA at low concentrations and participating in peptidoglycan synthesis at high concentrations.
  • These dual functions suggest FmtA adapts to different cellular conditions, possibly reflecting responses to cell wall stress.

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