Related Experiment Videos
Lif, the lysostaphin immunity factor, complements FemB in staphylococcal peptidoglycan interpeptide bridge formation
M Tschierske1, K Ehlert, A M Strandén
1Institute of Medical Microbiology, University of Zürich, Switzerland.
Abstract:
The formation of the Staphylococcus aureus peptidoglycan pentaglycine interpeptide chain needs FemA and FemB for the incorporation of glycines Gly2-Gly3, and Gly4-Gly5, respectively. The lysostaphin immunity factor Lif was able to complement FemB, as could be shown by serine incorporation and by an increase in lysostaphin resistance in the wild-type as well as in a femB mutant. However, Lif could not substitute for FemA in femA or in femAB-null mutants. Methicillin resistance, which is dependent on functional FemA and FemB, was not complemented by Lif, suggesting that serine-substituted side chains are a lesser substrate for penicillin-binding protein PBP2' in methicillin resistance.
Insights
The Staphylococcus aureus FemB protein
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Staphylococcus aureus peptidoglycan synthesis is crucial for bacterial cell wall integrity.
- The pentaglycine interpeptide chain formation requires specific enzymes, FemA and FemB.
- Methicillin resistance in S. aureus is linked to the FemA and FemB proteins.
Purpose of the Study:
- To investigate the function of the lysostaphin immunity factor (Lif) in peptidoglycan synthesis.
- To determine if Lif can substitute for FemA or FemB.
- To assess the impact of Lif on methicillin resistance in S. aureus.
Main Methods:
- Complementation assays using serine incorporation.
- Assessing lysostaphin resistance in wild-type and mutant strains.
- Evaluating Lif's effect on methicillin resistance.
Main Results:
- Lif complemented the function of FemB, indicated by serine incorporation and increased lysostaphin resistance.
- Lif could not substitute for FemA in femA or femAB-null mutants.
- Lif did not complement methicillin resistance, suggesting serine-substituted side chains are poor substrates for PBP2'.
Conclusions:
- Lif functionally complements FemB in Staphylococcus aureus peptidoglycan synthesis.
- Lif's inability to complement FemA or methicillin resistance highlights specific roles for FemA and FemB.
- The findings suggest implications for understanding antibiotic resistance mechanisms.