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Biochemical and Structural Characterization of the Carbohydrate Transport Substrate-binding-protein SP0092
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Structure-based modeling and dynamics of MurM, a Streptococcus pneumoniae penicillin resistance determinant present

Anna York1, Adrian J Lloyd1, Charo I Del Genio2

  • 1School of Life Science, University of Warwick, Coventry, West Midlands CV4 7AL, UK.

Structure (London, England : 1993)
|March 19, 2021
PubMed

Insights

MurM protein is crucial for penicillin resistance in Streptococcus pneumoniae. Its activity is enhanced by cardiolipin, a membrane phospholipid, which may be key to peptidoglycan structure and resistance.

Area of Science:

  • Microbiology
  • Structural Biology
  • Biochemistry

Background:

  • Peptidoglycan synthesis is essential for bacterial cell wall integrity.
  • MurM protein is vital for producing Branched Lipid II, a precursor for indirectly crosslinked peptidoglycan.
  • MurM is a key factor in high-level penicillin resistance in Streptococcus pneumoniae.

Purpose of the Study:

  • To investigate the structural and functional interactions of MurM with the bacterial membrane.
  • To elucidate the role of membrane phospholipids in MurM activity and penicillin resistance.

Main Methods:

  • X-ray crystallography of Staphylococcus aureus FemX (MurM homolog).
  • Homology modeling to create a MurM model.
  • Molecular docking and molecular dynamics simulations.
  • Experimental validation of phospholipid effects on MurM activity.

Main Results:

  • A homology model of MurM was generated using the FemX crystal structure.
  • Molecular simulations suggested MurM associates with cardiolipin in the phospholipid bilayer.
  • Experimental data confirmed cardiolipin enhances MurM activity, while phosphatidylglycerol inhibits it.

Conclusions:

  • Cardiolipin's interaction with MurM is critical for its function.
  • Membrane phospholipid composition influences MurM activity, impacting peptidoglycan synthesis.
  • These interactions are potentially vital for Streptococcus pneumoniae's penicillin resistance mechanism.
Keywords:
MurMStreptococcus pneumoniaehomology modelingindirect crosslinkslipid bilayermolecular dockingmolecular dynamicspenicillin resistancepeptidoglycan

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