Tertiary structure of Staphylococcus aureus cell wall murein

Area of Science:

• Microbiology
• Biophysics
• Computational Biology

Background:

• The Gram-negative bacterial cell wall scaffold model describes perpendicular glycan strands and parallel peptide bridges.
• Understanding Gram-positive bacterial cell wall architecture, particularly Staphylococcus aureus, requires refined models.

Purpose of the Study:

• To propose a refined model for Staphylococcus aureus peptidoglycan arrangement based on computer simulations.
• To investigate the critical role of peptide bridge orientation in the highly cross-linked murein architecture of S. aureus.

Main Methods:

• Computer simulations were employed to study the peptidoglycan arrangement.
• The study utilized the scaffold model as a basis for simulations.

Main Results:

• The proposed model suggests both glycan and oligopeptide chains in staphylococcal murein are perpendicular to the plasma membrane.
• Oligopeptide chains adopt a zigzag conformation, zippering adjacent glycan strands.
• This model explains the high degree of cross-linking characteristic of the S. aureus cell wall.

Conclusions:

• Peptide bridge orientation is critical for the highly cross-linked murein architecture of Staphylococcus aureus.
• The refined model is consistent with S. aureus cytokinesis features, including division plane alterations and centripetal septum closure.