Nutrient-Dependent Structural Changes in S. aureus Peptidoglycan Revealed by Solid-State NMR Spectroscopy
| Autor: | Xiaoxue Zhou, Lynette Cegelski |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Staphylococcus aureus
Pseudopeptidoglycan Peptidoglycan Biology medicine.disease_cause Biochemistry Mass Spectrometry Article Bacterial cell structure chemistry.chemical_compound Microscopy Electron Transmission chemistry Solid-state nuclear magnetic resonance Carbohydrate Conformation medicine Carbohydrate conformation Cell envelope Nuclear Magnetic Resonance Biomolecular Chromatography High Pressure Liquid Macromolecule |
| Zdroj: | Biochemistry. 51:8143-8153 |
| ISSN: | 1520-4995 0006-2960 |
| Popis: | The bacterial cell wall is essential to cell survival and is a major target of antibiotics. The main component of the bacterial cell wall is peptidoglycan, a cage-like macromolecule that preserves cellular integrity and maintains cell shape. The insolubility and heterogeneity of peptidoglycan pose a challenge to conventional structural analyses. Here we use solid-state NMR combined with specific isotopic labeling to probe a key structural feature of the Staphylococcus aureus peptidoglycan quantitatively and nondestructively. We observed that both the cell-wall morphology and the peptidoglycan structure are functions of growth stage in S. aureus synthetic medium (SASM). Specifically, S. aureus cells at stationary phase have thicker cell walls with non-uniformly thickened septa compared to cells in exponential phase and, remarkably, 12% (±2%) of the stems in their peptidoglycan do not have pentaglycine bridges attached. Mechanistically, we determined that these observations are triggered by the depletion of glycine in the nutrient medium, which is coincident with the start of the stationary phase, and that the production of the structurally altered peptidoglycan can be prevented by the addition of excess glycine. We also demonstrated that the structural changes primarily arise within newly synthesized peptidoglycan rather than through the modification of previously synthesized peptidoglycan. Collectively, our observations emphasize the plasticity in bacterial cell-wall assembly and the possibility to manipulate peptidoglycan structure with external stimuli. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|