Molecular changes in Staphylococcus aureus fem (factors essential for methicillin resistance) mutants, analyzed via Mass Spectrometry




Nguyen, Thanh

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As Staphylococcus aureus is becoming increasingly resistant to beta-lactam antibiotics, it is important to identify the mechanism of resistance on a molecular level. This study seeks to explore the molecular changes in cross-linking, cross-linking efficiency, alanylation, and O-acetylation of the S. aureus peptidoglycan in fem (factors essential to methicillin resistance) mutants which control glycine bridge linkage. Three different samples, BB255, UK-17, and UT34-2 were accessed by mass spectrometry, which is a technique used to measure the different molecules within the sample. The data was analyzed for changes in the cell wall via a program created by a Baylor graduate student within MassLynx. Results indicated that femB with three glycine linkages has a greater crosslinking efficiency than femA. Alanylation was similar for both mutants, and O-acetylation was slightly more prominent in femB. These results are consistent with previous experiments that used nuclear magnetic resonance techniques. Triglycine bridges of S. aureus peptidoglycan seem to yield more resistance to methicillin antibiotics than monoglycine bridges do.



Staphylococcus aureus., Gram-postive bacteria., Peptidoglycan., Mass Spectrometry., Fem mutants., Cross Linking., Alanylation., Acetylation., Antibiotic resistance., Methicillin.