Journal: BMC Microbiology
Article Title: Induction kinetics of the Staphylococcus aureus cell wall stress stimulon in response to different cell wall active antibiotics
doi: 10.1186/1471-2180-11-16
Figure Lengend Snippet: Schematic representation of the enzymatic steps involved in S. aureus cell wall synthesis and the targets of cell wall active antibiotics . Fosfomycin inhibits the enzyme MurA (UDP- N -acetylglucosamine-3-enolpyruvyl transferase) that catalyses the addition of phosphoenolpyruvate (PEP) to UDP- N -acetyl-glucosamine (GlcNAc) to form UDP-N-acetyl-muramic acid (UDP-MurNAc) . D-cycloserine prevents the addition of D-alanine to the peptidoglycan precursor by inhibiting D-alanine:D-alanine ligase A and alanine racemase . Tunicamycin is a glycoprotein antibiotic that inhibits the transfer of peptidoglycan precursor (phospho-MurNAc-pentapeptide) to the lipid carrier undecaprenyl pyrophosphate (or C55-isoprenyl pyrophosphate), catalysed by the translocase MraY [ , ]. Sub-lethal concentrations of tunicamycin also inhibit TarO, the first enzyme in the wall teichoic acid pathway [ , ]. Bacitracin forms a metal-dependent complex with the lipid carrier undecaprenyl pyrophosphate, thereby preventing dephosphorylation and the recycling of the lipid carrier required for cell wall synthesis [ , ]. Flavomycin (a moenomycin complex) is a phosphoglycolipid antibiotic that inhibits transglycosylation through binding of the transglycosylase domain of penicillin-binding protein 2 (PBP2) . Glycopeptide antibiotics, such as vancomycin and teicoplanin, inhibit cell wall synthesis by binding the D-ala-D-ala of the lipid II and sterically hindering transglycosylation and transpeptidation. Teicoplanin activity is enhanced through its interaction with the cytoplasmic membrane . ß-lactam antibiotics, such as oxacillin, bind the transpeptidase active domain of penicillin-binding proteins (PBPs) by mimicking the D-ala-D-ala end of the pentapeptide . The mode of action of daptomycin is not fully known, it causes calcium-dependent disruption of membrane function and potassium efflux , but was also predicted to directly or indirectly inhibit peptidoglycan systhesis . Lysostaphin is a zinc metalloenzyme that cleaves the pentaglycine crosslinking bridge specific for the cell wall of S. aureus . (Adapted from ).
Article Snippet: Cultures were grown to OD 0.3 - 0.5 and pre-induction samples were collected before the cultures were induced with increasing concentrations of the antibiotics: fosfomycin (disodium salt, Sigma), D-cycloserine (Sigma), bacitracin (from Bacillus lincheniformis , Sigma), vancomycin (Vancocin, Eli Lilly), teicoplanin (Hoechst Marion Roussel), oxacillin (InfectoPharm), flavomycin (BC Biochemie GmbH), daptomycin (Cubist Pharmaceuticals), tunicamycin (AG Scientifics) and lysostaphin (ambicin, AMBI).
Techniques: De-Phosphorylation Assay, Binding Assay, Activity Assay
![Schematic representation of the enzymatic steps involved in S. aureus cell wall synthesis and the targets of cell wall active antibiotics . <t>Fosfomycin</t> inhibits the enzyme MurA (UDP- N -acetylglucosamine-3-enolpyruvyl transferase) that catalyses the addition of phosphoenolpyruvate (PEP) to UDP- N -acetyl-glucosamine (GlcNAc) to form UDP-N-acetyl-muramic acid (UDP-MurNAc) . D-cycloserine prevents the addition of D-alanine to the peptidoglycan precursor by inhibiting D-alanine:D-alanine ligase A and alanine racemase . Tunicamycin is a glycoprotein antibiotic that inhibits the transfer of peptidoglycan precursor (phospho-MurNAc-pentapeptide) to the lipid carrier undecaprenyl pyrophosphate (or C55-isoprenyl pyrophosphate), catalysed by the translocase MraY [ , ]. Sub-lethal concentrations of tunicamycin also inhibit TarO, the first enzyme in the wall teichoic acid pathway [ , ]. Bacitracin forms a metal-dependent complex with the lipid carrier undecaprenyl pyrophosphate, thereby preventing dephosphorylation and the recycling of the lipid carrier required for cell wall synthesis [ , ]. Flavomycin (a moenomycin complex) is a phosphoglycolipid antibiotic that inhibits transglycosylation through binding of the transglycosylase domain of penicillin-binding protein 2 (PBP2) . Glycopeptide antibiotics, such as vancomycin and teicoplanin, inhibit cell wall synthesis by binding the D-ala-D-ala of the lipid II and sterically hindering transglycosylation and transpeptidation. Teicoplanin activity is enhanced through its interaction with the cytoplasmic membrane . ß-lactam antibiotics, such as oxacillin, bind the transpeptidase active domain of penicillin-binding proteins (PBPs) by mimicking the D-ala-D-ala end of the pentapeptide . The mode of action of daptomycin is not fully known, it causes calcium-dependent disruption of membrane function and potassium efflux , but was also predicted to directly or indirectly inhibit peptidoglycan systhesis . Lysostaphin is a zinc metalloenzyme that cleaves the pentaglycine crosslinking bridge specific for the cell wall of S. aureus . (Adapted from ).](https://pub-med-central-images-cdn.bioz.com/pub_med_central_ids_ending_with_2642/pmc03032642/pmc03032642__1471-2180-11-16-1.jpg)
