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Structural and kinetic analyses of penicillin-binding protein 4 (PBP4)-mediated antibiotic resistance in Staphylococcus aureus
- Publication Year :
- 2018
- Publisher :
- American Society for Biochemistry and Molecular Biology, 2018.
-
Abstract
- Methicillin-resistant Staphylococcus aureus (MRSA) causes serious community-acquired and nosocomial infections worldwide. MRSA strains are resistant to a variety of antibiotics, including the classic penicillin and cephalosporin classes of β-lactams, making them intractable to treatment. Although β-lactam resistance in MRSA has been ascribed to the acquisition and activity of penicillin-binding protein 2a (PBP2a, encoded by mecA), it has recently been observed that resistance can also be mediated by penicillin-binding protein 4 (PBP4). Previously, we have shown that broad-spectrum β-lactam resistance can arise following serial passaging of a mecA-negative COL strain of S. aureus, creating the CRB strain. This strain has two missense mutations in pbp4 and a mutation in the pbp4 promoter, both of which play an instrumental role in β-lactam resistance. To better understand PBP4's role in resistance, here we have characterized its kinetics and structure with clinically relevant β-lactam antibiotics. We present the first crystallographic PBP4 structures of apo and acyl-enzyme intermediate forms complexed with three late-generation β-lactam antibiotics: ceftobiprole, ceftaroline, and nafcillin. In parallel, we characterized the structural and kinetic effects of the PBP4 mutations present in the CRB strain. Localized within the transpeptidase active-site cleft, the two substitutions appear to have different effects depending on the drug. With ceftobiprole, the missense mutations impaired the K(m) value 150-fold, decreasing the proportion of inhibited PBP4. However, ceftaroline resistance appeared to be mediated by other factors, possibly including mutation of the pbp4 promoter. Our findings provide evidence that S. aureus CRB has at least two PBP4-mediated resistance mechanisms.
- Subjects :
- 0301 basic medicine
Models, Molecular
Staphylococcus aureus
Penicillin binding proteins
medicine.drug_class
030106 microbiology
Antibiotics
Ceftobiprole
medicine.disease_cause
Biochemistry
Microbiology
03 medical and health sciences
Antibiotic resistance
Bacterial Proteins
Catalytic Domain
medicine
polycyclic compounds
Penicillin-Binding Proteins
Amino Acid Sequence
Nafcillin
Molecular Biology
Chemistry
Drug Resistance, Microbial
Cell Biology
biochemical phenomena, metabolism, and nutrition
3. Good health
Penicillin
Multiple drug resistance
Kinetics
030104 developmental biology
Protein Structure and Folding
medicine.drug
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....5eb49d8573091928d97777112e35cf22