Structural Insights into Ceftobiprole Inhibition of Pseudomonas aeruginosa Penicillin-Binding Protein 3

Antimicrob Agents Chemother. 2020 Apr 21;64(5):e00106-20. doi: 10.1128/AAC.00106-20. Print 2020 Apr 21.


Ceftobiprole is an advanced-generation broad-spectrum cephalosporin antibiotic with potent and rapid bactericidal activity against Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus, as well as susceptible Gram-negative pathogens, including Pseudomonas sp. pathogens. In the case of Pseudomonas aeruginosa, ceftobiprole acts by inhibiting P. aeruginosa penicillin-binding protein 3 (PBP3). Structural studies were pursued to elucidate the molecular details of this PBP inhibition. The crystal structure of the His-tagged PBP3-ceftobiprole complex revealed a covalent bond between the ligand and the catalytic residue S294. Ceftobiprole binding leads to large active site changes near binding sites for the pyrrolidinone and pyrrolidine rings. The S528 to L536 region adopts a conformation previously not observed in PBP3, including partial unwinding of the α11 helix. These molecular insights can lead to a deeper understanding of β-lactam-PBP interactions that result in major changes in protein structure, as well as suggesting how to fine-tune current inhibitors and to develop novel inhibitors of this PBP.

Keywords: beta-lactam antibiotic; penicillin-binding protein; protein crystallography.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Anti-Bacterial Agents / metabolism
  • Anti-Bacterial Agents / pharmacology*
  • Binding Sites / physiology
  • Catalytic Domain / drug effects
  • Cephalosporins / metabolism*
  • Cephalosporins / pharmacology
  • Crystallography, X-Ray
  • Humans
  • Methicillin-Resistant Staphylococcus aureus / drug effects
  • Microbial Sensitivity Tests
  • Molecular Conformation
  • Penicillin-Binding Proteins / antagonists & inhibitors*
  • Penicillin-Binding Proteins / metabolism*
  • Protein Binding
  • Pseudomonas aeruginosa / drug effects*


  • Anti-Bacterial Agents
  • Cephalosporins
  • Penicillin-Binding Proteins
  • ceftobiprole