3PBN

Crystal Structure of Apo PBP3 from Pseudomonas aeruginosa

Summary for 3PBN

• Entry DOI: 10.2210/pdb3pbn/pdb
• Related: 3PBO 3PBQ 3PBR 3PBS 3PBT
• Descriptor: Penicillin-binding protein 3 (2 entities in total)
• Functional Keywords: pbp3, hydrolase-antibiotic complex, hydrolase/antibiotic
• Biological source: Pseudomonas aeruginosa
• Total number of polymer chains: 1
• Total formula weight: 58329.45

Authors

Han, S. (deposition date: 2010-10-20, release date: 2010-12-22, Last modification date: 2024-02-21)

Primary citation

Han, S.,Zaniewski, R.P.,Marr, E.S.,Lacey, B.M.,Tomaras, A.P.,Evdokimov, A.,Miller, J.R.,Shanmugasundaram, V.
Structural basis for effectiveness of siderophore-conjugated monocarbams against clinically relevant strains of Pseudomonas aeruginosa.
Proc.Natl.Acad.Sci.USA, 107:22002-22007, 2010

PubMed Abstract: Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen that causes nosocomial infections for which there are limited treatment options. Penicillin-binding protein PBP3, a key therapeutic target, is an essential enzyme responsible for the final steps of peptidoglycan synthesis and is covalently inactivated by β-lactam antibiotics. Here we disclose the first high resolution cocrystal structures of the P. aeruginosa PBP3 with both novel and marketed β-lactams. These structures reveal a conformational rearrangement of Tyr532 and Phe533 and a ligand-induced conformational change of Tyr409 and Arg489. The well-known affinity of the monobactam aztreonam for P. aeruginosa PBP3 is due to a distinct hydrophobic aromatic wall composed of Tyr503, Tyr532, and Phe533 interacting with the gem-dimethyl group. The structure of MC-1, a new siderophore-conjugated monocarbam complexed with PBP3 provides molecular insights for lead optimization. Importantly, we have identified a novel conformation that is distinct to the high-molecular-weight class B PBP subfamily, which is identifiable by common features such as a hydrophobic aromatic wall formed by Tyr503, Tyr532, and Phe533 and the structural flexibility of Tyr409 flanked by two glycine residues. This is also the first example of a siderophore-conjugated triazolone-linked monocarbam complexed with any PBP. Energetic analysis of tightly and loosely held computed hydration sites indicates protein desolvation effects contribute significantly to PBP3 binding, and analysis of hydration site energies allows rank ordering of the second-order acylation rate constants. Taken together, these structural, biochemical, and computational studies provide a molecular basis for recognition of P. aeruginosa PBP3 and open avenues for future design of inhibitors of this class of PBPs.

PubMed: 21135211
DOI: 10.1073/pnas.1013092107

Experimental method

X-RAY DIFFRACTION (2 Å)