Structural Characterization of Diazabicyclooctane β-Lactam “Enhancers” in Complex with Penicillin-Binding Proteins PBP2 and PBP3 of Pseudomonas aeruginosa
- 23 February 2021
- journal article
- research article
- Published by American Society for Microbiology in mBio
- Vol. 12 (1)
- https://doi.org/10.1128/mbio.03058-20
Abstract
Multidrug-resistant (MDR) pathogens pose a significant public health threat. A major mechanism of resistance expressed by MDR pathogens is β-lactamase-mediated degradation of β-lactam antibiotics. The diazabicyclooctane (DBO) compounds zidebactam and WCK 5153, recognized as β-lactam “enhancers” due to inhibition of Pseudomonas aeruginosa penicillin-binding protein 2 (PBP2), are also class A and C β-lactamase inhibitors. To structurally probe their mode of PBP2 inhibition as well as investigate why P. aeruginosa PBP2 is less susceptible to inhibition by β-lactam antibiotics compared to the Escherichia coli PBP2, we determined the crystal structure of P. aeruginosa PBP2 in complex with WCK 5153. WCK 5153 forms an inhibitory covalent bond with the catalytic S327 of PBP2. The structure suggests a significant role for the diacylhydrazide moiety of WCK 5153 in interacting with the aspartate in the S-X-N/D PBP motif. Modeling of zidebactam in the active site of PBP2 reveals a similar binding mode. Both DBOs increase the melting temperature of PBP2, affirming their stabilizing interactions. To aid in the design of DBOs that can inhibit multiple PBPs, the ability of three DBOs to interact with P. aeruginosa PBP3 was explored crystallographically. Even though the DBOs show covalent binding to PBP3, they destabilized PBP3. Overall, the studies provide insights into zidebactam and WCK 5153 inhibition of PBP2 compared to their inhibition of PBP3 and the evolutionarily related KPC-2 β-lactamase. These molecular insights into the dual-target DBOs advance our knowledge regarding further DBO optimization efforts to develop novel potent β-lactamase-resistant, non-β-lactam PBP inhibitors. IMPORTANCE Antibiotic resistance is a significant clinical problem. Developing novel antibiotics that overcome known resistance mechanisms is highly desired. Diazabicyclooctane inhibitors such as zidebactam possess this potential as they readily inactivate penicillin-binding proteins, yet cannot be degraded by β-lactamases. In this study, we characterized the inhibition by diazabicyclooctanes of penicillin-binding proteins PBP2 and PBP3 from Pseudomonas aeruginosa using protein crystallography and biophysical analyses. These structures and analyses help define the antibiotic properties of these inhibitors, explain the decreased susceptibility of P. aeruginosa PBP2 to be inhibited by β-lactam antibiotics, and provide insights that could be used for further antibiotic development.Keywords
Funding Information
- HHS | NIH | National Institute of Allergy and Infectious Diseases (R01AI100560, R01AI063517, R01AI072219)
- U.S. Department of Veterans Affairs (1I01BX001974)
- Wockhardt
This publication has 39 references indexed in Scilit:
- Comparative Evaluation of the In Vitro Activities of WCK 5222 (Cefepime-Zidebactam) and Combination Antibiotic Therapies against Carbapenem-Resistant Pseudomonas aeruginosaAntimicrobial Agents and Chemotherapy, 2020
- Effective inhibition of PBPs by cefepime and zidebactam in the presence of VIM-1 drives potent bactericidal activity against MBL-expressing Pseudomonas aeruginosaJournal of Antimicrobial Chemotherapy, 2020
- Efficacy of human-simulated bronchopulmonary exposures of cefepime, zidebactam and the combination (WCK 5222) against MDR Pseudomonas aeruginosa in a neutropenic murine pneumonia modelJournal of Antimicrobial Chemotherapy, 2020
- In Vivo Efficacy of WCK 5222 (Cefepime-Zidebactam) against Multidrug-Resistant Pseudomonas aeruginosa in the Neutropenic Murine Thigh Infection ModelAntimicrobial Agents and Chemotherapy, 2019
- Discovery, research, and development of new antibiotics: the WHO priority list of antibiotic-resistant bacteria and tuberculosisThe Lancet Infectious Diseases, 2018
- WCK 5222 (Cefepime-Zidebactam) Antimicrobial Activity against Clinical Isolates of Gram-Negative Bacteria Collected Worldwide in 2015Antimicrobial Agents and Chemotherapy, 2017
- WCK 5222 (cefepime/zidebactam) antimicrobial activity tested against Gram-negative organisms producing clinically relevant β-lactamasesJournal of Antimicrobial Chemotherapy, 2017
- In vitro activity of cefepime/zidebactam (WCK 5222) against Gram-negative bacteriaJournal of Antimicrobial Chemotherapy, 2017
- New β-Lactamase Inhibitors in the ClinicInfectious Disease Clinics of North America, 2016
- Morphogenesis of rod-shaped sacculiFEMS Microbiology Reviews, 2008