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Published on: November 1, 2019
Phenylboronic Acid Derivatives as Validated Leads Active in Clinical Strains Overexpressing KPC-2: A Step against
Giuseppe Celenza1, Mattia Vicario2, Pierangelo Bellio1
1Dipartimento di Scienze Cliniche Applicate e Biotecnologie, Università dell'Aquila, Via Vetoio 1, 67100, L'Aquila, Italy.
Abstract:
The emergence and dissemination of multidrug resistant (MDR) pathogens resistant to nearly all available antibiotics poses a significant threat in clinical therapy. Among them, Klebsiella pneumoniae clinical isolates overexpressing KPC-2 carbapenemase are the most worrisome, extending bacterial resistance to last-resort carbapenems. In this study, we investigate the molecular recognition requirements in the KPC-2 active site by small phenylboronic acid derivatives. Four new phenylboronic acid derivatives were designed and tested against KPC-2. For the most active, despite their simple chemical structures, nanomolar affinity was achieved. The new derivatives restored susceptibility to meropenem in clinical strains overexpressing KPC-2. Moreover, no cytotoxicity was detected in cell-viability assays, which further validated the designed leads. Two crystallographic binary complexes of the best inhibitors binding KPC-2 were obtained at high resolution. Kinetic descriptions of slow binding, time-dependent inhibition, and interaction geometries in KPC-2 were fully investigated. This study will ultimately lead toward the optimization and development of more-effective KPC-2 inhibitors.
Insights
New phenylboronic acid derivatives show nanomolar affinity for KPC-2 carbapenemase, restoring meropenem susceptibility in resistant Klebsiella pneumoniae strains without cytotoxicity.
Area of Science:
- Medicinal Chemistry
- Molecular Biology
- Antimicrobial Resistance
Background:
- Multidrug-resistant (MDR) pathogens, particularly Klebsiella pneumoniae overexpressing KPC-2 carbapenemase, present a critical clinical challenge due to resistance to last-resort antibiotics like carbapenems.
- Effective therapeutic strategies are urgently needed to combat infections caused by these highly resistant bacteria.
Purpose of the Study:
- To investigate the molecular recognition principles governing the interaction between KPC-2 carbapenemase and small phenylboronic acid derivatives.
- To design and synthesize novel phenylboronic acid derivatives as potential inhibitors of KPC-2.
Main Methods:
- Design and synthesis of four novel phenylboronic acid derivatives.
- In vitro testing against KPC-2 carbapenemase to determine inhibitory activity and affinity.
- Assessment of meropenem susceptibility restoration in clinical KPC-2-overexpressing Klebsiella pneumoniae strains.
- Cell-viability assays to evaluate cytotoxicity.
- High-resolution crystallography to determine the binding mode of inhibitors within the KPC-2 active site.
- Kinetic studies to characterize the inhibition mechanism.
Main Results:
- Achieved nanomolar affinity with simple phenylboronic acid derivatives against KPC-2.
- Restored meropenem susceptibility in clinical KPC-2-overexpressing Klebsiella pneumoniae isolates.
- Demonstrated no significant cytotoxicity in cell-viability assays.
- Obtained high-resolution crystal structures of two binary inhibitor-KPC-2 complexes.
- Characterized slow, time-dependent inhibition kinetics and detailed interaction geometries.
Conclusions:
- Novel phenylboronic acid derivatives are potent KPC-2 inhibitors with potential for therapeutic development.
- These inhibitors effectively restore antibiotic susceptibility in clinically relevant resistant strains.
- Structural and kinetic data provide a foundation for optimizing KPC-2 inhibitor design to combat carbapenem resistance.
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