Structural Determinants for Reversible β-lactamase Inhibition
- Author(s): DeFrees, Kyle
- Advisor(s): Renslo, Adam R
- et al.
Antibiotic resistance is one the largest health concerns of the modern era, threatening decades of progress in antibacterial research and development. β-lactams, the first line of defense against most Gram positive and negative pathogens, are increasingly ineffective in clinical settings, driven in large part by the proliferation of β-lactamases, enzymes which degrade β-lactams. While these proteins have evolved over millions of years with hundreds of known variants, clinical selection has led to the proliferation of extended spectrum β-lactamases and carbapenems like CTX-M and KPC-2, respectively. Previous generation β-lactamase inhibitors such as clavulanic acid and sulbactam are ineffective against these enzymes, creating a pressing need for new inhibitor development.
While the recent discovery and approval of covalent avibactam and vaborbactam have shown great promise in bridging this gap, further clinical selection will likely drive new enzymes and mutations resistant to these agents, such as the spread of metallo-lactamases, or mutations within the KPC-2 family. Given the paucity of information around non-covalent β-lactamase inhibition, we sought to further characterize the specific interactions of a potent, non-covalent CTX-M inhibitor, revealing the importance of amide-π stacking against the β3 backbone (Chapter 2). Building off of this work, we also discovered new non-covalent scaffolds for the inhibition of KPC-2 (Chapters 3 and 4). Our work revealed how the improved hydrophobicity and conformational flexibility of carbapenemases such as KPC-2 can be exploited for building non-covalent affinity, supporting future efforts towards combating emerging resistance.