Discovery and optimization of inhibitors and probes that target New Delhi metallo-[beta]-lactamase

Since the discovery of penicillin in 1928, β-lactam antibiotics have been used worldwide to treat a broad spectrum of bacterial infections. However, the rise of bacterial resistance through the evolution of β-lactam hydrolyzing enzymes, known as β-lactamases, threatens their clinical efficacy. β-lactamases typically have a conserved serine in their active site that serves as a nucleophile in hydrolysis of the β-lactam substrate. Codrugs in the form of covalent inhibitors that target this nucleophilic serine are prescribed along β lactam antibiotics to counteract this form of resistance. However, an emerging class of β lactamases, known as metallo-β-lactamases (MBLs), poses a threat to this approach. MBLs instead have two zinc ions in their active site that coordinate a hydroxide molecule that serves as the nucleophile, rendering them resistant to canonical β-lactamase inhibitors. Currently, there are no FDA-approved drugs that can effectively inhibit MBLs. This is particularly alarming in the case of New Delhi Metallo-β-lactamase (NDM) which is the most widespread and clinically threatening MBL. NDM has a shallow, non-selective active site that confers resistance to multiple classes of β-lactam antibiotics including last resort carbapenems. This has placed NDM-expressing bacteria on the Center of Disease Control’s list of “urgent threats”, its highest-ranking level of concern. The emergence of NDM variants with low catalytic residue conservation makes it difficult to design reversible inhibitors that can establish strong enough interactions to effectively outcompete an administered β-lactam without driving further mutations. The use of hypothesis-driven screening and lead optimization that led to the discovery of novel irreversible covalent inhibitors of NDM is reported. Furthermore, the development and characterization of a reversible fluorescent probe that can be used to monitor the dynamic metalation, substrate turnover, and inhibitor binding of NDM in living cells is reported. The results of these experiments will aid in the characterization of NDM as well as the development of codrugs that can be used to counteract this urgent threat to global health.

Author dc:creator

• Rivera, Dann Diego

Contributors dc:contributor

• Whitman, Christian P.
• Fast, Walter L.
• Que, Emily

• New Delhi metallo-β-lactamase
• β-lactam
• NDM-1
• Covalent inhibitor
• Inhibitor
• Antibiotic resistance

Language dc:language

English

Identifier

https://doi.org/10.26153/tsw/62076

OAI identifier oai:identifier

oai:tdl-ir.tdl.org:2152/134754