Date

Friday 20 Mar 2026

Time

15:15 - 15:45

Location

BW020

Supervisor

Marta Artola Perez de Azanza

2nd reviewer

Zach Armstrong

Jury

Stephan Hacker

Infectious diseases are a major cause of mortality worldwide and antimicrobial resistance against traditional antibiotics increases this problem. Antimicrobial resistance by mutated and evolved bacteria is mostly caused by excessive use of antibiotics that focus on common targets like DNA replication, protein synthesis, or cell wall synthesis. That is why in this research project, novel antimicrobial strategies are explored by focusing on less common targets, the peptidoglycan recycling pathway. Peptidoglycans are important for the structure of the bacterial cell wall and disruption of this recycling pathway decreases viability of bacteria. The enzyme N-acetylglucosamine-6-phosphate deacetylase (NagA) plays an important role in this pathway and in this study, inhibitory warheads of the Haemophilus influenzae homologue of NagA (HiNagA) are identified with high throughput screening (HTS) of the Enamine covalent fragment library (CFL).

A fluorescamine-based activity assay was optimised to achieve efficient and complete deactivation of NagA using a pH quenching method. This les to time-efficient and accurate screenings. Six different warheads were identified as promising inhibitory warheads of HiNagA. IC50 assays, time-dependent assays, and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) were used to evaluate the warheads on their potential binding and inhibition of HiNagA. α-chloro β-ketoamide warheads were found to most efficiently inhibit the enzyme and might be able to be used in future research to make covalent inhibitors of NagA to treat infections in H influenzae as well as other bacteria. Covalent inhibitors that are able to penetrate the bacterial cell wall and disrupt the peptidoglycan recycling pathway by inhibiting NagA, offer novel antimicrobial strategies to battle antimicrobial resistance.