Date

Wednesday 10 Sep 2025

Time

15:15 - 15:45

Location

EM117

Supervisor

Stephan Hacker

2nd reviewer

Zach Armstrong

Jury

Stefan van der Vorm

Antimicrobial resistance (AMR) is a growing global health threat, with bacterial pathogens increasingly developing resistance against current antibiotic therapies. Recent predictions estimated that by 2050, 1.91 million deaths will be attributable to AMR annually. The urgent need for new antibiotic therapies has renewed interest in covalent inhibitors as a drug strategy, which offers advantages such as prolonged duration of action, increased drug-likeness and the ability to target previously ‘undruggable’ proteins.

In this study, a series of 2-chloro-N-(4-phenylthiazol-2-yl)acetamides, previously shown to have potent antibacterial activity against Gram-negative Neisseria gonorrhoeae (NG), were evaluated for their antibacterial activity against Gram-positive methicillin-resistant Staphylococcus aureus (MRSA). Minimum inhibitory concentration (MIC) assays revealed several highly potent 2-chloro-N-(4-phenylthiazol-2-yl)acetamide compounds active against MRSA, from which a qualitative structure-activity relationship (SAR) was established. In addition, a 4-phenyl-2-aminothiazole-based activity-based probe was synthesized and used for competitive residue-specific chemoproteomic experiments to identify specific target proteins. Notably, two halogen-substituted analogs (EN177 and 2) exhibited competitive binding to the essential protein tRNA-specific 2-thiouridylase MnmA (MnmA) by engaging with the catalytic Cys199 residue.

This study highlights the potential for broader-spectrum use of 2-chloro-N-(4-phenylthiazol-2-yl)acetamides and provided a 4-phenyl-2-aminothiazole-based activity based probe for chemoproteomic experiments. Future studies should pharmacologically evaluate EN177 and 2 for their binding affinity and inhibitory efficacy using purified MnmA protein and assess its biological relevance. In addition, future studies should expand the 4-phenylthiazole library, include phenotypic screening with a panel of both Gram-negative and Gram-positive ESKAPEE pathogens, and screen potent inhibitors in human toxicity assays.