Covalent inhibitors of bacterial peptidoglycan biosynthesis enzyme MurA with chloroacetamide warhead

Grabrijan, Katarina (author), Hrast, Martina (author), Proj, Matic (author), Dolšak, Ana (author), Zdovc, Irena (author), Imre, Tímea (author), Petri, László (author), Ábrányi-Balogh, Péter (author), Keserü M., György (author), Gobec, Stanislav (author)

MurA (UDP-N-acetylglucosamine enolpyruvyl transferase) catalyzes the first committed step in the cytoplasmic part of peptidoglycan biosynthesis and is a validated target enzyme for antibacterial drug discovery; the inhibitor fosfomycin has been used clinically for decades. Like fosfomycin, most MurA inhibitors are small heterocyclic compounds that inhibit the enzyme by forming a covalent bond with the active site cysteine. The reactive chloroacetamide group was selected from a series of suitable electrophilic thiol-reactive warheads. The predominantly one-step synthesis led to the construction of the final library of 47 fragment-sized chloroacetamide compounds. Several new E. coli MurA inhibitors were identified, with the most potent compound having an IC$_{50}$ value in the low micromolar range. The electrophilic reactivity of all chloroacetamide fragments in our library was evaluated by a high-throughput spectrophotometric assay using the reduced Ellman reagent as a surrogate for the cysteine thiol. LC-MS/MS experiments confirmed the covalent binding of the most potent inhibitor to Cys115 of the digested MurA enzyme. The covalent binding was further investigated by a biochemical time-dependent assay and a dilution assay, which confirmed the irreversible and time-dependent mode of action. The efficacy of chloroacetamide derivatives against MurA does not correlate with their thiol reactivity, making the active fragments valuable starting points for fragment-based development of new antibacterial agents targeting MurA.

• Language: English
• Keywords: antibacterial agents, UDP-N-acetylglucosamine enolpyruvyl transferase, thiol reactivity
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FFA - Faculty of Pharmacy; VF - Veterinary Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2022
• Number of pages: 15 str.
• Numbering: Vol. 243, art. 114752
• PID: 20.500.12556/RUL-141439
• UDC: 579.8:615.4:54
• ISSN on article: 0223-5234
• DOI: 10.1016/j.ejmech.2022.114752
• COBISS.SI-ID: 123442179
• Publication date in RUL: 29.09.2022

Record is a part of a journal

• Title: European journal of medicinal chemistry
• Shortened title: Eur. j. med. chem.
• Publisher: Elsevier
• ISSN: 0223-5234
• COBISS.SI-ID: 25429760

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: antibakterijska sredstva, UDP-N-acetilglukozamin enolpiruvil transferaza, tiolna reaktivnost, bakterije, farmacevtska kemija