de Munnik M, Lohans CT, Langley GW, Bon C, Brem J, Schofield CJ. A Fluorescence-Based Assay for Screening β-Lactams Targeting the Mycobacterium tuberculosis Transpeptidase Ldt
Mt2.
Chembiochem 2020;
21:368-372. [PMID:
31322798 PMCID:
PMC7028133 DOI:
10.1002/cbic.201900379]
[Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Indexed: 12/24/2022]
Abstract
Mycobacterium tuberculosis l,d-transpeptidases (Ldts), which are involved in cell-wall biosynthesis, have emerged as promising targets for the treatment of tuberculosis. However, an efficient method for testing inhibition of these enzymes is not currently available. We present a fluorescence-based assay for LdtMt2 , which is suitable for high-throughput screening. Two fluorogenic probes were identified that release a fluorophore upon reaction with LdtMt2 , thus making it possible to assess the availability of the catalytic site in the presence of inhibitors. The assay was applied to a panel of β-lactam antibiotics and related inhibitors; the results validate observations that the (carba)penem subclass of β-lactams are more potent Ldt inhibitors than other β-lactam classes, though unexpected variations in potency were observed. The method will enable systematic structure-activity relationship studies on Ldts, thereby facilitating the identification of new antibiotics active against M. tuberculosis.
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