(1128-A) Active-site and allosteric cyclic peptide inhibitors of secreted M. Tuberculosis Chorismate Mutase
Monday, February 5, 2024
12:00 PM – 1:00 PM EST
Location: Exhibit Halls AB
Abstract: The secreted Chorismate Mutase enzyme of Mycobacterium tuberculosis is an under explored potential target for the development of new antitubercular agents. As an enzyme suspected to be involved in virulence and host-pathogen interactions, disruption of its function could influence the difficulty of treating tuberculosis infected granulomas. However, high throughput screening for ligands inhibiting the function of chorismate mutase is prohibited by an enzyme activity assay performed in cuvette scale that requires addition of strong acid and base, making it incompatible with automated liquid dispensers. Here, we miniaturized the activity assay to 1536-well format and subsequently utilized the Random Peptide Integrated Discovery (RaPID) system to screen a vast library of macrocyclic peptides for novel Chorismate Mutase inhibiting molecules. Peptides identified from the RaPID selection, and analogs thereof identified by analyzing the selection population dynamics, yielded two noteworthy lead compounds whose binding modes were elucidated by X-ray crystallography. The first was identified as an allosteric binding peptide revealing a novel inhibition approach, while the second is an active-site binding peptide that when conjugated to a fluorescein probe allowed the development of a fluorescence-based ligand-displacement assay compatible with high throughput screening.