Indazole to 2-cyanoindole scaffold progression for mycobacterial lipoamide dehydrogenase inhibitors achieves extended target residence time and improved antibacterial activity Journal Article


Authors: Sun, S.; Ginn, J.; Kochanczyk, T.; Arango, N.; Jiang, X.; Huggins, D. J.; Bean, J.; Michino, M.; Baxt, L.; Liverton, N.; Meinke, P. T.; Bryk, R.
Article Title: Indazole to 2-cyanoindole scaffold progression for mycobacterial lipoamide dehydrogenase inhibitors achieves extended target residence time and improved antibacterial activity
Abstract: Tuberculosis remains a leading cause of death from a single infection worldwide. Drug resistance to existing and even new antimycobacterials calls for research into novel targets and unexplored mechanisms of action. Recently we reported on the development of tight-binding inhibitors of Mycobacterium tuberculosis (Mtb) lipoamide dehydrogenase (Lpd), which selectively inhibit the bacterial but not the human enzyme based on a differential modality of inhibitor interaction with these targets. Here we report on the striking improvement in inhibitor residence time on the Mtb enzyme associated with scaffold progression from an indazole to 2-cyanoindole. Cryo-EM of Lpd with the bound 2-cyanoindole inhibitor 19 confirmed displacement of the buried water molecule deep in the binding channel with a cyano group. The ensuing hours-long improvement in on-target residence time is associated with enhanced antibacterial activity in axenic culture and in primary mouse macrophages. Resistance to 2-cyanoindole inhibitors involves mutations within the inhibitor binding site that have little effect on inhibitor affinity but change the modality of inhibitor-target interaction, resulting in fast dissociation from Lpd. These findings underscore that on-target residence time is a major determinant of antibacterial activity and in vivo efficacy. © 2024 Wiley-VCH GmbH.
Keywords: binding sites; dissociation; tuberculosis; lipoamide dehydrogenase; mycobacteria; scaffolds; scaffolds (biology); anti-bacterial activity; residence time; tight binding; on-target residence time; tight binding inhibitor; binding inhibitors; indazole
Journal Title: Angewandte Chemie - International Edition
Volume: 63
Issue: 44
ISSN: 1433-7851
Publisher: Wiley Blackwell  
Date Published: 2024-10-24
Start Page: e202407276
Language: English
DOI: 10.1002/anie.202407276
PROVIDER: scopus
PUBMED: 38997232
PMCID: PMC11887847
DOI/URL:
Notes: Article -- MSK Cancer Center Support Group (P30 CA008748) acknowledged in PubMed and PDF -- Source: Scopus
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MSK Authors
  1. James M Bean
    24 Bean
  2. Nancy M Arango
    7 Arango