Targeted protein degradation in mycobacteria uncovers antibacterial effects and potentiates antibiotic efficacy.

Proteolysis-targeting chimeras (PROTACs) represent a new therapeutic modality involving selectively directing disease-causing proteins for degradation through proteolytic systems. Our ability to exploit targeted protein degradation (TPD) for antibiotic development remains nascent due to our limited understanding of which bacterial proteins are amenable to a TPD strategy. Here, we use a genetic system to model chemically-induced proximity and degradation to screen essential proteins in Mycobacterium smegmatis (Msm), a model for the human pathogen M.

Structure of the drug target ClpC1 unfoldase in action provides insights on antibiotic mechanism of action.

The unfoldase ClpC1 is one of the most exciting drug targets against tuberculosis. This AAA+ unfoldase works in cooperation with the ClpP1P2 protease and is the target of at least four natural product antibiotics: cyclomarin, ecumicin, lassomycin, and rufomycin. Although these molecules are promising starting points for drug development, their mechanisms of action remain largely unknown.

ClpX Is Essential and Activated by Single-Strand DNA Binding Protein in Mycobacteria.

The ClpP1P2 proteolytic complex is essential in Proteolysis by ClpP1P2 requires an associated ATPase, either ClpX or ClpC1. Here, we sought to define the unique contributions of the ClpX ATPase to mycobacterial growth. We formally demonstrated that ClpX is essential for mycobacterial growth, and to understand its essential functions, we identified ClpX-His-interacting proteins by pulldown and tandem mass spectrometry.

Pyrazinamide triggers degradation of its target aspartate decarboxylase.

Pyrazinamide is a sterilizing first-line tuberculosis drug. Genetic, metabolomic and biophysical analyses previously demonstrated that pyrazinoic acid, the bioactive form of the prodrug pyrazinamide (PZA), interrupts biosynthesis of coenzyme A in Mycobacterium tuberculosis by binding to aspartate decarboxylase PanD. While most drugs act by inhibiting protein function upon target binding, we find here that pyrazinoic acid is only a weak enzyme inhibitor.