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ACS Infect Dis. 2017 Nov 10;3(11):807-819. doi: 10.1021/acsinfecdis.7b00079. Epub 2017 Oct 18.

Pyrazinoic Acid Inhibits Mycobacterial Coenzyme A Biosynthesis by Binding to Aspartate Decarboxylase PanD.

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Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore , 5 Science Drive 2, Singapore 117545.
School of Biological Sciences, Nanyang Technological University , 60 Nanyang Drive, Singapore 639798.
Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey , 225 Warren Street, Newark, New Jersey 07103, United States.


Previously, we showed that a major in vitro and in vivo mechanism of resistance to pyrazinoic acid (POA), the bioactive component of the critical tuberculosis (TB) prodrug pyrazinamide (PZA), involves missense mutations in the aspartate decarboxylase PanD, an enzyme required for coenzyme A biosynthesis. What is the mechanism of action of POA? Upon demonstrating that treatment of M. bovis BCG with POA resulted in a depletion of intracellular coenzyme A and confirming that this POA-mediated depletion is prevented by either missense mutations in PanD or exogenous supplementation of pantothenate, we hypothesized that POA binds to PanD and that this binding blocks the biosynthetic pathway. Here, we confirm both hypotheses. First, metabolomic analyses showed that POA treatment resulted in a reduction of the concentrations of all coenzyme A precursors downstream of the PanD-mediated catalytic step. Second, using isothermal titration calorimetry, we established that POA, but not its prodrug PZA, binds to PanD. Binding was abolished for mutant PanD proteins. Taken together, these findings support a mechanism of action of POA in which the bioactive component of PZA inhibits coenzyme A biosynthesis via binding to aspartate decarboxylase PanD. Together with previous works, these results establish PanD as a genetically, metabolically, and biophysically validated target of PZA.


aspartate decarboxylase; coenzyme A; pyrazinamide; pyrazinoic acid; tuberculosis

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