Pyrazinamide-activated targets (PZA targets)

Pyrazinamide-activated targets refer to a group of essential proteins within Mycobacterium tuberculosis that are inhibited by pyrazinoic acid (POA), the active metabolite of the prodrug pyrazinamide. The primary targets identified include Ribosomal protein S1 (RpsA), which is crucial for the trans-translation process required to rescue stalled ribosomes, and Aspartate decarboxylase (PanD), an enzyme vital for the biosynthesis of coenzyme A. Additionally, POA is thought to interact with the chaperone ClpC1 and potentially Fatty acid synthase I (FAS-I), while also causing non-specific disruption of the bacterial membrane potential and acidification of the intracellular environment. These interactions are particularly effective against semi-dormant bacilli residing in acidic environments, such as within macrophages or necrotic lesions. Resistance to pyrazinamide most commonly arises from mutations in the pncA gene, which encodes the enzyme responsible for activating the drug, though mutations in the target proteins themselves have also been documented.

Other names

Pyrazinoic acid targetsMycobacterium tuberculosis PZA targetsRpsAPanDClpC1

Pyrazinamide is a prodrug converted by bacterial pyrazinamidase (PncA) into the active form, pyrazinoic acid (POA). POA inhibits multiple targets including Ribosomal protein S1 (RpsA), interfering with trans-translation; Aspartate decarboxylase (PanD), disrupting coenzyme A biosynthesis; and ClpC1, affecting protein homeostasis. It also disrupts the bacterial membrane potential and acidifies the cytoplasm.