Pyrazinoic acid targets (POA targets)

Pyrazinoic acid (POA) is the active metabolite of the prodrug pyrazinamide (PZA), an essential first-line antibiotic used to treat Mycobacterium tuberculosis infections [1.1.1, 1.2.1]. POA is unique among anti-tuberculosis agents because it specifically targets non-replicating, "semi-dormant" bacilli in acidic environments, such as those found within macrophages or necrotic lesions [1.2.5, 1.3.1]. The molecular targets of POA have been a subject of extensive debate, with evidence suggesting a multi-targeted mechanism rather than a single receptor [1.1.2, 1.3.3]. Key proposed targets include Ribosomal protein S1 (RpsA), which is involved in trans-translation; Aspartate decarboxylase (PanD), which is critical for coenzyme A biosynthesis; and Fatty acid synthase I (FAS-I), which is involved in mycolic acid synthesis [1.1.1, 1.4.1]. Additionally, POA acts as a protonophore, disrupting the bacterial membrane potential and lowering intracellular pH, which leads to the depletion of ATP reserves and cellular death [1.2.2, 1.3.2]. Resistance to POA is primarily mediated by mutations in the pncA gene, which encodes the activating enzyme pyrazinamidase, but can also arise from mutations in the target genes themselves [1.4.2, 1.4.3].

Other names

Pyrazinamide targetsPZA targetsRibosomal protein S1 (RpsA)Aspartate decarboxylase (PanD)Fatty acid synthase I (FAS-I)Caseinolytic protease C1 (ClpC1)Polynucleotide phosphorylase (PNPase)

Inhibition of trans-translation, coenzyme A biosynthesis, and fatty acid synthesis, alongside disruption of bacterial membrane potential and pH homeostasis.