Pyrazinamide (PZA) is a prodrug used in the treatment of tuberculosis. PZA is converted to the active pyrazinoic acid by the bacterial PZAase enzyme; mutations in PZAase can therefore confer PZA resistance to M. tuberculosis. The gene product of Pyrococcus horikoshii 999 (PH999) shows PZAase and nicotinamidase activity, and extensive sequence homology to M. tuberculosis PZAase.
Defined by 9 residues: ASP:A-10ASP:A-52HIS:A-54SER:A-60HIS:A-71LYS:A-94GLU:A-101ALA:A-129CYS:A-133