title: Study of pyrazinamidase structural changes in pyrazinamide resistant and susceptible isolates of Mycobacterium tuberculosis.
abstract: BACKGROUND
  Pyrazinamide is one of the first line four drugs for treatment of tuberculosis. It was proved that mutations in two nucleotides of 359 and 374 pnc genes are highly associated with resistance to pyrazinamide.
  
  
  METHODS
  In this study, mutations in these two codones in 30 clinical isolates of Mycobacterium tuberculosis were detected by means of sequencing. Protein structures encoded by this gene with and without mutation were investigated in resistant and susceptible isolates to pyrazinamide, respectively.
  
  
  RESULTS
  Mutation in the positions 359 and 374 altered some parameters like change in electronic charge, distance change of mutated amino acids to situation of active enzyme and metal connection situation. In these conditions, structure and function of pyrozinamidase enzyme were changed and antibiotic was ineffective and consequently caused resistance to pyrazinamide in M. tuberculosis.
  
  
  CONCLUSIONS
  This work was revealed protein changes in resistance to pyrazinamide in clinical isolates of M. tuberculosis.
authors.affiliation: Tuberculosis and Pediatric Infectious Diseases Research Center, Faculty of Medicine, Arak University, Arak, Iran.
authors.forename: Azam
authors.initials: A
authors.lastname: Ahmady
authors.forename: Toktam
authors.initials: T
authors.lastname: Poolad
authors.forename: Poorya
authors.initials: P
authors.lastname: Rafee
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Tousheh
authors.forename: Manijeh
authors.initials: M
authors.lastname: Kahbazi
authors.forename: Mohammad
authors.initials: M
authors.lastname: Arjomandzadegan
mesh_terms: D000581:Amidohydrolases / Q000235:genetics*; D000995:Antitubercular Agents / Q000494:pharmacology* / Q000627:therapeutic use; D024881:Drug Resistance, Bacterial / Q000235:genetics; D006801:Humans; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000201:enzymology*; D011718:Pyrazinamide / Q000494:pharmacology* / Q000627:therapeutic use; D014376:Tuberculosis / Q000382:microbiology*
chemical_list: D000995:Antitubercular Agents; D011718:Pyrazinamide; D000581:Amidohydrolases; C022490:pyrazinamide deamidase