DFT study on the effect of proximal residues on the Mycobacterium tuberculosiscatalase-peroxidase (katG) heme compound I intermediate and its bonding interaction with isoniazid.
Mutation at position 315 in the katG gene, encoding the catalase-peroxidase (KatG) enzyme, is the major cause of INH resistance in Mycobacterium tuberculosis.
Due to the similar clinical and histopathological picture of sarcoidosis and tuberculosis, Mycobacterium tuberculosis antigens such early secreted antigen (ESAT-6), heat shock proteins (Mtb-HSP), catalase-peroxidase (katG) enzyme and superoxide dismutase A peptide (sodA) have been often considered as factors in the etiopathogenesis of sarcoidosis.
Analysis of interactions of clinical mutants of catalase-peroxidase (KatG) responsible for isoniazid resistance in Mycobacterium tuberculosis with derivatives of isoniazid.
Literature reports have shown that Mycobacterium tuberculosis, the causative agent of TB, has become resistant to this treatment by means of point mutations in the target enzymes of these drugs, such as catalase-peroxidase (KatG).
Matrix-assisted laser desorption/ionization time of flight mass spectrometry identified Mycobacterium tuberculosiscatalase-peroxidase (mKatG) as one of these tissue antigens.
Resistance to isoniazid (INH) is the most prevalent form of resistance in M. tuberculosis and is mainly caused by mutations in the catalase peroxidase gene (katG).
A mutation (CCG-->CTG [Arg-->Leu]) in codon 463 of katG (catalase peroxidase) of Mycobacterium tuberculosis has been found in isoniazid (INH)-resistant strains.
This medium has an acidic pH of 6.0 instead of the usual for agar media, pH 6.8, to provide optimal conditions for PZA activity, and it also differs from conventional Middlebrook 7H10/7H11 agar in that animal serum (fetal or calf bovine or fetal equine serum) is used instead of oleic acid-albumin-dextrose-catalase to support good growth of M. tuberculosis at the low pH of 6.0.
Drug resistance in M. tuberculosis is attributed primarily to the accumulation of mutations in the drug target genes; these mutations lead either to an altered target (e.g., RNA polymerase and catalase-peroxidase in rifampicin and isoniazid resistance, respectively) or to a change in titration of the drug (e.g., InhA in isoniazid resistance).
Characterization of the catalase-peroxidase gene (katG) and inhA locus in isoniazid-resistant and -susceptible strains of Mycobacterium tuberculosis by automated DNA sequencing: restricted array of mutations associated with drug resistance.
However, site-directed mutagenesis experiments demonstrated that the presence of a leucine at codon 463 did not alter the activity of the M. tuberculosiscatalase-peroxidase and did not affect the capacity of this enzyme to restore isoniazid susceptibility to isoniazid-resistant, KatG-defective Mycobacterium smegmatis BH1 cells.