Abstract:
:Recent studies examining the molecular mechanisms of isoniazid (INH) resistance in Mycobacterium tuberculosis have demonstrated that a significant percentage of drug-resistant strains are mutated in the katG gene which encodes a catalase-peroxidase, and the majority of these alterations are missense mutations which result in the substitution of a single amino acid. In previous reports, residues which may be critical for enzymatic activity and the drug-resistant phenotype have been identified by evaluating INH-resistant clinical isolates and in vitro mutants. In this study, site-directed mutagenesis techniques were utilized to alter the wild-type katG gene from M. tuberculosis at 13 of these codons. The effects of these mutations were determined using complementation assays in katG-defective, INH-resistant strains of Mycobacterium smegmatis and Mycobacterium bovis BCG. This mutational analysis revealed that point mutations in the katG gene at nine of the 13 codons can cause drug resistance, and that enzymatic activity and resistance to INH are inversely related. In addition, mutations in the mycobacterial catalase-peroxidase which reduce catalase activity also decrease peroxidase activity.
journal_name
Mol Microbioljournal_title
Molecular microbiologyauthors
Rouse DA,DeVito JA,Li Z,Byer H,Morris SLdoi
10.1046/j.1365-2958.1996.00133.xsubject
Has Abstractpub_date
1996-11-01 00:00:00pages
583-92issue
3eissn
0950-382Xissn
1365-2958journal_volume
22pub_type
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