Expression of the catalase-peroxidase of Caulobacter crescentus, a gram-negative member of the alpha subdivision of the Proteobacteria, is 50-fold higher in stationary-phase cultures than in exponential cultures. To identify regulators of the starvation response, Tn5 insertion mutants were isolated with reduced expression of a katG::lacZ fusion on glucose starvation. One insertion interrupted a...

Catalase-peroxidases (KatG) are bifunctional enzymes possessing both catalase and peroxidase activities. Three crystal structures of different KatGs revealed the presence of a novel Met-Tyr-Trp cross-link that has been suggested to impart catalatic activity to the KatGs. High-performance liquid chromatographic separation of the peptide fragments resulting from tryptic digestion of recombinant M...

Objective: The Rifampicin resistance and susceptibility of Mycobacterium tuberculosis are caused by mutations in the 81-base pair region of the rpoB gene encoding the b-subunit of RNA polymerase. Methods: Isoniazid resistance of M. tuberculosis is related to mutations in inha , oxyR and ahpC genes which 30 to 90 percent of Isoniazid resistance is occurred in 3015 codons of kat...

We used metalloregulated luciferase reporter fusions and spectroscopic quantification of soluble Hg(II) to determine that the hydroperoxidase-catalase, KatG, of Escherichia coli can oxidize monatomic elemental mercury vapor, Hg(0), to the water-soluble, ionic form, Hg(II). A strain with a mutation in katG and a strain overproducing KatG were used to demonstrate that the amount of Hg(II) formed ...

Synthetic oligonucleotide primers based on the DNA sequence data of the Escherichia coli, Mycobacterium tuberculosis, and Mycobacterium intracellulare katG genes encoding the heme-containing enzyme catalase-peroxidase were used to amplify and analyze the Mycobacterium leprae katG region by PCR. A 1.6-kb DNA fragment, which hybridized to an M. tuberculosis katG probe, was obtained from an M. lep...

Quorum sensing (QS) plays important roles in the pathogenicity of Burkholderia glumae, the causative agent of bacterial rice grain rot. We determined how QS is involved in catalase expression in B. glumae. The QS-defective mutant of B. glumae exhibited less catalase activity than wild-type B. glumae. A beta-glucuronidase assay of a katG::Tn3-gusA78 reporter fusion protein revealed that katG exp...

Elucidation of the molecular basis of isoniazid (INH) resistance in Mycobacterium tuberculosis has led to the development of different genotypic approaches for the rapid detection of INH resistance in clinical isolates. Mutations in katG, in particular the S315T substitution, are responsible for INH resistance in a large proportion of tuberculosis cases. However, the frequency of the katG S315T...

BACKGROUND Depending on the presence of mutations that determine isoniazid (INH) susceptibility (katG and inhA), Mycobacterium tuberculosis may be susceptible to high doses of INH or ethionamide (ETH). OBJECTIVE To describe the INH resistance profile and association of katG mutation with previous INH treatment and level of drug resistance based on rapid molecular drug susceptibility testing (...