title: Cloning, expression, and characterization of the katG gene, encoding catalase-peroxidase, from the polycyclic aromatic hydrocarbon-degrading bacterium Mycobacterium sp. strain PYR-1.
abstract: A 81-kDa protein from Mycobacterium sp. strain PYR-1 was expressed in response to exposure of the strain to the polycyclic aromatic hydrocarbon pyrene and recovered by two-dimensional gel electrophoresis. The N-terminal sequence of the protein indicated that it was similar to catalase-peroxidase. An oligonucleotide probe designed from this sequence was used to screen a genomic library of Mycobacterium sp. strain PYR-1, and a positive clone, containing a part of the gene encoding the 81-kDa protein, was isolated. A gene-walking technique was used to sequence the entire gene, which was identified as katG for catalase-peroxidase. The deduced KatG protein sequence showed significant homology to KatGII of Mycobacterium fortuitum and clustered with catalase-peroxidase proteins from other Mycobacterium species in a phylogenetic tree. The katG gene was expressed in Escherichia coli to produce a protein with catalase-peroxidase activity. Since the induction of this catalase-peroxidase occurred in pyrene-induced cultures and the exposure of these cultures to hydrogen peroxide reduced pyrene metabolism, our data suggest that this enzyme plays a role in polycyclic aromatic hydrocarbon metabolism by strain PYR-1.
authors.affiliation: Microbiology Division, National Center for Toxicological Research, Food and Drug Administration, Jefferson, Arkansas 72079, USA.
authors.forename: R F
authors.initials: RF
authors.lastname: Wang
authors.forename: D
authors.initials: D
authors.lastname: Wennerstrom
authors.forename: W W
authors.initials: WW
authors.lastname: Cao
authors.forename: A A
authors.initials: AA
authors.lastname: Khan
authors.forename: C E
authors.initials: CE
authors.lastname: Cerniglia
mesh_terms: D001426:Bacterial Proteins; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D005822:Genetic Vectors; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007700:Kinetics; D008969:Molecular Sequence Data; D009161:Mycobacterium / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D010544:Peroxidases / Q000235:genetics* / Q000378:metabolism*; D010802:Phylogeny; D010957:Plasmids; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism*; D011721:Pyrenes / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D011084:Polycyclic Aromatic Hydrocarbons; D011721:Pyrenes; D011994:Recombinant Proteins; C030984:pyrene; D006861:Hydrogen Peroxide; D010544:Peroxidases; C076136:catalase HPI