TY - JOUR
T1 - A peroxide/ascorbate-inducible catalase from Haemophilus influenzae is homologous to the Escherichia coli katE gene product
AU - Bishai, W. R.
AU - Smith, H. O.
AU - Barcak, G. J.
PY - 1994
Y1 - 1994
N2 - Bacterial catalases are induced by exposure to peroxides (e.g., Escherichia coli katG) or entry into stationary phase (e.g., E. coli katE). To study regulatory systems in Haemophilus influenzae, we complemented an E. coli rpoS mutant, which is unable to induce katE in stationary phase, with a plasmid library of H. influenzae Rd- chromosomal DNA. Nineteen complementing clones with a catalase-positive phenotype were obtained and characterized after screening about 105 transformants. All carried the same structural gene for an H. influenzae catalase. The DNA sequence of this gene, called hktE, encodes a 508-amino-acid polypeptide with strong homology to eukaryotic catalases and E. coli katE. However, hktE is regulated like E. coli katG, with catalase activity increasing 10-fold and hktE mRNA levels increasing 4- fold upon exposure to ascorbic acid, which serves to generate hydrogen peroxide. Mutations in the known global regulatory genes of H. influenzae- crp, cya, and sxy-do not affect the inducibility of hktE. The hktE gene maps to a 225-kb segment of the H. influenzae chromosome in a region encoding resistance to spectinomycin.
AB - Bacterial catalases are induced by exposure to peroxides (e.g., Escherichia coli katG) or entry into stationary phase (e.g., E. coli katE). To study regulatory systems in Haemophilus influenzae, we complemented an E. coli rpoS mutant, which is unable to induce katE in stationary phase, with a plasmid library of H. influenzae Rd- chromosomal DNA. Nineteen complementing clones with a catalase-positive phenotype were obtained and characterized after screening about 105 transformants. All carried the same structural gene for an H. influenzae catalase. The DNA sequence of this gene, called hktE, encodes a 508-amino-acid polypeptide with strong homology to eukaryotic catalases and E. coli katE. However, hktE is regulated like E. coli katG, with catalase activity increasing 10-fold and hktE mRNA levels increasing 4- fold upon exposure to ascorbic acid, which serves to generate hydrogen peroxide. Mutations in the known global regulatory genes of H. influenzae- crp, cya, and sxy-do not affect the inducibility of hktE. The hktE gene maps to a 225-kb segment of the H. influenzae chromosome in a region encoding resistance to spectinomycin.
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U2 - 10.1128/jb.176.10.2914-2921.1994
DO - 10.1128/jb.176.10.2914-2921.1994
M3 - Article
C2 - 8188593
AN - SCOPUS:0028272385
SN - 0021-9193
VL - 176
SP - 2914
EP - 2921
JO - Journal of bacteriology
JF - Journal of bacteriology
IS - 10
ER -