title: Molecular cloning of an immunogenic and acid-induced isocitrate dehydrogenase gene from Coxiella burnetii.
abstract: The Coxiella burnetii icd gene encoding an immunogenic dimeric NADP(+)-dependent isocitrate dehydrogenase (IDH) was cloned by screening a C. burnetii genomic library with a human positive serum and sequenced. The predicted gene product consists of 427 amino acids (M(r) = 46,600) and showed high identity to the IDHs of Escherichia coli (74%), Salmonella enterica (73%) and IDH-I of Vibrio sp. (71%). The cloned gene complemented an icd-defective E. coli mutant producing a recombinant IDH that had the same biochemical properties as the enzyme from purified C. burnetii. Unlike the homologs from other bacteria, the cloned enzyme was expressed to the highest level in low pH conditions. This distinct property of the cloned IDH suggests that C. burnetii icd gene may have a role in the adaptation of the organism to the harsh acidic environment of the eucaryotic phagolysosomes.
authors.affiliation: Department of Veterinary Microbiology, Faculty of Agriculture, Gifu University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Van Nguyen
authors.forename: H
authors.initials: H
authors.lastname: To
authors.forename: T
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: H
authors.initials: H
authors.lastname: Fukushi
authors.forename: K
authors.initials: K
authors.lastname: Hirai
mesh_terms: D001483:Base Sequence; D003001:Cloning, Molecular; D016997:Coxiella burnetii / Q000201:enzymology / Q000235:genetics*; D004790:Enzyme Induction; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007521:Isocitrate Dehydrogenase / Q000737:chemistry / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D008969:Molecular Sequence Data; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA
chemical_list: D007521:Isocitrate Dehydrogenase