title: Identification and genetic characterization of the Pseudomonas aeruginosa leuB gene encoding 3-isopropylmalate dehydrogenase.
abstract: The Pseudomonas aeruginosa leuB gene, encoding 3-isopropylmalate dehydrogenase, was identified upstream of asd, encoding aspartate-beta-semialdehyde dehydrogenase. Genetic analysis indicated that leuB is identical to the previously mapped gene defined by the leu-10 allele. The chromosomal leuB locus was inactivated by gene replacement. The insertions had no adverse effect on expression of the downstream asd gene but resulted in leucine auxotrophy. The leuB gene encodes a protein containing 360 amino acids (with a molecular weight of 39153), which was expressed in Escherichia coli as a M, 42000 protein. The results suggested that, in contrast to the situation in other bacteria (E. coli, Salmonella typhimurium and Bacillus subtilis) the P. aeruginosa leuB gene is physically separated from the genes encoding the other enzymes of the isopropylmalate pathway.
authors.affiliation: Department of Microbiology, Colorado State University, Fort Collins 80523, USA.
authors.forename: T T
authors.initials: TT
authors.lastname: Hoang
authors.forename: H P
authors.initials: HP
authors.lastname: Schweizer
mesh_terms: D050539:3-Isopropylmalate Dehydrogenase; D000429:Alcohol Oxidoreductases / Q000235:genetics* / Q000302:isolation & purification; D000595:Amino Acid Sequence; D001223:Aspartate-Semialdehyde Dehydrogenase / Q000235:genetics; D001483:Base Sequence; D002874:Chromosome Mapping; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D007930:Leucine / Q000096:biosynthesis / Q000235:genetics; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009154:Mutation; D009876:Operon; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism
chemical_list: D004269:DNA, Bacterial; D000429:Alcohol Oxidoreductases; D050539:3-Isopropylmalate Dehydrogenase; D001223:Aspartate-Semialdehyde Dehydrogenase; D007930:Leucine