title: Identification of the aceA gene encoding isocitrate lyase required for the growth of Pseudomonas aeruginosa on acetate, acyclic terpenes and leucine.
abstract: Pseudomonas aeruginosa PAO1 mutants affected in acyclic monoterpenes, n-octanol, and acetate assimilation were isolated using transposon mutagenesis. The isocitrate lyase gene (aceA) corresponding to ORF PA2634 of the PAO1 strain genome was identified in one of these mutants. The aceA gene encodes a protein that is 72% identical to the isocitrate lyase (ICL) characterized from Colwellia maris, but is less than 30% identical to their homologues from pseudomonads. The genetic arrangement of aceA suggests that it is a monocistronic gene, and no adjacent related genes were found. The ICL protein was detected as a 60-kDa band in sodium dodecyl sulfate polyacrylamide gel electrophoresis from cultures grown on acetate, but not in glucose-grown PAO1 cultures. Genetic complementation further confirmed that the aceA gene encodes the ICL enzyme. The ICL enzyme activity in crude extracts from cultures of the PAO1 strain was induced by acetate, citronellol and leucine, and repressed by growth on glucose or citrate. These results suggest that ICL is involved in the assimilation of acetate, acyclic monoterpenes of the citronellol family, alkanols, and leucine, in which the final intermediary acetyl-coenzyme A may be channelled to the glyoxylate shunt.
authors.affiliation: Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, Mexico.
authors.forename: Alma Laura
authors.initials: AL
authors.lastname: Díaz-Pérez
authors.forename: Celinda
authors.initials: C
authors.lastname: Román-Doval
authors.forename: César
authors.initials: C
authors.lastname: Díaz-Pérez
authors.forename: Carlos
authors.initials: C
authors.lastname: Cervantes
authors.forename: Carlos R
authors.initials: CR
authors.lastname: Sosa-Aguirre
authors.forename: Joel E
authors.initials: JE
authors.lastname: López-Meza
authors.forename: Jesús
authors.initials: J
authors.lastname: Campos-García
mesh_terms: D000085:Acetates / Q000378:metabolism*; D000080462:Acyclic Monoterpenes; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D004251:DNA Transposable Elements; D015964:Gene Expression Regulation, Bacterial; D007522:Isocitrate Lyase / Q000235:genetics* / Q000378:metabolism; D007930:Leucine / Q000378:metabolism*; D008969:Molecular Sequence Data; D039821:Monoterpenes / Q000378:metabolism*; D016254:Mutagenesis, Insertional; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D017422:Sequence Analysis, DNA
chemical_list: D000085:Acetates; D000080462:Acyclic Monoterpenes; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D039821:Monoterpenes; D007522:Isocitrate Lyase; D007930:Leucine; C007078:citronellol