The Pseudomonas aeruginosa hscA gene encodes Hsc66, a DnaK homologue.
Under heat-stress conditions bacteria induce, among other heat-shock proteins, the Hsp70 molecular chaperone (DnaK), which is involved in protein stabilization. It has been shown in Escherichia coli that an Hsp70 homologue called Hsc66, which is widespread in bacteria, functions as a chaperone in vitro. This paper reports the isolation of a Pseudomonas aeruginosa W51D mutant (W51M22) by insertion of the mini-Tn5-Hg transposon, which was unable to grow on ethanol and other short-chain alcohols as sole source of carbon. The transposon insertion in this mutant was shown to be located in the hscA gene encoding Hsc66. The inability of mutant W51M22 to use ethanol was complemented by the E. coli hscBA-fdx operon. The authors characterized the transcriptional arrangement of hscA, showing that it forms part of an operon with the upstream hscB gene, and that it is also expressed from its own promoter. These results are compatible with the P. aeruginosa Hsc66 protein being a functional molecular chaperone involved in the stabilization, in the presence of ethanol, of some proteins required for bacterial growth on short-chain alcohols.
Campos-Garcı A
Jesús
J
Departamento de Microbiologı́a Molecular, Instituto de Biotecnologı́a, Universidad Nacional Autónoma de México, Apdo Postal 510-3, Cuernavaca, Morelos, Mexico1.
G Ordóñez
Leandro
L
Departamento de Microbiologı́a Molecular, Instituto de Biotecnologı́a, Universidad Nacional Autónoma de México, Apdo Postal 510-3, Cuernavaca, Morelos, Mexico1.
Soberón-Chávez
Gloria
G
Departamento de Microbiologı́a Molecular, Instituto de Biotecnologı́a, Universidad Nacional Autónoma de México, Apdo Postal 510-3, Cuernavaca, Morelos, Mexico1.
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009876:Operon; D010641:Phenotype; D011401:Promoter Regions, Genetic; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; C085650:hscA protein, E coli; C063842:dnaK protein, E coli