title: Chaperone-mediated activation in vivo of a Pseudomonas cepacia lipase.
abstract: An extracellular Pseudomonas cepacia lipase, LipA, is inactive when expressed in the absence of the product of the limA gene. Evidence has been presented that LimA is a molecular chaperone. The lipA and limA genes have been cloned in separate and independently inducible expression systems in Escherichia coli. These systems were used to test the molecular chaperone hypothesis by investigating whether LimA could activate presynthesized prelipase and whether presynthesized LimA could activate newly synthesized prelipase. The results show that LimA cannot activate presynthesized prelipase and that presynthesized LimA can activate only a limited number of de novo synthesized prelipase molecules. Co-immunoprecipitation of prelipase/lipase with LimA generated a 1:1 complex of prelipase/lipase and LimA. The results suggest that a 1:1 complex of LipA and LimA is required for prelipase processing and secretion of active lipase.
authors.affiliation: Department of Genetics, Trinity College, IE-Dublin, Ireland.
authors.forename: J L
authors.initials: JL
authors.lastname: Aamand
authors.forename: A H
authors.initials: AH
authors.lastname: Hobson
authors.forename: C M
authors.initials: CM
authors.lastname: Buckley
authors.forename: S T
authors.initials: ST
authors.lastname: Jørgensen
authors.forename: B
authors.initials: B
authors.lastname: Diderichsen
authors.forename: D J
authors.initials: DJ
authors.lastname: McConnell
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis / Q000378:metabolism*; D016956:Burkholderia cepacia / Q000201:enzymology*; D004789:Enzyme Activation / Q000502:physiology; D004792:Enzyme Precursors / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D002479:Inclusion Bodies / Q000201:enzymology; D008049:Lipase / Q000096:biosynthesis / Q000378:metabolism*; D018832:Molecular Chaperones / Q000096:biosynthesis / Q000502:physiology*; D011233:Precipitin Tests; D011994:Recombinant Proteins / Q000096:biosynthesis
chemical_list: D001426:Bacterial Proteins; D004792:Enzyme Precursors; C079999:LipA protein, Bacteria; D018832:Molecular Chaperones; D011994:Recombinant Proteins; D008049:Lipase