title: A low-Mr lipase activation factor cooperating with lipase modulator protein LimL in Pseudomonas sp. strain 109.
abstract: Pseudomonas sp. strain 109 produces a unique lipase (LipL) which efficiently catalyses intramolecular transesterification of omega-hydroxyesters to form macrocyclic lactones. In vivo production of enzymically active LipL requires lipase modulator protein (LimL), which functions as a molecular chaperone for the correct folding of LipL. However, previous work has shown that LipL forms a tight complex with LimL in vitro and the resulting LipL-LimL complex is only partially active, suggesting an additional mechanism that facilitates the dissociation of the complex to form enzymically active LipL. In the present work, a low-Mr compound (lipase activation factor, LAF) was found in Pseudomonas sp. strain 109 that when added to the LipL-LimL complex resulted in the activation of LipL. Ca2+ ions also enhanced lipase activity, but the instantaneous activation by Ca2+ was different from the gradual and time-dependent activation by LAF, indicating the novel nature of this compound. LAF passed through an ultrafiltration membrane with an Mr cut-off of 3000 and showed an apparent Mr of 330+/-30 on Superdex Peptide gel-filtration chromatography. Treatment of the LipL-LimL complex with LAF liberated free active LipL, indicating that LAF was necessary to dissociate the LipL-LimL complex.
authors.affiliation: Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Tanaka
authors.forename: F
authors.initials: F
authors.lastname: Ihara
authors.forename: T
authors.initials: T
authors.lastname: Nihira
authors.forename: Y
authors.initials: Y
authors.lastname: Yamada
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D004789:Enzyme Activation; D020536:Enzyme Activators / Q000737:chemistry / Q000378:metabolism*; D008049:Lipase / Q000378:metabolism*; D046911:Macromolecular Substances; D008565:Membrane Proteins; D011549:Pseudomonas / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D020536:Enzyme Activators; C092194:LimL protein, Pseudomonas; D046911:Macromolecular Substances; D008565:Membrane Proteins; D008049:Lipase; C120013:lactonizing lipase protein, Pseudomonas; D002118:Calcium