Interaction of the Pseudomonas cepacia DSM3959 lipase with its chaperone, LimA

The lipA gene of Pseudomonas cepacia DSM3959 requires a downstream gene, limA, in oder to express lipase activity. The product of the lim gene, LimA, is a molecular chaperone required during the folding of lipase in oder for the lipase to adopt an active conformation. The lipase and LimA proteins have been shown to form a complex precipitable with either an anti-lipase or anti-LimA antibody. LimA has been shown to form a 1:1 complex with with prelipase and lipase isolated from "natural" P. cepacia system. The mature lipase (lacking its signal peptide) has been expressed in the presence and absence of LimA in Escherichia coli. LimA can activate mature lipase during a urea denaturation-renaturation experiment, indicating that the signal peptide is not required for the lipase to be activated by LimA. The effects of various reagents on the renaturation of lipase from 8 M urea have been examined. We propose a mechanism for the function of the LimA chaperone during the production of active extracellular lipase.