Abstract
The lipA gene of Pseudomonas cepacia DSM3959 requires a downstream gene, limA, in order to express lipase activity. The product of the limA gene, LimA, is a molecular chaperone required during the folding of lipase in order 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 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 8M urea have been examined. We propose a mechanism for the function of the LimA chaperone during the production of active extracellular lipase.
