GENE CLONING AND PRODUCTION OF ACTIVE RECOMBINANT BRUGIA-MALAYI MICROFILARIAL CHITINASE

Canlas and coworkers [Canlas et al. (1984) Am. J. Trop. Med. Hyg. 33, 420-424] isolated a monoclonal antibody (MF1) which, upon passive tran sfer, led to the clearance of Brugia malayi (Bm) microfilariae (mf) fr om infected jirds. The target of MF1 is a developmentally regulated mf chitinase (Cht) (Fuhrman et al. (1992) Proc. Natl. Acad. Sci. USA 89, 1548-1552). This paper describes the production of enzymatically acti ve Bm Cht in Escherichia coli. Standard expression conditions resulted in production of an insoluble maltose-binding protein (MBP)::Cht fusi on protein, but by optimizing expression conditions, the amount of sol uble MBP::Cht was increased 25-fold. The specific activity of the solu ble MBP::Cht isolated from the E. coli cytoplasm was low. Exporting MB P::Cht into the E. coli periplasmic space increased the specific activ ity by 12-fold. This suggests that secretion through the membrane and/ or the environment of the periplasmic space results in improved foldin g of recombinant Bm Cht.