PRODUCTION OF ACTIVE SERRATIA-MARCESCENS METALLOPROTEASE FROM ESCHERICHIA-COLI BY ALPHA-HEMOLYSIN HLYB AND HLYD

Serratia marcescens produces an abundant extracellular metalloprotease . The gene for this protease had previously been cloned and expressed in Escherichia coli, in which no functional protease could be found. H owever, the protease gene carries the LXGGXGND repeat motif found in a lpha-hemolysin and other proteins secreted by homologous systems. Usin g a dual-plasmid complementation system, we show that the alpha-hemoly sin hlyB and hlyD transport determinants are sufficient to allow secre tion and activation of a functional metalloprotease species from E. co li, as are the comparable protease secretion functions of Erwinia chry santhemi. However, strains expressing protease with the hlyBD transpor t system are unstable and rapidly lose the ability to produce function al protease.