Protease MP,secreted by marine bacterium YS-80-122,was a cold-adapted metalloprotease.In our previous study,the gene lupA of protease MP was cloned and expressed in Escherichia coli,but intracellular accumulation occurred.Nucleotide sequencing of lupA includes four glycinerichrepeats(GGXGXD)in the C-terminus,which appear in many ABC exporter-secreted proteins.With the genome-walking method,the downstream sequences of lupA were obtained.Amino acid sequence analysis revealed that there are three components of the ABC exporter,lupD,lupE,lupF and another protease inhibitor lupI.Expression plasmids harboring the protease structure gene and ABC exporter apparatus were constructed.The active cold-adapted metalloprotease was successfully secreted to the culture medium by co-expression.In addition,results of enzyme assay and immunoblot analysis demonstrated that the secretion of cold-adapted metalloprotease MP was temperature dependent.