A novel protein secretion factor from a Vibrio species which operates in Escherichia coli.

A DNA fragment specific to a Vibrio species was found to promote extracellular secretion of proteins, when cloned into Escherichia coli. Cells harboring a plasmid carrying this fragment secreted significant amounts of periplasmic beta-lactamase and alkaline phosphatase into the medium, however most cytoplasmic beta-galactosidase was retained within the cell. The DNA sequence essential for this property was found to be a gene encoding 76 amino acids, which was designated as the 'PAS factor'. Highly expressed PAS factor is harmful to the cell, this may be due to a disruption of the membrane structure and/or function.