BACTERIOCIN RELEASE PROTEINS - MODE OF ACTION, STRUCTURE, AND BIOTECHNOLOGICAL APPLICATION

The mechanism by which Gram-negative bacteria like Escherichia coli se crete bacteriocins into the culture medium is unique and quite differe nt from the mechanism by which other proteins are translocated across the two bacterial membranes, namely through the known branches of the general secretory pathway. The release of bacteriocins requires the ex pression and activity of a so-called bacteriocin release protein and t he presence of the detergent-resistant phospholipase A in the outer me mbrane. The bacteriocin release proteins are highly expressed small li poproteins which are synthesized with a signal peptide that remains st able and which accumulates in the cytoplasmic membrane after cleavage. The combined action of these stable, accumulated signal peptides, the lipid-modified mature bacteriocin release proteins (BRPs) and phospho lipase A cause the release of bacteriocins. The structure and mode of action of these BRPs as well as their application in the release of he terologous proteins by E. coli is described in this review.