EXPRESSION OF THE PCLODF13 ENCODED BACTERIOCIN RELEASE PROTEIN OR ITSSTABLE SIGNAL PEPTIDE CAUSES EARLY EFFECTS ON PROTEIN-BIOSYNTHESIS AND MG2+ TRANSPORT

The effect of the pCloDF13 encoded bacteriocin release protein (BRP) o n Escherichia coli cell lethality was studied. Induction of the BRP re sulted in a strong inhibition of the incorporation of radioactive labe led amino acids and affected the transport of Mg2+ ions. Similar effec ts were obtained when the BRP stable signal peptide was expressed as a separate entity. Kinetic studies revealed that these effects occurred prior to quasi-lysis and release of cloacin DF13. The results indicat ed that the BRP induced cell lethality is caused by early effects on p rotein synthesis and Mg2+ transport, due to the accumulation of stable BRP signal peptides in the cytoplasmic membrane.