This family consists of the entericidin antidote/toxin peptides. The entericidin locus is activated in stationary phase under high osmolarity conditions by rho-S and simultaneously repressed by the osmoregulatory EnvZ/OmpR signal transduction pathway. The entericidin locus encodes tandem paralogous genes (ecnAB) and directs the synthesis of two small cell-envelope lipoproteins which can maintain plasmids in bacterial population by means of post-segregational killing [1].

1: The entericidin locus of Escherichia coli and its implications for programmed bacterial cell death. Bishop RE, Leskiw BK, Hodges RS, Kay CM, Weiner JH; J Mol Biol 1998;280:583-596. PMID:9677290