Regulation of Mannitol Metabolism in Enterococcus faecalis and Association with Toxin-Antitoxin Locus Function.

The type I toxin-antitoxin locus is situated between genes for two paralogous mannitol family phosphoenolpyruvate phosphotransferase systems (PTSs). In order to address the possibility that function was associated with sugar metabolism, genetic and phenotypic analyses were performed on the flanking genes. It was found that the genes were transcribed as two operons: the downstream operon essential for mannitol transport and metabolism and the upstream operon performing a regulatory function.

Charged Residues Flanking the Transmembrane Domain of Two Related Toxin-Antitoxin System Toxins Affect Host Response.

A majority of toxins produced by type I toxin-antitoxin (TA-1) systems are small membrane-localized proteins that were initially proposed to kill cells by forming non-specific pores in the cytoplasmic membrane. The examination of the effects of numerous TA-1 systems indicates that this is not the mechanism of action of many of these proteins. produces two toxins of the Fst/Ldr family, one encoded on pheromone-responsive conjugative plasmids (Fst) and the other on the chromosome, Fst.