par stability determinant

FstAT
File:FstAT SScons.png Secondary structure of FstAT
Identifiers
Symbol	fstAT
Rfam	RF01797
Other data
RNA type	Gene; antitoxin
Domain	Enterococcus faecalis
PDB structures	PDBe

Fst Type I toxin-antitoxin system
Identifiers
Symbol	Fst_toxin
Pfam	PF13955
TCDB	1.C.64
OPM superfamily	225
OPM protein	2kv5
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

The par stability determinant is a 400 bp locus of the pAD1 plasmid which encodes a type I toxin-antitoxin system in Enterococcus faecalis. It was the first such plasmid addiction module to be found in gram-positive bacteria.

The par locus contains two genes: fst which encodes a 33-amino acid toxic protein and a gene for RNAII, the small RNA anti-toxin which inhibits fst translation. The two genes are found on opposite DNA strands and share a 5' region which is where they are thought to have an antisense interaction. Their RNA secondary structures have been predicted computationally, the complementary regions appear to be presented on exposed loops for interaction.

par maintains pAD1 by means of post-segregational killing (PSK). If a daughter cell does not inherit the par locus, the unstable RNAII will quickly degrade leaving the long-lived fst toxin to damage or kill the daughter cell.

See also

• Hok/sok system

External links

• Page for fst antitoxin sRNA (RNAII) at Rfam