Par stability determinant

FstAT
Secondary structure of FstAT
Identifiers
Symbol	fstAT
Rfam	RF01797
Other data
RNA type	Gene; antitoxin
Domain(s)	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.[1][2] It was the first such plasmid addiction module to be found in gram-positive bacteria.[3]

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.[4] 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.[4] Their RNA secondary structures have been predicted computationally, the complementary regions appear to be presented on exposed loops for interaction.[4]

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.[5]

See also

• Hok/sok system

References

1. Weaver KE, Walz KD, Heine MS (November 1998). "Isolation of a derivative of Escherichia coli-Enterococcus faecalis shuttle vector pAM401 temperature sensitive for maintenance in E. faecalis and its use in evaluating the mechanism of pAD1 par-dependent plasmid stabilization". Plasmid. 40 (3): 225–232. doi:10.1006/plas.1998.1368. PMID 9806859.
2. Weaver KE, Jensen KD, Colwell A, Sriram SI (April 1996). "Functional analysis of the Enterococcus faecalis plasmid pAD1-encoded stability determinant par". Mol. Microbiol. 20 (1): 53–63. doi:10.1111/j.1365-2958.1996.tb02488.x. PMID 8861204. S2CID 30452609.
3. Shokeen S, Greenfield TJ, Ehli EA, Rasmussen J, Perrault BE, Weaver KE (March 2009). "An intramolecular upstream helix ensures the stability of a toxin-encoding RNA in Enterococcus faecalis". J. Bacteriol. 191 (5): 1528–1536. doi:10.1128/JB.01316-08. PMC 2648210. PMID 19103923.
4. Greenfield TJ, Ehli E, Kirshenmann T, Franch T, Gerdes K, Weaver KE (August 2000). "The antisense RNA of the par locus of pAD1 regulates the expression of a 33-amino-acid toxic peptide by an unusual mechanism". Mol. Microbiol. 37 (3): 652–660. doi:10.1046/j.1365-2958.2000.02035.x. PMID 10931358.
5. Gerdes K, Gultyaev AP, Franch T, Pedersen K, Mikkelsen ND (1997). "Antisense RNA-regulated programmed cell death". Annu. Rev. Genet. 31: 1–31. doi:10.1146/annurev.genet.31.1.1. PMID 9442888.

Further reading

• Gerdes K, Gultyaev AP, Franch T, Pedersen K, Mikkelsen ND (1997). "Antisense RNA-regulated programmed cell death". Annu. Rev. Genet. 31: 1–31. doi:10.1146/annurev.genet.31.1.1. PMID 9442888.
• Poulsen LK, Larsen NW, Molin S, Andersson P (November 1989). "A family of genes encoding a cell-killing function may be conserved in all gram-negative bacteria". Mol. Microbiol. 3 (11): 1463–1472. doi:10.1111/j.1365-2958.1989.tb00131.x. PMID 2693900. S2CID 41192501.
• Hayes F (September 2003). "Toxins-antitoxins: plasmid maintenance, programmed cell death, and cell cycle arrest". Science. 301 (5639): 1496–1499. Bibcode:2003Sci...301.1496H. doi:10.1126/science.1088157. PMID 12970556. S2CID 10028255.
• Gerdes K, Rasmussen PB, Molin S (May 1986). "Unique type of plasmid maintenance function: postsegregational killing of plasmid-free cells". Proc. Natl. Acad. Sci. U.S.A. 83 (10): 3116–3120. Bibcode:1986PNAS...83.3116G. doi:10.1073/pnas.83.10.3116. PMC 323463. PMID 3517851.

External links

• Page for fst antitoxin sRNA (RNAII) at Rfam