TA Pair: Xre-Fic
#OrganismToxinAntitoxinLocus IDReplicon
1Bacteroides thetaiotaomicron VPI-5482717 BT_4530BT_4529NC_004663
2Bdellovibrio bacteriovorus HD1001282 Bd1707Bd1706NC_005363
3Caulobacter sp. K315071 Caul_5362Caul_5363NC_010333
4Cellvibrio japonicus Ueda1075754 CJA_1211CJA_1212NC_010995
5Chlorobium chlorochromatii CaD32124 Cag_0294Cag_0295NC_007514
6Chlorobium limicola DSM 2455619 Clim_2242Clim_2243NC_010803
7Chlorobium phaeobacteroides BS15662 Cphamn1_0743Cphamn1_0742NC_010831
8Clostridium difficile 6303597 CD630_31550CD630_31540NC_009089
9Geobacter lovleyi SZ5622 Glov_0191Glov_0190NC_010814
10Geobacter lovleyi SZ5641 Glov_3534Glov_3533NC_010814
11Geobacter lovleyi SZ5636 Glov_2565Glov_2564NC_010814
12Geobacter sulfurreducens PCA1533 GSU1391GSU1390NC_002939
13Heliobacterium modesticaldum Ice15077 HM1_0044HM1_0043NC_010337
14Lactobacillus plantarum WCFS1701 lp_3477lp_3478NC_004567
15Mesorhizobium loti MAFF303099209 mll2066mll2068NC_002678
16Pelobacter carbinolicus DSM 23802075 Pcar_1093Pcar_1094NC_007498
17Pseudomonas putida W6195209 PputW619_2025PputW619_2024NC_010501
18Rhodopseudomonas palustris BisA532996 RPE_3410RPE_3411NC_008435
19Shewanella putrefaciens CN-323810 Sputcn32_3625Sputcn32_3624NC_009438
20Shewanella sp. ANA-33140 Shewana3_4245Shewana3_4246NC_008573
21Shewanella sp. ANA-33159 Shewana3_3804Shewana3_3803NC_008577
22Shewanella sp. MR-72878 Shewmr7_0336Shewmr7_0337NC_008322
23Shewanella sp. W3-18-13300 Sputw3181_3765Sputw3181_3764NC_008750
24Streptococcus agalactiae 2603V/R637 SAG2119SAG2118NC_004116
25Sulfurovum sp. NBC37-14306 SUN_1611SUN_1612NC_009663
26Verminephrobacter eiseniae EF01-23425 Veis_0004Veis_0005NC_008786
27Xanthobacter autotrophicus Py24390 Xaut_4941Xaut_4942NC_009717
28Xanthomonas axonopodis pv. citri str. 306738 XAC1501XAC1499NC_003919
29Yersinia pestis Antiqua2776 YPA_3839YPA_3840NC_008150
30Yersinia pestis biovar Microtus str. 910011407 YP_3737YP_3738NC_005810
31Yersinia pestis Nepal5162759 YPN_0316YPN_0315NC_008149
32Yersinia pseudotuberculosis IP 329531523 YPTB0589YPTB0588NC_006155
33Yersinia pseudotuberculosis PB1/+5477 YPTS_0611YPTS_0610NC_010634
34Yersinia pseudotuberculosis YPIII5151 YPK_3619YPK_3620NC_010465

Antitoxin domain: Xre. Helix-turn-helix XRE-family like proteins. Prokaryotic DNA binding proteins belonging to the xenobiotic response element family of transcriptional regulators.

Toxin domain: Fic. Fic/Doc family. This family consists of the Fic (filamentation induced by cAMP) protein and doc (death on curing). The Fic protein is involved in cell division and is suggested to be involved in the synthesis of PAB or folate, indicating that the Fic protein and cAMP are involved in a regulatory mechanism of cell division via folate metabolism. This family contains a central conserved motif HPFXXGNG in most members. The exact molecular function of these proteins is uncertain. P1 lysogens of Escherichia coli carry the prophage as a stable low copy number plasmid. The frequency with which viable cells cured of prophage are produced is about 10(-5) per cell per generation. A significant part of this remarkable stability can be attributed to a plasmid-encoded mechanism that causes death of cells that have lost P1. In other words, the lysogenic cells appear to be addicted to the presence of the prophage. The plasmid withdrawal response depends on a gene named doc (death on curing) that is represented by this family. Doc induces a reversible growth arrest of E. coli cells by targetting the protein synthesis machinery. Doc hosts the C-terminal domain of its antitoxin partner Phd (prevents host death) through fold complementation, a domain that is intrinsically disordered in solution but that folds into an alpha-helix on binding to Doc.

(1) Makarova KS et al. (2009) Comprehensive comparative-genomic analysis of type 2 toxin-antitoxin systems and related mobile stress response systems in prokaryotes. Biol Direct 4:19. [PudMed:19493340] in_silico