Table 1.

Three-dimensional structures of the type II TA systems described in this minireview

TA Family	Toxin	Antitoxin	Mechanism of Toxicity	PDB IDs	Method	Organisms
vapBC	VapC	VapB	Ribosome-independent mRNA cleavage	1W8I, 2FE1, 3TND, 4CHG, 4XGQ, 4XGR, 3ZVK, 3H87, 3DBO, 1Y82	X-ray diffraction	Archaeoglobus fulgidus, Pyrobaculum aerophilum, Shigella flexneri, Mycobacterium tuberculosis, Rickettsia felis, Pyrococcus furiosus
mazEF	MazF	MazE	Ribosome-independent mRNA cleavage	3NFC, 1UB4, 4MDX, 4ME7, 4MZP, 4MZT, 2MF2, 4MZM, 4OF1	X-ray diffraction and solution NMR	Escherichia coli, Bacillus subtilis, Staphylococcus aureus
relBE	RelE	RelB	Ribosome-dependent mRNA cleavage	1WMI, 2K29, 3BPQ, 2KC9, 2KC8, 3G5O, 2KHE, 3OEI, 4FXI, 4FXH, 4FXE, 4V7J, 4V7K	X-ray diffraction and solution NMR	Escherichia coli, Pyrococcus horikoshii, Methanocaldococcus jannaschii, Mycobacterium tuberculosis, Thermus thermophilus
higBA	HigB	HigA	Ribosome-dependent mRNA cleavage	4YPB, 4YZV, 4MCX, 4MCT, 2ICT, 4PX8	X-ray diffraction	Escherichia coli, Proteus vulgaris
ccd	CcdB	CcdA	Inhibits DNA gyrase	2H3A, 2H3C, 3TCJ, 2ADL, 2H3C, 2ADN, 3G7Z, 3HPW, 3VUB, 2VUB, 2KMT, 3JRZ, 3JSC, 1X75, 4VUB, 1VUB, 4ELZ, 4ELY	X-ray diffraction and solution NMR	Escherichia coli, Aliivibrio fischeri, Shigella flexneri
parDE	ParE	ParD	Inhibits DNA gyrase	3KXE, 2AN7	X-ray diffraction and solution NMR	Escherichia coli, Caulobacter crescentus
hipBA	HipA	HipB	Phosphorylates glutamyl-transfer RNA synthase	4YG7, 4YG4, 4YG1, 3DNV, 3HZI, 3FBR, 3DNU, 3DNT, 2WIU, 3TPB, 3TPD, 3TPT, 3TPV, 4PU3, 4PU4, 4PU5, 4PU7, 4PU8	X-ray diffraction	Escherichia coli, Shewanella oneidensis
phd-doc	Doc	PhD	Inhibits the 30S ribosome and Phosphorylates EF-Tu	3K33, 3KH2, 3HS2, 3HRY, 3DD7, 3DD9	X-ray diffraction	Escherichia coli, Enterobacteria phage P1, Enterobacteria phage P2

Note: The information was collected from the Protein Data Bank (www.rcsb.org).⁶³