. 2012 Jun 25;7:18. doi: 10.1186/1745-6150-7-18

Table 3.

Phyletic distribution and associated toxins of Immunity proteins associated with polymorphic toxin systems

Immunity protein	Fold; Conservation¹	Associated toxins²	Phyletic distribution	Additional Notes
Imm-SUKH	α + β (PDB: 3D5P); Several hydrophobic residues and family-specific differences. Refer to previous paper for details	HNH fold families: Tox-SHH,Tox-HNH,Tox-HNH-CIDE, Tox-WHH, Tox-DHNNK, Tox-LHH, Tox-GHH, Tox-HHH, Tox-NucA, Tox-ColE7;	Acidobacteria, actinobacteria, αβγδϵ-proteobacteria, bacteroidetes,, chloroflexi, cyanobacteria, deinococci, firmicutes, fusobacteria, planctomycetes, spirochaetes, synergistetes, verrucomicrobia **Eukaryotes: Giardia, ciliophora, choanoflagellida, fungi,Naegleria, metazoa, stramenopiles, viridiplantae, chlorophyta, eukaryotic viruses**	This superfamily comprises 5 major families (SUKH1-5), which have been combined in this study; Shows fusions on occasions to toxins and immunity domains; For e.g. fusions to Tox-GHH, Imm-SuFu, Imm33, Imm37, Imm66, Imm67, Imm68, Imm69. Found in homogeneous and heterogenous polyimmunity loci
		Restriction endonuclease fold families: Tox-REase-4, Tox-REase-3;
		Deaminase families: YwqJ, XOO2897, BURPS668_1122
		Proteases: YabG, Tox-PL1; Other toxins: Tox-EndoU, Tox-DOC, Caspase, Tox-ParBL1, Tox-ComI, Ntox15, Ntox20, Tox-ABhydrolase2, Tox-ABhydrolase3
Imm-SuFu	α + β (PDB: 1M1L); GxS, E, E, DxxR	NGO1392-like Tox-HNH fold domain^a (SuFu-associated nuclease), Tox-GHE^b, Tox-ParB^c, Tox-DHNNK ^d, Tox-AHH^e, Tox-HNH^f, Tox-EndoU^g, Tox-EDA39C^h, Tox-PL-C39-like peptidaseⁱ,Tox- ALF-MPTase^j, Ntox7^k	Acidobacteria, actinobacteria^ab,d, α,β^{a,b,c, f},γa^{,c, d},δ^{e, h},ϵ-proteobacteria, bacteroidetes^b,I,k, chloroflexi, firmicutes^b,e,g, fusobacteria, planctomycetes, spirochaetes^j, tenericutes verrucomicrobia.	Fused to members of the SUKH family, ankyrin repeats, Imm5, Imm11, Imm33, Imm36, Imm66, Imm67, Imm68, Imm69, PsbP/MOG1. Found in homo- and heterogeneous polyimmunity loci. See Pfam PF05076
			**Eukaryotes:chlorophyta, ascomycota, choanoflagellida, metazoa**
Imm-SuFu- family 2	α + β; [ST]xxG, [DE]	Tox-ColE7^a, Tox-DHNNK, Tox-HNH fold^b, Tox-ALFMPTase^c,Tox-GDPD^d	actinobacteria α^d,β,γ,δ,ϵ-proteobacteria, bacteroidetes, cyanobacteria, fibrobacteres, firmicutes ^a,b, fusobacteria, gammaproteobacteria, planctomycetes, proteobacteria, spirochaetes^c, verrucomicrobia	Fused to Imm34, Imm33, Imm66, Imm67, Imm68, Imm69; Found in heterogeneous polyimmunity loci
Imm-Cloacin	FKBP-like α + β; EYSxD, NxG	Tox-ColE3^a	Plasmid ^a,ColE6-CT14 ^a, γ-proteobacteria ^a
HEAT repeats	All α;	Tox-REase-7^a	Actinobacteria^a,bacteroidetes,cyanobacteria,γ-proteobacteria,planctomycetes^a,verrucomicrobia^a
Ankyrin repeats (Imm-ank)	All α;	Tox-AHH^a	Firmicutes^a, planctomycetes^a, γ-proteobacteria^a	Fused to SuFu-like immunity domains in firmicutes and found in heterogeneous polyimmunity loci
LRR-repeats	α/β;	Next to T5SS^a toxins	actinobacteria,bacteria,β,γ^a,ϵ-proteobacteria, firmicutes, tenericutes	Found in heterogeneous polyimmunity loci
Imm-CdiI	Two transmembrane helices; several hydrophobic residues	CdiAC	γ-proteobacteria
Imm-NTF2	NTF2 fold (α + β); W, W, W	Tox-NucA ^a	Bacteroidetes, β,γ ^a,ϵ-proteobacteria, firmicutes, fusobacteria, verrucomicrobia	Fused to ankyrin repeats and Imm13 in some proteins
Imm-NTF2-2	NTF2 fold (α + β); Y,W	Tox-JAB-2	γ –proteobacteria (E. coli only)	Although related in structure to Imm-NTF2, the sequences are quite divergent from each other
Imm-PA2201	Two all-α domains(PDB: 2FEF); D, W,GxWxxE, D, YPxD	Tox-REase-1^a, Tox-AHH^b	Bacteroidetes^a, β ^a,γ ^{a, b},ϵ ^a -proteobacteria, firmicutes ^a	See Pfam DUF1910 + DUF1911
Imm-Barstar	α/β (PDB: 1BRS); DxxxD and several hydrophobic residues	Tox-Barnase-like ribonuclease^a	Acidobacteria, actinobacteria^a, α, β^a,γ^a,δ^a,ϵ^a-proteobacteria bacteroidetes^a, chlamydiae^a, chloroflexi^a, cyanobacteria^a, deinococci^a, elusimicrobia, firmicutes^a,fusobacteria^a, nitrospirae^a, planctomycetes^a, verrucomicrobia, Archaea: euryarchaea^a, **Eukaryotes:dictyosteliida,Naegleria,chlorophyta**	See Pfam PF01337
Imm-ADP-RGHD; ADP ribosyl glycohydrolase	All-α; (PDB: 1t5j); D, D[DE], [RK], H	Tox-ART-RSE^a	acidobacteria, β,γ^a-proteobacteria, firmicutes^a	See Pfam Pf03747; an example of an enzymatic immunity protein
Imm-NMB0513	wHTH fold (α + β, PDB: 2O5H); W, W	Ntox20^a, Ntox7^b	betaproteobacteria^a,b gammaproteobacteria^a	Corresponds to Pfam DUF596
Imm-ComJ	Mostly β; W, F[DE], PF, Y, Y	Tox-ComI-like competence nuclease^a	α^aβ^aγ^a-proteobacteria, bacteroidetes^a, cyanobacteria, firmicutes^a,
			**Eukaryotes:viridiplantae**
Imm-VC0424	α + β; α + β RRM fold, W at C-terminus	-	Firmicutes, fusobacteria, α,β,γ-proteobacteria	Also known as DUF1260 in the Pfam database. Only a subset of members is found in polymorphic toxin systems as potential immunity proteins. These species are listed in column 3
Imm-My6CBD	α + β; E, R, F, W	Tox-ART-HYD1^a	actinobacteria ^a, bacteroidetes ^a, firmicutes ^a, fusobacteria, β ^a,γ ^a –proteobacteria, **Eukaryotes: Metazoa**	The type VI myosin cargo-binding domain of metazoa appears to have been acquired by lateral transfer from a bacterial version
Imm1	α + β; aromatic and W at C-terminus	SCP1.201 deaminases^a	Actinobacteria^a, bacteroidetes, cyanobacteria, firmicutes, planctomycetes α,β,γ-proteobacteria, verrucomicrobia
Imm2	All α; acidic and hydrophobic residues	BURPS668_1122 deaminases	β, γ- proteobacteria
Imm3	All α; charged, V	BURPS668_1122 deaminases	Firmicutes	found in heterogeneous polyimmunity loci
Imm4	α + β	SCP1.201 deaminases	Burkholderia pseudomallei
Imm5	Mostly α; R, D	DYW deaminases^a, CdiAC^b	Actinobacteria^a, bacteroidetes^a, firmicutes^a, α,β,γ^{a, b},proteobacteria	Fused to Imm36 on occasions
Imm6	Mostly α; P, [DE]	YwqJ deaminases^a	Actinobacteria^a, α-proteobacteria, firmicutes^a	Found in homo and heterogeneous polyimmunity loci
Imm7	α + β; GxaG	Tox-REase-3^a	actinobacteria, firmicutes ^a, planctomycetes
Imm8	α + β; WEa (a:aromatic) at C-terminus	Ntox7^a	Acidobacteria, actinobacteria, bacteroidetes ^a, firmicutes ^a, α, β ^a, γ ^a, δ-proteobacteria
Imm9	α + β; K and several conserved acidic residues	Tox-URI2	Bacteroidetes, γ-proteobacteria	Found in heterogeneous polyimmunity loci
Imm10	Mostly β; R and several hydrophobic residues	Pput_2613 deaminase^a	actinobacteria bacteroidetes chloroflexi firmicutes β, γ^a,δ,ϵ-proteobacteria; **Eukaryotes:ascomycetes**	Lateral transfer to fungi, found in heterogeneous polyimmunity loci
Imm11	α + β; several conserved hydrophobic residues	Tox-AHH^a, Tox-HNH^b, Tox-SHH^c	Bacteroidetes^a, chloroflexi, cyanobacteria, firmicutes^a, planctomycetes^a, α,β^a,γ^a,δ^a,b,c,ϵ^a-proteobacteria spirochaetes^a verrucomicrobia^a	Listed in the Pfam database as DUF1629. Fused to SuFu on occasions. Found in heterogeneous and homogeneous polyimmunity loci.
Imm12	α + β; several conserved charged and hydrophobic residues	Tox-URI2^a	Bacteroidetes^a, spirochaetes	Found in heterogeneous polyimmunity loci
Imm13	α + β; D, D, D, D	Tox-DOC^a	Actinobacteria, bacteroidetes cyanobacteria, firmicutes, fusobacteria^a, spirochaetes, verrucomicrobia, α,β,γ,δ-proteobacteria,	Note lateral transfer to eukaryotes. Found in heterogeneous polyimmunity loci. Fused to Imm33 in some instances
			*Eukaryotes: Naegleria*
Imm14	Mostly β; several hydrophobic residues	Tox-URI1^a, Tox-HNH^b	Actinobacteria^a, α,β^a,γ^a,,δ^b-proteobacteria, bacteroidetes^a, chlamydiae^a, chloroflexi^a, cyanobacteria, firmicutes^a, fusobacteria, spirochaetes, verrucomicrobia	Found in heterogeneous polyimmunity loci; Fused to Imm51 in one instance
Imm15	α + β; several polar and hydrophobic residues		Bacteroidetes, firmicutes, synergistetes	Found in heterogeneous polyimmunity loci
Imm16	α + β; several hydrophobic residues including a highly conserved W	Ntox8^a	Actinobacteria, bacteroidetes ^a, β ^a,γ,δ-proteobacteria, firmicutes ^a, planctomycetes, spirochaetes, verrucomicrobia	Also known as DUF2750
Imm17	Two TM helices; WxW and a R in the region between them		Bacteroidetes, firmicutes, fusobacteria, spirochaetes	Found in heterogeneous polyimmunity loci
Imm18	Mostly β; highly conserved D	Tox-HNH ^a	Actinobacteria ^a, αβ ^a γ ^a δ ^a -proteobacteria, bacteroidetes ^a, firmicutes	Found in heterogeneous polyimmunity loci
Imm19	α + β; HxxRN motif and several conserved hydrophobic residues	-	Bacteroidetes	Found in heterogeneous polyimmunity loci
Imm20	α + β; several conserved hydrophobic residues	Tox-AHH ^a, Tox-ParB ^b	Acidobacteria, actinobacteria, bacteroidetes, β ^{a, b},γ ^a,δ-proteobacteria, cyanobacterium firmicutes ^a, fusobacteria, planctomycetes, spirochaetes, verrucomicrobia, **Eukaryotes:ascomycota**	Found in heterogeneous polyimmunity loci. Note presence in ascomycetes
Imm21	α + β; absolutely conserved WxG, YxxxC and several hydrophobic residues	NGO1392-like HNH fold^a	Actinobacteria, α,δ-proteobacteria, bacteroidetes, firmicutes^a, verrucomicrobia	Found in heterogeneous polyimmunity loci
Imm22	α + β; W, Y, and an acidic residue (mostly D)	ColD/E5 fold^a, Tox-REase-4^b, Ntox49^c, Ntox14^d	Actinobacteria, bacteroidetes^a,c, β,γ-proteobacteria, firmicutes ^b,d, fusobacteria, planctomycetes, verrucomicrobia, **Eukaryotes:ascomycota**	Previously known as SNCF1. Found in heterogeneous polyimmunity loci across a wide range of bacteria
Imm23	α + β; several hydrophobic residues including a WxW motif	Tox-AHH^a, Tox-REase-7^b	bacteroidetes^a cyanobacteria ^b, firmicutes γ-proteobacteria verrucomicrobia	Some versions fused to Imm11; found in heterogeneous polyimmunity loci
Imm24	Mostly α-helical with C-terminal β-hairpin; several hydrophobics including a PxG motif (where x is mostly C)	Tox-AHH^a, Tox-SHH^b	Bacteroidetes^c, β^a,γ^a,ϵ-proteobacteria, firmicutes^a,b, verrucomicrobia	found in heterogeneous polyimmunity loci
Imm25	α + β; highly conserved in limited sequences	-	Bacteroidetes	Potential immunity protein found in heterogeneous polyimmunity loci, and a limited phyletic presence
Imm26	Mostly α; R and D and several hydrophobic residues	Tox-URI1^a	Actinobacteria, bacteroidetes^a, β,γ^a,δ-proteobacteria, firmicutes, fusobacteria, planctomycetes, spirochaetes, **Eukaryotes:Ascomycota**	Note presence in ascomycetes, present in heterogeneous polyimmunity loci
Imm27	α + β; D, GGxP	Ntox10^a, Tox-ParB^b	Actinobacteria, bacteroidetes ^a, β,δ^b-proteobacteria, verrucomicrobia ^a	Wide distribution but sporadic numbers
Imm28	Mostly α; acidic, P,G, R	Tox-WHH^a, Tox-EndoU^b, Ntox20^c	Actinobacteria, α^a,β^b,c,γ^a-proteobacteria	Note presence in Odyssella, present in heterogeneous polyimmunity loci
Imm29	Mostly α; R and acidic and several hydrophobic residues	Ntox18 ^a	Actinobacteria, α ^a,β ^a,γ ^a -proteobacteria, bacteroidetes, firmicutes, fusobacteria	Note presence in Odyssella, present in heterogeneous polyimmunity loci
Imm30	Mostly α; Several conserved hydrophobics and DxG motif	Tox-SHH^a	α ^a,β^,γ ^a –proteobacteria	Note presence in Odyssella. Limited number of hits, present in heterogeneous polyimmunity loci
Imm31	All-β; GxS, [R]	Ntox17^a, Ntox7^b	α ^a,β^b,γ ^a,δ-proteobacteria, cyanobacteria	Note presence in Odyssella. Limited distribution
Imm32	α + β; H, and several conserved residues	Ntox12^a, Ntox37 ^b, Ntox7 ^c	α ^a,β,γ ^a,c,δ-proteobacteria, chlamydiae, bacteroidetes ^b, firmicutes ^a, verrucomicrobia	Note presence in Odyssella, chlamydiae. Limited distribution
Imm33	Mostly β; W	Tox-HNH ^a, Tox-DHNNK ^b,^, NGO1392-like- HNH^c	Acidobacteria, actinobacteria, αβ ^a,c γδ^c-proteobacteria, bacteroidetes, chloroflexi, firmicutes, ^b, fusobacteria, planctomycetes, **Eukaryotes:dictyosteliida**	Also known as DUF2185 in the Pfam database, fused to Imm- SUKH, Imm13, Imm34 and Imm-SuFu, Note presence in dictyosteliida where it is fused to Imm34, present in homo and heterogeneous polyimmunity loci
Imm34	Mostly β; ExxW, C-terminal D	-	Actinobacteria, α,β,γ,δ,ϵ-proteobacteria, bacteroidetes, firmicutes, fusobacteria, planctomycetes, spirochaetes, verrucomicrobia, **Eukaryotes:dictyosteliida, heterolobosea, cnidaria**	Also known as DUF2314. Fused to Imm-SuFu family 2, Imm33, ankyrin repeats, TM helices, fusion to Imm33 appears to have occurred on multiple occasions independently, present in heterogeneous polyimmunity loci. Note presence in Naegleria, dictyosteliida and cnidarians. In dictyostellids, it is fused to Imm33
Imm35	α + β; W, [ST]	Tox-PL1^a, Ntox40^b	Actinobacteria^{a, b}, bacteroidetes^a, β,γ^a-proteobacteria, planctomycetes	Fused to Papain-like toxin and ADP-ribosyl glycohydrolase and Peptidase S8, in some instances. Possible protease inhibitor
Imm36	BH3703-like fold (α + β); W, W	Tox-NucA^a, DYW-Deaminase^b, Ntox40^c, Tox-CdiAC^d, Tox-Caspase^e	Actinobacteria^{a, c, e}, α^a,β^a,γ^a,d,δ-proteobacteria, bacteroidetes^a,b, firmicutes^a, fusobacteria, spirochaetes^a	Also known as DUF600, fused to Tox-NucA, Imm-SuFu, Imm5, on occasions. Tox-NucA appears to be the primary toxin association. One of the large families. Found in homo and heterogeneous poly-immunity loci. Profile-profile analysis predicts a BH3703-like fold
Imm37	α + β; ExG	Tox-WHH^a	Acidobacteria, actinobacteria, αβγ^aϵ-proteobacteria, bacteroidetes, chloroflexi, cyanobacteria, deinococci, firmicutes^a, fusobacteria^a, planctomycetes, verrucomicrobia	Previously known as SNCF2, fused to SUKH in some instances. Found in heterogeneous polyimmunity loci
Imm38	Mostly α; W at N and aromatic residue at C	Ntox19^a, NGO1392-like- HNH^b	Actinobacteria, bacteroidetes ^a, β ^a,b,γ ^a,δ ^a -proteobacteria, firmicutes ^a, fusobacteria ^a, nitrospirae	Also known as DUF2247. Found in heterogeneous polyimmunity loci
Imm39	α + β; GR, GxK and several polar and hydrophobic residues	Tox-URI2 ^a	α ^a γ ^a-proteobacteria	Limited distribution
Imm40	α + β; GGD, F, W	Ntox19^a	bacteroidetes^a, chloroflexi firmicutes, β^a,ϵ,γ^a- proteobacteria
Imm41	α + β; SF, W and several hydrophobic residues	Ntox21^a, Ntox29 ^b, Tox-ART-RSE ^c	Actinobacteria, β ^a,b,γ^c,ϵ-proteobacteria, firmicutes, planctomycetes	Found in homo- and heterogeneous polyimmunity loci
Imm42	α + β; Several conserved hydrophobic residues	Ntox18^a	α,β ^a,γ ^a -proteobacteria, firmicutes ^a
Imm43	α/β; W, P, D, S, R	Tox-AHH^a	Bacteroidetes^a, β-proteobacteria^a, firmicutes	Found in heterogeneous polyimmunity loci
Imm44	α + β; Multiple polar and hydrophobic residiues	Tox-URI1^a, Tox-URI2^b, Tox-ParBL1^c	Bacteroidetes, β-proteobacteria^a,b, firmicutes^c	Limited phyletic distribution; Found in heterogeneous polyimmunity loci that show variations in structure even between closely related strains
Imm45	α + β; C-terminal W	Tox-ColE3^a	bacteroidetes,β ^a,γ ^a,ϵ-proteobacteria, firmicutes
Imm46	α + β; E, W, E	-	Bacteroidetes, β-proteobacteria	Limited phyletic distribution. Found next to a predicted toxin
Imm47	α + β; KxGDxxK	-	β-proteobacteria, firmicutes	Found in heterogeneous polyimmunity loci
Imm48	All-α; HRG	-	Firmicutes,verrucomicrobia	Found in heterogeneous polyimmunity loci
Imm49	All α; Hydrophobic residues, P	Tox-REase-1^a, Tox-REase-6^b	Actinobacteria ^b, Bacteroidetes ^a,b, cyanobacteria ^b, firmicutes ^a, fusobacteria ^a, planctomycetes, β ^a,b,δ,γ ^a,b -proteobacteria	Also known as DUF556
Imm50	Mostly β; Several hydrophobic residues	Tox-HHH^a, Ntox24^b	actinobacteria, bacteroidetes^a, firmicutes^a, planctomycetes, α,β^a,b,γ^a-proteobacteria, verrucomicrobia
Imm51	α + β; W, Dx[DE] and several hydrophobic residues	Tox-RES^a, Tox-URI1^b	Actinobacteria, bacteroidetes^a, β,γ-proteobacteria, cyanobacteria,firmicutes ^b, fusobacteria, spirochaetes	Fused to Imm14 on one occasion, Found in polyimmunity loci
Imm52	α + β; W,GT,F	Tox-REase-5^a	Caudoviruses^a, α,β ^a,γ ^a,δ ^a –proteobacteria
Imm53	α + β (Central β-sheet with flanking α-helices); W, WE, PGW, W	Ntox24^a, Ntox10^b	Acidobacteria, actinobacteria, α,β,γ,δ,ϵ-proteobacteria, bacteroidetes, chlamydiae ^b, cyanobacteria, firmicutes ^a, spirochaetes, verrucomicrobia
Imm54	α + β; GF, Q	Tox-REase-9^a, Tox-RelE^b, Tox-URI^c, Tox-REase-4^d, Tox-REase-7^e, Tox-REase-10^f	actinobacteria, bacteroidetes ^{a, c, d}, chlamydiae ^a, firmicutes ^{a, c, d,e}, fusobacteria^b,f, planctomycetes, α,β ^c,γ ^a,δ,ϵ-proteobacteria, spirochaetes, verrucomicrobia	Found in heterogeneous polyimmunity loci
Imm55	α + β; G and several hydrophobic residues	Tox-SHH^a	actinobacteria, bacteroidetes^a, cyanobacteria^a, firmicutes^a, lentisphaerae, planctomycetes, α,β,γ^a-proteobacteria, synergistetes, verrucomicrobia
Imm56	α + β; D, GR	Ntox38^a, Tox-HNH^b	Actinobacteria ^a,b,
			chloroflexi ^a
Imm57	Mostly α; D, SE, C	Tox-LD-peptidase^a, Tox-Caspase^b	β^a,γ^{a, b}-proteobacteria
Imm58	α + β; YxxxD, WxG, KxxxE	Unknown toxins with RHS repeats	β,δ -proteobacteria	Limited distribution
Imm59	α + β (Central β-sheet with flanking α-helices); [DE]R motif	Ntox13^a, Ntox40^b	firmicutes ^a,b	Fused to Imm63 on some instances
Imm60	Mostly β; N, W	Ntox40 ^a, Ntox48^b	bacteroidetes	Found in heterogeneous polyimmunity loci
			firmicutes ^a, fusobacteria, α ^b,γ^b –proteobacteria,
			euryarchaea
Imm61	α + β; R	Ntox40^a	actinobacteria ^a
Imm62	α + β; -(mostly E), W	Ntox31^a, Ntox48^b	Firmicutes^{a, b},	Found in heterogeneous polyimmunity loci
			γ-proteobacteria
Imm63	α + β; E + G, -(mostly E)xxY	Ntox40^a, Tox-CdiAC^b, Tox-ARC	actinobacteria ^a,c	Found in polyimmunity loci
			bacteroidetes
			firmicutes^a, β,γ^a,b -proteobaceria
Imm64	α + β; DxEA, R motifs	Tox-ColD^a	Euryarchaea^a, firmicutes^a, ϵ-proteobacteria
Imm65	α + β; YxC, and several charged residues	Tox-JAB-1	Bacteroidetes	Contains a signal peptide and a lipbox
Imm66	Mostly α; D, W, F, Y,W	Tox-ABhydrolase3^a, Ntox48^b	Actinobacteria, bacteroidetes, cyanobacteria, firmicutes	Fused to one or more immunity domains such as Imm68, SUKH, Imm-SuFu- family 2, Imm33, Imm69, Imm67, Imm-SuFu, Imm66, and TPR repeats. Some proteins in firmicutes have up to 10 immunity domains
			Fusobacteria, α,β ^a,γ^b,ϵ-proteobacteria, spirochaetes, verrucomicrobia, **Eukaryotes:Ascomycota, viridiplantae**
Imm67	α + β; W, E, W	-	actinobacteria, bacteroidetes, chloroflexi, cyanobacteria, firmicutes, fusobacteria, planctomycetes, α,β,γ,δ, ϵ-proteobacteria, spirochaetes, verrucomicrobia	Fused to one or more immunity domains such as Imm68, Imm33, Imm-SUKH, Imm-SuFu-family 2, Imm69, Imm-SuFu, Imm66, Imm67, TPR and ankyrin repeats. Some proteins in firmicutes have up to 10 immunity domains
Imm68	α + β; E	-	actinobacteria, bacteroidetes, firmicutes, spirochaetes	Fused to one or more immunity domains such as Imm-SUKH, Imm-SuFu, Imm67, Imm66, Imm-SuFu-family 2, Imm69, Imm33, Imm68 andTPR repeats. Some proteins in firmicutes have up to 10 immunity domains
Imm69	α + β; W,hGE(h: hydrophobic)	Tox-ABhydrolase3^a	Actinobacteria, bacteroidetes, firmicutes ^a, fusobacteria, planctomycetes, α,β.γ,ϵ-proteobacteria,, spirochaetes, verrucomicrobia	Fused to one or more immunity domains such as Imm68, Imm-SUKH, Imm33, Imm-SuFu-family 2, Imm-SuFu, Imm67, Imm66, SP, Imm69 and TPR repeats. Some proteins in firmicutes have up to 10 immunity domains
Imm70	α + β; Y,W	Tox-REase-10^a	Acidobacteria, actinobacteria, bacteroidetes, firmicutes^a, β^a,γ^a,ϵ^a-proteobacteria, spirochaetes^a, verrucomicrobia
Imm71	Mostly α; R,F, R	Ntox48^a	acidobacteria ^a, β ^a,γ ^a -proteobacteria	Often fused to Imm72
			**Eukaryotes:viridiplantae**
Imm72	All-β; GxxE, WxDxRY, E	Ntox48^a	acidobacteria ^a, β ^a,γ ^a -proteobacteria	Often fused to Imm71
Imm73	All-α; Several hydrophobic residues	Tox-PL-2^a, Tox-HNH^b	acidobacteria, actinobacteria^b, bacteroidetes, cyanobacteria ^a, firmicutes ^a, fusobacteria, β,γ,δ ^a -proteobacteria, verrucomicrobia	Sometimes found in 2–3 tandem copies in a polypeptide
Imm74	α + β; G[DE], [DE]	Tox-Arc^a	bacteroidetes^a, firmicutes^a, planctomycetes, α,β,γ^a,δ -proteobacteria,	Found in heterogeneous polyimmunity loci

1. Where possible, known or predicted folds are described. The folds are further classified as All-α (composed entirely of α-helices), All-β (composed entirely of β-strands), α + β (Containing α-helices and β-strands) or α/β (comprising repeated α-helix-β-strand units) depending on the arrangement of their structural elements. Individual conserved residues and motifs are separated by commas. Alternative residues are enclosed in square brackets; ‘x’ denotes any residue.

2. Each toxin in column3 that is present in a gene neighborhood along with the corresponding immunity protein in column 1 in the toxin-immunity gene order is marked by a superscript letter, so as to identify the phyletic pattern of this association in column 4.