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Table 3 Phyletic distribution and associated toxins of Immunity proteins associated with polymorphic toxin systems

From: Polymorphic toxin systems: Comprehensive characterization of trafficking modes, processing, mechanisms of action, immunity and ecology using comparative genomics

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 domaina (SuFu-associated nuclease), Tox-GHEb, Tox-ParBc, Tox-DHNNK d, Tox-AHHe, Tox-HNHf, Tox-EndoUg, Tox-EDA39Ch, Tox-PL-C39-like peptidasei,Tox- ALF-MPTasej, Ntox7k Acidobacteria, actinobacteriaab,d, α,βa,b,c, f,γa,c, de, h,ϵ-proteobacteria, bacteroidetesb,I,k, chloroflexi, firmicutesb,e,g, fusobacteria, planctomycetes, spirochaetesj, 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-ColE7a, Tox-DHNNK, Tox-HNH foldb, Tox-ALFMPTasec,Tox-GDPDd actinobacteria αd,β,γ,δ,ϵ-proteobacteria, bacteroidetes, cyanobacteria, fibrobacteres, firmicutes a,b, fusobacteria, gammaproteobacteria, planctomycetes, proteobacteria, spirochaetesc, verrucomicrobia Fused to Imm34, Imm33, Imm66, Imm67, Imm68, Imm69; Found in heterogeneous polyimmunity loci
Imm-Cloacin FKBP-like α + β; EYSxD, NxG Tox-ColE3a Plasmid a,ColE6-CT14 a, γ-proteobacteria a  
HEAT repeats All α; Tox-REase-7a Actinobacteriaa,bacteroidetes,cyanobacteria,γ-proteobacteria,planctomycetesa,verrucomicrobiaa  
Ankyrin repeats (Imm-ank) All α; Tox-AHHa Firmicutesa, planctomycetesa, γ-proteobacteriaa Fused to SuFu-like immunity domains in firmicutes and found in heterogeneous polyimmunity loci
LRR-repeats α/β; Next to T5SSa toxins actinobacteria,bacteria,β,γa,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-1a, Tox-AHHb Bacteroidetesa, β aa, ba -proteobacteria, firmicutes a See Pfam DUF1910 + DUF1911
Imm-Barstar α/β (PDB: 1BRS); DxxxD and several hydrophobic residues Tox-Barnase-like ribonucleasea Acidobacteria, actinobacteriaa, α, βaaaa-proteobacteria bacteroidetesa, chlamydiaea, chloroflexia, cyanobacteriaa, deinococcia, elusimicrobia, firmicutesa,fusobacteriaa, nitrospiraea, planctomycetesa, verrucomicrobia, Archaea: euryarchaeaa, Eukaryotes: dictyosteliida, Naegleria, chlorophyta See Pfam PF01337
Imm-ADP-RGHD; ADP ribosyl glycohydrolase All-α; (PDB: 1t5j); D, D[DE], [RK], H Tox-ART-RSEa acidobacteria, β,γa-proteobacteria, firmicutesa See Pfam Pf03747; an example of an enzymatic immunity protein
Imm-NMB0513 wHTH fold (α + β, PDB: 2O5H); W, W Ntox20a, Ntox7b betaproteobacteriaa,b gammaproteobacteriaa Corresponds to Pfam DUF596
Imm-ComJ Mostly β; W, F[DE], PF, Y, Y Tox-ComI-like competence nucleasea αaβaγa-proteobacteria, bacteroidetesa, cyanobacteria, firmicutesa,  
    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-HYD1a actinobacteria a, bacteroidetes a, firmicutes a, fusobacteria, β aa –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 deaminasesa Actinobacteriaa, 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 deaminasesa, CdiACb Actinobacteriaa, bacteroidetesa, firmicutesa, α,β,γa, b,proteobacteria Fused to Imm36 on occasions
Imm6 Mostly α; P, [DE] YwqJ deaminasesa Actinobacteriaa, α-proteobacteria, firmicutesa Found in homo and heterogeneous polyimmunity loci
Imm7 α + β; GxaG Tox-REase-3a actinobacteria, firmicutes a, planctomycetes  
Imm8 α + β; WEa (a:aromatic) at C-terminus Ntox7a 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 deaminasea actinobacteria bacteroidetes chloroflexi firmicutes β, γa,δ,ϵ-proteobacteria; Eukaryotes: ascomycetes Lateral transfer to fungi, found in heterogeneous polyimmunity loci
Imm11 α + β; several conserved hydrophobic residues Tox-AHHa, Tox-HNHb, Tox-SHHc Bacteroidetesa, chloroflexi, cyanobacteria, firmicutesa, planctomycetesa, α,βaaa,b,ca-proteobacteria spirochaetesa verrucomicrobiaa 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-URI2a Bacteroidetesa, spirochaetes Found in heterogeneous polyimmunity loci
Imm13 α + β; D, D, D, D Tox-DOCa Actinobacteria, bacteroidetes cyanobacteria, firmicutes, fusobacteriaa, 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-URI1a, Tox-HNHb Actinobacteriaa, α,βaa,b-proteobacteria, bacteroidetesa, chlamydiaea, chloroflexia, cyanobacteria, firmicutesa, 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 Ntox8a 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, ba,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 folda Actinobacteria, α,δ-proteobacteria, bacteroidetes, firmicutesa, verrucomicrobia Found in heterogeneous polyimmunity loci
Imm22 α + β; W, Y, and an acidic residue (mostly D) ColD/E5 folda, Tox-REase-4b, Ntox49c, Ntox14d Actinobacteria, bacteroidetesa,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-AHHa, Tox-REase-7b bacteroidetesa 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-AHHa, Tox-SHHb Bacteroidetesc, βaa,ϵ-proteobacteria, firmicutesa,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-URI1a Actinobacteria, bacteroidetesa, β,γa,δ-proteobacteria, firmicutes, fusobacteria, planctomycetes, spirochaetes, Eukaryotes: Ascomycota Note presence in ascomycetes, present in heterogeneous polyimmunity loci
Imm27 α + β; D, GGxP Ntox10a, Tox-ParBb Actinobacteria, bacteroidetes a, β,δb-proteobacteria, verrucomicrobia a Wide distribution but sporadic numbers
Imm28 Mostly α; acidic, P,G, R Tox-WHHa, Tox-EndoUb, Ntox20c Actinobacteria, αab,ca-proteobacteria Note presence in Odyssella, present in heterogeneous polyimmunity loci
Imm29 Mostly α; R and acidic and several hydrophobic residues Ntox18 a Actinobacteria, α aaa -proteobacteria, bacteroidetes, firmicutes, fusobacteria Note presence in Odyssella, present in heterogeneous polyimmunity loci
Imm30 Mostly α; Several conserved hydrophobics and DxG motif Tox-SHHa α a,γ a –proteobacteria Note presence in Odyssella. Limited number of hits, present in heterogeneous polyimmunity loci
Imm31 All-β; GxS, [R] Ntox17a, Ntox7b α aba,δ-proteobacteria, cyanobacteria Note presence in Odyssella. Limited distribution
Imm32 α + β; H, and several conserved residues Ntox12a, 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- HNHc Acidobacteria, actinobacteria, αβ a,c γδc-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-PL1a, Ntox40b Actinobacteriaa, b, bacteroidetesa, β,γa-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-NucAa, DYW-Deaminaseb, Ntox40c, Tox-CdiACd, Tox-Caspasee Actinobacteriaa, c, e, αaaa,d,δ-proteobacteria, bacteroidetesa,b, firmicutesa, fusobacteria, spirochaetesa 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-WHHa Acidobacteria, actinobacteria, αβγaϵ-proteobacteria, bacteroidetes, chloroflexi, cyanobacteria, deinococci, firmicutesa, fusobacteriaa, 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 Ntox19a, NGO1392-like- HNHb Actinobacteria, bacteroidetes a, β a,baa -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 Ntox19a bacteroidetesa, chloroflexi firmicutes, βa,ϵ,γa- proteobacteria  
Imm41 α + β; SF, W and several hydrophobic residues Ntox21a, Ntox29 b, Tox-ART-RSE c Actinobacteria, β a,bc,ϵ-proteobacteria, firmicutes, planctomycetes Found in homo- and heterogeneous polyimmunity loci
Imm42 α + β; Several conserved hydrophobic residues Ntox18a α,β aa -proteobacteria, firmicutes a  
Imm43 α/β; W, P, D, S, R Tox-AHHa Bacteroidetesa, β-proteobacteriaa, firmicutes Found in heterogeneous polyimmunity loci
Imm44 α + β; Multiple polar and hydrophobic residiues Tox-URI1a, Tox-URI2b, Tox-ParBL1c Bacteroidetes, β-proteobacteriaa,b, firmicutesc 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-ColE3a bacteroidetes,β aa,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-1a, Tox-REase-6b 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-HHHa, Ntox24b actinobacteria, bacteroidetesa, firmicutesa, planctomycetes, α,βa,ba-proteobacteria, verrucomicrobia  
Imm51 α + β; W, Dx[DE] and several hydrophobic residues Tox-RESa, Tox-URI1b Actinobacteria, bacteroidetesa, 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-5a Caudovirusesa, α,β aaa –proteobacteria  
Imm53 α + β (Central β-sheet with flanking α-helices); W, WE, PGW, W Ntox24a, Ntox10b Acidobacteria, actinobacteria, α,β,γ,δ,ϵ-proteobacteria, bacteroidetes, chlamydiae b, cyanobacteria, firmicutes a, spirochaetes, verrucomicrobia  
Imm54 α + β; GF, Q Tox-REase-9a, Tox-RelEb, Tox-URIc, Tox-REase-4d, Tox-REase-7e, Tox-REase-10f actinobacteria, bacteroidetes a, c, d, chlamydiae a, firmicutes a, c, d,e, fusobacteriab,f, planctomycetes, α,β ca,δ,ϵ-proteobacteria, spirochaetes, verrucomicrobia Found in heterogeneous polyimmunity loci
Imm55 α + β; G and several hydrophobic residues Tox-SHHa actinobacteria, bacteroidetesa, cyanobacteriaa, firmicutesa, lentisphaerae, planctomycetes, α,β,γa-proteobacteria, synergistetes, verrucomicrobia  
Imm56 α + β; D, GR Ntox38a, Tox-HNHb Actinobacteria a,b,  
    chloroflexi a  
Imm57 Mostly α; D, SE, C Tox-LD-peptidasea, Tox-Caspaseb βaa, 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 Ntox13a, Ntox40b firmicutes a,b Fused to Imm63 on some instances
Imm60 Mostly β; N, W Ntox40 a, Ntox48b bacteroidetes Found in heterogeneous polyimmunity loci
    firmicutes a, fusobacteria, α bb –proteobacteria,  
    euryarchaea  
Imm61 α + β; R Ntox40a actinobacteria a  
Imm62 α + β; -(mostly E), W Ntox31a, Ntox48b Firmicutesa, b, Found in heterogeneous polyimmunity loci
    γ-proteobacteria  
Imm63 α + β; E + G, -(mostly E)xxY Ntox40a, Tox-CdiACb, Tox-ARC actinobacteria a,c Found in polyimmunity loci
    bacteroidetes  
    firmicutesa, β,γa,b -proteobaceria  
Imm64 α + β; DxEA, R motifs Tox-ColDa Euryarchaeaa, firmicutesa, 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-ABhydrolase3a, Ntox48b 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 ab,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-ABhydrolase3a 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-10a Acidobacteria, actinobacteria, bacteroidetes, firmicutesa, βaaa-proteobacteria, spirochaetesa, verrucomicrobia  
Imm71 Mostly α; R,F, R Ntox48a acidobacteria a, β aa -proteobacteria Often fused to Imm72
    Eukaryotes: viridiplantae  
Imm72 All-β; GxxE, WxDxRY, E Ntox48a acidobacteria a, β aa -proteobacteria Often fused to Imm71
Imm73 All-α; Several hydrophobic residues Tox-PL-2a, Tox-HNHb acidobacteria, actinobacteriab, 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-Arca bacteroidetesa, firmicutesa, planctomycetes, α,β,γa,δ -proteobacteria, Found in heterogeneous polyimmunity loci
  1. 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. 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.