Browse anti-prokaryotic immune system families by Host order

AD families AD genes Defense system CLAN ID Phages/MGEs References Description
APIS002 vs.4 cyclic oligonucleotide-based antiphage signaling system (CBASS) CLAN018 T4 of E. coli PMID:36848932 Vs.4 antagonized cGAS signaling by binding tightly to cGAMP (dissociation constant of approximately 30 nM) and sequestering it; Bioinformatic analyses identified 198 homologues of Vs.4 in diverse phages; belongs to PHROG 717.
APIS003 ArdA restriction-modification (RM) CLAN004 plasmid pKM101 of E. coli PMID:2989658 DNA mimetics, i.e. structurally and electrostatically imitate the B-form of DNA and thus function as competitive inhibitors of restriction enzymes.
APIS006 abc1 RecBCD CLAN014 Salmonella phage S149 Silas et al., 2023 Trigger programmed cell death (PCD) by P4 prophage.
APIS009 Ral restriction-modification (RM) CLAN013 Lambda of E. coli PMID:3023633 Ral of phage λ can activate the activity of the MTase and thereby accelerate protection of the phage DNA.
APIS010 Ocr restriction-modification (RM);bacteriophage exclusion (BREX) CLAN020 T7 of E. coli PMID:32338761 329108 12235377 11804597 Ocr physically associates with BrxX methyltransferase to neutralizes their ability to both methylate and exclude incoming phage DNA. Ocr structurally mimics the DNA phosphate backbone and interacts directly with EcoKI (both the MTase and REase domain of this type I R–M enzyme), thereby interfering with the activity of this system.
APIS011 gp4.5 toxin-antitoxin (TA) CLAN023 T7 of E. coli PMID:23478446 Protein gp4.5 allows T7 to block Lon (protease) from degrading antitoxins (the SanTA system in E. coli), including SanaA, thereby preventing liberation of SanaT. However, beyond a possible interaction between gp4.5 and Lon in uninfected cells, this speculative model remains untested.
APIS012 tifA toxin-antitoxin (TA) CLAN022 T4 of E. coli PMID:35924892 Original gene 61.4, experimentally evolved T4 phage to overcome a phage-defensive toxin-antitoxin system (toxIN) in E. coli. Through recombination, T4 rapidly acquires segmental amplifications of a previously uncharacterized gene, now named tifA, encoding an inhibitor of the toxin, ToxN.
APIS013 Dmd toxin-antitoxin (TA) CLAN027 T4 of E. coli PMID:22403819 T4 produces Dmd, an antitoxin that inhibits E. coli RnlA and LsoA toxins. Dmd differs from the RnlB or LsoB antitoxins, suggesting it evolved independently, which is highlighted by its different toxin neutralization mechanism.
APIS014 PinA toxin-antitoxin (TA) CLAN026 T4 of E. coli PMID:9417110 PinA encoded by T4 was discovered 20 years ago, it could help T4 block TA defense systems that require Lon, but in vivo function for pinA has not been reported.
APIS015 IpII restriction-modification (RM) CLAN010 T4 of E. coli Silas et al., 2023 T4 internal-protein, a T2-restricting defense system was disabled by IpII. IpII restored T2 and T6 plaquing but did not further enhance T4 infection.
APIS016 Acb1 cyclic oligonucleotide-based antiphage signaling system (CBASS) CLAN019 T4 of E. coli PMID:35395152 Acb1 rapidly degrades the CBASS signals 3′3′-cGAMP, cUA and cAAA, but does not cleave cGG.
APIS017 Alt toxin-antitoxin (TA) CLAN024 T4 of E. coli PMID:26395283 T4 protein Alt (an ADP-ribosyltransferase) is injected with phage DNA, which chemically modifies the MazF toxin. ADP-ribosylated MazF has reduced cleavage activity, enabling the survival of the phage.
APIS018 Arn restriction-modification (RM) CLAN011 T4 of E. coli PMID:25118281 T4 phage protein Arn (Anti restriction nuclease) was identified as an inhibitor of the restriction enzyme McrBC.
APIS019 gnarl2 O-antigen-based barrier CLAN035 Escherichia phage Mu Silas et al., 2023 Putative O-antigen modifiers, interfere with O-antigen biosynthesis.
APIS020 Abc2 RecBCD CLAN016 Salmonella phage P22 PMID:10669596 36533901 Bacteriophage P22 Abc2 protein binds to the RecBCD enzyme from E. coli to promote phage growth and recombination; the RecBCD-Abc2 structure shows that Abc2 binds to the Chi-recognition domains of the RecC subunit in a position that might enable it to mediate the loading of phage recombinases onto its single-stranded DNA products.
APIS021 SieA restriction-modification (RM) CLAN005 Salmonella phage P22 Silas et al., 2023 Superinfection exclusion.
APIS022 adfA toxin-antitoxin (TA) CLAN025 RB69 of E. coli PMID:35725776 Gene adfA(gp61.2) is encoded as a DarT (TA system) inhibitor.
APIS023 gp5.9 RecBCD CLAN017 T7 of E. coli PMID:36533901 Gp5.9 completely inhibits RecBCD by preventing it from binding to DNA. The RecBCD-gp5.9 structure shows that gp5.9 acts by substrate mimicry, binding predominantly to the RecB arm domain and competing sterically for the DNA binding site.
APIS026 orf126 broad-spectrum counter-defense CLAN029 Salmonella phage SPFM20 Silas et al., 2023 Broad-spectrum counter-defense.
APIS030 DarB restriction-modification (RM) CLAN009 P1 of E. coli PMID:3029954 Bind to phage DNA, thereby masking type I R–M recognition sites and preventing degradation of phage DNA.
APIS031 DarA restriction-modification (RM) CLAN006 P1 of E. coli PMID:3029954 Bind to phage DNA, thereby masking type I R–M recognition sites and preventing degradation of phage DNA.
APIS032 Cor superinfection exclusion CLAN032 Enterobacteria phage phi80 PMID:15518820 Superinfection exclusion, inactivates FhuA receptor.
APIS033 Lar restriction-modification (RM) CLAN007 Escherichia phage vB_EcoP_24B PMID:7476171 Lar is functionally similar to RaI, is able to alleviate restriction and enhance modification by EcoKI. And the nucleotide sequences of their genes share 47% identity, indicating a common origin.
APIS034 gnarl1 O-antigen-based barrier CLAN036 Klebsiella phage vB_KpnM_KpV79 Silas et al., 2023 Putative O-antigen modifiers, interfere with O-antigen biosynthesis.
APIS035 orf148 broad-spectrum counter-defense CLAN028 Escherichia phage OSYSP Silas et al., 2023 Broad-spectrum counter-defense.
APIS036 gnarl3 O-antigen-based barrier CLAN034 Escherichia phage Mangalitsa Silas et al., 2023 Putative O-antigen modifiers, interfere with O-antigen biosynthesis.
APIS043 CLAN031 Pasteurella phage Pm86
APIS059 CLAN002 Pseudoalteromonas phage HM1
APIS065 CLAN001 Shewanella sp. phage 1/4
APIS075 CLAN028 Pectobacterium phage A38
APIS077 CLAN020 Proteus phage PM 116
APIS078 CLAN023 Morganella phage vB_MmoP_MP2
APIS080 CLAN023 Klebsiella phage VLCpiA3d
APIS084 CLAN023 Pectobacterium phage phiPccP-1
APIS085 CLAN020 Escherichia phage T7
APIS086 CLAN022 Escherichia phage vB_EcoM_CE1
APIS087 CLAN020 Shigella phage ESh23
APIS090 IpI restriction-modification (RM) CLAN008 T4 of E. coli PMID:17188297 18037438 Restriction endonuclease inhibitor IpI blocks the ancestral two-component type IV R-M system and represents a third generation bacteriophage defense against restriction nucleases of the Gmr type.
APIS091 HOS17_gp01 restriction-modification (RM);bacteriophage exclusion (BREX) CLAN015 T3 of E. coli Andriianov et al., 2023 T3 encodes a SAMase that circumvents the SAM-dependent Type I R-M defence of the host E. coli through cleavage of S-adenosyl-methionine (SAM). SAMase also allows T3 to evade BREX defence.
APIS092 Gam RecBCD CLAN021 Lambda of E. coli PMID:24086157 The protein Gam inhibits the host RecBCD exonuclease activity thus allowing efficient rolling-circle replication.
APIS093 CLAN015 Pantoea phage vB_PagP-SK1
ArdB ArdB restriction-modification (RM) CLAN003 plasmid pKM101 of E. coli PMID:8393008 Like ArdA, ArdB efficiently inhibits restriction by members of the three known families of type I systems of E. coli and only slightly affects the type II enzyme, EcoRI.
Stp Stp restriction-modification (RM) CLAN012 T4 of E. coli PMID:7791212 Stp has been implicated with activation of the anticodon nuclease and inhibition of EcoprrI restriction.