Browse anti-prokaryotic immune system protein families

The list of 380 APIS protein families built from close homologs of 125 seed proteins in four virome/phage DBs

APIS families APIS genes Immune system CLAN ID Phages/MGEs References Description
APIS001 Apyc1 pyrimidine cyclase system for antiphage resistance (Pycsar) CLAN008 Bsp38 of Bacillus subtilis PMID:35395152 SBSphiJ Apyc1 efficiently hydrolyses a wide range of cyclic mononucleotides; 273 Acb1 and 107 Apyc1 phage proteins were identified.
APIS002 vs.4 cyclic oligonucleotide-based antiphage signaling system (CBASS) CLAN056 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) CLAN005 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.
APIS004 Acb2 cyclic oligonucleotide-based antiphage signaling system (CBASS) CLAN036 PaMx33 of Pseudomonas aeruginosa PMID:36750095 Anti-CBASS protein ("Acb2") that forms a hexamer with three 3',3'-cGAMP molecules and reduces phospholipase activity.
APIS005 Gad1 Gabija CLAN009 phi3T of B. subtilis Yirmiya et al., 2023 Antine et al., 2023 Gad1 forms an octameric web that encases the GajAB complex and inhibits DNA recognition and cleavage.
APIS006 abc1 RecBCD CLAN037 Salmonella phage S149 Silas et al., 2023 Trigger programmed cell death (PCD) by P4 prophage.
APIS007 KlcA restriction-modification (RM) CLAN011 IncP-1b plasmid of Bordetella pertussis PMID:20007596 ArdB and KlcA act as anti-restriction proteins and inhibit the four main families of Type I RM systems in vivo.
APIS008 Gad2 Gabija CLAN023 SPbetaL7 of B. subtilis Yirmiya et al., 2023 Alphafold2 predicted that Gad2 is an enzyme with a nucleotidyltransferase protein domain, suggesting that it inhibits Gabija via a mechanism of action different than Gad1.
APIS009 Ral restriction-modification (RM) CLAN057 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) CLAN017 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) CLAN024 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) CLAN038 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) CLAN058 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) CLAN059 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) CLAN060 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) CLAN061 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) CLAN062 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) CLAN063 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 CLAN064 Escherichia phage Mu Silas et al., 2023 Putative O-antigen modifiers, interfere with O-antigen biosynthesis.
APIS020 Abc2 RecBCD CLAN065 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) CLAN039 Salmonella phage P22 Silas et al., 2023 Superinfection exclusion.
APIS022 adfA toxin-antitoxin (TA) CLAN066 RB69 of E. coli PMID:35725776 Gene adfA(gp61.2) is encoded as a DarT (TA system) inhibitor.
APIS023 gp5.9 RecBCD CLAN067 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.
APIS024 Tad1 Thoeris CLAN001 SBSphiJ7 of B. subtilis PMID:36174646 Tad1 proteins are not an enzymes, but are 'sponges' that bind and sequester the immune signaling molecule (cyclic ADP-ribose or gcADPR) produced by TIR-domain proteins, thus decoupling phage sensing from immune effector activation and rendering Thoeris inactive.
APIS025 Had1 Hachiman CLAN068 SBSphiJ4 of B. subtilis Yirmiya et al., 2023 Had1 (Hachiman anti-defense 1) is a Hachiman-inhibiting family of phage proteins. The mechanism of Hachiman defense is unknown.
APIS026 orf126 broad-spectrum counter-defense CLAN069 Salmonella phage SPFM20 Silas et al., 2023 Broad-spectrum counter-defense.
APIS027 DSAD1 defence-associated sirtuin (DSR) CLAN070 SPbeta phages of B. subtilis PMID:36192536 DSAD1 is a phage anti-DSR2 protein that binds and inhibits Defence-associated sirtuins (DSR2). In bacteria, N-terminal sirtuin (SIR2) domains within DSR2 were shown to participate in defence systems including prokaryotic argonautes (pAgo), Thoeris, AVAST, defence-associated sirtuin (DSR), etc.
APIS029 Tad2 Thoeris CLAN001 Bacillus phage SPO1 Yirmiya et al., 2023 Tad2 is a "sponge" that sequesters the immune signaling molecules produced by Thoeris TIR-domain proteins in response to phage.
APIS030 DarB restriction-modification (RM) CLAN071 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) CLAN040 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 CLAN072 Enterobacteria phage phi80 PMID:15518820 Superinfection exclusion, inactivates FhuA receptor.
APIS033 Lar restriction-modification (RM) CLAN041 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 CLAN073 Klebsiella phage vB_KpnM_KpV79 Silas et al., 2023 Putative O-antigen modifiers, interfere with O-antigen biosynthesis.
APIS035 orf148 broad-spectrum counter-defense CLAN018 Escherichia phage OSYSP Silas et al., 2023 Broad-spectrum counter-defense.
APIS036 gnarl3 O-antigen-based barrier CLAN074 Escherichia phage Mangalitsa Silas et al., 2023 Putative O-antigen modifiers, interfere with O-antigen biosynthesis.
APIS037 CLAN011
APIS038 CLAN011
APIS039 CLAN011
APIS040 CLAN041
APIS041 CLAN008
APIS042 CLAN039
APIS043 CLAN001 Pasteurella phage Pm86
APIS044 CLAN008 Bacillus phage W.Ph.
APIS045 CLAN001
APIS046 CLAN009
APIS047 CLAN018
APIS048 CLAN036 Ralstonia phage YO108_2
APIS049 CLAN037
APIS050 CLAN018
APIS051 CLAN005
APIS052 CLAN001
APIS053 CLAN009
APIS054 CLAN008
APIS055 CLAN011 Pseudomonas phage Churro
APIS056 CLAN023
APIS057 CLAN009
APIS058 CLAN008
APIS059 CLAN023 Pseudoalteromonas phage HM1
APIS060 CLAN008
APIS061 CLAN001
APIS062 CLAN008
APIS063 CLAN005
APIS064 CLAN008
APIS065 CLAN009 Shewanella sp. phage 1/4
APIS066 CLAN008
APIS067 CLAN005
APIS068 CLAN009
APIS069 CLAN011
APIS070 CLAN001
APIS071 CLAN009
APIS072 CLAN005
APIS073 CLAN008
APIS074 CLAN018
APIS075 CLAN018 Pectobacterium phage A38
APIS076 CLAN008
APIS077 CLAN017 Proteus phage PM 116
APIS078 CLAN024 Morganella phage vB_MmoP_MP2
APIS079 CLAN001 Pseudomonas phage Skulduggery
APIS080 CLAN024 Klebsiella phage VLCpiA3d
APIS081 CLAN040
APIS082 CLAN018
APIS083 CLAN009 Clostridioides phage ES-S-0107-01
APIS084 CLAN024 Pectobacterium phage phiPccP-1
APIS085 CLAN017 Escherichia phage T7
APIS086 CLAN038 Escherichia phage vB_EcoM_CE1
APIS087 CLAN017 Shigella phage ESh23
APIS088 CLAN009
APIS089 CLAN023
APIS090 IpI restriction-modification (RM) CLAN075 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) CLAN042 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 CLAN076 Lambda of E. coli PMID:24086157 The protein Gam inhibits the host RecBCD exonuclease activity thus allowing efficient rolling-circle replication.
APIS093 CLAN042 Pantoea phage vB_PagP-SK1
APIS094 Rad Retron CLAN025 Escherichia phage SP15 Azam et al., 2023 Rad inhibited retron function by degrading noncoding RNA, the precursor of msDNA.
APIS095 CLAN006
APIS096 CLAN004
APIS097 CLAN005
APIS098 CLAN005
APIS099 CLAN006
APIS100 CLAN011
APIS101 ugi DNA repair CLAN077 Bacillus phage AR9 PMID: 6776115 Uracil-DNA-glycosylase inhibitor.
APIS102 CLAN029
APIS103 NTases CBASS,Pycsar,CRISPR–Cas (type III) CLAN010 Bacillus phage BCP1 PMID:36952342 A family of bacteriophage nucleotidyltransferases (NTases) that synthesize competitor cyclic dinucleotide (CDN) ligands and inhibit TIR NADase effectors activated via a linked STING CDN sensor domain (TIR-STING). 
APIS104 narp2_nampt NAD+ reconstitution pathway (NARP) CLAN043 Vibrio phage KVP40 Osterman et al., 2024 Nicotinamide phosphoribosyltransferase activity (Nampt), capable of producing NMN from PRPP and nicotinamide.
APIS105 CLAN004
APIS106 CLAN019
APIS107 dam restriction-modification (RM) CLAN026 Escherichia phage T4 PMID:6307815 DNA adenine methylases methylate adenine residues in specific sequences, the methylation site of the host Escherichia coli dam+ methylase. Methylation protects the site against cleavage by the MboI restriction nuclease.
APIS108 ardc restriction-modification (RM) CLAN078 Enterobacterales PMID:10686096 This anti-restriction protein is able in vitro to protect the single-stranded DNA against the activity of type II restriction endonuclease HhaI.
APIS109 CLAN006
APIS110 CLAN004
APIS111 mom restriction-modification (RM) CLAN079 Escherichia phage Mu PMID:2934296 Methylcarbamoylase for DNA modification.
APIS112 CLAN006
APIS113 antiDnd_p0020 Dnd CLAN044 Vibrio phage 44E38.1 PMID:35760840 Two genes (p0020 and p0021) provide resistance to the Dnd system (anti-Dnd), p0020 encodes a protein with a phosphoadenosine phosphosulphate reductase (PAPS) domain and a DNA N-6-adenine-methyltransferase (Dam) domain.
APIS114 CLAN044
APIS115 CLAN020
APIS116 CLAN025
APIS117 mga47 toxin-antitoxin (TA) CLAN080 Escherichia phage SECphi18 PMID:35725776 DNA polymerase
APIS118 CLAN019
APIS119 Ulx restriction-modification (RM) CLAN081 Escherichia phage P1 PMID:28509398 Ulx is a protein included in the P1 antirestriction system. It acts as a chaperone or packaging factor to increase the amount of DarB incorporated into the virion.
APIS120 CLAN006
APIS121 CLAN010
APIS122 CLAN010
APIS123 CLAN006
APIS124 CLAN030
APIS125 U56 toxin-antitoxin (TA) CLAN045 Escherichia phage Ukendt PMID:38788717 Retron-Eco1 inhibitor
APIS126 CLAN019
APIS127 CLAN004
APIS128 CLAN005
APIS129 Lidtsur-6 AVAST (Antiviral STAND) CLAN031 Escherichia phage Lidtsur PMID:35951700 Lidtsur-6, Lidtsur-17 and Forsur-7 were active in phage plaque assays and restored phage propagation on Avs-containing E. coli.
APIS130 RacC Retron CLAN082 prophage of Escherichia coli str. K-12 substr. MG1655 PMID:35850148 RacC is a Rac prophage gene, function as retron TA blocker. It directly blocks RcaT toxicity, inhibit the toxin of abortive infection systems.
APIS131 vcrx091 CRISPR-Cas evasion by DNA repair CLAN083 Vibrio cholerae PMID:32556263 CRISPR–Cas evasion by repairing double-strand DNA breaks via recombination between short sequence repeats
APIS132 MpaR SOS response CLAN029 prophage of Listeria monocytogenes 10403S PMID:31754112 MpaR plays a critical role in the de-repression (induction) of the two phage elements and is sufficient for ϕ10403S induction.
APIS133 vcrx092 CRISPR-Cas evasion by DNA repair CLAN046 Vibrio cholerae PMID:32556263 CRISPR–Cas evasion by repairing double-strand DNA breaks via recombination between short sequence repeats
APIS134 CLAN004
APIS135 CLAN030
APIS136 hia5 restriction-modification (RM) CLAN084 Haemophilus influenzae PMID:22102579 hin1523, nma1821 and hia5 are all DNA adenine N6-methyltransferases. Plasmid DNA overexpressing these novel DNA methyltransferases was resistant to cleavage by many restriction enzymes sensitive to adenine methylation.
APIS137 CLAN010
APIS138 CLAN027
APIS139 CLAN004
APIS140 CLAN031
APIS141 CLAN020
APIS142 CLAN025
APIS143 Hdf restriction-modification (RM) CLAN030 Escherichia phage P1 PMID:28509398 A key member in the P1 Dar antirestriction system. The absence of either Hdf or DarA results in failure to incorporate any of the other antirestriction proteins.
APIS144 CLAN010
APIS145 CLAN027
APIS146 CLAN005
APIS147 CLAN005
APIS148 OrbA bacteriophage exclusion (BREX) CLAN085 Vibrio phage ICP1 PMID:34326207 Clinical phage ICP1 overcomes cocirculating SXT ICEs through acquisition of epigenetic RM as well as an anti-BREX protein, OrbA.
APIS149 CLAN046
APIS150 Atd1 TIR-STING CLAN019 Pseudoalteromonas phage PH357 PMID:36952342 Functional screen identifies Atd1, a phage MazG-like suppressor of TIR-STING cell suicide
APIS151 CLAN020
APIS152 dmt restriction-modification (RM) CLAN026 Escherichia phage P1 PMID:14715260 DNA methyltransferase (M.EcoP1I) encoded by prophage P1, may protect the phage genome from restriction by type III restriction enzymes and thus could be considered as an anti-restriction system.
APIS153 antiDnd_p0021 Dnd CLAN086 Vibrio phage 44E38.1 PMID:35760840 Two genes (p0020 and p0021) provide resistance to the Dnd system (anti-Dnd), p0021 encodes a protein of unknown function.
APIS154 CLAN006
APIS155 CLAN010
APIS156 CLAN047
APIS157 CLAN004
APIS158 CLAN020
APIS159 CLAN005
APIS160 narp1_adps NAD+ reconstitution pathway (NARP) CLAN027 Escherichia phage JohannRWettstein Osterman et al., 2024 Phage enzyme ADPR-PP synthetase (Adps).
APIS161 CLAN026
APIS162 CLAN019
APIS163 CLAN010
APIS164 Lidtsur-17 AVAST (Antiviral STAND) CLAN087 Escherichia phage Lidtsur PMID:35951700 Lidtsur-17 inhibits SeAvs3 nuclease activity in vitro.
APIS165 Ddra restriction-modification (RM) CLAN088 Escherichia phage P1 PMID:28509398 It's included in the P1 restriction system. The proteins Hdf, DarA and DdrA are required for the protection of phage DNA from restriction by the EcoA Type I R-M system.
APIS166 vcrx089 restriction-modification (RM) CLAN004 Vibrio cholerae PMID:32556263 vcrx089 and vcrx090 promote resistance against type I restriction-modification.
APIS167 CLAN045
APIS168 CLAN010
APIS169 CLAN006
APIS170 narp2_nmnat NAD+ reconstitution pathway (NARP) CLAN020 Vibrio phage KVP40 Osterman et al., 2024 Nicotinamide mononucleotide adenylyltransferase (Nmnat), capable of generating NAD+ by conjugating AMP to NMN.
APIS171 CLAN004
APIS172 CLAN006
APIS173 CLAN006
APIS174 CLAN027
APIS175 CLAN004
APIS176 CLAN005
APIS177 CLAN006
APIS178 AriS SOS response CLAN047 prophage of Listeria monocytogenes 10403S PMID:35443160 LMRG_02920 (AriS) encodes in prophage L. monocytogenes strain 10403S. It acts as a RecA inhibitor and inhibits the bacterial SOS response.
APIS179 Ddrb restriction-modification (RM) CLAN089 Escherichia phage P1 PMID:28509398 It's included in the P1 restriction system. The presence of DdrB results in reduced antirestriction activity, presumably by negatively affecting DarB but the mechanism is not known.
APIS180 psib SOS response CLAN090 Escherichia coli PMID:19818715 PsiB protein works as an SOS inhibitor that binds to RecA to inhibit its activities.
APIS181 CLAN029
APIS182 CLAN004
APIS183 CLAN004
APIS184 CLAN004
APIS185 vcrx093 CRISPR-Cas evasion by DNA repair CLAN006 Vibrio cholerae PMID:32556263 CRISPR–Cas evasion by repairing double-strand DNA breaks via recombination between short sequence repeats
APIS186 CLAN004
APIS187 CLAN005
APIS188 CLAN006
APIS189 CLAN010
APIS190 CLAN004
APIS191 CLAN025
APIS192 CLAN026
APIS193 Forsur-7 AVAST (Antiviral STAND) CLAN031 Escherichia phage forsur PMID:35951700 Forsur-7 inhibits SeAvs3 nuclease activity in vitro to a lesser degree.
APIS194 CLAN005
APIS195 AdfN toxin-antitoxin (TA) CLAN091 Escherichia phage T4 PMID:39026772 Anti-DarT factor NADAR (AdfN), removes ADP-ribose modifications from phage DNA during infection thereby enabling replication in DarTG1-containing bacteria. AdfN, like DarG1, is in the NADAR superfamily of ADP-ribosylglycohydrolases.
APIS196 CLAN006
APIS197 narp1_namat NAD+ reconstitution pathway (NARP) CLAN043 Escherichia phage JohannRWettstein Osterman et al., 2024 Phage enzyme Nicotinamide ADPR-transferase (Namat)
APIS198 CLAN004
APIS199 CLAN006
APIS200 CLAN048
APIS201 CLAN012
APIS202 CLAN002
APIS203 CLAN001
APIS204 dpda restriction-modification (RM) CLAN028 Escherichia phage CAjan PMID:31784519 In Enterobacteria phage 9g, dpdA is associated with G+ synthesis. This modification is proposed to play an anti-restriction role because 7-deazaguanine derivatives can block the activity of a wide variety of restriction enzymes
APIS205 CLAN001
APIS206 CLAN012
APIS207 adfB toxin-antitoxin (TA) CLAN092 Vibrio phage ICP1 PMID:39287445 AdfB functions as an antitoxin, abrogating DarT toxicity through direct interactions.
APIS208 CLAN032
APIS209 CLAN013
APIS210 CLAN002
APIS211 SequestinJ Thoeris CLAN001 PMID:41785351 Thoeris anti-defense sponge; sequesters 3′cADPR and blocks ThsA activation
APIS212 CLAN021
APIS213 surt AbiU CLAN013 Vibrio phage 1.217.O._10N.261.45.A1 Lopatina et al., 2024 Phage anti-AbiU protein; counteracts AbiU abortive-infection defense and restores phage propagation in AbiU-containing hosts.
APIS214 CLAN014
APIS215 CLAN028
APIS216 CLAN002
APIS217 CLAN012
APIS218 CLAN002
APIS219 CLAN015
APIS220 CLAN003
APIS221 CLAN001
APIS222 CLAN012
APIS223 CLAN002
APIS224 acb4 cyclic oligonucleotide-based antiphage signalling system (CBASS) CLAN093 Bacillus phage SPO1 PMID:40845805 Acb4 proteins bind nucleotide signals and inhibit a broad range of CBASS operons.
APIS225 CLAN002
APIS226 CLAN003
APIS227 CLAN001
APIS228 CLAN003
APIS229 CLAN002
APIS230 CLAN001
APIS231 CLAN007
APIS232 CLAN015
APIS233 CLAN013
APIS234 CLAN003
APIS235 CLAN007
APIS236 CLAN013
APIS237 CLAN049
APIS238 CLAN016
APIS239 CLAN028
APIS240 Tad6 type I Thoeris CLAN016 PMID:39855193 Tad3, Tad4, and Tad6 each have a conserved loop that blocks the active site pocket and interacts with the catalytic E85 residue of the type I ThsB
APIS241 CLAN016
APIS242 Tad7 type II Thoeris CLAN033 PMID:39855193 The conserved loop of Tad7 binds the catalytic E99 residue of type II ThsB via a hydrogen bond.
APIS243 CLAN014
APIS244 orf72 BREX type I CLAN050 Escherichia phage Dru_SM1 Ojima et al., 2024 ORF72 has anti-Brex type I activity, was predicted to be a Plasmid replication region DNA-binding N-term
APIS245 SequestinM Thoeris CLAN001 PMID:41785351 Sequestin-family anti-defense protein; inhibits type I Thoeris signaling, most likely by binding 3′cADPR.
APIS246 CLAN003
APIS247 CLAN001
APIS248 CLAN003
APIS249 CLAN015
APIS250 CLAN021
APIS251 CLAN051
APIS252 CLAN001
APIS253 CLAN014
APIS254 CLAN001
APIS255 CLAN002
APIS256 CLAN001
APIS257 CLAN007
APIS258 Tad4 type I Thoeris CLAN015 PMID:39855193 Tad3, Tad4, and Tad6 each have a conserved loop that blocks the active site pocket and interacts with the catalytic E85 residue of the type I ThsB.
APIS259 CLAN007
APIS260 CLAN002
APIS261 CLAN052
APIS262 CLAN022
APIS263 CLAN013
APIS264 CLAN007
APIS265 anti_TerI1 TerI CLAN053 Listeria monocytogenes 10403S Azulay et al., 2025 Anti-TerI1 counteract TerI during prophage induction to allow virion production.
APIS266 CLAN003
APIS267 CLAN002
APIS268 CLAN001
APIS269 oad1 Class 1 OLD nucleases CLAN094 Vibrio phage ICP1 PMID:39829814 OLD anti-defense 1 (Oad1) is a direct inhibitor of Vibrio cholerae-encoded Class 1 OLD family nuclease.
APIS270 Tad8 type II Thoeris CLAN034 PMID:39855193 The conserved loops in Tad8 occupy the pocket within ThsA responsible for His-ADPR binding.
APIS271 CLAN001
APIS272 CLAN003
APIS273 CLAN013
APIS274 CLAN013
APIS275 CLAN013
APIS276 T7K Retron-Eco9,DarTG1 CLAN017 Escherichia phage T7 Bartolec et al., 2024 The T7 kinase weakens the activity of phage defense systems by phosphorylation, and is likely a broadly-acting phage counter-defense system.
APIS277 CLAN016
APIS278 CLAN007
APIS279 T5Dmp Kongming CLAN021 Escherichia phage T5 PMID:39977546 A deoxyribonucleoside 5′-monophosphatase functions as an anti-Kongming factor.
APIS280 CLAN001
APIS281 fole restriction-modification (RM) CLAN035 Enterobacteria phage 9g PMID:31784519 Enzyme to synthesize deazaguanines in G+ synthesis for anti-RM
APIS282 svarog Septu CLAN095 Vibrio phage 1.066.O._10N.286.46.E8 Lopatina et al., 2024 Anti-Septu phage protein; functionally suppresses Septu defense, likely by interfering with the PtuAB effector module or its activation.
APIS283 SequestinD Thoeris CLAN001 PMID:41785351 Thoeris anti-defense sponge; sequesters 3′cADPR and blocks ThsA activation
APIS284 CLAN003
APIS285 CLAN003
APIS286 VPG01_164 Kongming CLAN021 Vibrio phage VPG01 PMID:39977546 The protein robustly suppressed cell death triggered by Kongming and their respective DNKs, indicating anti-Kongming function.
APIS287 Acb5A Type I CBASS CLAN002 PMID:41785351 cleaves cyclic guanosine monophosphate–adenosine monosphosphate (3′3′-cGaMP) and related molecules
APIS288 LockinE Type II Thoeris CLAN003 PMID:41785351 Lockin-family type II Thoeris inhibitor; expected to neutralize the type II Thoeris signal His-ADPR.
APIS289 CLAN050
APIS290 CLAN003
APIS291 CLAN002
APIS292 dap1 Lon-mediated antiviral defense CLAN096 Pseudomonas phage PaoP5 PMID:38886583 Dap1 directly binds to phage HNH endonuclease, prohibiting host Lon-mediated HNH degradation and promoting phage genome packaging.
APIS293 ZadI-1 Zorya type I CLAN097 Pseudomonas phage vB_PaeM_SMS12 PMID:40639337 ZadI-1 inhibits Zorya type I defense, as shown by efficiency of plating, culture collapse,and phage propagation assays
APIS294 qued restriction-modification (RM) CLAN049 Enterobacteria phage 9g PMID:31784519 Enzyme to synthesize deazaguanines in G+ synthesis for anti-RM
APIS295 CLAN014
APIS296 CLAN015
APIS297 Bdi1 Zorya type I,RADAR,Hypnos,Druantia type I CLAN098 Pseudomonas phage PB1 PMID:40639337 Bdi1 and Bdi2 function as multipurpose anti-defense proteins capable of inhibiting four defense systems.
APIS298 CLAN012
APIS299 CLAN003
APIS300 CLAN034
APIS301 CLAN002
APIS302 CLAN001
APIS303 CLAN003
APIS304 CLAN003
APIS305 CLAN032
APIS306 CLAN001
APIS307 orf65 hhe CLAN099 Escherichia phage Dru_SM1 Ojima et al., 2024 ORF65 shows anti-hhe activity, predicted as a transcriptional regulator protein (SplA).
APIS308 orf35 Tmn CLAN100 Escherichia phage SM_S22 PMID:39987292 Deletion of ORF35 from the ΦSMS22 genome resulted in reduced infectivity against E. coli expressing Tmn, suggesting that ORF35 functions as an anti-Tmn
APIS309 CLAN007
APIS310 CLAN001
APIS311 CLAN012
APIS312 orf55 AVAST type III CLAN022 Escherichia phage Dru_SM1 Ojima et al., 2024 It has anti-AVAST type III activity, was predicted to be a ATP-dependent DNA ligase.
APIS313 CLAN003
APIS314 CLAN034
APIS315 SequestinK Thoeris CLAN001 PMID:41785351 Sequestin-family Thoeris inhibitor; anti-defense protein that blocks the 3′cADPR → ThsA signaling pathway.
APIS316 CLAN007
APIS317 CLAN002
APIS318 CLAN001
APIS319 CLAN015
APIS320 CLAN021
APIS321 CLAN003
APIS322 CLAN035
APIS323 CLAN001
APIS324 CLAN053
APIS325 orf46 BREX type I CLAN101 Escherichia phage Dru_SM1 Ojima et al., 2024 ORF46 exhibits anti-Brex type I activity, as a trimethylamine methyltransferase corrinoid protein.
APIS326 CLAN016
APIS327 CLAN001
APIS328 CLAN002
APIS329 CLAN033
APIS330 CLAN014
APIS331 CLAN001
APIS332 CLAN001
APIS333 CLAN001
APIS334 CLAN001
APIS335 CLAN003
APIS336 CLAN035
APIS337 CLAN002
APIS338 CLAN002
APIS339 CLAN002
APIS340 CLAN002
APIS341 CLAN001
APIS342 CLAN014
APIS343 CLAN002
APIS344 CLAN001
APIS345 orf58 Sir2-HerA,DUF4297-HerA CLAN032 Escherichia phage Dru_SM1 Ojima et al., 2024 ORF58 has anti-SIR2+HerA and DUF4297+HerA activity as well as Reron Ec86 sensor activity, was predicted to be a “Mu-like prophage host-nuclease inhibitor protein Gam
APIS346 CLAN012
APIS347 CLAN016
APIS348 CLAN002
APIS349 CLAN007
APIS350 CLAN007
APIS351 Tad3 type I Thoeris CLAN014 PMID:39855193 Tad3, Tad4, and Tad6 each have a conserved loop that blocks the active site pocket and interacts with the catalytic E85 residue of the type I ThsB.
APIS352 CLAN022
APIS353 CLAN001
APIS354 orf83 AVAST type III CLAN012 Escherichia phage Dru_SM1 Ojima et al., 2024 ORF83 exhibits anti-AVAST type III activity, was predicted to be a “nucleotide-binding protein DprA/Smf involved in DNA uptake”.
APIS355 T5.014 bNACHT CLAN102 Escherichia phage T5 PMID:37160116 The gene orf015 (T5.014) alter the activity of a wide variety of bNACHT genes and provide evidence for a complicated relationship between phage genes and bNACHT-based host defense systems, where orf008 activates and orf015 inhibits bNACHT proteins.
APIS356 SequestinI Thoeris CLAN001 PMID:41785351 Sequestin-family antidefense protein; neutralizes Thoeris signaling molecules and allows phage escape from Thoeris defense.
APIS357 CLAN017
APIS358 CLAN003
APIS359 LockinB Type I Thoeris CLAN003 PMID:41785351 Lockin-family type I Thoeris inhibitor; sponge protein that sequesters 3′cADPR, preventing Thoeris effector activation.
APIS360 CLAN001
APIS361 Acb5B Type I CBASS CLAN002 PMID:41785351 cleaves cyclic guanosine monophosphate–adenosine monosphosphate (3′3′-cGaMP) and related molecules
APIS362 CLAN001
APIS363 quee restriction-modification (RM) CLAN103 Enterobacteria phage 9g PMID:31784519 Enzyme to synthesize deazaguanines in G+ synthesis for anti-RM
APIS364 CLAN003
APIS365 CLAN007
APIS366 CLAN033
APIS367 CLAN002
APIS368 CLAN022
APIS369 acb3 type III CBASS CLAN007 PMID:39855193 Acb3 encodes a conserved loop that is predicted to block the active site of CD-NTases and interact with the nucleotidyltransferase catalytic residues via hydrogen and ionic bonds. 
APIS370 CLAN003
APIS371 CLAN001
APIS372 SequestinC Thoeris CLAN001 PMID:41785351 Small phage anti-defense protein from the Sequestin family; inhibits type I Thoeris by interfering with 3′cADPR-mediated immune activation.
APIS373 SequestinG Thoeris CLAN001 PMID:41785351 Anti-Thoeris sponge protein; blocks Thoeris immune signaling, likely through sequestration of 3′cADPR.
APIS374 CLAN001
APIS375 CLAN022
APIS376 CLAN016
APIS377 CLAN015
APIS378 SequestinA Thoeris CLAN001 PMID:41785351 Phage-encoded anti-Thoeris sponge protein; binds/sequesters the type I Thoeris immune signal 3′cADPR, preventing activation of the ThsA NADase effector.
APIS379 CLAN028
APIS380 CLAN054
APIS381 CLAN002