Browse anti-prokaryotic immune system families by Defense system

AD families AD genes Defense system CLAN ID Phages/MGEs References Description
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.
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.
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.
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.
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.
APIS021 SieA restriction-modification (RM) CLAN039 Salmonella phage P22 Silas et al., 2023 Superinfection exclusion.
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.
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.
APIS037 CLAN011
APIS038 CLAN011
APIS039 CLAN011
APIS040 CLAN041
APIS042 CLAN039
APIS051 CLAN005
APIS055 CLAN011 Pseudomonas phage Churro
APIS063 CLAN005
APIS067 CLAN005
APIS069 CLAN011
APIS072 CLAN005
APIS081 CLAN040
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.
APIS093 CLAN042 Pantoea phage vB_PagP-SK1
APIS096 CLAN004
APIS097 CLAN005
APIS098 CLAN005
APIS100 CLAN011
APIS105 CLAN004
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.
APIS110 CLAN004
APIS111 mom restriction-modification (RM) CLAN079 Escherichia phage Mu PMID:2934296 Methylcarbamoylase for DNA modification.
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.
APIS124 CLAN030
APIS127 CLAN004
APIS128 CLAN005
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.
APIS136 hin1523 restriction-modification (RM) CLAN084 Haemophilus influenzae Rd KW20 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.
APIS136 nma1821 restriction-modification (RM) CLAN084 Neisseria meningitidis 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.
APIS139 CLAN004
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.
APIS146 CLAN005
APIS147 CLAN005
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.
APIS157 CLAN004
APIS159 CLAN005
APIS161 CLAN026
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.
APIS171 CLAN004
APIS175 CLAN004
APIS176 CLAN005
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.
APIS182 CLAN004
APIS183 CLAN004
APIS184 CLAN004
APIS186 CLAN004
APIS187 CLAN005
APIS190 CLAN004
APIS192 CLAN026
APIS194 CLAN005
APIS198 CLAN004
ArdB ArdB restriction-modification (RM) CLAN011 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.
ardk ardk restriction-modification (RM) CLAN111 Plasmid pKM101 PMID: 8393008 ArdK and ArdR likely serve as ardKR-dependent regulatory system that controls the expression of ArdA and ArdB.
ardr ardr restriction-modification (RM) CLAN112 Plasmid pKM101 PMID: 8393008 ArdK and ArdR likely serve as ardKR-dependent regulatory system that controls the expression of ArdA and ArdB.
ardu ardu restriction-modification (RM) CLAN005 Shuttle vector pI3 PMID:10966401 The gene was from contructed E. coli-D. radiodurans shuttle vector,pI3, and trikingly similar to the known plasmid-encoded antirestriction proteins like ArdA.
Stp Stp restriction-modification (RM) CLAN107 T4 of E. coli PMID:7791212 Stp has been implicated with activation of the anticodon nuclease and inhibition of EcoprrI restriction.
vcrx090 vcrx090 restriction-modification (RM) CLAN119 Vibrio cholerae PMID:32556263 vcrx089 and vcrx090 promote resistance against type I restriction-modification.
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
APIS281 fole restriction-modification (RM) CLAN035 Enterobacteria phage 9g PMID:31784519 Enzyme to synthesize deazaguanines in G+ synthesis for anti-RM
APIS294 qued restriction-modification (RM) CLAN049 Enterobacteria phage 9g PMID:31784519 Enzyme to synthesize deazaguanines in G+ synthesis for anti-RM
APIS363 quee restriction-modification (RM) CLAN103 Enterobacteria phage 9g PMID:31784519 Enzyme to synthesize deazaguanines in G+ synthesis for anti-RM
APIS215 CLAN028
APIS237 CLAN049
APIS239 CLAN028
APIS322 CLAN035
APIS336 CLAN035
APIS379 CLAN028