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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) CLAN003 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) CLAN006 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) CLAN008 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) CLAN009 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.
APIS015 IpII restriction-modification (RM) CLAN014 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) CLAN017 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) CLAN020 Salmonella phage P22 Silas et al., 2023 Superinfection exclusion.
APIS030 DarB restriction-modification (RM) CLAN027 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) CLAN028 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) CLAN030 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 CLAN006
APIS038 CLAN006
APIS039 CLAN006
APIS040 CLAN030
APIS042 CLAN020
APIS051 CLAN003
APIS055 CLAN006 Pseudomonas phage Churro
APIS063 CLAN003
APIS067 CLAN003
APIS069 CLAN006
APIS072 CLAN003
APIS077 CLAN009 Proteus phage PM 116
APIS081 CLAN028
APIS085 CLAN009 Escherichia phage T7
APIS087 CLAN009 Shigella phage ESh23
APIS090 IpI restriction-modification (RM) CLAN034 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) CLAN035 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 CLAN035 Pantoea phage vB_PagP-SK1
APIS096 CLAN039
APIS097 CLAN003
APIS098 CLAN003
APIS100 CLAN006
APIS105 CLAN039
APIS107 dam restriction-modification (RM) CLAN045 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) CLAN046 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 CLAN039
APIS111 mom restriction-modification (RM) CLAN047 Escherichia phage Mu PMID:2934296 Methylcarbamoylase for DNA modification.
APIS119 Ulx restriction-modification (RM) CLAN051 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 CLAN028
APIS127 CLAN039
APIS128 CLAN003
APIS134 CLAN039
APIS135 CLAN028
APIS136 hia5 restriction-modification (RM) CLAN045 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) CLAN045 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) CLAN045 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 CLAN039
APIS143 Hdf restriction-modification (RM) CLAN028 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 CLAN003
APIS147 CLAN003
APIS152 dmt restriction-modification (RM) CLAN045 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 CLAN039
APIS159 CLAN003
APIS161 CLAN045
APIS165 Ddra restriction-modification (RM) CLAN062 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) CLAN039 Vibrio cholerae PMID:32556263 vcrx089 and vcrx090 promote resistance against type I restriction-modification.
APIS171 CLAN039
APIS175 CLAN039
APIS176 CLAN003
APIS179 Ddrb restriction-modification (RM) CLAN063 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 CLAN039
APIS183 CLAN039
APIS184 CLAN039
APIS186 CLAN039
APIS187 CLAN003
APIS190 CLAN039
APIS192 CLAN045
APIS194 CLAN003
APIS198 CLAN039
ArdB ArdB restriction-modification (RM) CLAN006 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) CLAN068 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) CLAN069 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) CLAN003 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) CLAN072 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) CLAN073 Vibrio cholerae PMID:32556263 vcrx089 and vcrx090 promote resistance against type I restriction-modification.