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Mode of Action (MoA)
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binds to the MTase of the type I RM complex and blocks it. Triggers Ronin defence.
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Evidence
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Infection assays using bacteriophage λ demonstrated that ArdA inhibits restriction and modification by multiple E. coli type I systems (EcoA, EcoB, EcoD, EcoK, and EcoR124), with efficiency of plating (EOP) restored by factors of up to 10,000 (Table 1). ArdA also showed partial activity against the type II enzyme EcoRI, but not against type III (EcoPI) or McrA/McrBC systems, indicating specificity. Genetic evidence from Tn5 mutagenesis localized ArdA activity to a defined region of pKM101, where insertions abolished antirestriction function. A neighboring regulatory gene, ardR, was shown to suppress ArdA expression, while its disruption derepressed activity by 200-fold. Another locus, ardK, prevented ArdA-mediated lethality when cloned in trans, confirming ArdA's kil-type potential if unregulated.
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MoA Category
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binds and inhibits host defence system
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Subtype(s) of the defence system(s) inhibited by the protein
Defence Subtype
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Escherichia coli type I RM
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Relevant publication(s)
DOI
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10.1128/jb.174.15.5079-5085.1992
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Other components of the anti-defence system
Multicomponent System
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ardr;
ardc;
ardk
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Known structure in PDB
PDB ID
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2W82_A
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Genome(s) encoding the protein
Protein Source
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Plasmid pKM101
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Defence system(s) inhibited by the protein
Defences
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RM
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