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Mode of Action (MoA)
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modifies adenine residues to N6-methyladenine.
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Evidence
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Hia5 was cloned from Haemophilus influenzae biotype aegyptius ATCC 11116. Its DNA methyltransferase activity was demonstrated in multiple assays. In vitro assays using [³H]-AdoMet showed significant methyl group incorporation into λ DNA, which was abolished in the catalytically dead D194A mutant (ECO_0000315). Thin-layer chromatography (ECO_0000325) confirmed the modified base as N6-methyladenine (m6A). Restriction enzyme protection assays showed that plasmid DNA from E. coli expressing Hia5 became resistant to 30 restriction endonucleases known to be blocked by m6A methylation, indicating broad adenine modification. HPLC analysis quantified that Hia5 methylated ~61% of adenines in λ DNA. Kinetic assays using synthetic oligonucleotides showed Hia5 methylated most adenine-containing dinucleotides (e.g., CA, GA, TA) except poly(A) tracts, suggesting minimal sequence specificity (AB or BA, where B = C, G, or T)
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MoA Category
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modifies phage molecules to avoid recognition
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Subtype(s) of the defence system(s) inhibited by the protein
Defence Subtype
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Diverse set of REases from type I RMs
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Relevant publication(s)
DOI
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10.1093/nar/gkr1039
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Other components of the anti-defence system
Multicomponent System
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-
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Known structure in PDB
PDB ID
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-
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Genome(s) encoding the protein
Protein Source
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Prophage in Haemophilus influenzae
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Defence system(s) inhibited by the protein
Defences
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RM
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View homologs from eukaryotic dsDNA viruses
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