This family consists of several bacterial antirestriction (ArdA) proteins. ArdA functions in bacterial conjugation to allow an unmodified plasmid to evade restriction in the recipient bacterium and yet acquire cognate modification [1].

1: Plasmid R16 ArdA protein preferentially targets restriction activity of the type I restriction-modification system EcoKI. Thomas AT, Brammar WJ, Wilkins BM; J Bacteriol 2003;185:2022-2025. PMID:12618468

2: Nucleotide sequence of the gene (ard) encoding the antirestriction protein of plasmid colIb-P9. Delver EP, Kotova VU, Zavilgelsky GB, Belogurov AA; J Bacteriol. 1991;173:5887-5892. PMID:1653225

3: IncN plasmid pKM101 and IncI1 plasmid ColIb-P9 encode homologous antirestriction proteins in their leading regions. Belogurov AA, Delver EP, Rodzevich OV; J Bacteriol. 1992;174:5079-5085. PMID:1321121

4: Plasmid-encoded antirestriction protein ArdA can discriminate between type I methyltransferase and complete restriction-modification system. Nekrasov SV, Agafonova OV, Belogurova NG, Delver EP, Belogurov AA; J Mol Biol. 2007;365:284-297. PMID:17069852