This superfamily represents the bacterial antirestriction (ArdA) protein N-terminal domain 1. ArdA functions in bacterial conjugation to allow an unmodified plasmid to evade restriction in the recipient bacterium and yet acquire cognate modification PMID:12618468. ArdA forms a dimer and each monomer is comprised of three small alpha-beta domains, each with a different fold, arranged in a row in each monomer.

This entry represents domain 1 located at the N-terminal end of the monomeric subunit of ArdA. The N-terminal domain consists of a three-stranded anti-parallel beta-sheet and one short alpha-helix interspersed with three large loops of 10 or more residues. Domain 1 is not essential for anti-restriction as it can be deleted, indicating that the key aspect of anti-restriction by ArdA is the binding to the MTase core using domains 2 and 3. PMID:19506028.

PFAM:PF07275,INTERPRO:IPR009899