This family of proteins represents the N-terminal domain of DnaA, a protein involved in the initiation of bacterial chromosomal replication. The structure of this domain is known [1]. It is also found in three copies in some proteins such as Swiss:B5V0X4. The exact function of this domain is uncertain but it has been suggested to play a role in oligomerisation.

1: NMR structure of the N-terminal domain of the replication initiator protein DnaA. Lowery TJ, Pelton JG, Chandonia JM, Kim R, Yokota H, Wemmer DE; J Struct Funct Genomics. 2007;8:11-17. PMID:17680349