Replication protein O is necessary for the initiation of bacteriophage DNA replication. Protein O interacts with the lambda replication origin, and also with replication protein P to form an oligomer [1]. It is speculated that the N-terminal half interacts with the replication origin while the C terminal half mediates protein-protein interaction (annotation of Swiss: P14815).

1: Bacteriophage lambda replication proteins: formation of a mixed oligomer and binding to the origin of lambda DNA. Zylicz M, Gorska I, Taylor K, Georgopoulos C; Mol Gen Genet 1984;196:401-406. PMID:6239082