DNA helicase loader protein that participates in viral DNA replication, recombination, and repair (PubMed:10871615). At the fork, required for loading of the replicative helicase onto DNA protected by the ssDNA-binding protein (PubMed:11459967, PubMed:7806533, PubMed:10871615, PubMed:22427673). Coordinates simultaneous synthesis of leading- and lagging-strands (PubMed:11459969). Monomer (PubMed:19700405). Homohexamer; when associated with DNA (PubMed:19700405). Interacts (via C-terminus) with the DnaB-like replicative helicase (via C-terminus); this interaction brings about the rapid assembly of the helicase onto ssDNA (PubMed:11459967, PubMed:7806533, PubMed:10871615, PubMed:22427673). Interacts (via C-terminus) with the single-stranded DNA-binding protein; a ternary complex between the helicase assembly protein, the single-stranded DNA-binding protein and ssDNA is an obligatory intermediate in the helicase loading mechanism (PubMed:11459967, PubMed:24338568, PubMed:15507125, PubMed:7806533, PubMed:22427673). Interacts with the viral DNA polymerase (PubMed:15909989). Binds to single and double-stranded DNA (PubMed:10669611). Part of the replicase complex that includes the DNA polymerase, the polymerase clamp, the clamp loader complex, the single-stranded DNA binding protein (SSB), the primase, the DnaB-like replicative helicase and the helicase assembly factor (PubMed:16800624). Belongs to the Tequatrovirus DNA helicase assembly protein family.