Single-stranded DNA binding protein required for the elongation during viral DNA replication by strand displacement (PubMed:7473731, PubMed:1899235, PubMed:2499869, PubMed:8196055). Displaced viral DNA strands are transiently coated with the ssDNA-binding protein and therefore protected against nucleases (PubMed:7473731) (PubMed:2499869). The latter is then probably removed by the replisome that performs lagging strand synthesis or during the events that lead up to the recombination process (PubMed:7473731). Stimulates in vitro DNA replication several fold (PubMed:1899235). Has helix-destabilizing activity since it removes secondary structure from the ssDNA in replicative intermediates (PubMed:7473731). Monomer. Belongs to the phi29likevirus single-strand-binding protein family.