Acts as a primer for DNA elongation during viral genomic replication (PubMed:6813861). Acts as the small terminase protein during packaging (PubMed:18674782). Recruits the phage DNA polymerase to the bacterial nucleoid (PubMed:20823229). Primer terminal protein (TP) is covalently linked to the 5'-ends of both strands of the genome through a phosphodiester bond between the beta-hydroxyl group of a serine residue and the 5'-phosphate of the terminal deoxyadenylate (dAMP) (PubMed:6813861). To start replication, the DNA polymerase forms a heterodimer with a free TP that recognizes the replication origins at both 5' ends of the linear chromosome, and initiates replication using as primer the OH-group of Ser-232 of the TP (PubMed:22210885, PubMed:25081208). Since the polymerase initiates the replication on the second thymine, the TP-dAMP initiation product slides backwards to recover the template information of the first nucleotide (PubMed:19011105). Hydrolyzes host peptidoglycans during virus entry. Interacts with the viral polymerase; this interaction allows the initiation of TP-primed DNA replication at both viral DNA ends (PubMed:22210885). Binds to ssDNA (PubMed:6779279). Interacts with the replication protein p1 (PubMed:11032825). Part of a DNA-gp3-gp16 complex (PubMed:9086269). Associates with the host bacterial nucleoid through its N-terminal region. Belongs to the phi29likevirus DNA terminal protein family.