The part of the viral terminase complex that contains the translocase and endonuclease activities and allows the translocation of the phage DNA into the procapsid. The large subunit usually assembles as a heterooligomer with the small subunit.
Source:
GOC:bm,
GOC:jh2,
GOC:ch,
PMID:18687036
Comment
This term should only be used when the large subunit consists of more than one polypeptide.