There is an endonuclease domain in the bacteriophage terminase large subunit TerL that is important for packaging DNA in bacteriophages and related viruses. This domain is called Terminase large subunit-like endonuclease (IPR046462). TerL is composed of an N-terminal ATPase domain (IPR046461) that facilitates DNA translocation, and a C-terminal endonuclease domain that cleaves tandem DNA at the initiation stage at a sequence-specific site and at the completion stage of the DNA packaging process when the capsid is full.