The large terminase DNA packaging motor grips DNA with its ATPase domain for cleavage by the flexible nuclease domain.
Hilbert BJ, Hayes JA, Stone NP, Xu RG, Kelch BA. The large terminase DNA packaging motor grips DNA with its ATPase domain for cleavage by the flexible nuclease domain. Nucleic Acids Res. 2017 04 07; 45(6):3591-3605.