This is the C-terminal domain of Type ISP restriction-modification enzyme LLaBIII present in Lactococcus lactis subsp. cremoris. Type ISP restriction-modification (RM) enzymes provide a potent defence against infection by foreign and bacteriophage DNA. This domain interacts extensively with DNA and is known as the target recognition domain (TRD). TRD works by recognising 6/7 base pairs of asymmetric sequence [1].

1: Translocation-coupled DNA cleavage by the Type ISP restriction-modification enzymes. Chand MK, Nirwan N, Diffin FM, van Aelst K, Kulkarni M, Pernstich C, Szczelkun MD, Saikrishnan K; Nat Chem Biol. 2015;11:870-877. PMID:26389736