This domain is found in nicking enzyme in S. aureus. NES initiates and terminates the transfer of plasmids that variously confer resistance to a range of drugs, including vancomycin and gentamicin. This domain is found in the C-terminal region of NES. The C-terminal region is required for conjugation and significantly impacts the catalytic activity of the N-terminal relaxase [1].

1: Molecular basis of antibiotic multiresistance transfer in Staphylococcus aureus. Edwards JS, Betts L, Frazier ML, Pollet RM, Kwong SM, Walton WG, Ballentine WK 3rd, Huang JJ, Habibi S, Del Campo M, Meier JL, Dervan PB, Firth N, Redinbo MR; Proc Natl Acad Sci U S A. 2013;110:2804-2809. PMID:23359708