This family includes the Eco47II (which recognises GGNCC, but the cleavage site unknown) restriction endonuclease.

1: Cloning and characterization of the unusual restriction-modification system comprising two restriction endonucleases and one methyltransferase. Stankevicius K, Povilionis P, Lubys A, Menkevicius S, Janulaitis A; Gene. 1995;157:49-53. PMID:7607524

2: Sequence, structure and functional diversity of PD-(D/E)XK phosphodiesterase superfamily. Steczkiewicz K, Muszewska A, Knizewski L, Rychlewski L, Ginalski K; Nucleic Acids Res. 2012;40:7016-7045. PMID:22638584