A type III restriction enzyme that recognizes 2 inversely oriented double-stranded sequences 5'-CGAAT-3' and cleaves 25-27 base pairs downstream. After binding to one recognition site undergoes random one-dimensional diffusion along DNA until it collides with a stationary enzyme bound to the second DNA site, which is when DNA cleavage occurs. DNA restriction requires both the Res and Mod subunits (By similarity). Endonucleolytic cleavage of DNA to give specific double-stranded fragments with terminal 5'-phosphates. Contains two different subunits: Res and Mod. Has a helicase-type domain in its N-terminus and an endonuclease-type domain in its C-terminus. Belongs to the type III restriction-modification system Res protein family.