The C-terminal catalytic domain of the Restriction Endonuclease EcoRII has a restriction endonuclease-like fold with a central five-stranded mixed beta-sheet surrounded on both sides by alpha-helices. It cleaves DNA specifically at single 5' CCWGG sites [1].

1: Crystal structure of type IIE restriction endonuclease EcoRII reveals an autoinhibition mechanism by a novel effector-binding fold. Zhou XE, Wang Y, Reuter M, Mucke M, Kruger DH, Meehan EJ, Chen L; J Mol Biol. 2004;335:307-319. PMID:14659759