The type III restriction enzyme C-terminal endonuclease (IPR045572) represents the C-terminal endonuclease domain of a variety of type III restriction endonuclease proteins, including the EcoPI/EcoP15I Res subunit of the type III restriction modification system EcoPI from Escherichia coli and the BceSI Res subunit of the type III restriction modification enzyme BceSI from Bacillus cereus.