N-terminal DNA recognition domain of restriction endonuclease FokI and similar proteinsRestriction endonuclease FokI (EC18.104.22.168), also called R.FokI, or endonuclease FokI, is a type IIS restriction enzyme that require only divalent metals (such as Mg2+ or Mn2+) as cofactors to catalyze the hydrolysis of DNA. FokI recognizes the double-stranded sequence 5'-GGATG-3'/3'-CATCC-5' and cleaves 14 bases after G-1 and 13 bases before C-1, respectively. It contains an N-terminal DNA recognition domain and a C-terminal endonuclease domain. This model describes the DNA recognition domain. The family also includes endonuclease StsI, a type IIS restriction endonuclease found in Streptococcus sanguinis 54. It recognizes the same sequence as FokI but cleaves at different positions.