BfiI, a restriction endonuclease from Bacillus firmus S8120, which recognizes the novel non-palindromic sequence 5'-ACTGGG(N)5/4-3'.

A new type IIS restriction endonuclease Bfi I hasbeen partially purified from Bacillus firmus S8120. Bfi I recognizes the non-palindromic hexanucleotide sequence 5'-ACTGGG(N)5/4-3' and makes a staggered cut at the fifth base pair downstream of the recognition sequence on the upper strand, producing a single base 3' protruding end.