[Site-specific endonuclease BstM6I from Bacillus stearothermophilus M6]

A site-specific endonuclease activity was found in extract of Bacillus stearothermophilus M6 isolated from molasses. The functionally pure enzyme designated as BstM6I was obtained by consecutive chromatographies on blue sepharose, hydroxyapatite, and heparin-sepharose. The endonuclease recognizes the nucleotide sequence CC decreases WGG in double-stranded DNA and cleaves it as indicated by the arrow to give one-nucleotide 5'-protruding ends. Consequently, the site-specific endonuclease BstM6I is an isoshizomer of BstNI.