A SITE-SPECIFIC ENDONUCLEASE BSPR7I FROM THERMOPHILIC STRAIN BACILLUSSP R7

A site-specific endonuclease BspR7I preparation has been isolated and purified to homogeneity from the thermophilic strain Bacillus sp. R7. DNA cleavage proceeds according to the scheme 5'-CC down arrow TNAGG-3 ' 3'-GGANT up arrow CC-5' and thus the enzyme belongs to the second cl ass of restriction endonucleases and is an isoschizomer of Bsu36I. The isolated protein has a molecular mass of 37 kD and is present in solu tion in the form of a monomer. BspR7I is active over a wide range of t emperatures, from 37 to 48 degrees C. The enzyme is relatively stable.