[Restriction endonuclease Sse9I from Sporosarcina sp. strain 9D recognizes the 5'-AATT-3' DNA sequence]

A new restriction endonuclease Sse9I was isolated from the bacterial strain Sporosarcina sp. 9D. The enzyme belongs to Type II restrictases and recognizes the tetranucleotide sequence 5'-AATT-3'. The enzyme cleaves DNA before the first adenine residue, so it is a true isoschizomer of Tsp509I restrictase. However, unlike the prototype, Sse9I digests DNA at 55 degrees C and loses its activity after 20 min storage at 65 degrees C.