Sequence-specific endonuclease from the transformable cyanobacterium Anacystis nidulans R2

Extracts of the transformable cyanobacterial strain Anacystis nidulans R2 were analyzed for the presence of restriction endonuclease. One enzyme, Ani I, was found and determined to be sequence-specific on the basis of its ability to cleave several Bacillus plasmids at a limited number of sites. The activity of this enzyme is significantly reduced in extracts prepared from cell cultures grown at 38°C.