Isolation and characterization of a new restriction endonuclease, Sru30DI, from Selenomonas ruminantium.

The restriction endonuclease (ENase) Sru30DI, an isoschizomer of StuI, which recognizes the sequence 5'-AGG/CCT-3', was purified from a natural isolate of Selenomonas ruminatinum. The ENase was isolated from cell extracts using single-step purification by phosphocellulose column chromatography. Activity of Sru30DI is inhibited by overlapping Dcm methylation. The ENase is extremely stable at 37 degrees C and is active over a wide range of pH, temperature and salt concentrations.