BsiY I, a novel thermophilic restriction endonuclease that recognizes 5' CCNNNNNNNGG 3' and the discovery of a wrongly sequenced site in pACYC177.

A new type II restriction endonuclease designated BsiY I has been purified from a thermophilic soil Bacillus stearothermophilus strain. This enzyme recognizes and cleaves the highly degenerate sequence 5' CCNNNNN!NNGG 3'. During the identification of the recognition sequence of BsiY I, we discovered that there should be five G nucleotides instead of four at position 1227-1230 of the plasmid pACYC177.