ISOLATION AND CHARACTERIZATION OF THE STYD4I RESTRICTION-ENDONUCLEASE, A NEOSCHIZOMER OF SCRFI, FROM ESCHERICHIA-COLI K-12 CARRYING A SMALLMULTICOPY HSD PLASMID OF SALMONELLA-TYPHI ORIGIN

A restriction endonuclease, designated StyD4I, a neoschizomer of ScrFI , has been isolated from Escherichia coli K-12 carrying a small multic opy host specificity for DNA (Hsd) plasmid of Salmonella typhi D4 orig in. In the presence of 10 mM Mg2+, StyD4I cleaves the sequence 5'-/CCN GG-3' and generates a 5-nucleotide cohesive end. StyD4I should be usef ul for recombinant DNA technology, because of the stability and ease i n handling the producer cells.