Universal restriction endonucleases: designing novel cleavage specificities by combining adapter oligodeoxynucleotide and enzyme moieties.

Class IIS restriction endonucleases cleave double-stranded (ds) DNA at precise distances from their recognition sequences. A method is proposed which utilizes this separation between the recognition site and the cut site to allow a class IIS enzyme, e.g., FokI, to cleave practically any predetermined sequence by combining the enzyme with a properly designed oligodeoxynucleotide adapter. Such an adapter is constructed from the constant recognition site domain (a hairpin containing the ds sequence, e.g., GGATG CCTAC for FokI) and a variable, single-stranded (ss) domain complementary to the ss sequence to be cleaved (at 9 and 13 nucleotides on the paired strands from the recognition sequence in the example of FokI). The ss sequence designated to be cleaved could be provided by ss phage DNA (e.g., M13), gapped ds plasmids, or supercoiled ds plasmids that were alkali denatured and rapidly neutralized. Combination of all three components, namely the class IIS enzyme, the ss DNA target sequence, and the complementing adapter, would result in target DNA cleavage at the specific predetermined site. The target ss DNA could be converted to the precisely cleaved ds DNA by DNA polymerase, utilizing the adapter oligodeoxynucleotide as primer. This novel procedure represents the first example of changing enzyme specificity by synthetic design. A practically unlimited assortment of new restriction specificities could be produced. The method should have many specific and general applications when its numerous ramifications are exploited.