A process for producing a polynucleotide encoding a restriction endonuclease
with
an altered specificity, which process comprises:
- (a) mutagenising a polynucleotide encoding a restriction endonuclease
with specificity for a recognition sequence so as to produce one or more mutated
polynucleotides; and
- (b) isolating therefrom a polynucleotide encoding a mutated restriction
endonuclease with specificity for an altered recognition sequence by selecting
a polynucleotide which expresses a restriction endonuclease with methylase specificity
for the altered recognition sequence.
