The specific nucleotide sequence in DNA that is recognised by a type II restriction endonuclease and within which it makes a double-stranded cut. Restriction sites usually comprise four or six base pairs that typically are palindromic (q.v.),

e.g., 5´GGCC3´

3´CCGG5´

The two strands may be cut either opposite to one another, to create blunt ends, or in a staggered manner, giving sticky ends, depending on the enzyme involved.