Recognition sequence of a restriction endonuclease from Haemophilus gallinarum.

From comparison of the sequences in and around the cleavage sites of restriction endonuclease HgaI isolated from Haemophilus gallinarum, the recognition sequence and cleavage site of this enzyme was deduced as below: (formula: see text) This enzyme recognizes a specific but asymmetric penta-nucleotide sequence, GCGTC, and introduces staggered cleavages at appointed positions away from the recognition sequence, generating protruding 5'-ends of five nucleotides. The sequences surrounding the cleavage sites bear no obvious relation to one another.