Site-specific integration of the Haemophilus influenzae bacteriophage HP1: location of the boundaries of the phage attachment site.

Plasmids containing DNA segments from the attachment region of phage HP1 were constructed and tested for the ability to replace the phage attachment site substrate in site-specific recombination reactions. The distance separating the boundaries of the functional site was 418 bp. Replacements within the 11-residue segment 5'-GGCGGTTATCG at the left boundary or within the 12-residue segment 5'-GGATTTTTTGAA at the right boundary abolished substrate activity. A segment of the 418-residue sequence preserves the integrity of an operon of three Haemophilus influenzae tRNA genes after HP1 insertion within the coding sequence.