1AIH:
reference: Molecular organization in site-specific recombination: the catalytic domain of bacteriophage HP1 integrase at 2.7 A resolution., Hickman AB, Waninger S, Scocca JJ, Dyda F, Cell 1997 Apr 18;89(2):227-37. PMID: 9108478

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).