1QFT:
reference: Tick histamine-binding proteins: isolation, cloning, and three-dimensional structure., Paesen GC, Adams PL, Harlos K, Nuttall PA, Stuart DI, Mol Cell 1999 May;3(5):661-71. PMID: 10360182

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