4AQD:
reference: Human butyrylcholinesterase produced in insect cells: huprine-based affinity purification and crystal structure., Brazzolotto X, Wandhammer M, Ronco C, Trovaslet M, Jean L, Lockridge O, Renard PY, Nachon F, FEBS J. 2012 Aug;279(16):2905-16. doi: 10.1111/j.1742-4658.2012.08672.x. Epub, 2012 Jul 12. PMID: 22726956

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