3THC:
reference: Crystal structure of human beta-galactosidase: structural basis of Gm1 gangliosidosis and morquio B diseases., Ohto U, Usui K, Ochi T, Yuki K, Satow Y, Shimizu T, J Biol Chem. 2012 Jan 13;287(3):1801-12. doi: 10.1074/jbc.M111.293795. Epub 2011 , Nov 28. PMID: 22128166

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