3USR:
reference: Mechanisms of monomeric and dimeric glycogenin autoglucosylation., Issoglio FM, Carrizo ME, Romero JM, Curtino JA, J Biol Chem. 2012 Jan 13;287(3):1955-61. Epub 2011 Nov 29. PMID: 22128147

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