3FGA:
reference: Structure and function of the PP2A-shugoshin interaction., Xu Z, Cetin B, Anger M, Cho US, Helmhart W, Nasmyth K, Xu W, Mol Cell. 2009 Aug 28;35(4):426-41. PMID: 19716788

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