2X8F:
reference: New evidence for the role of calcium in the glycosidase reaction of GH43 arabinanases., De Sanctis D, Inacio JM, Lindley PF, De Sa-Nogueira I, Bento I, FEBS J. 2010 Sep 10. doi: 10.1111/j.1742-4658.2010.07870.x. PMID: 20883454

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