2P3X:
reference: Cloning, sequencing, purification, and crystal structure of Grenache (Vitis vinifera) polyphenol oxidase., Virador VM, Reyes Grajeda JP, Blanco-Labra A, Mendiola-Olaya E, Smith GM, Moreno A, Whitaker JR, J Agric Food Chem. 2010 Jan 27;58(2):1189-201. PMID: 20039636

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