2WHY:
reference: Structural Basis and Stereochemistry of Triscatecholate Siderophore Binding by FeuA., Peuckert F, Miethke M, Albrecht AG, Essen LO, Marahiel MA, Angew Chem Int Ed Engl. 2009 Sep 11. PMID: 19746494

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