4HMO:
reference: Structures of Streptococcus pneumoniae PiaA and Its Complex with Ferrichrome Reveal Insights into the Substrate Binding and Release of High Affinity Iron Transporters., Cheng W, Li Q, Jiang YL, Zhou CZ, Chen Y, PLoS One. 2013;8(8):e71451. doi: 10.1371/journal.pone.0071451. PMID: 23951167

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