3CAK:
reference: Structure of diethyl phosphate bound to the binuclear metal center of phosphotriesterase., Kim J, Tsai PC, Chen SL, Himo F, Almo SC, Raushel FM, Biochemistry. 2008 Sep 9;47(36):9497-504. Epub 2008 Aug 15. PMID: 18702530

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