2F9R:
reference: Structural basis for metal-ion coordination and the catalytic mechanism of sphingomyelinases D., Murakami MT, Fernandes-Pedrosa MF, Tambourgi DV, Arni RK, J Biol Chem 2005 Jan 14;. PMID: 15654080

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