4AP9:
reference: Identification of a novel ligand binding site in phosphoserine phosphatase from the hyperthermophilic archaeon Thermococcus onnurineus., Jung TY, Kim YS, Oh BH, Woo E, Proteins. 2012 Dec 14. doi: 10.1002/prot.24238. PMID: 23239422

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