4G2D:
reference: Structural and enzymatic characterization of the lactonase SisLac from Sulfolobus islandicus., Hiblot J, Gotthard G, Chabriere E, Elias M, PLoS One. 2012;7(10):e47028. doi: 10.1371/journal.pone.0047028. Epub 2012 Oct 10. PMID: 23071703

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