4OK7:
reference: Structure of bacteriophage SPN1S endolysin reveals an unusual two-module fold for the peptidoglycan lytic and binding activity., Park Y, Lim JA, Kong M, Ryu S, Rhee S, Mol Microbiol. 2014 Apr;92(2):316-25. doi: 10.1111/mmi.12555. Epub 2014 Mar 12. PMID: 24641441

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