3PTE:
reference: The refined crystallographic structure of a DD-peptidase penicillin-target enzyme at 1.6 A resolution., Kelly JA, Kuzin AP, J Mol Biol. 1995 Nov 24;254(2):223-36. PMID: 7490745

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