1LNS:
reference: The structural basis for catalysis and specificity of the X-prolyl dipeptidyl aminopeptidase from Lactococcus lactis., Rigolet P, Mechin I, Delage MM, Chich JF, Structure (Camb) 2002 Oct;10(10):1383-94. PMID: 12377124

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