7K3U:
reference: Crystallographic structure of recombinant Lactococcus lactis prolidase to support proposed structure-function relationships., Kgosisejo O, Chen JA, Grochulski P, Tanaka T, Biochim Biophys Acta Proteins Proteom. 2017 May;1865(5):473-480. doi:, 10.1016/j.bbapap.2017.02.004. Epub 2017 Feb 4. PMID: 28179139

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