4PF1:
reference: New aminopeptidase from "microbial dark matter" archaeon., Michalska K, Steen AD, Chhor G, Endres M, Webber AT, Bird J, Lloyd KG, Joachimiak A, FASEB J. 2015 Sep;29(9):4071-9. doi: 10.1096/fj.15-272906. Epub 2015 Jun 10. PMID: 26062601

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