2RN4:
reference: NMR structure note: alkaline proteinase inhibitor APRin from Pseudomonas aeruginosa., Arumugam S, Gray RD, Lane AN, J Biomol NMR. 2008 Mar;40(3):213-7. Epub 2008 Jan 24. PMID: 18214691

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