4NFG:
reference: Engineering specificity in a dynamic protein complex with a single conserved mutation., Bashir Q, Meulenbroek EM, Pannu NS, Ubbink M, FEBS J. 2014 Sep 2. doi: 10.1111/febs.13028. PMID: 25180929

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