3QHB:
reference: A diiron protein autogenerates a valine-phenylalanine cross-link., Cooley RB, Rhoads TW, Arp DJ, Karplus PA, Science. 2011 May 20;332(6032):929. PMID: 21596985

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