1SY7:
reference: Unusual Cys-Tyr covalent bond in a large catalase., Diaz A, Horjales E, Rudino-Pinera E, Arreola R, Hansberg W, J Mol Biol 2004 Sep 17;342(3):971-85. PMID: 15342250

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