1AT0:
reference: Crystal structure of a Hedgehog autoprocessing domain: homology between Hedgehog and self-splicing proteins., Hall TM, Porter JA, Young KE, Koonin EV, Beachy PA, Leahy DJ, Cell 1997 Oct 3;91(1):85-97. PMID: 9335337

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