1RYP:
reference: Structure of 20S proteasome from yeast at 2.4 A resolution., Groll M, Ditzel L, Lowe J, Stock D, Bochtler M, Bartunik HD, Huber R, Nature 1997 Apr 3;386(6624):463-71. PMID: 9087403

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