| 1QYJ: reference: Is histoaspartic protease a serine protease with a pepsin-like fold?, Andreeva N, Bogdanovich P, Kashparov I, Popov M, Stengach M, Proteins. 2004 May 15;55(3):705-10. PMID: 15103632 |
This OCA 
Structure page
uses Jmol,
developed by the Jmol Development Team
(documentation).