2O40:
reference: Convergent chemical synthesis and crystal structure of a 203 amino acid "covalent dimer" HIV-1 protease enzyme molecule., Torbeev VY, Kent SB, Angew Chem Int Ed Engl. 2007;46(10):1667-70. PMID: 17397076

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