4EP2:
reference: Structural, kinetic, and thermodynamic studies of specificity designed HIV-1 protease., Alvizo O, Mittal S, Mayo SL, Schiffer CA, Protein Sci. 2012 May 1. doi: 10.1002/pro.2086. PMID: 22549928

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