6KTS:
reference: Structural and Functional Characterization of the Secondary Mutation N126K Selected by Various HIV-1 Fusion Inhibitors., Yu D, Su Y, Ding X, Zhu Y, Qin B, Chong H, Cui S, He Y, Viruses. 2020 Mar 18;12(3). pii: v12030326. doi: 10.3390/v12030326. PMID: 32197300

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