1DFB:
reference: Structure of a human monoclonal antibody Fab fragment against gp41 of human immunodeficiency virus type 1., He XM, Ruker F, Casale E, Carter DC, Proc Natl Acad Sci U S A 1992 Aug 1;89(15):7154-8. PMID: 1496010

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