3DJ9:
reference: Structure of an isolated unglycosylated antibody C(H)2 domain., Prabakaran P, Vu BK, Gan J, Feng Y, Dimitrov DS, Ji X, Acta Crystallogr D Biol Crystallogr. 2008 Oct;64(Pt 10):1062-7. Epub 2008, Sep 19. PMID: 18931413

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