2KWD:
reference: Supramolecular Protein Structure Determination by Site-Specific Long-Range Intermolecular Solid State NMR Spectroscopy., Nieuwkoop AJ, Rienstra CM, J Am Chem Soc. 2010 May 13. PMID: 20465251

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