2GPX:
reference: Selenium derivatization of nucleic acids for crystallography., Jiang J, Sheng J, Carrasco N, Huang Z, Nucleic Acids Res. 2007;35(2):477-85. Epub 2006 Dec 14. PMID: 17169989

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