3NAO:
reference: A DNA crystal designed to contain two molecules per asymmetric unit., Wang T, Sha R, Birktoft J, Zheng J, Mao C, Seeman NC, J Am Chem Soc. 2010 Nov 10;132(44):15471-3. PMID: 20958065

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