2K4G:
reference: Solution Structure of a Peptide Nucleic Acid Duplex from NMR Data: Features and Limitations., He W, Hatcher E, Balaeff A, Beratan DN, Gil RR, Madrid M, Achim C, J Am Chem Soc. 2008 Sep 10. PMID: 18781753

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