1EMQ:
reference: NMR observation of T-tetrads in a parallel stranded DNA quadruplex formed by Saccharomyces cerevisiae telomere repeats., Patel PK, Hosur RV, Nucleic Acids Res 1999 Jun 15;27(12):2457-64. PMID: 10352174

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