Na⁺ and K⁺ forms of Oxy-1.5

P. Schultze, F.W. Smith, N.V. Hud, and J. Feigon: "The effect of sodium, potassium, and ammonium ions on the conformation of the dimeric quadruplex formed by the Oxytricha nova telomere repeat oligonucleotide d(G₄T₄G₄)", Nucleic Acids Res. 27, 3018-3028 (1999). [abstract]

PDB Code: 1K4X

Ensemble of eight structures each of the Na⁺ and K⁺ forms of Oxy-1.5. Residue numbers are shown for one T₄ loop. The symmetry equivalent strands are distinguished by red versus green color for G residues and orange versus blue for the T₄ loops.