title: Double-helical structures for polyxanthylic acid.
mesh_terms: D001482:Base Composition; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D008968:Molecular Conformation; D011119:Polynucleotides; D014961:X-Ray Diffraction; D014970:Xanthines
chemical_list: D011119:Polynucleotides; D014970:Xanthines; C010304:poly(xanthylic acid)