title: Structural details of double-helix observed for DNAs containing alternating purine and pyrimidine sequences.
mesh_terms: D004247:DNA; D006859:Hydrogen; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011685:Purine Nucleotides; D011742:Pyrimidine Nucleotides; D014961:X-Ray Diffraction
chemical_list: D011685:Purine Nucleotides; D011742:Pyrimidine Nucleotides; D006859:Hydrogen; D004247:DNA