title: Natural DNA sequences can form left-handed helices in low salt solution under conditions of topological constraint.
mesh_terms: D001483:Base Sequence; D002942:Circular Dichroism; D004247:DNA; D009690:Nucleic Acid Conformation; D009994:Osmolar Concentration; D011089:Polydeoxyribonucleotides; D013059:Spectrum Analysis, Raman
chemical_list: D011089:Polydeoxyribonucleotides; C019530:poly(dC-dG); D004247:DNA