title: Z-DNA forms without an alternating purine-pyrimidine sequence in solution.
abstract: Nuclear magnetic resonance spectra (proton and phosphorus-31) and ultraviolet absorption spectra of the DNA decamer d(br5CGbr5CGATbr5CGbr5CG), in which the central two adenine-thymine base pairs are out of order with the rest of the purine-pyrimidine alternation sequence, indicate that under appropriate solvent conditions (high salt and methanol) the molecule undergoes a structural transition from a right-handed B-DNA conformation to a left-handed Z-DNA conformation. Measurements of the two-dimensional nuclear Overhauser effect on the decamer indicate that all of the guanines as well as the two equivalent thymines adopt the syn conformation.
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D009690:Nucleic Acid Conformation; D013056:Spectrophotometry, Ultraviolet
chemical_list: D004247:DNA