The sequence (dC-dA)n X (dG-dT)n forms left-handed Z-DNA in negatively supercoiled plasmids.
Z-DNA-specific antibodies have been used to demonstrate the formation of left-handed Z-DNA in sequences of (dC-dA)32 X (dG-dT)32 in negatively supercoiled plasmids. Z-DNA was found to form at physiological negative superhelical densities (sigma = -0.05) in the absence of high salt concentration or chemical modifications. The binding site of the antibody to the DNA sequences was demonstrated by crosslinking experiments. (dC-dA)n X (dG-dT)n sequences are widespread in eukaryotic DNA, and possible roles for such Z elements in chromatin activation or genome rearrangements are suggested.
D000918:Antibody Specificity; D001483:Base Sequence; D004278:DNA, Superhelical / Q000276:immunology; D009690:Nucleic Acid Conformation; D010957:Plasmids; D013329:Structure-Activity Relationship
D004278:DNA, Superhelical