title: Left-handed Z-DNA is induced by supercoiling in physiological ionic conditions.
abstract: In physiological ionic conditions (200 mM NaCl), the (dC-dG)16 and (dC-dG)13 blocks in plasmid pRW751 are in a left-handed state when the negative superhelical density of the plasmid is greater than 0.972. As the salt concentration decreases or when (dmC-dG) sequences are present, less negative supercoiling is required to induce the right- to left-handed DNA transition. Furthermore, the single strand-specific nuclease, S1, recognizes and cleaves aberrant structural features at the junction between neighbouring right- and left-handed DNA regions.
mesh_terms: D004278:DNA, Superhelical; D004587:Electrophoresis, Agar Gel; D004720:Endonucleases; D004926:Escherichia coli / Q000235:genetics; D004996:Ethidium; D008745:Methylation; D008962:Models, Theoretical; D009690:Nucleic Acid Conformation; D010957:Plasmids; D015719:Single-Strand Specific DNA and RNA Endonucleases; D012965:Sodium Chloride
chemical_list: D004278:DNA, Superhelical; D012965:Sodium Chloride; D004720:Endonucleases; D015719:Single-Strand Specific DNA and RNA Endonucleases; D004996:Ethidium