title: Site-specific OsO4 modification of the B-Z junctions formed at the (dA-dC)32 region in supercoiled DNA.
abstract: OsO4 in the presence of pyridine specifically modifies the structural distortions of the primary helix of supercoiled pRW777 near the (dA-dC)32 sequence. Modification occurs at the same negative superhelix density value as required for formation of the Z-helix within the polymer block. Fine mapping of the distorted regions, which are probably the B-Z junctions, is presented. OsO4 reactions provide a powerful and sensitive chemical approach to study DNA polymorphism in solution.
mesh_terms: D001483:Base Sequence; D004262:DNA Restriction Enzymes; D004278:DNA, Superhelical / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D008970:Molecular Weight; D009690:Nucleic Acid Conformation; D009992:Osmium / Q000494:pharmacology*; D009993:Osmium Tetroxide / Q000494:pharmacology*; D010957:Plasmids; D011089:Polydeoxyribonucleotides / Q000378:metabolism*; D011110:Polymorphism, Genetic
chemical_list: D004278:DNA, Superhelical; D011089:Polydeoxyribonucleotides; D009992:Osmium; D004262:DNA Restriction Enzymes; D009993:Osmium Tetroxide