Chemical footprinting of the interaction between left-handed Z-DNA and anti-Z-DNA antibodies by diethylpyrocarbonate carbethoxylation.
Diethylpyrocarbonate (DEPC) carbethoxylates Z-DNA to an increased extent because the reactive N-7 atoms of purine residues appear structurally more accessible on Z-DNA as opposed to B-DNA. This chemical probe was used in DEPC footprinting experiments, which confirm the specificity of binding of anti-Z-DNA monoclonal antibodies and which probe regions of close contact in this DNA-protein complex. Antibody binding to segments of Z-DNA existing in supercoiled plasmids resulted in specific protection from DEPC hyper-reactivity within the Z-DNA segment and induction of hyper-reactivity in purines lying adjacent to the Z-segment. Two different monoclonal immunoglobulin preparations, Z22 and Z44, are shown to generate specific and distinct footprint patterns when bound to the Z-helix. Binding of these antibodies was also found to affect DNA conformation within the Z-DNA segment by influencing the equilibrium between the B- and Z-helical conformations.
D000974:Antibodies, Antinuclear / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D001666:Binding Sites, Antibody; D003201:Computers; D004247:DNA / Q000187:drug effects / Q000276:immunology*; D004278:DNA, Superhelical; D004047:Diethyl Pyrocarbonate / Q000494:pharmacology*; D000939:Epitopes; D005561:Formates / Q000494:pharmacology*; D009690:Nucleic Acid Conformation
D000974:Antibodies, Antinuclear; D000911:Antibodies, Monoclonal; D004278:DNA, Superhelical; D000939:Epitopes; D005561:Formates; D004247:DNA; D004047:Diethyl Pyrocarbonate