Runkel L, Nordheim A
J Mol Biol. 1986 Jun 5;189(3):487-501. doi: 10.1016/0022-2836(86)90319-0.
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.
焦碳酸二乙酯（DEPC）使Z-DNA发生乙氧基化的程度更高，因为与B-DNA相比，嘌呤残基中具有反应活性的N-7原子在Z-DNA上在结构上似乎更容易接近。这种化学探针被用于DEPC足迹实验，该实验证实了抗Z-DNA单克隆抗体结合的特异性，并探测了这种DNA-蛋白质复合物中的紧密接触区域。抗体与超螺旋质粒中存在的Z-DNA片段结合，导致Z-DNA片段内的DEPC高反应性受到特异性保护，并诱导Z片段相邻的嘌呤发生高反应性。当与Z-螺旋结合时，两种不同的单克隆免疫球蛋白制剂Z22和Z44显示出产生特异性且不同的足迹模式。还发现这些抗体的结合通过影响B-螺旋和Z-螺旋构象之间的平衡来影响Z-DNA片段内的DNA构象。
