The KD of binding of topoIIα or topoIIβ (in nM) to DNA with no metal, 10 mM MgCl2, or 10 mM CaCl2.

The average of at least two independent experiments is shown with standard error of the mean indicated.实验结果以至少两次独立重复实验的平均值呈现，并标注了均值标准误（standard error of the mean）。