中性和碱性溶液中存在 Zn2+ 离子时的 DNA 构象平衡。
DNA conformational equilibrium in the presence of Zn2+ ions in neutral and alkaline solutions.
机构信息
B.I. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Lenin Avenue, Kharkov 61103, Ukraine.
出版信息
Int J Biol Macromol. 2012 Apr 1;50(3):854-60. doi: 10.1016/j.ijbiomac.2011.11.011. Epub 2011 Nov 22.
Effect of Zn(2+) ions on DNA transition from B-form to a metallized form (m-DNA) in Tris and tetraborate buffers at pH 8.5 has been studied by visible and differential UV-spectroscopy and by thermal denaturation. The results have been compared to those obtained at pH 6.5 in cacodylate buffer. It was found that in alkaline solutions Zn(2+) ions induced a hypochromicity of the DNA absorption in the whole spectral range monitored, which was attributed to DNA transition from B- to the m-form. Complete metallization occurred only upon heating the DNA solutions containing more than ~2×10(-4) M of Zn(2+) ions. Phase diagrams of the DNA-zinc complexes at pH 6.5 and 8.5 have been obtained for the first time. The m-DNA form showed higher thermal stability compared to B-DNA.
在 Tris 和四硼酸盐缓冲液（pH 值 8.5）中，研究了 Zn(2+) 离子对 DNA 从 B 型向金属化形式（m-DNA）转变的影响，使用可见和差示紫外光谱法和热变性法进行了研究。将结果与在 pH 值 6.5 的碳酰二胺缓冲液中获得的结果进行了比较。结果发现，在碱性溶液中，Zn(2+) 离子诱导 DNA 在整个监测光谱范围内的吸光度下降，这归因于 DNA 从 B 型向 m 型的转变。只有当加热含有超过约 2×10(-4) M 的 Zn(2+) 离子的 DNA 溶液时，才会完全发生金属化。首次获得了 pH 值为 6.5 和 8.5 时 DNA-锌配合物的相图。与 B-DNA 相比，m-DNA 形式具有更高的热稳定性。
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