不同价态金属离子对DNA构象的影响

用紫外分光光度法研究了不同价态金属离子对DNA大分子溶液构象的影响。研究结果显示: 金属离子与DNA的作用使DNA溶液的紫外吸收值下降, 即呈现减色效应, 同时减色效应的强弱与金属离子的价态有关。随着价态升高, 减色效应增强。由此说明, 金属离子与DNA的作用使DNA的构象趋于缩拢; 且随着金属离子价态升高, 缩拢程度增强, 甚至产生缩合。还用现代多聚电解质理论对以上现象进行了讨论, 结果是令人满意的。

THE EFFECT OF METAL IONS OF DIFFERENT VALENCES ON CONFORMATION OF DNA MOLECULES

The effect of metal ions of different valences on the conformation of DNAmolecules by UV spectra has been studied. The result shows that a hypochromicityoccurs at 257 nm after adding metal ions, and the degree of hypochromicity dependson the valence of metal ions. The higher the valence of metal ion, the stronger thehypochromicity. It follows that interactions of metal ions with DNA molecules causecontraction of DNA conformation. The higher the valence of the metal ion, thestronger the effect, eventually, DNA condensation may be induced. The phenomenahas been disscussed according to Modern Polyelectrolyte. Theory, and the result issatisfactory.