Binding of Mg2+, Cd2+, and Ni2+ to Liquid Crystalline NaDNA: Polarized Light Microscopy and NMR Investigations
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- 作者：Andrea Catte ; Flaminia Cesare-Marincola ; Johan R. C. van der Maarel ; Giuseppe Saba ; and Adolfo Lai
- 刊名：Biomacromolecules
- 出版年：2004
- 出版时间：July 2004
- 年：2004
- 卷：5
- 期：4
- 页码：1552 - 1556
- 全文大小：79K
- 年卷期：v.5,no.4(July 2004)
- ISSN：1526-4602
文摘
The interaction of the divalent metal ions Mg2+, Cd2+, and Ni2+ with liquid crystalline NaDNA solutions(molar ratios Me2+/DNA-phosphate 
0.050) was investigated by polarized light microscopy and multinuclear31P, 2H, and 23Na NMR. Our findings show that the state of the cholesteric NaDNA phase at equal MgCl2,CdCl2, or NiCl2 concentration is affected in a different way and to a different extent by the nature of thedivalent cation. Indeed, we found that the occurrence of an isotropic phase is markedly favored by Mg2+,and to a lower extent by Cd2+, and that the pitch of the cholesteric phase decreases in the presence of Cd2+or Ni2+. 23Na NMR spectroscopy also shows differences between the binding behavior of Mg2+ and thetransition metal ions in the counterion atmosphere around DNA. The results are discussed in terms of differentbinding modes of the metal ions.
0.050) was investigated by polarized light microscopy and multinuclear31P, 2H, and 23Na NMR. Our findings show that the state of the cholesteric NaDNA phase at equal MgCl2,CdCl2, or NiCl2 concentration is affected in a different way and to a different extent by the nature of thedivalent cation. Indeed, we found that the occurrence of an isotropic phase is markedly favored by Mg2+,and to a lower extent by Cd2+, and that the pitch of the cholesteric phase decreases in the presence of Cd2+or Ni2+. 23Na NMR spectroscopy also shows differences between the binding behavior of Mg2+ and thetransition metal ions in the counterion atmosphere around DNA. The results are discussed in terms of differentbinding modes of the metal ions.