Lithium ion induced stabilization of the liquid crystalline DNA.
Lithium ion induced stabilization of the liquid crystalline DNA.
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锂离子诱导液晶 DNA 的稳定。
DOI：
10.1002/mabi.200500145
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Pillai,ChennakkatuKrishnaSaolashiuan
中科院分区：
文献类型：
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作者：
Sundaresan,Neethu;Thomas,Thresia;Thomas,ThekkumkatJohn;Pillai,ChennakkattuKrishnaSadasivan;Pillai,ChennakkatuKrishnaSaolashiuan
摘要：利用偏振光显微镜比较研究了碱金属离子Li+、Na+、K+、Rb+和Cs+对高分子量小牛胸腺DNA液晶组织的影响。与其他离子相比，Li+的行为有很大的不同。除了Li+外，所有的一价离子的临界DNA浓度都是相同的。DNA最初表现为胆甾相结构，后来所有离子都转变为更高阶的柱状相，随着反离子大小的增加，胆甾-柱状转变更加容易。对于Li+离子，最初形成向列纹影状结构，几天后转变为高度稳定（超过2个月）的双相胆甾柱状排列。观察到的Li+与其他碱金属离子之间的差异可以从Li+的水合水分子数量及其络合行为来解释。高度稳定的DNA中间相可以应用于纳米电子学、生物传感单元设计和DNA芯片等领域。37℃条件下，在Li+离子存在下，经过5小时的培养，得到了向列纹影状织构。放大10×。
Summary:A comparative study of the effects of alkali metal ions Li+, Na+, K+, Rb+, and Cs+on the liquid crystalline organization of high‐molecular‐weight calf thymus DNA using polarized light microscopy was performed. Major differences in the behavior of Li+as compared to the other ions were found. Critical DNA concentration expected to exhibit anisotropic behavior was found to be the same for all the monovalent ions, except for Li+. DNA initially showed cholesteric textures, which later changed to higher ordered columnar phase for all ions, with the cholesteric‐columnar transition facilitated upon increasing the size of the counterion. For Li+ion, a nematic schlieren‐like texture was formed initially, which after a few days changed to a highly stable (for more than 2 months) biphasic cholesteric‐columnar arrangement. The observed differences between Li+and other alkali metal ions could be rationalized on the basis of the higher number of hydration water molecules of Li+and its complexation behavior. Highly stable DNA mesophases may find applications in the field of nanoelectronics, in designing biosensing units, and in DNA chips.Nematic schlieren‐like texture obtained in presence of Li+ion after 5 h of incubation at 37 °C. Magnification 10×.