Liquid crystalline phase behavior of high molecular weight DNA: a comparative study of the influence of metal ions of different size, charge and binding mode.
Liquid crystalline phase behavior of high molecular weight DNA: a comparative study of the influence of metal ions of different size, charge and binding mode.
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DOI：
10.1021/bm800101x
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发表时间：
2008-05
影响因子：
6.2
通讯作者：
N. Sundaresan;C. Suresh;T. Thomas;T. Thomas;C. Pillai
中科院分区：
文献类型：
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作者：
N. Sundaresan;C. Suresh;T. Thomas;T. Thomas;C. Pillai
研究了Li(+)、Na(+)、K(+)、Rb(+)、Cs(+)、Mg(2+)、Ca(2+)、Sr(2+)、Ba(2+)、Cu(2+)、Cd(2+)、Al(3+)、V(4+)、Hg(2+)、Pd(2+)、Au(3+)和Pt(4+)对高分子量DNA液晶相的诱导能力。碱金属和碱土金属离子引起典型的胆甾体/柱状结构，而过渡金属离子则使DNA沉淀成固体/半透明的凝胶状聚集体。重金属离子降低了DNA溶液的粘度，破坏了LC织构所需的刚性棒状DNA结构。Li(+)、Na(+)、K(+)、Mg(2+)和Ca(2+)结合DNA片段的三层量子力学/分子力学(QM/MM)研究表明，这些离子与磷酸基团有几种可能的结合方式。金属结合的双阴离子模式，包括DNA的两条链上的磷酸基团，允许碱土金属离子与DNA结合更高的亲和力。这些结果对理解金属离子的生物学作用和开发基于DNA的传感器和纳米电子器件具有重要意义。
The ability of Li(+), Na(+), K(+), Rb(+), Cs(+), Mg(2+), Ca(2+), Sr(2+), Ba(2+), Cu(2+), Cd(2+), Al(3+), V(4+), Hg(2+), Pd(2+), Au(3+), and Pt(4+) to provoke liquid crystalline (LC) phases in high molecular weight DNA was investigated. The alkali and alkaline earth metal ions provoked typical cholesteric/columnar structures, whereas transition metal ions precipitated DNA into solid/translucent gel-like aggregates. Heavy metal ions reduced viscosity of DNA solution, disrupting rigid, rod-like DNA structure necessary for LC textures. Three-layer quantum mechanical-molecular mechanical (QM/MM) studies of Li(+), Na(+), K(+), Mg(2+), and Ca(2+) binding DNA fragment suggested several possible binding modes of these ions to the phosphate groups. The dianion mode of metal binding, involving the phosphate groups of both strands of DNA, allowed for higher DNA binding affinity of the alkaline earth metal ions. These results have implications in understanding the biological role of metal ions and developing DNA-based sensors and nanoelectronic devices.