DNA mesophases induced by spermidine: Structural properties and biological implications
DNA mesophases induced by spermidine: Structural properties and biological implications
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DOI：
10.1016/s0006-3495(96)79232-9
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发表时间：
1996-07-01
影响因子：
3.4
通讯作者：
Livolant, F
中科院分区：
文献类型：
--
作者：
Pelta, J;Durand, D;Livolant, F
通过添加亚精胺的DNA聚集体的形成条件，确定与146个碱基对的DNA片段作为亚精胺和NaCl浓度的函数。获得了两种不同相的亚精胺-DNA复合物：具有大螺距的螺旋液晶相，螺旋间距为31.6至32.6埃，以及具有受限流动性的柱状六方相，其中DNA分子更紧密地堆积（29.85 +/-0.05埃）。在这两个阶段中，DNA分子都保持其B形式。这些相总是在与稀释的各向同性溶液的平衡中观察到，并且它们的相图是针对1 mg/ml的DNA浓度定义的。亚精胺诱导的DNA液晶相进行比较与DNA中间相已经描述的浓缩溶液中的亚精胺的情况下。我们建议，亚精胺DNA复合物的液晶特性是参与在许多实验文章中报道的DNA的功能特性的刺激，我们讨论了如何相的性质可以调节分子的活性程度。
Conditions of formation of DNA aggregates by the addition of spermidine were determined with 146 base pair DNA fragments as a function of spermidine and NaCl concentration. Two different phases of spermidine-DNA complexes are obtained: a cholesteric liquid crystalline phase with a large helical pitch, with interhelix distances ranging from 31.6 to 32.6 Angstrom, and a columnar hexagonal phase with a restricted fluidity in which DNA molecules are more closely packed (29.85 +/- 0.05 Angstrom). In both phases, the DNA molecule retains its B form. These phases are always observed in equilibrium with the dilute isotropic solution, and their phase diagram is defined for a DNA concentration of 1 mg/ml. DNA liquid crystalline phases induced by spermidine are compared with the DNA mesophases already described in concentrated solutions in the absence of spermidine. We propose that the liquid crystalline character of the spermidine DNA complexes is involved in the stimulation of the functional properties of the DNA reported in numerous experimental articles, and we discuss how the nature of the phase could regulate the degree of activity of the molecule.