Interhelical spacing in liquid crystalline spermine and spermidine-DNA precipitates
Interhelical spacing in liquid crystalline spermine and spermidine-DNA precipitates
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DOI：
10.1529/biophysj.104.040113
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发表时间：
2005-01-01
影响因子：
3.4
通讯作者：
Livolant, F
中科院分区：
文献类型：
--
作者：
Raspaud, E;Durand, D;Livolant, F
通过X射线衍射研究了多胺-DNA沉淀物的结构。在不同的NaCl、多胺和DNA浓度下获得螺旋间距a（H）的精确测量。大多数结果是用精胺得到的，很少有用亚精胺得到的。沉淀物是液晶的，或者是六方和/或六方的，具有取决于离子浓度和聚胺类型的螺旋间距。在我们的实验条件下，间距从28.15到33.4埃不等。这种变化被解释为沉淀物内部存在的不同离子组分，并被认为调节DNA的内聚能值。这些结果进行了讨论，在有关的生物过程中，需要一个封闭的双螺旋和多胺类似物在癌症治疗中发挥的作用。
The structure of polyamines-DNA precipitates was studied by x-ray diffraction. Precise measurements of the interhelix distance a(H) were obtained at different NaCl, polyamine, and DNA concentrations. Most of the results were obtained using spermine and few others using spermidine. The precipitates are liquid crystalline, either hexagonal and/or cholesteric, with an interhelical spacing that depends on the ionic concentrations and on the polyamine type. In our experimental conditions, the spacing varies from 28.15 to 33.4 Angstrom. This variation is interpreted in terms of different ionic components that are present inside the precipitates and that are thought to regulate the value of the cohesive energy of DNA. These results are discussed in relation to the biological processes requiring a closeness of double helices and to the role played by polyamine analogs in cancer therapy.