关于DNA分子中A 型和B 型片段之间边界的灵活性
On the flexibility of the boundaries between the A-form and B-form sections in DNA molecule.
作者信息
Zavriev S K, Minchenkova L E, Frank-Kamenetskii M D, Ivanov V I
出版信息
Nucleic Acids Res. 1978 Jul;5(7):2657-63. doi: 10.1093/nar/5.7.2657.
The degree of orientation of DNA in a flow has been studied within the interval of the B - A transition induced by ethanol. The orientation of the B DNA (60-65% ethanol, v/v) and that of the A DNA (80-82% ethanol) are nearly identical. This means that both conformations have similar persistence lengths and that there is no aggregation in the course of formation of the A form. Within the transition range (65-78% ethanol) the orientation attains a sharp minimum which coincides with the half-transition point (73% ethanol). The cooperative character of the B - A transition presupposes the existence of boundaries between the alternating sections of the A and B conformations that may entail an increased flexibility of the DNA molecule and a corresponding drop of orientation. Theory predicts an elliptical dependence of the number of boundaries on the proportion of the A form. The experimental degree of orientation follows the same pattern. Quantitative evaluation shows that the flexibility of a boundary is small, so that several dozen of boundaries are required to simulate free rotation.
在由乙醇诱导的B - A转变区间内，研究了DNA在流动中的取向程度。B型DNA（60 - 65%乙醇，体积/体积）和A型DNA（80 - 82%乙醇）的取向几乎相同。这意味着两种构象具有相似的持久长度，并且在A型形成过程中不存在聚集现象。在转变范围内（65 - 78%乙醇），取向达到一个急剧的最小值，该最小值与半转变点（73%乙醇）重合。B - A转变的协同特性意味着在A和B构象交替区域之间存在边界，这可能导致DNA分子的柔韧性增加以及相应的取向下降。理论预测边界数量与A型比例呈椭圆关系。实验得到的取向程度遵循相同模式。定量评估表明，边界的柔韧性较小，因此需要几十条边界来模拟自由旋转。
Zotero 插件