Simpson R T, Shindo H
Nucleic Acids Res. 1980 May 10;8(9):2093-103. doi: 10.1093/nar/8.9.2093.
We have studied the conformation of poly (dG-dC) . poly (dG-dC) in three conditions; i) associated with histones octamers, ii) alone at ionic strength 0.1, and ii) in solutions of over 2.5 M NaCl. The circular dichroism spectrum for the polymer bound to histones differs from that for the free polymer; the difference spectrum is similar to those for native and poly (dA-dT) . poly (dA-dT) core particles. Under the first two conditions, the 31P NMR spectrum is symmetric with line widths of 91 and 41 Hz, respectively, at 109.3 MHz. In high salt, two 31P peaks of equal intensity are observed, confirming recent results of Patel et al. (1) and indicating an alternating geometry for the phosphodiester backbone. Using this highly homogeneous DNA, we confirm that the Pohl-Jovin transition (2) is an intramolecular rearrangement, not requiring complete strand separation.
我们研究了聚（dG-dC）·聚（dG-dC）在三种条件下的构象：i）与组蛋白八聚体结合；ii）在离子强度为0.1时单独存在；iii）在氯化钠浓度超过2.5M的溶液中。与组蛋白结合的聚合物的圆二色光谱不同于游离聚合物的光谱；差异光谱类似于天然的和聚（dA-dT）·聚（dA-dT）核心颗粒的光谱。在前两种条件下，31P核磁共振谱是对称的，在109.3MHz时线宽分别为91Hz和41Hz。在高盐条件下，观察到两个强度相等的31P峰，证实了帕特尔等人（1）最近的结果，并表明磷酸二酯主链具有交替的几何结构。使用这种高度均匀的DNA，我们证实了波尔-约文转变（2）是一种分子内重排，不需要完全的链分离。
