THE HELICAL PERIODICITY OF DNA ON THE NUCLEOSOME
THE HELICAL PERIODICITY OF DNA ON THE NUCLEOSOME
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DOI：
10.1093/nar/9.17.4267
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发表时间：
1981-01-01
影响因子：
14.9
通讯作者：
LUTTER, LC
中科院分区：
文献类型：
--
作者：
KLUG, A;LUTTER, LC
核小体核心颗粒中 DNA 双螺旋每圈碱基对的精确数量一直是争议的主题。本文从三个维度分析了核酸酶切割位点的位置。以核小体二元组上 DNA 的中点为原点，将沿 DNA 链测量的切割位点位置映射到包含不同螺旋周期 DNA 的核小体核心模型上。发现每转 10.5 个碱基对的螺旋周期导致切割位点位置在空间上难以接近。相比之下，每转 10.0 个碱基对的周期性导致切割位点位置不仅在空间上合理，而且落入一种模式，例如当核酸酶进入 DNA 受到一侧组蛋白核心和另一侧 DNA 相邻超螺旋转的存在限制时所预期的模式。正如我们之前提出的 (1)，核小体上每转接近 10 个碱基对的螺旋周期性值，加上溶液中 DNA 接近 10.5 的周期性（现已确定的值），解决了所谓的连锁数悖论。
The precise number of base pairs per turn of the DNA double helix in the nucleosome core particle has been the subject of controversy. In this paper the positions of nuclease cutting sites are analysed in three dimensions. Using the midpoint of the DNA on the nucleosome dyad as origin, the cutting site locations measured along a strand of DNA are mapped onto models of the nucleosome core containing DNA of different helical periodicities.It is found that a helical periodicity of 10.5 base pairs per turn leads to cutting site positions which are sterically inaccessible. In contrast, a periodicity of 10.0 base pairs per turn leads to cutting site positions which are not only sterically sound, but which fall into a pattern such as would be expected when the access of the nuclease to the DNA is restricted by the presence of the histone core on one side and of the adjacent superhelical turn of DNA on the other. As proposed earlier by us (1), a value for the helical periodicity close to 10 base pairs per turn on the nucleosome, taken together with a periodicity close to 10.5 for DNA in solution - a value now established - resolves the so-called linkage number paradox.