Selective dissociation of histones from calf thymus nucleoprotein.
Selective dissociation of histones from calf thymus nucleoprotein.
复制标题
组蛋白与小牛胸腺核蛋白的选择性解离。
DOI：
10.1016/0022-2836(67)90143-x
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发表时间：
1967
影响因子：
5.6
通讯作者：
N. Davidson
中科院分区：
文献类型：
--
作者：
H. Ohlenbusch;B. Olivera;D. Y. Tuan;N. Davidson
通过增加氯化钠和高氯酸钠的浓度，已经测量了组蛋白从核组蛋白解离的程度。在一定的盐介质中，通过差速离心将解离的组蛋白与核组蛋白分离。组蛋白组分通过凝胶电泳鉴定，或者在一些初步实验中，通过柱层析鉴定。组蛋白组分I在0.4至0.5m范围内被NaCl从核组蛋白解离。组蛋白II被0.8 - 1. 2 m-NaCl解离。凝胶电泳显示组蛋白III-IV由B1和A两种组分组成。B1组分在0.8 - 1. 2 m-NaCl范围内与天然核组蛋白解离，A组分在0.9 - 1. 6 m-NaCl范围内与天然核组蛋白解离。NaClO 4的研究并不详细，但一般的结果是，解离某个组蛋白组分所需的NaClO 4浓度大约是NaCl浓度的一半，组蛋白组分的解离在某种程度上是合作的，并且发生在相当小的盐浓度范围内。这些结果表明，静电和非静电相互作用有助于组蛋白和DNA之间的结合强度。沉淀分离的结果通过在不同盐浓度下的电泳分离得到证实。此外，正如预期的那样，更多的组蛋白从核组蛋白中解离，后者的电泳速度越大。在低盐浓度的介质中，部分解离的核组蛋白的光学熔解曲线介于完全覆盖的核组蛋白和DNA的光学熔解曲线之间。部分覆盖的材料的熔解曲线比完全覆盖的核组蛋白或DNA的熔解曲线宽，但不明显是双相的。因此，结果表明，组蛋白是有点不均匀分布沿着DNA链。完全覆盖的天然核组蛋白在0.15至0.30mM范围内的氯化钠浓度下不溶。用0. 6 m-NaCl抽提除去组蛋白I后的核组蛋白溶于0.15 ~ 0. 30 m-NaCl。
The extent of the dissociation of histones from nucleohistone by increasing concentrations of sodium chloride and sodium perchlorate has been measured. Dissociated histones were separated from nucleohistone in a given salt medium by differential centrifugation. The histone fractions were identified by gel electrophoresis, or, in some preliminary experiments, by column chromatography. Histone fraction I is dissociated from nucleohistone by NaCl in the range of 0.4 to 0.5m. Histone II is dissociated by 0.8 to 1.2m-NaCl. Histone III–IV consists of two components B1and A, by gel electrophoresis. The B1component is dissociated from native nucleohistone in the range 0.8 to 1.2m-NaCl, the A component in the range 0.9 to 1.6m. The NaClO4studies are not as detailed, but the general result is that the concentration of NaClO4needed to dissociate a certain histone fraction is about half the concentration of NaCl needed.The dissociation of a histone fraction is somewhat co-operative and takes place over a rather small salt concentration range. These results imply that both electrostatic and non-electrostatic interactions contribute to the strength of the binding between histones and DNA. The results of the sedimentation separations were confirmed by electrophoretic separations in different salt concentrations. Furthermore, and as expected, the more histone dissociated from a nucleohistone, the greater the electrophoretic velocity of the latter.The optical melting profiles of partially dissociated nucleohistones in a medium of low salt concentration are intermediate between those of fully covered nucleohistone and DNA. The melting curves for the partially covered materials are broader than those for fully covered nucleohistone or for DNA, but not clearly biphasic. The results therefore suggest that the histones are somewhat heterogeneously distributed along the DNA chain. Fully covered native nucleohistone is insoluble at sodium chloride concentrations in the range 0.15 to 0.30m. Nucleohistone, from which histone I has been removed by extraction with 0.6m-NaCl, is soluble in 0.15 to 0.30m-NaCl.