Effect of nucleosome distortion on the linking deficiency in relaxed minichromosomes.
Effect of nucleosome distortion on the linking deficiency in relaxed minichromosomes.
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核小体扭曲对松弛微型染色体连接缺陷的影响。
DOI：
10.1016/0022-2836(89)90450-6
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发表时间：
1989
影响因子：
5.6
通讯作者：
Bauer,WR
中科院分区：
文献类型：
--
作者：
White,JH;Gallo,R;Bauer,WR
闭合环状DNA在蛋白质表面的包裹，随后用拓扑异构酶松弛并去除蛋白质，产生特征性DNA连接缺陷ΔLk。我们表明，Δ Lk的大小取决于表面形状，我们计算的变化Δ Lk所造成的特定扭曲的蛋白质包装表面。如果DNA在扭曲过程中仍然附着在表面上，DNA缠绕数Φ不会改变。ΔLkis的变化等于表面连接数SLk的变化，SLk是DNA在表面周围缠绕的直接测量。对于左旋缠绕，如核小体，SLk= −n，即DNA轴围绕蛋白质复合物轴缠绕的次数。我们计算值SLk的螺旋包装的恒定长度的DNA蛋白质表面具有的形状的圆柱体和椭圆体和双曲面的革命。如果蛋白质的赤道半径固定，从圆柱体到双曲面的形状变化会增加SLk，而相应的椭圆体变化会减少SLk。我们将一般结果应用于解释微型染色体在不同温度下用拓扑异构酶松弛并测定ΔLkis的实验。结果是，核小体核心的变形最多为5%（轴向末端相对于赤道的半径变化）就足以解释观察到的Δ Lk变化。
The wrapping of closed circular DNA on a protein surface, followed by relaxation with a topoisomerase and removal of proteins, produces a characteristic DNA linking deficiency,ΔLk. We show that the magnitude ofΔLkdepends upon the surface shape, and we calculate changes inΔLkcaused by particular distortions of the protein wrapping surface. If the DNA remains attached to the surface during distortion, the DNA winding number, Φ, is not altered. The change inΔLkis then equal to the change in the surface linking number,SLk, which is a straightforward measure of the wrapping of the DNA around the surface. For left-handed wrapping, as in a nucleosome,SLk= −n, the number of times that the DNA axis winds around the axis of the protein complex. We calculate values ofSLkfor the helical wrapping of a constant length of DNA on protein surfaces having the shapes of cylinders and of ellipsoids and hyperboloids of revolution. If the equatorial radius of the protein is fixed, change in shape from a cylinder to a hyperboloid increasesSLk, while the corresponding change to an ellipsoid reducesSLk. We apply the general results to the interpretation of experiments in which minichromosomes are relaxed with topoisomerase at various temperatures andΔLkis determined. The result is that a distortion of the nucleosome core by at most 5 % (the change in the radius at the axial extremity relative to the equator) is sufficient to explain the observedΔLkchanges.
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溶液中组蛋白八聚体的形状分析。
DOI：
10.1126/science.3704649
发表时间：
1986
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Uberbacher,EC;Harp,JM;Wilkinson-Singley,E;Bunick,GJ
通讯作者：
Bunick,GJ
175 个碱基对核小体的展开。
影响因子：
2.9
作者：
Schlessinger,FB;Dattagupta,N;Crothers,DM
通讯作者：
Crothers,DM
小 DNA 环上的染色质重建。
影响因子：
5.6
作者：
Y. Zivanovic;I. Goulet;B. Révet;M. Le Bret;A. Prunell
通讯作者：
A. Prunell
表面包裹 DNA 的螺旋重复和连接数。
影响因子：
56.9
作者：
James H. White;N. Cozzarelli;William R. Bauer
通讯作者：
William R. Bauer
影响因子：
3.2
作者：
R. Simon
通讯作者：
R. Simon