Nucleosomes in solution exist as a mixture of twist-defect states
Nucleosomes in solution exist as a mixture of twist-defect states
复制标题
DOI：
10.1016/j.jmb.2004.10.012
复制
发表时间：
2005-01-07
影响因子：
5.6
通讯作者：
Luger, K
中科院分区：
文献类型：
--
作者：
Edayathumangalam, RS;Weyermann, P;Luger, K
与二价吡咯-咪唑聚酰胺复合的核小体核心颗粒的2.0埃晶体结构揭示了这种“钳”有效地交叉支撑DNA超螺旋的两个回旋，从而稳定核小体以防解离。使用X-射线晶体学和足迹技术，我们表明，钳优先结合核小体超过游离DNA，核小体DNA存在于溶液中的多个扭曲缺陷的中间体的混合物。核小体以两种不同构象之一存在于各种晶体结构中，即使在强定位序列上也能捕获扭曲缺陷中间体。已经获得的证据支持存在的扭曲缺陷状态的核小体DNA在溶液中，类似于在晶体结构中获得的。我们的研究结果也证实了这一想法，扭转扩散可能是一个重要的手段，改变核小体DNA的可及性在存在和不存在ATP依赖的染色质重塑酶。(C)2004爱思唯尔有限公司保留所有权利。
The 2.0 Angstrom crystal structure of a nucleosome core particle in complex with a bivalent pyrrole-imidazole polyamide reveals that this "clamp" effectively crossbraces the two gyres of the DNA superhelix, thereby stabilizing the nucleosome against dissociation. Using X-ray crystallography and footprinting techniques, we show that the clamp preferentially binds nucleosomes over free DNA, and that nucleosomal DNA exists as a mixture of multiple twist-defect intermediates in solution. The nucleosomes exist in one of two different conformations in various crystal structures that trap twist-defect intermediates, even on a strong positioning sequence. Evidence has been obtained supporting the existence of twist-defect states in nucleosomal DNA in solution that are similar to those obtained in crystal structures. Our results also substantiate the idea that twist diffusion may represent an important means of altering the accessibility of nucleosomal DNA both in the presence and in the absence of ATP-dependent chromatin-remodelling enzymes. (C) 2004 Elsevier Ltd. All rights reserved.