Howard Hughes Medical Institute and Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA.
Annu Rev Biophys. 2011;40:99-117. doi: 10.1146/annurev-biophys-042910-155329.
Chromatin is a highly regulated, modular nucleoprotein complex that is central to many processes in eukaryotes. The organization of DNA into nucleosomes and higher-order structures has profound implications for DNA accessibility. Alternative structural states of the nucleosome, and the thermodynamic parameters governing its assembly and disassembly, need to be considered in order to understand how access to nucleosomal DNA is regulated. In this review, we provide a brief historical account of how the overriding perception regarding aspects of nucleosome structure has changed over the past thirty years. We discuss recent technical advances regarding nucleosome structure and its physical characterization and review the evidence for alternative nucleosome conformations and their implications for nucleosome and chromatin dynamics.
染色质是一种高度调控的模块化核蛋白复合物，是真核生物中许多过程的核心。DNA 形成核小体和高级结构，这对 DNA 的可及性有深远的影响。为了理解核小体 DNA 的可及性是如何受到调控的，需要考虑核小体的替代结构状态以及控制其组装和拆卸的热力学参数。在这篇综述中，我们简要回顾了过去三十年中，人们对核小体结构某些方面的认识是如何发生变化的。我们讨论了最近关于核小体结构及其物理特性的技术进展，并回顾了替代核小体构象的证据及其对核小体和染色质动力学的影响。
