Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.
Nat Struct Mol Biol. 2013 Jun;20(6):657-61. doi: 10.1038/nsmb.2581. Epub 2013 Jun 5.
Histones have two structurally and functionally distinct domains: globular domains forming the nucleosomal core around which DNA is wrapped and unstructured tails protruding from the nucleosomal core. Whereas post-translational modifications (PTMs) in histone tails are well studied, much less is currently known about histone-core PTMs. Many core PTMs map to residues located on the lateral surface of the histone octamer, close to the DNA, and they have the potential to alter intranucleosomal histone-DNA interactions. Here we discuss recent advances in understanding the function of lateral-surface PTMs. Whereas modifications in the histone tails might have limited structural impact on the nucleosome itself and function as signals to recruit specific binding proteins, PTMs in the lateral surface can have a direct structural effect on nucleosome and chromatin dynamics, even in the absence of specific binding proteins, which adds a twist to the debate on the functionality and causality of PTMs.
球状结构域形成核小体核心，DNA 围绕该核心缠绕，未折叠的尾部从核小体核心伸出。虽然组蛋白尾部的翻译后修饰（PTM）已经得到了很好的研究，但目前对组蛋白核心 PTM 的了解要少得多。许多核心 PTM 位于组蛋白八聚体的侧面，靠近 DNA，它们有可能改变核小体内部的组蛋白-DNA 相互作用。在这里，我们讨论了理解侧向表面 PTM 功能的最新进展。虽然尾部的修饰可能对核小体本身的结构影响有限，并作为招募特定结合蛋白的信号，但侧向表面的修饰可以对核小体和染色质动力学产生直接的结构影响，即使在没有特定结合蛋白的情况下，这为 PTM 的功能和因果关系的争论增添了一个转折。
