Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom.
J Biol Chem. 2012 May 25;287(22):18730-7. doi: 10.1074/jbc.M111.337204. Epub 2012 Apr 9.
The chromoshadow domain (CSD) of heterochromatin protein 1 (HP1) was recently shown to contribute to chromatin binding and transcriptional regulation through interaction with histone H3. Here, we demonstrate the structural basis of this interaction for the CSD of HP1α. This mode of H3 binding is dependent on dimerization of the CSD and recognition of a PxVxL-like motif, as for other CSD partners. NMR chemical shift mapping showed that the H3 residues that mediate the CSD interaction occur in and adjacent to the αN helix just within the nucleosome core. Access to the binding region would require some degree of unwrapping of the DNA near the nucleosomal DNA entry/exit site.
最近的研究表明，异染色质蛋白 1（HP1）的 chromoshadow 结构域（CSD）通过与组蛋白 H3 的相互作用，有助于染色质结合和转录调控。在这里，我们展示了 HP1α 的 CSD 与 H3 相互作用的结构基础。这种 H3 结合模式依赖于 CSD 的二聚化和对 PxVxL 样基序的识别，就像其他 CSD 伴侣一样。NMR 化学位移映射显示，介导 CSD 相互作用的 H3 残基位于核小体核心内的αN 螺旋内及其附近。要访问结合区域，需要在核小体 DNA 进入/退出位点附近对 DNA 进行一定程度的解缠绕。
