酵母 NuA4 组蛋白乙酰转移酶复合物的结构与灵活性。
Structure and flexibility of the yeast NuA4 histone acetyltransferase complex.
机构信息
College of Chemistry, University of California, Berkeley, Berkeley, United States.
EpiCypher, Inc, Research Triangle Park, Durham, United States.
出版信息
Elife. 2022 Oct 20;11:e81400. doi: 10.7554/eLife.81400.
The NuA4 protein complex acetylates histones H4 and H2A to activate both transcription and DNA repair. We report the 3.1-Å resolution cryo-electron microscopy structure of the central hub of NuA4, which flexibly tethers the histone acetyltransferase (HAT) and Trimer Independent of NuA4 involved in Transcription Interactions with Nucleosomes (TINTIN) modules. The hub contains the large Tra1 subunit and a core that includes Swc4, Arp4, Act1, Eaf1, and the C-terminal region of Epl1. Eaf1 stands out as the primary scaffolding factor that interacts with the Tra1, Swc4, and Epl1 subunits and contributes the conserved HSA helix to the Arp module. Using nucleosome-binding assays, we find that the HAT module, which is anchored to the core through Epl1, recognizes H3K4me3 nucleosomes with hyperacetylated H3 tails, while the TINTIN module, anchored to the core via Eaf1, recognizes nucleosomes that have hyperacetylated H2A and H4 tails. Together with the known interaction of Tra1 with site-specific transcription factors, our data suggest a model in which Tra1 recruits NuA4 to specific genomic sites then allowing the flexible HAT and TINTIN modules to select nearby nucleosomes for acetylation.
NuA4 蛋白复合物将组蛋白 H4 和 H2A 乙酰化,以激活转录和 DNA 修复。我们报告了 NuA4 中心枢纽的 3.1Å 分辨率冷冻电镜结构,该结构灵活地连接了组蛋白乙酰转移酶 (HAT) 和 Trimer Independent of NuA4 involved in Transcription Interactions with Nucleosomes (TINTIN) 模块。枢纽包含大的 Tra1 亚基和一个核心,其中包括 Swc4、Arp4、Act1、Eaf1 和 Epl1 的 C 末端区域。Eaf1 作为主要支架因子脱颖而出,与 Tra1、Swc4 和 Epl1 亚基相互作用,并为 Arp 模块贡献保守的 HSA 螺旋。使用核小体结合测定,我们发现通过 Epl1 锚定在核心上的 HAT 模块识别具有超乙酰化 H3 尾巴的 H3K4me3 核小体,而通过 Eaf1 锚定在核心上的 TINTIN 模块识别具有超乙酰化 H2A 和 H4 尾巴的核小体。结合已知的 Tra1 与特定转录因子的相互作用,我们的数据表明了一种模型,其中 Tra1 将 NuA4 招募到特定的基因组位点,然后允许灵活的 HAT 和 TINTIN 模块选择附近的核小体进行乙酰化。