Methylation of histone H3 lysine 4 (H3K4) is catalyzed by the multi-component COMPASS or COMPASS-like complex, which is highly conserved from yeast to human, and plays essential roles in gene expression and transcription, cell cycle progression, and DNA repair. Here we present a cryo-EM map of the complete S. cerevisiae COMPASS complex. Through tag or Fab labeling strategy combined with cryo-EM 3D reconstruction and cross-linking and mass spectrometry (XL-MS) analysis, we uncovered new information on the subunit arrangement: Cps50, Cps35, and Cps30 were determined to group together to form the face region in the head of the complex, and Cps40 and the N-terminal portion of Set1 reside on the top of the head. Our map reveals the location of the active center and a canyon in the back of the head. Together, our study provides the first snapshot of the complete architecture of yeast COMPASS and a picture of its subunit interaction network, which could facilitate our understanding of the COMPASS machinery and its functionality.

中文翻译：

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完整的酿酒酵母COMPASS复合物的体系结构和亚基排列。

组蛋白H3赖氨酸4（H3K4）的甲基化由多组分COMPASS或COMPASS样复合物催化，这种复合物从酵母到人都是高度保守的，并且在基因表达和转录，细胞周期进程和DNA修复中起着至关重要的作用。在这里，我们介绍了完整的啤酒酵母COMPASS复合体的冷冻EM图。通过标签或Fab标记策略与冷冻EM 3D重建，交联和质谱（XL-MS）分析相结合，我们发现了有关亚基排列的新信息：确定Cps50，Cps35和Cps30一起分组以形成复合体头部的面部区域，Cps40和Set1的N端部分位于头部的顶部。我们的地图显示了活动中心的位置以及头部后部的峡谷。一起，