ジャーナル: Elife / 年: 2020 タイトル: Structural basis for PRC2 decoding of active histone methylation marks H3K36me2/3. 著者: Ksenia Finogenova / Jacques Bonnet / Simon Poepsel / Ingmar B Schäfer / Katja Finkl / Katharina Schmid / Claudia Litz / Mike Strauss / Christian Benda / Jürg Müller / 要旨: Repression of genes by Polycomb requires that PRC2 modifies their chromatin by trimethylating lysine 27 on histone H3 (H3K27me3). At transcriptionally active genes, di- and tri-methylated H3K36 ...Repression of genes by Polycomb requires that PRC2 modifies their chromatin by trimethylating lysine 27 on histone H3 (H3K27me3). At transcriptionally active genes, di- and tri-methylated H3K36 inhibit PRC2. Here, the cryo-EM structure of PRC2 on dinucleosomes reveals how binding of its catalytic subunit EZH2 to nucleosomal DNA orients the H3 N-terminus via an extended network of interactions to place H3K27 into the active site. Unmodified H3K36 occupies a critical position in the EZH2-DNA interface. Mutation of H3K36 to arginine or alanine inhibits H3K27 methylation by PRC2 on nucleosomes . Accordingly, H3K36A and H3K36R mutants show reduced levels of H3K27me3 and defective Polycomb repression of HOX genes. The relay of interactions between EZH2, the nucleosomal DNA and the H3 N-terminus therefore creates the geometry that permits allosteric inhibition of PRC2 by methylated H3K36 in transcriptionally active chromatin.
Phenix Resolve Cryo EM tool was used on the Relion 3D refined map and half maps to generate a density modified map. This map showed significant improvement in the H3 tail.
全体 : EM map of EZH2 on nucleosome obtained from signal particle subtra...
全体
名称: EM map of EZH2 on nucleosome obtained from signal particle subtraction and focused refinement on PHF1-PRC2:dinucleosome map.
要素
複合体: EM map of EZH2 on nucleosome obtained from signal particle subtraction and focused refinement on PHF1-PRC2:dinucleosome map.
複合体: SUZ12 and EZH2
タンパク質・ペプチド: Isoform 2 of Histone-lysine N-methyltransferase EZH2,Isoform 2 of Histone-lysine N-methyltransferase EZH2,Histone-lysine N-methyltransferase EZH2,Isoform 2 of Histone-lysine N-methyltransferase EZH2,Isoform 2 of Histone-lysine N-methyltransferase EZH2
タンパク質・ペプチド: Polycomb protein SUZ12
複合体: Histones
タンパク質・ペプチド: Histone H3.2
タンパク質・ペプチド: Histone H4
タンパク質・ペプチド: Histone H2A
タンパク質・ペプチド: Histone H2B 1.1
複合体: DNA
DNA: Widom601 DNA plus linker
DNA: Widom601 DNA plus linker
リガンド: ZINC ION
リガンド: S-ADENOSYL-L-HOMOCYSTEINE
+
超分子 #1: EM map of EZH2 on nucleosome obtained from signal particle subtra...
超分子
名称: EM map of EZH2 on nucleosome obtained from signal particle subtraction and focused refinement on PHF1-PRC2:dinucleosome map. タイプ: complex / ID: 1 / 親要素: 0 / 含まれる分子: #1-#8