Cryo-EM structure of Arabidopsis thaliana Met1 (RFTS free)
マップデータ
Sharpened map
試料
複合体: Met1
タンパク質・ペプチド: DNA (cytosine-5)-methyltransferase 1
リガンド: ZINC ION
リガンド: S-ADENOSYL-L-HOMOCYSTEINE
キーワード
DNA (cytosine-5)-methyltransferase / TRANSFERASE
機能・相同性
機能・相同性情報
zygote asymmetric cytokinesis in embryo sac / epigenetic programming in the endosperm / negative regulation of flower development / DNA-mediated transformation / inflorescence development / DNA (cytosine-5-)-methyltransferase / DNA (cytosine-5-)-methyltransferase activity / DNA methylation-dependent constitutive heterochromatin formation / negative regulation of gene expression via chromosomal CpG island methylation / methyltransferase activity ...zygote asymmetric cytokinesis in embryo sac / epigenetic programming in the endosperm / negative regulation of flower development / DNA-mediated transformation / inflorescence development / DNA (cytosine-5-)-methyltransferase / DNA (cytosine-5-)-methyltransferase activity / DNA methylation-dependent constitutive heterochromatin formation / negative regulation of gene expression via chromosomal CpG island methylation / methyltransferase activity / methylation / chromatin binding / DNA binding / nucleus 類似検索 - 分子機能
DNA (cytosine-5)-methyltransferase 1, replication foci domain / Cytosine specific DNA methyltransferase replication foci domain / DNA methylase, C-5 cytosine-specific, conserved site / C-5 cytosine-specific DNA methylases C-terminal signature. / : / DNA methylase, C-5 cytosine-specific, active site / C-5 cytosine-specific DNA methylases active site. / C-5 cytosine-specific DNA methylase (Dnmt) domain profile. / C-5 cytosine methyltransferase / C-5 cytosine-specific DNA methylase ...DNA (cytosine-5)-methyltransferase 1, replication foci domain / Cytosine specific DNA methyltransferase replication foci domain / DNA methylase, C-5 cytosine-specific, conserved site / C-5 cytosine-specific DNA methylases C-terminal signature. / : / DNA methylase, C-5 cytosine-specific, active site / C-5 cytosine-specific DNA methylases active site. / C-5 cytosine-specific DNA methylase (Dnmt) domain profile. / C-5 cytosine methyltransferase / C-5 cytosine-specific DNA methylase / Bromo adjacent homology domain / BAH domain / Bromo adjacent homology (BAH) domain / Bromo adjacent homology (BAH) domain superfamily / BAH domain profile. / S-adenosyl-L-methionine-dependent methyltransferase superfamily 類似検索 - ドメイン・相同性
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
米国
引用
ジャーナル: Plant Cell / 年: 2025 タイトル: Structure and autoinhibitory regulation of MET1 in the maintenance of plant CG methylation. 著者: Jiuwei Lu / Xinyi Chen / Jian Fang / Daniel Li / Huy Le / Xuehua Zhong / Jikui Song / 要旨: Plant DNA methyltransferase 1 (MET1) is responsible for maintaining genome-wide cytosine-phosphate-guanine (CG) methylation. Its dysregulation has been linked to profound biological disruptions, ...Plant DNA methyltransferase 1 (MET1) is responsible for maintaining genome-wide cytosine-phosphate-guanine (CG) methylation. Its dysregulation has been linked to profound biological disruptions, including genomic instability and developmental defects. However, the exact mechanism by which MET1 orchestrates these vital functions and coordinates its various domains to shape the plant-specific epigenome remains unknown. Here, we report the cryogenic electron microscopy (cryo-EM) structure of Arabidopsis thaliana MET1 (AtMET1), revealing an autoinhibitory mechanism that governs its DNA methylation activity. Between the 2 replication foci target sequence (RFTS) domains in AtMET1, the second RFTS domain (RFTS2) directly associates with the methyltransferase (MTase) domain, thereby inhibiting substrate-binding activity. Compared with DNMT1, AtMET1 lacks the CXXC domain and its downstream autoinhibitory linker, featuring only limited RFTS2-MTase interactions, resulting in a much-reduced autoinhibitory contact. In line with this difference, the DNA methylation activity of AtMET1 displays less temperature dependence than that of DNMT1, potentially allowing MET1 to maintain its activity across diverse temperature conditions. We further report the structure of AtMET1 bound to hemimethylated CG DNA, unveiling the molecular basis for substrate binding and CG recognition by AtMET1, and an activation mechanism that involves a coordinated conformational shift between 2 structural elements of its active site. In addition, our combined structural and biochemical analysis highlights distinct functionalities between the 2 RFTS domains of AtMET1, unraveling their evolutionary divergence from the DNMT1 RFTS domain. Together, this study offers a framework for understanding the structure and mechanism of AtMET1, with profound implications for the maintenance of CG methylation in plants.