6mm1
From Proteopedia
Structure of the cysteine-rich region from human EHMT2
Structural highlights
FunctionEHMT2_HUMAN Histone methyltransferase that specifically mono- and dimethylates 'Lys-9' of histone H3 (H3K9me1 and H3K9me2, respectively) in euchromatin. H3K9me represents a specific tag for epigenetic transcriptional repression by recruiting HP1 proteins to methylated histones. Also mediates monomethylation of 'Lys-56' of histone H3 (H3K56me1) in G1 phase, leading to promote interaction between histone H3 and PCNA and regulating DNA replication. Also weakly methylates 'Lys-27' of histone H3 (H3K27me). Also required for DNA methylation, the histone methyltransferase activity is not required for DNA methylation, suggesting that these 2 activities function independently. Probably targeted to histone H3 by different DNA-binding proteins like E2F6, MGA, MAX and/or DP1. May also methylate histone H1. In addition to the histone methyltransferase activity, also methylates non-histone proteins: mediates dimethylation of 'Lys-373' of p53/TP53. Also methylates CDYL, WIZ, ACIN1, DNMT1, HDAC1, ERCC6, KLF12 and itself.[1] [2] [3] [4] [5] Publication Abstract from PubMedEuchromatic histone-lysine N-methyltransferase 1 (EHMT1; G9a-like protein; GLP) and euchromatic histone-lysine N-methyltransferase 2 (EHMT2; G9a) are protein lysine methyltransferases that regulate gene expression and are essential for development and the ability of organisms to change and adapt. In addition to ankyrin repeats and the catalytic SET domain, the EHMT proteins contain a unique cysteine-rich region (CRR) that mediates protein-protein interactions and recruitment of the methyltransferases to specific sites in chromatin. We have determined the structure of the CRR from human EHMT2 by X-ray crystallography and show that the CRR adopts an unusual compact fold with four bound zinc atoms. The structure consists of a RING domain preceded by a smaller zinc-binding motif and an N-terminal segment. The smaller zinc-binding motif straddles the N-terminal end of the RING domain, and the N-terminal segment runs in an extended conformation along one side of the structure and interacts with both the smaller zinc-binding motif and the RING domain. The interface between the N-terminal segment and the RING domain includes one of the zinc atoms. The RING domain is partially sequestered within the CRR and unlikely to function as a ubiquitin ligase. The structure of the cysteine-rich region from human histone-lysine N-methyltransferase EHMT2 (G9a).,Kerchner KM, Mou TC, Sun Y, Rusnac DV, Sprang SR, Briknarova K J Struct Biol X. 2021 Jun 25;5:100050. doi: 10.1016/j.yjsbx.2021.100050. , eCollection 2021. PMID:34278292[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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