7xib
Cryo-EM structure of human DNMT1 (aa:351-1616) in complex with ubiquitinated H3 and hemimethylated DNA analog (CXXC-disordered form)
Structural highlights
DiseaseDNMT1_HUMAN Defects in DNMT1 are the cause of hereditary sensory neuropathy type 1E (HSN1E) [MIM:614116. A neurodegenerative disorder characterized by adult onset of progressive peripheral sensory loss associated with progressive hearing impairment and early-onset dementia.[1] FunctionDNMT1_HUMAN Methylates CpG residues. Preferentially methylates hemimethylated DNA. Associates with DNA replication sites in S phase maintaining the methylation pattern in the newly synthesized strand, that is essential for epigenetic inheritance. Associates with chromatin during G2 and M phases to maintain DNA methylation independently of replication. It is responsible for maintaining methylation patterns established in development. DNA methylation is coordinated with methylation of histones. Mediates transcriptional repression by direct binding to HDAC2. In association with DNMT3B and via the recruitment of CTCFL/BORIS, involved in activation of BAG1 gene expression by modulating dimethylation of promoter histone H3 at H3K4 and H3K9.[2] [3] [4] Publication Abstract from PubMedDNMT1 is an essential enzyme that maintains genomic DNA methylation, and its function is regulated by mechanisms that are not yet fully understood. Here, we report the cryo-EM structure of human DNMT1 bound to its two natural activators: hemimethylated DNA and ubiquitinated histone H3. We find that a hitherto unstudied linker, between the RFTS and CXXC domains, plays a key role for activation. It contains a conserved alpha-helix which engages a crucial "Toggle" pocket, displacing a previously described inhibitory linker, and allowing the DNA Recognition Helix to spring into the active conformation. This is accompanied by large-scale reorganization of the inhibitory RFTS and CXXC domains, allowing the enzyme to gain full activity. Our results therefore provide a mechanistic basis for the activation of DNMT1, with consequences for basic research and drug design. Structural basis for activation of DNMT1.,Kikuchi A, Onoda H, Yamaguchi K, Kori S, Matsuzawa S, Chiba Y, Tanimoto S, Yoshimi S, Sato H, Yamagata A, Shirouzu M, Adachi N, Sharif J, Koseki H, Nishiyama A, Nakanishi M, Defossez PA, Arita K Nat Commun. 2022 Nov 21;13(1):7130. doi: 10.1038/s41467-022-34779-4. PMID:36414620[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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