9u9k

Cryo-EM structure of hemi-methylated DNA-bound Tetrahymena DNA methyltransferase complex MTA1c (MTA9-B)

spinqualitylabelsall models 9u9k, resolution 2.96Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9u9k is a 6 chain structure with sequence from Tetrahymena thermophila SB210 and Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 2.96Å Ligands: 6MA, SAM Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q22GC0_TETTS Publication Abstract from PubMed In eukaryotes, DNA N(6)-methyladenine (6mA) modification plays important roles in various cellular functions, such as chromatin dynamics, gene expression regulation, and DNA damage response. It remains largely unknown how eukaryotic DNA 6mA methyltransferases (MTases) recognize their substrates. Here, we reported the structures of DNA-bound eukaryotic 6mA MTase complexes. The MTA1 complex (MTA1c) in ciliates is composed of MTA1, MTA9 (or MTA9-B), p1 and p2 subunits. Cryo-electron microscopy structures of MTA1c-DNA complexes reveal that DNA lies on the surface of the MTA1-MTA9/9-B dimer and is clamped by the p1 N-terminal region. The target deoxyadenosine is flipped out of the DNA duplex and approaches the catalytic center. Unmethylated and hemi-methylated DNA substrates bind MTA1c with differential conformational dynamics. Our structural and biochemical studies shed light on the activation and substrate recognition of MTA1c and provide a framework for understanding the molecular mechanism of DNA 6mA modification in eukaryotes. Mechanism for the substrate recognition by a eukaryotic DNA N(6)-adenine methyltransferase complex.,Xu Q, Xie Y, Shi Z Nat Commun. 2025 Sep 30;16(1):8690. doi: 10.1038/s41467-025-63738-y. PMID:41027852 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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