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Title | Structural insights into DNA N-adenine methylation by the MTA1 complex. |
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Journal, issue, pages | Cell Discov, Vol. 9, Issue 1, Page 8, Year 2023 |
Publish date | Jan 20, 2023 |
Authors | Junjun Yan / Feiqing Liu / Zeyuan Guan / Xuhui Yan / Xiaohuan Jin / Qiang Wang / Zican Wang / Junjie Yan / Delin Zhang / Zhu Liu / Shan Wu / Ping Yin / |
PubMed Abstract | N-methyldeoxyadenine (6mA) has recently been reported as a prevalent DNA modification in eukaryotes. The Tetrahymena thermophila MTA1 complex consisting of four subunits, namely MTA1, MTA9, p1, and ...N-methyldeoxyadenine (6mA) has recently been reported as a prevalent DNA modification in eukaryotes. The Tetrahymena thermophila MTA1 complex consisting of four subunits, namely MTA1, MTA9, p1, and p2, is the first identified eukaryotic 6mA methyltransferase (MTase) complex. Unlike the prokaryotic 6mA MTases which have been biochemically and structurally characterized, the operation mode of the MTA1 complex remains largely elusive. Here, we report the cryogenic electron microscopy structures of the quaternary MTA1 complex in S-adenosyl methionine (SAM)-bound (2.6 Å) and S-adenosyl homocysteine (SAH)-bound (2.8 Å) states. Using an AI-empowered integrative approach based on AlphaFold prediction and chemical cross-linking mass spectrometry, we further modeled a near-complete structure of the quaternary complex. Coupled with biochemical characterization, we revealed that MTA1 serves as the catalytic core, MTA1, MTA9, and p1 likely accommodate the substrate DNA, and p2 may facilitate the stabilization of MTA1. These results together offer insights into the molecular mechanism underpinning methylation by the MTA1 complex and the potential diversification of MTases for N-adenine methylation. |
External links | Cell Discov / PubMed:36658132 / PubMed Central |
Methods | EM (single particle) |
Resolution | 2.6 - 2.7 Å |
Structure data | EMDB-33853, PDB-7yi8: EMDB-33854, PDB-7yi9: |
Chemicals | ChemComp-SAH: ChemComp-SAM: |
Source |
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Keywords | DNA BINDING PROTEIN / N6-adenine methylation / MTAc holoenzyme |