6IMA

Crystal Structure of ALKBH1 without alpha-1 (N37-C369)

6IMA の概要

• エントリーDOI: 10.2210/pdb6ima/pdb
• 分子名称: Nucleic acid dioxygenase ALKBH1, CITRIC ACID (3 entities in total)
• 機能のキーワード: double-stranded beta helix, gene regulation
• 由来する生物種: Mus musculus (Mouse)
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 113964.77

構造登録者

Zhang, M.,Yang, S.,Zhao, W.,Li, H. (登録日: 2018-10-22, 公開日: 2020-01-22, 最終更新日: 2024-11-06)

主引用文献

Zhang, M.,Yang, S.,Nelakanti, R.,Zhao, W.,Liu, G.,Li, Z.,Liu, X.,Wu, T.,Xiao, A.,Li, H.
Mammalian ALKBH1 serves as an N6-mA demethylase of unpairing DNA.
Cell Res., 30:197-210, 2020

PubMed Abstract: N-methyladenine (N-mA) of DNA is an emerging epigenetic mark in mammalian genome. Levels of N-mA undergo drastic fluctuation during early embryogenesis, indicative of active regulation. Here we show that the 2-oxoglutarate-dependent oxygenase ALKBH1 functions as a nuclear eraser of N-mA in unpairing regions (e.g., SIDD, Stress-Induced DNA Double Helix Destabilization regions) of mammalian genomes. Enzymatic profiling studies revealed that ALKBH1 prefers bubbled or bulged DNAs as substrate, instead of single-stranded (ss-) or double-stranded (ds-) DNAs. Structural studies of ALKBH1 revealed an unexpected "stretch-out" conformation of its "Flip1" motif, a conserved element that usually bends over catalytic center to facilitate substrate base flipping in other DNA demethylases. Thus, lack of a bending "Flip1" explains the observed preference of ALKBH1 for unpairing substrates, in which the flipped N-mA is primed for catalysis. Co-crystal structural studies of ALKBH1 bound to a 21-mer bulged DNA explained the need of both flanking duplexes and a flipped base for recognition and catalysis. Key elements (e.g., an ALKBH1-specific α1 helix) as well as residues contributing to structural integrity and catalytic activity were validated by structure-based mutagenesis studies. Furthermore, ssDNA-seq and DIP-seq analyses revealed significant co-occurrence of base unpairing regions with N-mA in mouse genome. Collectively, our biochemical, structural and genomic studies suggest that ALKBH1 is an important DNA demethylase that regulates genome N-mA turnover of unpairing regions associated with dynamic chromosome regulation.

PubMed: 32051560
DOI: 10.1038/s41422-019-0237-5

実験手法

X-RAY DIFFRACTION (2.593 Å)