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Shang G, Yang M, Li M, Ma L, Liu Y, Ma J, Chen Y, Wang X, Fan S, Xie M, Wu W, Dai S, Chen Z. Structural Basis of Nucleic Acid Recognition and 6mA Demethylation by Caenorhabditis elegans NMAD-1A. Int J Mol Sci 2024; 25:686. [PMID: 38255759 PMCID: PMC10815869 DOI: 10.3390/ijms25020686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 12/30/2023] [Accepted: 12/31/2023] [Indexed: 01/24/2024] Open
Abstract
N6-methyladenine (6mA) of DNA is an emerging epigenetic mark in the genomes of Chlamydomonas, Caenorhabditis elegans, and mammals recently. Levels of 6mA undergo drastic fluctuation and thus affect fertility during meiosis and early embryogenesis. Here, we showed three complex structures of 6mA demethylase C. elegans NMAD-1A, a canonical isoform of NMAD-1 (F09F7.7). Biochemical results revealed that NMAD-1A prefers 6mA Bubble or Bulge DNAs. Structural studies of NMAD-1A revealed an unexpected "stretch-out" conformation of its Flip2 region, a conserved element that is usually bent over the catalytic center to facilitate substrate base flipping in other DNA demethylases. Moreover, the wide channel between the Flip1 and Flip2 of the NMAD-1A explained the observed preference of NMAD-1A for unpairing substrates, of which the flipped 6mA was primed for catalysis. Structural analysis and mutagenesis studies confirmed that key elements such as carboxy-terminal domain (CTD) and hypothetical zinc finger domain (ZFD) critically contributed to structural integrity, catalytic activity, and nucleosome binding. Collectively, our biochemical and structural studies suggest that NMAD-1A prefers to regulate 6mA in the unpairing regions and is thus possibly associated with dynamic chromosome regulation and meiosis regulation.
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Affiliation(s)
- Guohui Shang
- State Key Laboratory of Animal Biotech Breeding and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Meiting Yang
- State Key Laboratory of Animal Biotech Breeding and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Min Li
- National Protein Science Facility, Tsinghua University, Beijing 100084, China
| | - Lulu Ma
- State Key Laboratory of Animal Biotech Breeding and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Yunlong Liu
- School of Life Sciences, Tiangong University, Tianjin 300387, China
| | - Jun Ma
- State Key Laboratory of Animal Biotech Breeding and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Yiyun Chen
- Department of Biochemistry, University of Colorado, Boulder, CO 80303, USA
| | - Xue Wang
- State Key Laboratory of Animal Biotech Breeding and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Shilong Fan
- National Protein Science Facility, Tsinghua University, Beijing 100084, China
| | - Mengjia Xie
- State Key Laboratory of Animal Biotech Breeding and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Wei Wu
- State Key Laboratory of Animal Biotech Breeding and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Shaodong Dai
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Zhongzhou Chen
- State Key Laboratory of Animal Biotech Breeding and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China
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