Scaletti, E.R., Vallin, K.S., Bräutigam, L. et al. (5 more authors) (2020) MutT homologue 1 (MTH1) removes N6-methyl-dATP from the dNTP pool. Journal of Biological Chemistry, 295 (15). pp. 4761-4772. ISSN 0021-9258
Abstract
MutT homologue 1 (MTH1) removes oxidized nucleotides from the nucleotide pool and thereby prevents their incorporation into the genome and thereby reduces genotoxicity. We previously reported that MTH1 is an efficient catalyst of O6-methyl-dGTP hydrolysis suggesting that MTH1 may also sanitize the nucleotide pool from other methylated nucleotides. We here show that MTH1 efficiently catalyzes the hydrolysis of N6-methyl-dATP to N6-methyl-dAMP and further report that N6-methylation of dATP drastically increases the MTH1 activity. We also observed MTH1 activity with N6-methyl-ATP, albeit at a lower level. We show that N6-methyl-dATP is incorporated into DNA in vivo, as indicated by increased N6-methyl-dA DNA levels in embryos developed from MTH1 knock-out zebrafish eggs microinjected with N6-methyl-dATP compared with noninjected embryos. N6-methyl-dATP activity is present in MTH1 homologues from distantly related vertebrates, suggesting evolutionary conservation and indicating that this activity is important. Of note, N6-methyl-dATP activity is unique to MTH1 among related NUDIX hydrolases. Moreover, we present the structure of N6-methyl-dAMP–bound human MTH1, revealing that the N6-methyl group is accommodated within a hydrophobic active-site sub-pocket explaining why N6-methyl-dATP is a good MTH1 substrate. N6-methylation of DNA and RNA has been reported to have epigenetic roles and to affect mRNA metabolism. We propose that MTH1 acts in concert with adenosine deaminase–like protein isoform 1 (ADAL1) to prevent incorporation of N6-methyl-(d)ATP into DNA and RNA. This would hinder potential dysregulation of epigenetic control and RNA metabolism via conversion of N6-methyl-(d)ATP to N6-methyl-(d)AMP, followed by ADAL1 catalyzed deamination producing (d)IMP that can enter the nucleotide salvage pathway.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2020 The Authors. Article available under a Creative Commons license (https://creativecommons.org/licenses/by/4.0/) |
Keywords: | MutT homologue 1 (MTH1); N6-methyl-dATP; Nudix hydrolase 1 (NUDT1); X-ray crystallography; crystal structure; enzyme catalysis; enzyme kinetics; epigenetics; hydrolase; methylation; nucleoside/nucleotide metabolism; nucleotide hydrolysis; substrate specificity |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Medicine, Dentistry and Health (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 08 Apr 2020 06:51 |
Last Modified: | 25 Nov 2021 14:39 |
Status: | Published |
Publisher: | American Society for Biochemistry & Molecular Biology (ASBMB) |
Refereed: | Yes |
Identification Number: | 10.1074/jbc.ra120.012636 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:159273 |