| Structural highlights
Function
[8ODP_HUMAN] Antimutagenic. Acts as a sanitizing enzyme for oxidized nucleotide pools, thus suppressing cell dysfunction and death induced by oxidative stress. Hydrolyzes 8-oxo-dGTP, 8-oxo-dATP and 2-OH-dATP, thus preventing misincorporation of oxidized purine nucleoside triphosphates into DNA and subsequently preventing A:T to C:G and G:C to T:A transversions. Able to hydrolyze also the corresponding ribonucleotides, 2-OH-ATP, 8-oxo-GTP and 8-oxo-ATP.[1] [2] [3] [4] [5]
Publication Abstract from PubMed
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 subpocket 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.
MutT homologue 1 (MTH1) removes N6-methyl-dATP from the dNTP pool.,Scaletti ER, Vallin KS, Brautigam L, Sarno A, Warpman Berglund U, Helleday T, Stenmark P, Jemth AS J Biol Chem. 2020 Apr 10;295(15):4761-4772. doi: 10.1074/jbc.RA120.012636. Epub, 2020 Mar 6. PMID:32144205[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Fujikawa K, Kamiya H, Yakushiji H, Fujii Y, Nakabeppu Y, Kasai H. The oxidized forms of dATP are substrates for the human MutT homologue, the hMTH1 protein. J Biol Chem. 1999 Jun 25;274(26):18201-5. PMID:10373420
- ↑ Fujii Y, Shimokawa H, Sekiguchi M, Nakabeppu Y. Functional significance of the conserved residues for the 23-residue module among MTH1 and MutT family proteins. J Biol Chem. 1999 Dec 31;274(53):38251-9. PMID:10608900
- ↑ Fujikawa K, Kamiya H, Yakushiji H, Nakabeppu Y, Kasai H. Human MTH1 protein hydrolyzes the oxidized ribonucleotide, 2-hydroxy-ATP. Nucleic Acids Res. 2001 Jan 15;29(2):449-54. PMID:11139615
- ↑ Yoshimura D, Sakumi K, Ohno M, Sakai Y, Furuichi M, Iwai S, Nakabeppu Y. An oxidized purine nucleoside triphosphatase, MTH1, suppresses cell death caused by oxidative stress. J Biol Chem. 2003 Sep 26;278(39):37965-73. Epub 2003 Jul 10. PMID:12857738 doi:10.1074/jbc.M306201200
- ↑ Takagi Y, Setoyama D, Ito R, Kamiya H, Yamagata Y, Sekiguchi M. Human MTH3 (NUDT18) protein hydrolyzes oxidized forms of guanosine and deoxyguanosine diphosphates: comparison with MTH1 and MTH2. J Biol Chem. 2012 Jun 15;287(25):21541-9. doi: 10.1074/jbc.M112.363010. Epub 2012, May 3. PMID:22556419 doi:10.1074/jbc.M112.363010
- ↑ Scaletti ER, Vallin KS, Brautigam L, Sarno A, Warpman Berglund U, Helleday T, Stenmark P, Jemth AS. MutT homologue 1 (MTH1) removes N6-methyl-dATP from the dNTP pool. J Biol Chem. 2020 Apr 10;295(15):4761-4772. doi: 10.1074/jbc.RA120.012636. Epub, 2020 Mar 6. PMID:32144205 doi:http://dx.doi.org/10.1074/jbc.RA120.012636
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