Structure of Human MTH1, a Nudix Family Hydrolase That Selectively Degrades Oxidized Purine Nucleoside Triphosphates
| Autor: | Yuriko Yamagata, Yusaku Nakabeppu, Yasunari Sakai, Masaki Mishima, Shigenori Iwai, Masayuki Takahashi, Noriyuki Itoh, Masahiro Shirakawa, Masato Furuichi, Hiroyuki Kamiya |
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| Rok vydání: | 2004 |
| Předmět: |
Models
Molecular Purine Protein Folding Magnetic Resonance Spectroscopy Molecular Sequence Data Biology medicine.disease_cause Biochemistry Protein Structure Secondary Substrate Specificity chemistry.chemical_compound Hydrolase Escherichia coli medicine Nucleophilic substitution Humans Nucleotide Amino Acid Sequence Pyrophosphatases Purine Nucleotides Molecular Biology Conserved Sequence chemistry.chemical_classification Binding Sites Molecular Structure Escherichia coli Proteins Hydrolysis Deoxyguanine Nucleotides Hydrogen Bonding Cell Biology Nuclear magnetic resonance spectroscopy Phosphoric Monoester Hydrolases Recombinant Proteins DNA Repair Enzymes chemistry Heteronuclear molecule Mutation Asparagine Oxidation-Reduction Sequence Alignment Nucleoside |
| Zdroj: | Journal of Biological Chemistry. 279:33806-33815 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m402393200 |
| Popis: | Oxygen radicals generated through normal cellular respiration processes can cause mutations in genomic and mitochondrial DNA. Human MTH1 hydrolyzes oxidized purine nucleoside triphosphates, such as 8-oxo-dGTP and 2-hydroxy-dATP, to monophosphates, thereby preventing the misincorporation of these oxidized nucleotides during replication. Here we present the solution structure of MTH1 solved by multidimensional heteronuclear NMR spectroscopy. The protein adopts a fold similar to that of Escherichia coli MutT, despite the low sequence similarity between these proteins outside the conserved Nudix motif. The substrate-binding pocket of MTH1, deduced from chemical shift perturbation experiments, is located at essentially the same position as in MutT; however, a pocket-forming helix is largely displaced in MTH1 (approximately 9 A) such that the shape of the pocket differs between the two proteins. Detailed analysis of the pocket-forming residues enabled us to identify Asn33 as one of the key residues in MTH1 for discriminating the oxidized form of purine, and mutation of this residue modifies the substrate specificity. We also show that MTH1 catalyzes hydrolysis of 8-oxo-dGTP through nucleophilic substitution of water at the beta-phosphate. |
| Databáze: | OpenAIRE |
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