A molecular basis for the selective recognition of 2-hydroxy-dATP and 8-oxo-dGTP by human MTH1.
MTH1 hydrolyzes oxidized purine nucleoside triphosphates such as 8-oxo-dGTP, 8-oxo-dATP, 2-hydroxy-dATP, and 2-hydroxy rATP to monophosphates, and thus avoids errors caused by their misincorporation during DNA replication or transcription, which may result in carcinogenesis or neurodegeneration. This substrate specificity for oxidized purine nucleoside triphosphates was investigated by mutation analyses based on the sequence comparison with the Escherichia coli homolog, MutT, which hydrolyzes only 8-oxo-dGTP and 8-oxo-rGTP but not oxidized forms of dATP or ATP. Neither a replacement of the phosphohydrolase module of MTH1 with that of MutT nor deletions of the C-terminal region of MTH1, which is unique for MTH1, altered the substrate specificity of MTH1. In contrast, the substitution of residues at position Trp-117 and Asp-119 of MTH1, which showed apparent chemical shift perturbations with 8-oxo-dGDP in NMR analyses but are not conserved in MutT, affected the substrate specificity. Trp-117 is essential for MTH1 to recognize both 8-oxo-dGTP and 2-hydroxy-dATP, whereas Asp-119 is only essential for recognizing 2-hydroxy-dATP, thus suggesting that origins of the substrate-binding pockets for MTH1 and MutT are different.
Sakai
Yasunari
Y
Division of Neurofunctional Genomics, Medical Institute of Bioregulation, Kyushu University and CREST, Japan Science and Technology Corporation, Fukuoka 812-8582, Japan.
Furuichi
Masato
M
Takahashi
Masayuki
M
Mishima
Masaki
M
Iwai
Shigenori
S
Shirakawa
Masahiro
M
Nakabeppu
Yusaku
Y
D048868:Adaptor Proteins, Signal Transducing; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000378:metabolism*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism; D001665:Binding Sites; D015153:Blotting, Western; D018076:DNA, Complementary / Q000378:metabolism; D003848:Deoxyguanine Nucleotides / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins; D005656:Fungal Proteins / Q000737:chemistry* / Q000378:metabolism*; D017353:Gene Deletion; D005822:Genetic Vectors; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008565:Membrane Proteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009153:Mutagens; D009154:Mutation; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011755:Pyrophosphatases; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013696:Temperature; D013997:Time Factors
D048868:Adaptor Proteins, Signal Transducing; D001426:Bacterial Proteins; D018076:DNA, Complementary; D003848:Deoxyguanine Nucleotides; D029968:Escherichia coli Proteins; D005656:Fungal Proteins; C118806:MTH1 protein, S cerevisiae; D008565:Membrane Proteins; D009153:Mutagens; D029701:Saccharomyces cerevisiae Proteins; C078206:8-oxodeoxyguanosine triphosphate; C051607:8-hydroxyadenosine 5'-triphosphate; D000255:Adenosine Triphosphate; D010744:Phosphoric Monoester Hydrolases; D011755:Pyrophosphatases; C052211:mutT protein, E coli