Probing the substrate recognition mechanism of the human MTH1 protein by nucleotide analogs.

Hiroyuki Kamiya (1) , Hiroyuki Yakushiji (2) , Laurence Dugué (3) , Mitsuhide Tanimoto , Sylvie Pochet (3) , Yusaku Nakabeppu (4) , Hideyoshi Harashima (1)

1 Faculty of Pharmaceutical Sciences
2 Medical Institute of Bioregulation
3 Chimie Organique
4 Medical Institute of Bioregulation

To examine the substrate recognition mechanism of the human MTH1 protein, which hydrolyzes 2-hydroxy-dATP, 8-hydroxy-dATP, and 8-hydroxy-dGTP, ten nucleotide analogs (8-bromo-dATP, 8-bromo-dGTP, deoxyisoinosine triphosphate, 8-hydroxy-dITP, 2-aminopurine-deoxyriboside triphosphate, 2-amino-dATP, deoxyxanthosine triphosphate, deoxyoxanosine triphosphate, dITP, and dUTP) were incubated with the MTH1 protein. Of these, the former five nucleotides were hydrolyzed with various efficiencies. The fact that the syn-oriented brominated nucleotides were hydrolyzed suggests that the MTH1 protein binds to deoxynucleotides adopting the syn-conformation. However, 8-hydroxy-dITP, which lacks the 2-amino group of 8-hydroxy-dGTP, was degraded with tenfold less efficiency as compared with 8-hydroxy-dGTP. In addition, deoxyisoinosine triphosphate, lacking the 6-amino group of 2-hydroxy-dATP, was hydrolyzed as efficiently as 8-hydroxy-dGTP, but less efficiently than 2-hydroxy-dATP. These results clarify the effects of the anti/syn conformation and the functional groups on the 2 and 6 positions of the purine ring on the recognition by the human MTH1 protein.

Hiroyuki Kamiya, Hiroyuki Yakushiji, Laurence Dugué, Mitsuhide Tanimoto, Sylvie Pochet, et al.. Probing the substrate recognition mechanism of the human MTH1 protein by nucleotide analogs.. Journal of Molecular Biology, 2004, 336 (4), pp.843-50. ⟨10.1016/j.jmb.2003.12.060⟩. ⟨pasteur-00166618⟩