Probing the substrate recognition mechanism of the human MTH1 protein by nucleotide analogs.
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.
Kamiya
Hiroyuki
H
Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan. hirokam@pharm.hokudai.ac.jp
Yakushiji
Hiroyuki
H
Dugué
Laurence
L
Tanimoto
Mitsuhide
M
Pochet
Sylvie
S
Nakabeppu
Yusaku
Y
Harashima
Hideyoshi
H
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D045643:DNA Repair Enzymes; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D015394:Molecular Structure; D010744:Phosphoric Monoester Hydrolases / Q000737:chemistry* / Q000378:metabolism*; D013379:Substrate Specificity
D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D010744:Phosphoric Monoester Hydrolases; C078207:8-oxodGTPase; D045643:DNA Repair Enzymes