Dual hydrolysis of diphosphate and triphosphate derivatives of oxidized deoxyadenosine by Orf17 (NtpA), a MutT-type enzyme.
To determine whether the Orf17 (NtpA) protein of Escherichia coli, a MutT-type enzyme, functions as a hydrolyzing enzyme for a damaged deoxyribonucleotide, we purified the recombinant Orf17 protein and incubated it with oxidized deoxyribonucleotides. Of the deoxyribonucleoside 5'-triphosphates tested, 8-hydroxy-2'-deoxyadenosine 5'-triphosphate was hydrolyzed by this protein. Unexpectedly, the Orf17 protein degraded 8-hydroxy-2'-deoxyadenosine 5'-diphosphate 2.3-fold more efficiently than the corresponding triphosphate. Thus, this protein is the first MutT-type enzyme that hydrolyzes both the triphosphate and diphosphate derivatives of a deoxyribonucleoside, with similar efficiencies. These results suggest that the Orf17 protein may be involved in the hydrolysis of oxidized dATP and dADP.
Hori
Mika
M
Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan.
Fujikawa
Katsuyoshi
K
Kasai
Hiroshi
H
Harashima
Hideyoshi
H
Kamiya
Hiroyuki
H
D003001:Cloning, Molecular; D017931:DNA Primers; D003839:Deoxyadenosines / Q000378:metabolism*; D003854:Deoxyribonucleotides / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D006868:Hydrolysis; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism*; D011755:Pyrophosphatases; D017422:Sequence Analysis, DNA
D017931:DNA Primers; D003839:Deoxyadenosines; D003854:Deoxyribonucleotides; D029968:Escherichia coli Proteins; D010744:Phosphoric Monoester Hydrolases; D011755:Pyrophosphatases; C052211:mutT protein, E coli