5-Hydroxypyrimidine deoxynucleoside triphosphates are more efficiently incorporated into DNA by exonuclease-free Klenow fragment than 8-oxopurine deoxynucleoside triphosphates.
Recent studies with 8-oxodeoxyguanosine triphosphate (8-oxodGTP) have suggested that incorporation of oxidized nucleotides from the precursor pool into DNA may have deleterious effects. Here we show that 5-hydroxydeoxycytosine triphosphate (5-OHdCTP) and 5-hydroxydeoxyuridine triphosphate (5-OHdUTP) are more efficient substrates than 8-oxodGTP for Escherichia coli DNA polymerase I Klenow fragment lacking proofreading activity, while 8-oxodeoxyadenosine triphosphate (8-oxodGTP, 5-OHdCTP can mispair with dA in DNA but with lower efficiency. Since the 5-hydroxypyrimidines are present in normal and oxidized cellular DNA in amounts similar to the 8-oxopurines, these data suggest that enzymatic mechanisms might exist for removing them from the DNA precursor pools.
Purmal
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AA
Department of Microbiology and Molecular Genetics, Markey Center for Molecular Genetics, University of Vermont, Burlington 05405.
Kow
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YW
Wallace
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SS
D001483:Base Sequence; D004247:DNA / Q000096:biosynthesis*; D004256:DNA Polymerase I / Q000378:metabolism*; D003838:Deoxyadenine Nucleotides / Q000378:metabolism; D003845:Deoxycytosine Nucleotides / Q000138:chemical synthesis / Q000378:metabolism*; D003848:Deoxyguanine Nucleotides / Q000138:chemical synthesis / Q000378:metabolism*; D003856:Deoxyuracil Nucleotides / Q000138:chemical synthesis / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D013698:Templates, Genetic
C089929:2'-deoxy-5-hydroxycytosine triphosphate; C089930:8-oxodeoxyadenosine triphosphate; D003838:Deoxyadenine Nucleotides; D003845:Deoxycytosine Nucleotides; D003848:Deoxyguanine Nucleotides; D003856:Deoxyuracil Nucleotides; C078206:8-oxodeoxyguanosine triphosphate; C089928:2'-deoxy-5-hydroxyuridine triphosphate; D004247:DNA; D004256:DNA Polymerase I