Human and E.coli excinucleases are affected differently by the sequence context of acetylaminofluorene-guanine adduct.
Synthetic DNA substrates containing an acetylaminofluorene (AAF) adduct at each of the three guanine in the G1G2CG3CC sequence were constructed and tested as substrates for reconstituted E.coli (A)BC excinuclease and human excinuclease in HeLa cell-free extract (CFE). The (A)BC excinulcease repaired the three substrates with relative efficiencies of G1:G2:G3 of 100:18:66 in agreement with an earlier report [Seeberg, E., and Fuchs, R.P.P. (1990) Proc. Natl Acad. Sci. USA 87, 191-194]. The same lesions were repaired by the human excinuclease with the strikingly different efficiencies of G1:G2:G3 as 38:100:68. These results reveal that the human excinuclease is affected by the sequence context of the lesion in a different manner than its prokaryotic counterpart.
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Department of Biochemistry and Biophysics, University of North Carolina, School of Medicine, Chapel Hill.
Bertrand-Burggraf
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Huang
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JC
Fuchs
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RP
Sancar
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Fuchs
B P
BP
D001483:Base Sequence; D018736:DNA Adducts / Q000737:chemistry / Q000235:genetics; D004260:DNA Repair / Q000235:genetics; D004706:Endodeoxyribonucleases / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology; D029968:Escherichia coli Proteins; D006147:Guanine / Q000737:chemistry; D006801:Humans; D008969:Molecular Sequence Data; D011089:Polydeoxyribonucleotides / Q000138:chemical synthesis / Q000235:genetics
D018736:DNA Adducts; D029968:Escherichia coli Proteins; D011089:Polydeoxyribonucleotides; D006147:Guanine; D004706:Endodeoxyribonucleases; C036385:endodeoxyribonuclease uvrABC