ABC excinuclease incises both 5' and 3' to the CC-1065-DNA adduct and its incision activity is stimulated by DNA helicase II and DNA polymerase I.
CC-1065 is a large molecule that binds covalently to adenine residues of DNA in a sequence-specific manner and lies in the minor groove about four bases to the 5' side of the adducted residue. Using a reconstituted Escherichia coli nucleotide excision repair system, we have obtained data showing that the ABC excinuclease makes incisions both 5' and 3' to the CC-1065 adduct and that the incision activity is stimulated by the addition of helicase II and DNA polymerase I (and dNTPs). Our results with the CC-1065 adduct are consistent with the reported in vitro processing of other adducts (e.g., cisplatin, UV photoproducts) but do not agree with a recent study that reported anomalous processing of the CC-1065 adduct by ABC excinuclease and helicase II. Our results also imply that, in binding to damaged DNA, ABC excinuclease does not make important contacts in the minor groove four bases to the 5' side of the damaged residue.
Selby
C P
CP
Department of Biochemistry, University of North Carolina School of Medicine, Chapel Hill 27599-7260.
Sancar
A
A
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000903:Antibiotics, Antineoplastic; D001483:Base Sequence; D001665:Binding Sites; D004249:DNA Damage; D004265:DNA Helicases; D004256:DNA Polymerase I / Q000378:metabolism*; D004260:DNA Repair; D004269:DNA, Bacterial / Q000378:metabolism*; D004278:DNA, Superhelical / Q000378:metabolism; D000080890:Duocarmycins; D004706:Endodeoxyribonucleases / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D007211:Indoles; D007700:Kinetics; D007933:Leucomycins / Q000378:metabolism*; D008969:Molecular Sequence Data
D000903:Antibiotics, Antineoplastic; D004269:DNA, Bacterial; D004278:DNA, Superhelical; D000080890:Duocarmycins; D029968:Escherichia coli Proteins; D007211:Indoles; D007933:Leucomycins; C018782:CC 1065; D004256:DNA Polymerase I; D004706:Endodeoxyribonucleases; C036385:endodeoxyribonuclease uvrABC; D000251:Adenosine Triphosphatases; D004265:DNA Helicases