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Open complex formation around a lesion during nucleotide excision repair provides a structure for cleavage by human XPG protein
Author(s) -
Evans Elizabeth,
Fellows Jane,
Coffer Arnold,
Wood Richard D.
Publication year - 1997
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/16.3.625
Subject(s) - nucleotide excision repair , biology , dna repair , nuclease , dna , dna damage , nucleotide , dna footprinting , microbiology and biotechnology , biochemistry , dna binding protein , gene , transcription factor
Human XPG nuclease makes the 3′ incision during nucleotide excision repair of DNA. The enzyme cleaves model DNA bubble structures specifically near the junction of unpaired DNA with a duplex region. It is not yet known, however, whether an unpaired structure is an intermediate during actual DNA repair. We find here that XPG requires opening of >5 bp for efficient cleavage. To seek direct evidence for formation of an open structure around a lesion in DNA during a nucleotide excision repair reaction in vitro , KMnO 4 footprinting experiments were performed on a damaged DNA molecule bearing a uniquely placed cisplatin adduct. An unwound open complex spanning ∼25 nucleotides was observed that extended to the positions of 5′ and 3′ incision sites and was dependent on XPA protein and on ATP. Opening during repair occurred prior to strand incision by XPG.