title: Crystal structure of the catalytic core of Rad2: insights into the mechanism of substrate binding.
abstract: Rad2/XPG belongs to the flap nuclease family and is responsible for a key step of the eukaryotic nucleotide excision DNA repair (NER) pathway. To elucidate the mechanism of DNA binding by Rad2/XPG, we solved crystal structures of the catalytic core of Rad2 in complex with a substrate. Rad2 utilizes three structural modules for recognition of the double-stranded portion of DNA substrate, particularly a Rad2-specific α-helix for binding the cleaved strand. The protein does not specifically recognize the single-stranded portion of the nucleic acid. Our data suggest that in contrast to related enzymes (FEN1 and EXO1), the Rad2 active site may be more accessible, which would create an exit route for substrates without a free 5' end.
authors.affiliation: Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw 02-109, Poland.
authors.forename: Michał
authors.initials: M
authors.lastname: Miętus
authors.affiliation: Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw 02-109, Poland.
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Nowak
authors.affiliation: Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw 02-109, Poland.
authors.forename: Marcin
authors.initials: M
authors.lastname: Jaciuk
authors.affiliation: Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw 02-109, Poland.
authors.forename: Paweł
authors.initials: P
authors.lastname: Kustosz
authors.affiliation: Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw 02-109, Poland.
authors.forename: Justyna
authors.initials: J
authors.lastname: Studnicka
authors.affiliation: Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw 02-109, Poland mnowotny@iimcb.gov.pl.
authors.forename: Marcin
authors.initials: M
authors.lastname: Nowotny
mesh_terms: D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004706:Endodeoxyribonucleases / Q000737:chemistry* / Q000378:metabolism; D004720:Endonucleases / Q000235:genetics; D005090:Exodeoxyribonucleases / Q000737:chemistry; D045585:Flap Endonucleases / Q000737:chemistry; D008958:Models, Molecular; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics; D011485:Protein Binding; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics; D000099250:DNA Excision Repair Protein ERCC-5
chemical_list: D004247:DNA; D004268:DNA-Binding Proteins; D004706:Endodeoxyribonucleases; D004720:Endonucleases; D005090:Exodeoxyribonucleases; D045585:Flap Endonucleases; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D000099250:DNA Excision Repair Protein ERCC-5; C073998:RAD2 protein, S cerevisiae; C028450:exodeoxyribonuclease I