Structure of the DNA repair and replication endonuclease and exonuclease FEN-1: coupling DNA and PCNA binding to FEN-1 activity.
Flap endonuclease (FEN-1) removes 5' overhanging flaps in DNA repair and processes the 5' ends of Okazaki fragments in lagging strand DNA synthesis. The crystal structure of Pyrococcus furiosus FEN-1, active-site metal ions, and mutational information indicate interactions for the single- and double-stranded portions of the flap DNA substrate and identify an unusual DNA-binding motif. The enzyme's active-site structure suggests that DNA binding induces FEN-1 to clamp onto the cleavage junction to form the productive complex. The conserved FEN-1 C terminus binds proliferating cell nuclear antigen (PCNA) and positions FEN-1 to act primarily as an exonuclease in DNA replication, in contrast to its endonuclease activity in DNA repair. FEN-1 mutations altering PCNA binding should reduce activity during replication, likely causing DNA repeat expansions as seen in some cancers and genetic diseases.
Hosfield
D J
DJ
Department of Molecular Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
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Shen
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Tainer
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D000595:Amino Acid Sequence; D001665:Binding Sites; D002384:Catalysis; D004247:DNA / Q000378:metabolism; D004260:DNA Repair; D004261:DNA Replication; D004706:Endodeoxyribonucleases / Q000737:chemistry* / Q000378:metabolism; D004720:Endonucleases / Q000737:chemistry / Q000378:metabolism; D043211:Exodeoxyribonuclease V; D005090:Exodeoxyribonucleases / Q000737:chemistry; D005092:Exonucleases / Q000737:chemistry / Q000378:metabolism; D045585:Flap Endonucleases; D007477:Ions; D008274:Magnesium; D008969:Molecular Sequence Data; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D011487:Protein Conformation; D020027:Pyrococcus furiosus / Q000201:enzymology
D007477:Ions; D018809:Proliferating Cell Nuclear Antigen; D004247:DNA; D004706:Endodeoxyribonucleases; D004720:Endonucleases; D005090:Exodeoxyribonucleases; D005092:Exonucleases; D045585:Flap Endonucleases; D043211:Exodeoxyribonuclease V; D008274:Magnesium