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.
Department of Molecular Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
D J
DJ
Hosfield
C D
CD
Mol
B
B
Shen
J A
JA
Tainer
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