| Popis: |
Flap endonuclease 1 (FEN1) plays important roles in DNA replication, repair and recombination. Herein, we report biochemical characteristics and catalytic mechanism of a novel FEN1 from the hyperthermophilic euryarchaeon Thermococcus barophilus Ch5 (Tb-FEN1). As expected, the recombinant Tb-FEN1 can cleave 5'-flap DNA. However, the enzyme has no activity on cleaving pseudo Y DNA, which sharply contrasts with other archaeal and eukaryotic FEN1 homologs. Tb-FEN1 retains 24% relative activity after heating at 100 °C for 20 min, demonstrating that it is the most thermostable among all reported FEN1 proteins. The enzyme displays maximal activity in a wide range of pH from 7.0 to 9.5. The Tb-FEN1 activity is dependent on a divalent metal ion, among which Mg |
Full Text from ScienceDirect