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Interaction interface of human flap endonuclease-1 with its DNA substrates
Junzhuan Qiu1, Ren Liu, Brian R Chapados
1Department of Radiation Research, City of Hope National Medical Center and Beckman Research Institute, Duarte, California 91010, USA.
The Journal of Biological Chemistry
|March 24, 2004
Summary
Flap endonuclease-1 (FEN-1) interacts with DNA substrates via specific positively charged amino acid residues. This study maps these interactions, revealing how FEN-1 binds DNA during replication and repair.
Area of Science:
- Molecular Biology
- Biochemistry
- Structural Biology
Background:
- Flap endonuclease-1 (FEN-1) is a crucial enzyme for DNA replication, repair, and recombination.
- The precise molecular interactions between FEN-1 and its DNA substrates remain incompletely understood.
Purpose of the Study:
- To delineate the interaction boundaries between the FEN-1 protein and its DNA substrates.
- To identify specific amino acid residues and DNA regions involved in FEN-1-DNA binding.
Main Methods:
- Biochemical assays using modified flap DNA substrates.
- Analysis of binding-deficient point mutants of FEN-1.
- Integration of existing crystallographic data.
Main Results:
- Six clusters of conserved positively charged amino acid residues in FEN-1 directly contact DNA.
- Specific residues (Arg(47), Arg(70), Lys(326)-Arg(327)) interact with the upstream DNA duplex.
- Other residues (Lys(244)-Arg(245)) interact with the downstream DNA duplex, defining binding orientation.
- Arg(70) and Arg(47) were localized to specific nucleotide positions on the template strand.
Conclusions:
- A detailed model for human FEN-1 interaction with DNA substrates has been proposed.
- The identified interactions provide insights into FEN-1's role in DNA processing pathways.
- Understanding FEN-1 binding is key to its function in maintaining genome stability.