A conserved loop-wedge motif moderates reaction site search and recognition by FEN1
| Autor: | Mark J. Thompson, Barbara Ciani, Jane A. Grasby, Victoria J. B. Gotham |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
DNA Replication Models Molecular DNA Repair Base pair DNA repair Flap Endonucleases Protein Conformation Flap structure-specific endonuclease 1 Substrate Specificity 03 medical and health sciences chemistry.chemical_compound Protein structure Catalytic Domain Genetics Humans Amino Acid Sequence Binding Sites biology Sequence Homology Amino Acid Nucleic Acid Enzymes DNA replication Active site DNA 030104 developmental biology chemistry Duplex (building) Mutation biology.protein Biophysics Nucleic Acid Conformation Protein Binding |
| Zdroj: | Nucleic Acids Research |
| ISSN: | 1362-4962 |
| Popis: | DNA replication and repair frequently involve intermediate two-way junction structures with overhangs, or flaps, that must be promptly removed; a task performed by the essential enzyme flap endonuclease 1 (FEN1). We demonstrate a functional relationship between two intrinsically disordered regions of the FEN1 protein, which recognize opposing sides of the junction and order in response to the requisite substrate. Our results inform a model in which short-range translocation of FEN1 on DNA facilitates search for the annealed 3′-terminus of a primer strand, which is recognized by breaking the terminal base pair to generate a substrate with a single nucleotide 3′-flap. This recognition event allosterically signals hydrolytic removal of the 5′-flap through reaction in the opposing junction duplex, by controlling access of the scissile phosphate diester to the active site. The recognition process relies on a highly-conserved ‘wedge’ residue located on a mobile loop that orders to bind the newly-unpaired base. The unanticipated ‘loop–wedge’ mechanism exerts control over substrate selection, rate of reaction and reaction site precision, and shares features with other enzymes that recognize irregular DNA structures. These new findings reveal how FEN1 precisely couples 3′-flap verification to function. |
| Databáze: | OpenAIRE |
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