Resolution of the Holliday junction recombination intermediate by human GEN1 at the single-molecule level
| Autor: | Masateru Takahashi, Samir M. Hamdan, Muhammad Tehseen, Amer Bralic, Fahad Rashid, Vlad-Stefan Raducanu, Manal S. Zaher, Mohamed Abdelmaboud Sobhy |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Nuclear Envelope
Dimer Biology Cleavage (embryo) 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Genetics Holliday junction Molecule Humans Homologous Recombination 030304 developmental biology Recombination Genetic 0303 health sciences DNA Cruciform Endodeoxyribonucleases Nucleic Acid Enzymes Holliday Junction Resolvases Monomer Förster resonance energy transfer chemistry Biophysics Homologous recombination Dimerization 030217 neurology & neurosurgery Recombination |
| Zdroj: | Nucleic Acids Research |
| ISSN: | 1362-4962 |
| Popis: | Human GEN1 is a cytosolic homologous recombination protein that resolves persisting four-way Holliday junctions (HJ) after the dissolution of the nuclear membrane. GEN1 dimerization has been suggested to play key role in the resolution of the HJ, but the kinetic details of its reaction remained elusive. Here, single-molecule FRET shows how human GEN1 binds the HJ and always ensures its resolution within the lifetime of the GEN1-HJ complex. GEN1 monomer generally follows the isomer bias of the HJ in its initial binding and subsequently distorts it for catalysis. GEN1 monomer remains tightly bound with no apparent dissociation until GEN1 dimer is formed and the HJ is fully resolved. Fast on- and slow off-rates of GEN1 dimer and its increased affinity to the singly-cleaved HJ enforce the forward reaction. Furthermore, GEN1 monomer binds singly-cleaved HJ tighter than intact HJ providing a fail-safe mechanism if GEN1 dimer or one of its monomers dissociates after the first cleavage. The tight binding of GEN1 monomer to intact- and singly-cleaved HJ empowers it as the last resort to process HJs that escape the primary mechanisms. |
| Databáze: | OpenAIRE |
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