Junction resolving enzymes use multivalency to keep the Holliday junction dynamic

Nat Chem Biol. 2019 Mar;15(3):269-275. doi: 10.1038/s41589-018-0209-y. Epub 2019 Jan 21.


Holliday junction (HJ) resolution by resolving enzymes is essential for chromosome segregation and recombination-mediated DNA repair. HJs undergo two types of structural dynamics that determine the outcome of recombination: conformer exchange between two isoforms and branch migration. However, it is unknown how the preferred branch point and conformer are achieved between enzyme binding and HJ resolution given the extensive binding interactions seen in static crystal structures. Single-molecule fluorescence resonance energy transfer analysis of resolving enzymes from bacteriophages (T7 endonuclease I), bacteria (RuvC), fungi (GEN1) and humans (hMus81-Eme1) showed that both types of HJ dynamics still occur after enzyme binding. These dimeric enzymes use their multivalent interactions to achieve this, going through a partially dissociated intermediate in which the HJ undergoes nearly unencumbered dynamics. This evolutionarily conserved property of HJ resolving enzymes provides previously unappreciated insight on how junction resolution, conformer exchange and branch migration may be coordinated.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Arabidopsis Proteins
  • Chromosome Segregation / genetics
  • DNA Repair / physiology
  • DNA, Cruciform / metabolism*
  • DNA, Cruciform / physiology*
  • DNA-Binding Proteins / physiology
  • Deoxyribonuclease I
  • Endodeoxyribonucleases
  • Endonucleases
  • Escherichia coli Proteins
  • Fluorescence Resonance Energy Transfer / methods
  • Holliday Junction Resolvases / metabolism*
  • Holliday Junction Resolvases / physiology
  • Humans
  • Protein Binding
  • Recombination, Genetic / genetics
  • Single Molecule Imaging / methods
  • Substrate Specificity


  • Arabidopsis Proteins
  • DNA, Cruciform
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • ruvC protein, E coli
  • Endodeoxyribonucleases
  • Endonucleases
  • MUS81 protein, human
  • Holliday Junction Resolvases
  • XPG-like endonuclease 1, Arabidopsis
  • Deoxyribonuclease I