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Ligand binding characteristics of the Ku80 von Willebrand domain
- Source :
- DNA Repair (Amst)
- Publication Year :
- 2019
-
Abstract
- The N-terminal von Willebrand domain of Ku80 supports interactions with a Ku binding motif (KBM) that has been identified in at least three other DNA repair proteins: the non-homologous end joining (NHEJ) scaffold APLF, the modulator of retrovirus infection, MRI, and the Werner syndrome protein (WRN). A second, more recently identified Ku binding motif present in XLF and several other proteins (KBMX) has also been reported to interact with this domain. The isolated Ku80 von Willebrand antigen domain (vWA) from Xenopus laevis has a sequence that is 60% identical with the human domain, is readily expressed and has been used to investigate these interactions. Structural characterization of the complexes formed with the KBM motifs in human APLF, MRI, and WRN identify a conserved binding site that is consistent with previously-reported mutational studies. In contrast with the KBM binding site, structural studies indicate that the KBMX site is occluded by a distorted helix. Fluorescence polarization and 19F NMR studies of a fluorinated XLF C-terminal peptide failed to indicate any interaction with the frog vWA. It was hypothesized that availability of this binding site is conditional, i.e., dependent on specific experimental conditions or other repair factors to make the site available for binding. Modulating the fraction of KBMX-accessible binding site mutationally demonstrated that the more open site is capable of binding the KBMXXLF motif peptide. It is suggested that the conditional nature of KBMX binding limits formation of non-productive complexes so that activation-dependent site availability can more optimally support advancing the synapsis process.
- Subjects :
- Models, Molecular
Ku80
Werner Syndrome Helicase
DNA repair
Protein Conformation
Xenopus
Peptide
Xenopus Proteins
Ligands
Biochemistry
Article
03 medical and health sciences
Xenopus laevis
0302 clinical medicine
Retrovirus
Protein Domains
DNA-(Apurinic or Apyrimidinic Site) Lyase
Animals
Binding site
Poly-ADP-Ribose Binding Proteins
Molecular Biology
Ku Autoantigen
Conserved Sequence
030304 developmental biology
chemistry.chemical_classification
0303 health sciences
Binding Sites
biology
Synapsis
Cell Biology
biology.organism_classification
Cell biology
chemistry
030220 oncology & carcinogenesis
Fluorescence anisotropy
Protein Binding
Subjects
Details
- ISSN :
- 15687856
- Volume :
- 85
- Database :
- OpenAIRE
- Journal :
- DNA repair
- Accession number :
- edsair.doi.dedup.....b4e8543c94b29b7736e8a469cb12885b