1. The BRCT domain of PARP1 binds intact DNA and mediates intrastrand transfer
- Author
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Annette H. Erbse, Pamela N. Dyer, Genevieve H.L. Roberts, Jyothi Mahadevan, Karolin Luger, Uma M. Muthurajan, Johannes Rudolph, and Megan Palacio
- Subjects
Models, Molecular ,DNA repair ,DNA damage ,Poly ADP ribose polymerase ,Poly (ADP-Ribose) Polymerase-1 ,Article ,Mice ,chemistry.chemical_compound ,Animals ,Humans ,Nucleosome ,Protein Interaction Domains and Motifs ,Molecular Biology ,Cells, Cultured ,Polymerase ,biology ,DNA ,Cell Biology ,Fibroblasts ,Nucleosomes ,Chromatin ,BRCT domain ,chemistry ,Mutation ,Biophysics ,biology.protein ,Nucleic Acid Conformation ,DNA Damage ,Protein Binding - Abstract
Poly(ADP-ribose) polymerase 1 (PARP1) is a key player in the response to DNA damage and is the target of four different clinical inhibitors used for the treatment of cancers. Binding of PARP1 to damaged DNA leads to activation via destabilization of a subdomain of the catalytic domain, and activated PARP1 utilizes NAD+ to add chains of poly(ADP-ribose) onto itself and other nuclear proteins. PARP1 also binds abundantly to intact DNA and chromatin, where it remains enzymatically inactive. Here we show that intact DNA makes contacts with the BRCT domain, which was not previously recognized as a DNA-binding domain. This binding mode does not result in the concomitant reorganization and activation of the catalytic domain. We visualize the BRCT domain bound to nucleosomal DNA by cryogenic electron microscopy (cryoEM) and identify a key motif conserved from ancestral BRCT domains for binding phosphates on DNA and phospho-peptides. Finally, we demonstrate that the DNA-binding properties of the BRCT domain contribute to the ‘monkey-bar mechanism’ that mediates transfer of PARP1 from one DNA segment to another.
- Published
- 2021