Database of articles cited by EMDB/PDB/SASBDB data

Keywords
Structure methods	All X-ray diffraction NMR electron microscopy small angle scattering neutron diffraction fiber diffraction powder diffraction infrared spectroscopy EPR fluorescence transfer theoretical model Hybrid
Author
Journal
IF	>30 >20 >10 >5 all

Title	Bridging of DNA breaks activates PARP2-HPF1 to modify chromatin.
Journal, issue, pages	Nature, Vol. 585, Issue 7826, Page 609-613, Year 2020
Publish date	Sep 16, 2020
Authors	Silvija Bilokapic / Marcin J Suskiewicz / Ivan Ahel / Mario Halic /
PubMed Abstract	Breaks in DNA strands recruit the protein PARP1 and its paralogue PARP2 to modify histones and other substrates through the addition of mono- and poly(ADP-ribose) (PAR). In the DNA damage responses, ...Breaks in DNA strands recruit the protein PARP1 and its paralogue PARP2 to modify histones and other substrates through the addition of mono- and poly(ADP-ribose) (PAR). In the DNA damage responses, this post-translational modification occurs predominantly on serine residues and requires HPF1, an accessory factor that switches the amino acid specificity of PARP1 and PARP2 from aspartate or glutamate to serine. Poly(ADP) ribosylation (PARylation) is important for subsequent chromatin decompaction and provides an anchor for the recruitment of downstream signalling and repair factors to the sites of DNA breaks. Here, to understand the molecular mechanism by which PARP enzymes recognize DNA breaks within chromatin, we determined the cryo-electron-microscopic structure of human PARP2-HPF1 bound to a nucleosome. This showed that PARP2-HPF1 bridges two nucleosomes, with the broken DNA aligned in a position suitable for ligation, revealing the initial step in the repair of double-strand DNA breaks. The bridging induces structural changes in PARP2 that signal the recognition of a DNA break to the catalytic domain, which licenses HPF1 binding and PARP2 activation. Our data suggest that active PARP2 cycles through different conformational states to exchange NAD and substrate, which may enable PARP enzymes to act processively while bound to chromatin. The processes of PARP activation and the PARP catalytic cycle we describe can explain mechanisms of resistance to PARP inhibitors and will aid the development of better inhibitors as cancer treatments.
External links	Nature / PubMed:32939087 / PubMed Central
Methods	EM (single particle)
Resolution	2.2 - 10.0 Å
Structure data	21970 6wz5 EMDB-21970, PDB-6wz5: Bridging of double-strand DNA break activates PARP2/HPF1 to modify chromatin Method: EM (single particle) / Resolution: 2.2 Å 21971 6wz9 EMDB-21971, PDB-6wz9: Bridging of double-strand DNA break activates PARP2/HPF1 to modify chromatin Method: EM (single particle) / Resolution: 2.8 Å 21978 6x0l EMDB-21978, PDB-6x0l: Bridging of double-strand DNA break activates PARP2/HPF1 to modify chromatin Method: EM (single particle) / Resolution: 3.9 Å 21979 6x0m EMDB-21979, PDB-6x0m: Bridging of double-strand DNA break activates PARP2/HPF1 to modify chromatin Method: EM (single particle) / Resolution: 6.3 Å 21980 6x0n EMDB-21980, PDB-6x0n: Bridging of double-strand DNA break activates PARP2/HPF1 to modify chromatin Method: EM (single particle) / Resolution: 10.0 Å EMDB-21981: PARP2/HPF1_Nucleosome complex Method: EM (single particle) / Resolution: 6.6 Å EMDB-21982: PARP2/HPF1_Nucleosome complex Method: EM (single particle) / Resolution: 6.3 Å
Source	xenopus laevis (African clawed frog) synthetic construct (others) homo sapiens (human) African clawed frog (African clawed frog)
Keywords	GENE REGULATION / DNA repair / PARP1 / PARP2 / HPF1 / ADP-ribosylation / chromatin / histone modifications