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Dynamics of the HD regulatory subdomain of PARP-1; substrate access and allostery in PARP activation and inhibition

DOI: 10.1093/nar/gkab020 DOI Help

Authors: Tom E. H. Ogden (MRC Laboratory of Molecular Biology) , Ji-chun Yang (MRC Laboratory of Molecular Biology) , Marianne Schimpl (AstraZeneca) , Laura E. Easton (MRC Laboratory of Molecular Biology) , Elizabeth Underwood (AstraZeneca) , Philip b. Rawlins (AstraZeneca) , Michael m Mccauley (Thomas Jefferson University) , Marie-france Langelier (Université de Montréal) , John m. Pascal (Université de Montréal) , Kevin j. Embrey (AstraZeneca) , David Neuhaus (MRC Laboratory of Molecular Biology)
Co-authored by industrial partner: Yes

Type: Journal Paper
Journal: Nucleic Acids Research , VOL 25

State: Published (Approved)
Published: January 2021
Diamond Proposal Number(s): 17180 , 20015

Open Access Open Access

Abstract: PARP-1 is a key early responder to DNA damage in eukaryotic cells. An allosteric mechanism links initial sensing of DNA single-strand breaks by PARP-1’s F1 and F2 domains via a process of further domain assembly to activation of the catalytic domain (CAT); synthesis and attachment of poly(ADP-ribose) (PAR) chains to protein sidechains then signals for assembly of DNA repair components. A key component in transmission of the allosteric signal is the HD subdomain of CAT, which alone bridges between the assembled DNA-binding domains and the active site in the ART subdomain of CAT. Here we present a study of isolated CAT domain from human PARP-1, using NMR-based dynamics experiments to analyse WT apo-protein as well as a set of inhibitor complexes (with veliparib, olaparib, talazoparib and EB-47) and point mutants (L713F, L765A and L765F), together with new crystal structures of the free CAT domain and inhibitor complexes. Variations in both dynamics and structures amongst these species point to a model for full-length PARP-1 activation where first DNA binding and then substrate interaction successively destabilise the folded structure of the HD subdomain to the point where its steric blockade of the active site is released and PAR synthesis can proceed.

Subject Areas: Biology and Bio-materials, Chemistry

Instruments: I03-Macromolecular Crystallography , I04-Macromolecular Crystallography


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