NAD+analog reveals PARP-1 substrate-blocking mechanism and allosteric communication from catalytic center to DNA-binding domains.
Langelier, M.F., Zandarashvili, L., Aguiar, P.M., Black, B.E., Pascal, J.M.(2018) Nat Commun 9: 844-844
- PubMed: 29487285 
- DOI: https://doi.org/10.1038/s41467-018-03234-8
- Primary Citation of Related Structures:  
6BHV - PubMed Abstract: 
PARP-1 cleaves NAD + and transfers the resulting ADP-ribose moiety onto target proteins and onto subsequent polymers of ADP-ribose. An allosteric network connects PARP-1 multi-domain detection of DNA damage to catalytic domain structural changes that relieve catalytic autoinhibition; however, the mechanism of autoinhibition is undefined. Here, we show using the non-hydrolyzable NAD + analog benzamide adenine dinucleotide (BAD) that PARP-1 autoinhibition results from a selective block on NAD + binding. Following DNA damage detection, BAD binding to the catalytic domain leads to changes in PARP-1 dynamics at distant DNA-binding surfaces, resulting in increased affinity for DNA damage, and providing direct evidence of reverse allostery. Our findings reveal a two-step mechanism to activate and to then stabilize PARP-1 on a DNA break, indicate that PARP-1 allostery influences persistence on DNA damage, and have important implications for PARP inhibitors that engage the NAD + binding site.
Organizational Affiliation: 
Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC, H3C 3J7, Canada.