Download MendeleyPARP1 exhibits enhanced association and catalytic efficiency with gamma H2A.X-nucleosome.
Sharma, D., De Falco, L., Padavattan, S., Rao, C., Geifman-Shochat, S., Liu, C.F., Davey, C.A.(2019) Nat Commun 10: 5751-5751
- PubMed: 31848352
- DOI: https://doi.org/10.1038/s41467-019-13641-0
- Primary Citation of Related Structures:
6IPU, 6JXD, 6K1I, 6K1J, 6K1K - PubMed Abstract:
The poly(ADP-ribose) polymerase, PARP1, plays a key role in maintaining genomic integrity by detecting DNA damage and mediating repair. γH2A.X is the primary histone marker for DNA double-strand breaks and PARP1 localizes to H2A.X-enriched chromatin damage sites, but the basis for this association is not clear. We characterize the kinetics of PARP1 binding to a variety of nucleosomes harbouring DNA double-strand breaks, which reveal that PARP1 associates faster with (γ)H2A.X- versus H2A-nucleosomes, resulting in a higher affinity for the former, which is maximal for γH2A.X-nucleosome that is also the activator eliciting the greatest poly-ADP-ribosylation catalytic efficiency. The enhanced activities with γH2A.X-nucleosome coincide with increased accessibility of the DNA termini resulting from the H2A.X-Ser139 phosphorylation. Indeed, H2A- and (γ)H2A.X-nucleosomes have distinct stability characteristics, which are rationalized by mutational analysis and (γ)H2A.X-nucleosome core crystal structures. This suggests that the γH2A.X epigenetic marker directly facilitates DNA repair by stabilizing PARP1 association and promoting catalysis.
Organizational Affiliation:
School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore.
