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Mol Cell. 2015 Dec 3;60(5):755-768. doi: 10.1016/j.molcel.2015.10.013. Epub 2015 Nov 25.

PARP-1 Activation Requires Local Unfolding of an Autoinhibitory Domain.

Author information

1
Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6059, USA.
2
Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107-5544, USA.
3
Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6059, USA; Graduate Program in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6059, USA.
4
Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6059, USA; Graduate Program in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6059, USA. Electronic address: blackbe@mail.med.upenn.edu.
5
Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107-5544, USA. Electronic address: john.pascal@umontreal.ca.

Abstract

Poly(ADP-ribose) polymerase-1 (PARP-1) creates the posttranslational modification PAR from substrate NAD(+) to regulate multiple cellular processes. DNA breaks sharply elevate PARP-1 catalytic activity to mount a cell survival repair response, whereas persistent PARP-1 hyperactivation during severe genotoxic stress is associated with cell death. The mechanism for tight control of the robust catalytic potential of PARP-1 remains unclear. By monitoring PARP-1 dynamics using hydrogen/deuterium exchange-mass spectrometry (HXMS), we unexpectedly find that a specific portion of the helical subdomain (HD) of the catalytic domain rapidly unfolds when PARP-1 encounters a DNA break. Together with biochemical and crystallographic analysis of HD deletion mutants, we show that the HD is an autoinhibitory domain that blocks productive NAD(+) binding. Our molecular model explains how PARP-1 DNA damage detection leads to local unfolding of the HD that relieves autoinhibition, and has important implications for the design of PARP inhibitors.

PMID:
26626480
PMCID:
PMC4712911
DOI:
10.1016/j.molcel.2015.10.013
[Indexed for MEDLINE]
Free PMC Article

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