Download MendeleyDomain C of human poly(ADP-ribose) polymerase-1 is important for enzyme activity and contains a novel zinc-ribbon motif.
Tao, Z., Gao, P., Hoffman, D.W., Liu, H.W.(2008) Biochemistry 47: 5804-5813
- PubMed: 18452307
- DOI: https://doi.org/10.1021/bi800018a
- Primary Citation of Related Structures:
2JVN - PubMed Abstract:
Poly(ADP-ribose) polymerase-1 (PARP-1) is a multimodular nuclear protein that participates in many fundamental cellular activities. Stimulated by binding to nicked DNA, PARP-1 catalyzes poly(ADP-ribosyl)ation of the acceptor proteins using NAD (+) as a substrate. In this work, NMR methods were used to determine the solution structure of human PARP-1 protein. Domain C was found to contain a zinc-binding motif of three antiparallel beta-strands with four conserved cysteines positioned to coordinate the metal ligand, in addition to a helical region. The zinc-binding motif is structurally reminiscent of the "zinc-ribbon" fold, but with a novel spacing between the conserved cysteines (CX2CX12CX 9C). Domain C alone does not appear to bind to DNA. Interestingly, domain C is essential for PARP-1 activity, since a mixture containing nicked DNA and the PARP-1 ABDEF domains has only basal enzymatic activity, while the addition of domain C to the mixture initiated NAD (+) hydrolysis and the formation of poly(ADP-ribose), as detected by an NMR-based assay and autoradiography. The structural model for domain C in solution provides an important framework for further studies aimed at improving our understanding of how the various domains within the complex PARP-1 enzyme play their respective roles in regulating the enzyme activity when cells are under conditions of genotoxic stress.
Organizational Affiliation:
Division of Medicinal Chemistry, College of Pharmacy, Department of Chemistry and Biochemistry, Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712, USA.
