Alternative Modes of Binding of Poly(ADP-ribose) Polymerase 1 to Free DNA and Nucleosomes

作者：Nicholas Clark, Michael J. Kramer, Uma M. Muthurajan, Karolin Luger · 发表于：Journal of Biological Chemistry · 年份：2012 · DOI：10.1074/jbc.m112.397067 · 被引用次数：100 · 研究领域：PARP inhibition in cancer therapy、DNA Repair Mechanisms、Integrated Circuits and Semiconductor Failure Analysis

Poly(ADP-ribose) polymerase 1 (PARP-1) is an abundant nuclear protein that binds chromatin and catalyzes the transfer of ADP-ribose groups to itself and to numerous target proteins upon interacting with damaged DNA. The molecular basis for the dual role of PARP-1 as a chromatin architectural protein and a first responder in DNA repair pathways remains unclear. Here, we quantified the interactions of full-length PARP-1 and its N-terminal half with different types of DNA damage and with defined nucleosome substrates. We found that full-length PARP-1 prefers nucleosomes with two linker DNA extensions over any other substrate (including several free DNA models) and that the C-terminal half of PARP-1 is necessary for this selectivity. We also measured the ability of various substrates to activate PARP-1 activity and found that the most important feature for activation is one free DNA end rather than tight interaction with the activating nucleic acid. Our data provide insight into the different modes of interaction of this multidomain protein with nucleosomes and free DNA.