Irreversible binding of poly(ADP)ribose polymerase cleavage product to DNA ends revealed by atomic force microscopy: possible role in apoptosis.

作者：Mark E. Smulson, Dinghua Pang, Mira Jung, Alexander Dimtchev, Sergey Chasovskikh, Alexander Y. Spoonde, Cynthia Marie Simbulan-Rosenthal, Dean S. Rosenthal, Andrei A. Yakovlev, Anatoly Dritschilo · 发表于：PubMed · 年份：1998 · 被引用次数：89 · 研究领域：PARP inhibition in cancer therapy、Calcium signaling and nucleotide metabolism、CRISPR and Genetic Engineering

During apoptosis, DNA undergoes fragmentation and caspase-3 cleaves poly(ADP-ribose) polymerase (PARP) into both a 24-kDa fragment containing the DNA binding domain and an 89-kDa fragment containing the catalytic and automodification domains. Atomic force microscopy revealed that recombinant full-length PARP bound to plasmid DNA fragments and linked them into chainlike structures. Automodification of PARP in the presence of NAD+ resulted in its dissociation from the DNA fragments, which, nevertheless, remained physically aligned. A recombinant 28-kDa fragment of PARP containing the DNA binding domain but lacking the automodification domain irreversibly bound to and linked DNA fragments in the absence or presence of NAD+. Identical results were obtained on incubation of internucleosomal DNA fragments from apoptotic cells with the products of cleavage of recombinant PARP by purified caspase-3. The 24-kDa product of PARP cleavage by caspase-3 may contribute to the irreversibility of apoptosis by blocking the access of DNA repair enzymes to DNA strand breaks.