Poly(ADP-ribose) polymerase auto-modification and interaction with DNA: electron microscopic visualization.
The interaction between purified calf thymus poly(ADP-ribose) polymerase and its activating co-purified DNA (sDNA) was investigated by electron microscopy. We have shown that the enzyme-DNA complex possesses a nucleosome-like structure. The enzyme-bound DNA (sDNA) was found to be enriched in single-stranded regions and branched structures, presumed to be replication forks. The auto-ribosylated polymerase as well as the branched poly(ADP-ribose) formed were visualized by dark field electron microscopy during the auto-ADP-ribosylation reaction and the possible mechanism of this phenomenon is discussed.
D000818:Animals; D002417:Cattle; D004247:DNA / Q000378:metabolism*; D004261:DNA Replication; D004277:DNA, Single-Stranded / Q000378:metabolism; D008854:Microscopy, Electron; D009244:NAD+ Nucleosidase / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D011499:Protein Processing, Post-Translational
D004277:DNA, Single-Stranded; D004247:DNA; D011065:Poly(ADP-ribose) Polymerases; D009244:NAD+ Nucleosidase