CALIFORNIA UNIV SAN FRANCISCO CARDIOVASCULAR RESEARCH INST
Part I. Benzamide-DNA Interactions Deductions from Binding, Enzyme-Kinetics and from X-ray Structural Analysis of a 9-Ethyladenine-Benzamide Adduct The interaction of benzamide with the isolated components of calf thymus polyADP-ribose polymerase and with liver nuclei has been investigated. Part II. Molecular Interactions Between DNA, PolyADP-Ribose Polymerase and Histones Molecular interactions between purified polyADP-ribose polymerase, whole thymus histones, histone H1, rat fibroblast genomic DNA, and closed circular and linearized SV40 DNA were determined by the nitrocellulose filter binding technique. Binding of the polymerase protein, or histones, to DNA was greatly augmented when both enzyme protein and histones were present simultaneously. Part III. Analysis of the Molecular Contacts Between PolyADP-ribose Polymerase and DNA The interaction between poly ADP-ribose polymerase and various uniquely end labeled restriction fragments from SV40 an pBR322 DNAs was studied employing nuclease protection experiments. DNasel footprinting indicated that approximately 66-85 bp of DNA was protected by poly ADP-ribose polymerase from DNasel attack, and that a segment of DNA probably lies outside on the surface of the polymerase protein in the polymerase-DNA complex.