Search results for "DNA clamp"
showing 9 items of 9 documents
DNA-replication complex from cells infected with herpes virus.
2005
Herpes simplex virus (HSV) DNA synthesis is initiated in an intact cell system by a 36-residue ribonucleotide stretch [W.E.G. Müller, R.K. Zahn, J. Arendes, and D. Falke (1979) Virology, 98, 200-210]. In the present study a nucleoplasmic fraction was isolated from rabbit kidney cells infected with HSV (type 1), which catalyzes DNA synthesis. By means of specific assays, containing single-stranded deoxyribopolymers, it was elucidated that the replication complex contains both an RNA-synthesizing and a DNA-synthesizing enzyme. These enzymes were characterized as host cell RNA polymerase II and HSV-induced DNA polymerase. The RNA polymerase II synthesizes an RNA initiator with an average chain…
A neutralizing antibody against human DNA polymerase epsilon inhibits cellular but not SV40 DNA replication.
1999
The contribution of human DNA polymerase epsilon to nuclear DNA replication was studied. Antibody K18 that specifically inhibits DNA polymerase activity of human DNA polymerase epsilon in vitro significantly inhibits DNA synthesis both when microinjected into nuclei of exponentially growing human fibroblasts and in isolated HeLa cell nuclei. The capability of this neutralizing antibody to inhibit DNA synthesis in cells is comparable to that of monoclonal antibody SJK-132-20 against DNA polymerase alpha. Contrary to the antibody against DNA polymerase alpha, antibody K18 against DNA polymerase epsilon did not inhibit SV40 DNA replication in vitro. These results indicate that DNA polymerase e…
Generation of reporter plasmids containing defined base modifications in the DNA strand of choice
2012
Physiological effects of DNA bases other than A, G, C, and T as well as ways of removal of such bases from genomes are studied intensely. Methods for targeted insertion of modified bases into DNA, therefore, are highly demanded in the fields of DNA repair and epigenetics. This article describes efficient procedures for incorporation of modified DNA bases into a plasmid-borne enhanced green fluorescent protein (EGFP) gene. The procedure exploits excision of a stretch of 18 nt from either the transcribed or nontranscribed DNA strand with the help of the sequence-specific nicking endonucleases Nb.Bpu10I and Nt.Bpu10I. The excised single-stranded oligonucleotide is then swapped for a synthetic …
Influence of template inactivators on the binding of DNA polymerase to DNA.
1974
The agents daunomycin, ethidium bromide, distamycin A and cytochrome c inhibit DNA dependent DNA polymerase I (E. coli) reaction competitively to DNA. The influence of these template inactivators on the binding of DNA polymerase to native as well as denatured DNA has been determined by affinity chromatography. Cytochrome c blocks the binding of the enzyme to double-stranded and to single-stranded DNA Sepharose. In contrast to these results daunomycin, ethidium bromide or distamycin A reduce the binding affinity only with denatured DNA Sepharose as matrix. These data are discussed with respect to the modification by template inactivators of the affinity of DNA to the different binding sites …
UV-induced cross-linking of proteins to plasmid pBR322 containing 8-azidoadenine 2′-deoxyribonucleotides
1988
Abstract An efficient method of cross-linking DNA to protein is described. The method is based on the incorporation of photoactive 8-azidoadenine 2′-deoxyribonucleotides into DNA. We have found that 8-N 3 dATP is a substrate for E. coli DNA polymerase I and that 8-N 3 dATP can be incorporated into plasmid pBR322 by nick-translation. Subsequently we were able to cross-link a set of different proteins to 8-azido-2′-deoxyadenosine-containing pBR322 by UV irradiation (366 nm). No DNA-protein photocross-linking was observed under the same conditions when the non-photoactive plasmid pBR322 was used.
Sequence-specific and DNA structure-dependent interactions of Escherichia coli MutS and human p53 with DNA
2013
Many proteins involved in DNA repair systems interact with DNA that has structure altered from the typical B-form helix. Using magnetic beads to immobilize DNAs containing various types of structures, we evaluated the in vitro binding activities of two well-characterized DNA repair proteins, Escherichia coli MutS and human p53. E. coli MutS bound to double-stranded DNAs, with higher affinity for a G/T mismatch compared to a G/A mismatch and highest affinity for larger non-B-DNA structures. E. coli MutS bound best to DNA between pH 6 and 9. Experiments discriminated between modes of p53-DNA binding, and increasing ionic strength reduced p53 binding to nonspecific double-stranded DNA, but had…
Interaction of antimutagenic 1,4-dihydropyridine AV-153-Na with DNA and DNA-damaging molecules and its impact on DNA repair activity
2017
1,4-dihydropyridines (1,4-DHP) possess important biochemical and pharmacological properties, including antioxidant and antimutagenic activities. Interaction of some 1,4-DHP with DNA was recently reported. AV-153-Na, an antimutagenic and DNA-repair-enhancing compound appeared to be able to interact with DNA by intercalation. The aim of the current study was to characterize DNA’s capacity for the binding of AV-153-Na, and using different approaches, to test intracellular distribution of the compound, to test the ability of the compound to scavenge peroxynitrite and hydroxyl radical and to assess the ability of the compound to modify the activity of DNA repair enzymes. The DNA binding activity…
Bleomycin, a selective inhibitor of DNA-dependent DNA polymerase from oncogenic RNA viruses.
1972
Abstract Bleomycin, an antibiotic, inhibits the DNA-dependent DNA polymerase from Rauscher murine leukemia virus. Higher concentrations of BLM ∗ are required to inhibit it's RNA-dependent DNA polymerase. These inhibition effects of the non-competitive type are not altered by preincubation of the DNA with BLM. Under comparable conditions neither the DNA-dependent DNA polymerase activity from E. coli and mouse liver nor the DNA-dependent RNA polymerase activity from mouse lymphoma cells are affected by BLM.
Activity and kinetics of DNA dependent DNA and RNA polymerases n xeroderma pigmentosum and in normal human skin.
1971
1. DNA dependent DNA polymerase (E.C.2.7.7.7) was prepared from human normal and from Xeroderma pigmentosum skin. 2. DNA polymerase from normal skin has the same Michaelis constant with native and denatured DNA as templateKm= 120 ± 11 µg DNA/ml, with differing maximum reaction velocities. 3. The enzyme from Xeroderma pigmentosum has the same Michaelis constant for denatured DNA as the enzyme from normal skin, but with native DNA as template, theKmvalue is lower (97.2 ± 9.8). The maximum reaction velocities of the Xeroderma pigmentosum enzyme with native resp. denatured DNA as template are the same. 4. DNA dependent RNA polymerases (E.C.2.7.7.6) from normal and Xeroderma pigmentosum skin wer…