Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.31.1 (micrococcal nuclease)
 2,818 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have examined the nature of the nuclear antigen recognized by certain natural human antibodies that react specifically with both cell nuclei and plasma membranes from many species. Partial purification of these antibodies, called X-ANA, is achieved by binding to and rapid elution from the surface of viable human leukocytes. Chicken erythrocyte chromatin was solubilized by digestion with staphylococcal nuclease and fractionated into a 0.15 M NaCl soluble fraction that consisted of core mononucleosomes lacking H1/H5, and a 0.15 M NaCl insoluble fraction composed of polynucleosomes with H1/H5 present. No proteins other than histones were detected. Native and reconstituted mononucleosomes displaced IgG of the leukocyte eluates from nuclei of frozen mouse kidney sections and from the walls of plastic tubes coated with polynucleosomes. The reconstituted core mononucleosomes were 4- 10-fold less efficient inhibitors than native mononucleosomes. Trypsin digested mononucleosomes, free high m.w. DNA, and free histones displayed no or very weak inhibitory activity. The data indicate that X-ANA recognize a complex consisting of the core histones H2A, H2B, H3, H4, and DNA of 140 to 200 base pairs in length.
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PMID:The specificity of human autoantibodies that react with both cell nuclei and plasma membranes: the nuclear antigen is present on core mononucleosomes. 9 40

A quantitative study has been made on the action of rat nuclear Ca-Mg endonuclease on rat liver nuclei. In a standard 30 minute digest 0.5-1.5% of the DNA was rendered acid soluble, 1.5-4% of the chromatin was rendered buffer soluble, 50-60% of the potential cleavage sites were actually cleaved, and these cleavages were distributed evenly throughout the bulk of the genome. During these standard digests there was no significant loss of histones either in aggregate or relative to each other. Trypsin digestion of the nuclei to a trypsin resistant core did not lower the specificity of the Ca-Mg endonuclease cleavages or expose other sites to its action. Evidence is presented that indicates Ca-Mg endonuclease and micrococcal nuclease attack the same sites rather than different sites with the same spacing.
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PMID:The reaction of the Ca-Mg endonuclease with the A-sites of rat nucleoprotein. 117 28

Mononucleosomes released from Dictyostelium discoideum chromatin by micrococcal nuclease contained two distinctive DNA sizes (166-180 and 146 bp). Two dimensional gel electrophoresis suggested a lysine-rich protein protected the larger mononucleosomes from nuclease digestion. This was confirmed by stripping the protein from chromatin with Dowex resin. Subsequently, only the 146 bp mononucleosome was produced by nuclease digestion. Reconstitution of the stripped chromatin with the purified lysine-rich protein resulted in the reappearance of the larger mononucleosomes. Two-dimensional gel electrophoresis showed the protein was associated with mononucleosomes. Hence, the protein functions as an H1 histone in bringing the two DNA strands together at their exit point from the nucleosome. Trypsin digestion of the lysine-rich protein in nuclei resulted in a limiting peptide of approx. 10 kilodaltons. Trypsin concentrations which degraded the protein to peptides of 12-14 kilodaltons and partially degraded the core histones did not change the DNA digestion patterns obtained with micrococcal nuclease. Thus, the trypsin-resistant domain of the lysine-rich protein is able to maintain chromatosome structure.
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PMID:A lysine-rich protein functions as an H1 histone in Dictyostelium discoideum chromatin. 392 31