Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Virion RNA of poliovirus type 1 has been analyzed for the linkage between genome-protein VPg and the polyribonucleotide chain. Hydrolysis of the linkage with acid or alkali and enzymatic degradation lead to the conclusion that the bond is neither a phosphodiester such as nucleotidyl-(P-O)-serine (or threonine) nor a phosphoramidate such as nucleotidyl-(P-N)-amino acid. VPg-RNA can be iodinated by the Bolton and Hunter reagent [iodinated 3-(4-hydroxyphenyl)propionic acid N-hydroxysuccinimide ester] but not by the chloramine-T or lactoperoxidase procedures, an observation suggesting that VPg does not contain accessible tyrosine. However, VPg can be labeled with [3H]tyrosine in vivo. Hydrolysis of VPg-[32P]pUp with 5.6 M HCl at 110 degrees yielded 32P-labeled O4-(3'-phospho-5'-uridylyl)tyrosine that could be cleaved with micrococcal nuclease to O4-[32P]phosphotyrosine and uridine 3'-[32P]phosphate. These data establish that VPg is linked to the poliovirus genome by a bond between the O4 of tyrosine and the 5'-P atom of the terminal uridylic acid residue. The 5' end of polio genome RNA can now be described as VPg(Tyr-O)-pU-U-A-A-A-A-C-A-G.
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PMID:O4-(5'-uridylyl)tyrosine is the bond between the genome-linked protein and the RNA of poliovirus. 21 3

A small proportion (0.1-0.5%) of the total DNA content of native Chinese hamster metaphase chromosomes is protected from nucleolytic degradation following the removal of histones by extraction with either 0.2 N HCl or 2 M NaCl, and remains attached to the nonhistone protein core. Acid extraction followed by DNase I digestion leads to small fragments of 10-30 bases. Salt extraction followed by micrococcal nuclease digestion gives approx. 140 b.p. fragments which are undistinguishable in size from nucleosome core DNA fragments. Furthermore, DNase I treatment of salt extracted chromosomes gives DNA fragments containing single strands which are multiples of 10 bases in length, again characteristic of the nucleosome structure. Reassociation kinetics using the 32P-labelled 140 b.p. fragments as probes suggests they are enriched for rapidly reassociating sequences.
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PMID:A partial characterization of DNA fragments protected from nuclease degradation in histone depleted metaphase chromosomes of the Chinese hamster. 49 44

The identity of the amino acid residue that links the VPg of the potyvirus tobacco vein mottling virus (TVMV) to the viral RNA was determined. 32P-labeled TVMV RNA was digested with RNase A and micrococcal nuclease. The resulting 32P-labeled VPg was isolated and partially hydrolyzed with 6 N HCl at 110 degrees C for 2 h. Analysis by thin-layer electrophoresis revealed the presence of [32P]phosphotyrosine but not [32P]phosphoserine or [32P]phosphothreonine. Another preparation of TVMV RNA was treated with endoproteinase Lys-C, and the resulting peptide-RNA was purified by sodium dodecyl sulfate-sucrose gradient centrifugation. The sequence of the N-terminal 15 amino acid residues of the peptide, when compared with the RNA-derived amino acid sequence of the TVMV polyprotein, demonstrated that the peptide occurs in the small nuclear inclusion protein. These data suggest that Tyr-1860 of the polyprotein is the amino acid residue that links the TVMV VPg to the viral RNA.
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PMID:A tyrosine residue in the small nuclear inclusion protein of tobacco vein mottling virus links the VPg to the viral RNA. 170 64

The preparation of hybrid histone octamers with wheat histone H2A variants replacing chicken H2A in the chicken octamer is described. The fidelity of the reconstituted hybrid octamers was confirmed by dimethyl suberimidate cross-linking. Polyglutamic-acid-mediated assembly of these octamers on long DNA and subsequent micrococcal nuclease (MNase) digestion demonstrated that, whereas chicken octamers protected 167 base-pairs (representing 2 full turns of DNA), hybrid histone octamers containing wheat histone H2A(1) with its 19 amino acid residue C-terminal extension protected an additional 16 base pairs of DNA against nuclease digestion. The protection observed by hybrid histone octamers containing wheat histone H2A(3) with both a 15 residue N-terminal and a 19 residue C-terminal extension was identical with that observed with H2A(1)-containing hybrid histone octamers with only the 19 residue C-terminal extension. These results suggest that the role of the C-terminal extension is to bind to DNA of the "linker" region. The thermal denaturation of chicken and hybrid core particles was identical in 10 mM-Tris.HCl.20 mM-NaCl, 0.1 mM-EDTA, confirming that there was no interaction between the basic C-terminal extension and DNA of the core particle. Denaturation in EDTA, however, showed that hybrid core particles had enhanced stability, suggesting that the known conformational change of core particles at very low ionic strength allows the C-terminal extension to bind to core particle DNA under these conditions. A model accounting for the observed MNase protection is presented.
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PMID:Extended C-terminal tail of wheat histone H2A interacts with DNA of the "linker" region. 202 50

Two discrete supranucleosomal particles that differ in their electrophoretic migration on 1% agarose gels were isolated from unfertilized sea urchin eggs. Both particles contain the same complement of cleavage stage (CS) chromosomal proteins, which is identical to the complete set of basic proteins isolated directly from chromatin by extraction with 0.25 N HCl. DNA fragments between 210 and 1500 bp were found in both particles, and the basic unit of DNA repeat length determined by micrococcal nuclease digestion was 126 +/- 3 bp. The isolated nucleoparticles are electrophoretically stable over a wide range of DNA sizes (126-1500 bp) indicating that their structure is maintained by internal interactions among the CS chromosomal proteins, previously designated CS A through CS G. Based on these results we conclude that the CS chromosomal proteins are functionally equivalent to classical histones in their ability to direct higher ordered structures of chromatin.
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PMID:Analysis of supra-nucleosome particles from unfertilized eggs of sea urchins. 272 89

Incubation of extracts of Cp-1-infected Streptococcus pneumoniae with [alpha-32P]dATP produced a labeled treatment with micrococcal nuclease and sensitive to treatment with proteinase K. Incubation of the 32P-labeled protein with 5 M piperidine for 4 h at 50 degrees C released 5'-dAMP, indicating that a covalent complex between the terminal protein and 5'-dAMP was formed in vitro. When the four deoxynucleoside triphosphates were included in the reaction mixture, a labeled complex of slower electrophoretic mobility in sodium dodecyl sulfate-polyacrylamide gels than the terminal protein-dAMP complex was also found, indicating that the Cp-1 terminal protein-dAMP complex can be elongated and, therefore, that it is an initiation complex. Treatment of the 32P-labeled terminal protein-dAMP complex with 5.8 M HCl at 110 degrees C for 2 h yielded phosphothreonine. These results, together with the resistance of the terminal protein-DNA linkage to hydroxylamine, suggest that the Cp-1 terminal protein is covalently linked to the DNA through a phosphoester bond between L-threonine and 5'-dAMP, namely, a O-5'-deoxyadenylyl-L-threonine bond.
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PMID:Formation of a covalent complex between the terminal protein of pneumococcal bacteriophage Cp-1 and 5'-dAMP. 308 36

A macromolecule binding 3H-methylcholanthrene (3H-MCA) and 3H-benzo(a)pyrene (3H-BaP) and sedimenting in the 4-5 S region of sucrose gradient (4.5 S) was identified in rat liver cytosol. The binding was displaced by 100-fold molar excess unlabeled ligands whereas 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) was ineffective. The dissociation constant for both polycyclic aromatic hydrocarbons (PAHs) was of the order of 10(-8) M or lower. Both 3H-MCA and 3H-BaP bound to 4.5 S in a non covalent manner, since 92% of the bound radioactivity was extractable with ethyl ether. Furthermore the binding was strongly reduced by urea 8 M and by guanidine. HCl 4 M (99 and 70% respectively). Thin layer chromatography of the ethyl ether-solubilized radioactivity showed a peak comigrating with PAHs used as standards. When chromatographed on Sephadex G-200, 4.5 S was eluted as a sharp peak with an apparent molecular weight of 50-60,000 daltons. Enzyme treatment of liver cytosol showed that the 4.5 S binding sites were destroyed by micrococcal nuclease (92% of inhibition). Papain and phosphodiesterase I and II reduced the binding to 50%, whereas DNase I, DNase II, RNase, phospholipase A2 and C and trypsin were ineffective. These data suggest that the PAHs binding macromolecule of rat liver cytosol is a protein associated with a polynucleotide. The binding of both PAHs was enhanced by increasing the incubation temperature, the maximum being reached after 20-30 min at 37 degrees C. After 2.5 min at 65 degrees C, binding sites were completely destroyed. The same temperature-induced "activation" was obtained also by prewarming the cytosol at 37 degrees C in the absence of ligands.
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PMID:Polycyclic aromatic hydrocarbon binding macromolecules. Identification, characterization and temperature activation of a 4.5 S binding nucleoprotein. 406 Feb 44

The sera of patients with mixed connective tissue disease (MCTD) have high titers of antibodies directed against nuclear U1-ribonucleoprotein (U1-RNP). This antigen is easily extracted from nuclear preparations with physiologic saline and from tissue sections with 0.1 HCl, leaving the nucleic acids and nuclear matrix behind. When U1-RNP is extracted from HEp-2 cells with 0.1 N HCl, the sera of 32/32 patients with MCTD react with another antigen that is exposed by the extraction procedure. This antigen is not destroyed by trypsin and deoxyribonuclease 1 treatment but is sensitive to both purified ribonuclease A and purified micrococcal nuclease. Absorption studies showed that the antibody reacting with this antigen cannot be absorbed by sheep red blood cells coated with extracts of rabbit thymus that contain U1-RNP. Radioimmunoassay showed that the reaction of the unadsorbed antibody was with heterogeneous nuclear ribonucleoprotein or ribonucleic acid (hnRNP/RNA) and not with transfer RNA or ribosomal RNA. The hnRNP/RNA antigen is demonstrated as discrete particles in the internucleolar chromatin of interphase cells, but in metaphase cells the antigen is diffusely dispersed. The distribution, solubility, and biochemical characteristics suggest that the antigenic moiety is part of the nuclear matrix. Therefore, MCTD sera contain antibodies that react with at least two species of nuclear RNP: small nuclear RNP (snRNP), as described by others, and a high m.w. hnRNP/RNA bound to the nuclear matrix.
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PMID:Antibodies from patients with mixed connective tissue disease react with heterogeneous nuclear ribonucleoprotein or ribonucleic acid (hnRNP/RNA) of the nuclear matrix. 619 84

To investigate the role of protein p3 in bacteriophage phi 29 initiation of replication, we have studied the nature of the covalent linkage between protein p3 and phi 29 DNA. The protein-DNA compound was digested with micrococcal nuclease and pronase resulting in a nucleotidyl-peptide that was further digested by alkaline phosphatase and snake venom phosphodiesterase yielding 5'-dAMP. The DNA-protein linkage is sensitive to alkali. Treatment of the nucleotidyl-peptide with 0.1 M NaOH at 37 degrees C for 3 hr after phosphatase digestion released 5'-dAMP. Hydrolysis of the nucleotidyl-peptide with 5.8 M HCl at 110 degrees C for 90 min yielded O-phosphoserine. These results, together with the sensitivity of the DNA-protein linkage to snake venom phosphodiesterase and its resistance to hydroxylamine, indicate that protein p3 is covalently linked to phi 29 DNA through a phosphoester bond between L-serine and 5'-dAMP, namely a O,5'-deoxyadenylyl-L-serine bond.
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PMID:Protein p3 is linked to the DNA of phage phi 29 through a phosphoester bond between serine and 5'-dAMP. 677 79

Rat livers were disrupted in the TMS buffer (10 mM Tris-HCl, pH 7.6, 5 mM MgCl2, 0.25 M sucrose +70 microM beta-mercaptoethanol) and the nuclei were purified by sedimentation through 2.2 M sucrose with the same components as in TMS. Then the nuclei were resuspended and washed 3 times in TMS. After that the nuclei were resuspended to 1 mg DNA per ml in TM buffer (10 mM Tris-HCl, pH 7.6, 0.2 mM MgCl2) followed by centrifugation at low speed. About 60% of total nuclear DNP was recovered by this extraction. The protein/DNA ratio in the extracted chromatin fraction (DNPs) was about 1.1. The bulk of the non-extracted in TM residual chromatin fraction was released from the nuclear pellet after treatment with micrococcal nuclease. This matrix-associated chromatin fraction (DNPm) is significantly enriched in non-histone proteins as compared with the DNPs; hence the protein/DNA ratio of DNPm is at least two times higher than that of DNPs. The protein components of DNPs are represented by five histones containing negligible non-histone admixture. One of them was identified as protein A24, another--as non-dissociated from DNA in 0.6 M NaCl acid-soluble protein with m. w. of about 42,500. The possible structural features of these two distinguishable chromatin fractions are discussed.
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PMID:[Protein composition of chromatin fractions differing in their attachment to nuclear structures at low ionic strength]. 711 12


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