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:3.1.30.2 (endonuclease)
18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ten Staphylococcus intermedius isolates from cases of canine pyoderma and 10 from healthy carriers were examined by SDS-PAGE of exoproteins, immunoblotting and restriction endonuclease digest analysis. Similarities between banding patterns of the isolates were calculated as Dice coefficients for all three methods. For SDS-PAGE and immunoblotting, no significant differentiation was found between the pyoderma and "healthy" groups. Analysis of DNA digested with BglII indicated that S. intermedius is genetically heterogeneous; Dice coefficients for the pyoderma group were distinct from those for the healthy group (p < 0.001), and cluster analysis confirmed that the pyoderma isolates (9) formed a group separate from the majority (6 of 9) of the normal isolates.
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PMID:Characterisation of Staphylococcus intermedius isolates from canine pyoderma and from healthy carriers by SDS-PAGE of exoproteins, immunoblotting and restriction endonuclease digest analysis. 790 43

Analyses of cleavage ends of DNA fragments in apoptotic rat thymocytes induced by gamma-ray irradiation or by treatment with dexamethasone revealed that in both cases the fragments produced had 3'-hydroxyl (OH) and 5'-phosphoryl (P) ends of DNA chains. Rat thymocyte nuclei contained at least three endonuclease activities (deoxyribonucleases alpha, beta and gamma) that were able to cleave chromatin to mononucleosomal and oligonucleosomal fragments. The nuclei of apoptotic rat thymocytes induced by gamma-ray irradiation or dexamethasone retained considerable deoxyribonuclease gamma activity, but not alpha or beta deoxyribonuclease activity. During the induction of apoptosis, treatment with cycloheximide, which suppressed apoptosis, resulted in marked decreases of deoxyribonucleases alpha and beta activities. After release of cycloheximide inhibition, DNA fragmentation associated with apoptosis occurred in the cycloheximide-treated thymocyte nuclei, in which deoxyribonuclease gamma activity was only observed. The purified deoxyribonucleases alpha and beta were divalent cation-independent acidic endonucleases, which were separated on a CM5PW column by HPLC. The molecular masses of deoxyribonucleases alpha and beta were 28 kDa and 30 kDa, respectively, as determined by TSK G-2000SW gel-filtration HPLC, and both were 32 kDa in molecular mass as determined by SDS/PAGE. In contrast, deoxyribonuclease gamma, a neutral endonuclease, required both Ca2+ and Mg2+ for full activity and was inhibited by Zn2+. The molecular mass of deoxyribonuclease gamma was 31 kDa and 33 kDa when measured by gel filtration and SDS/PAGE, respectively. Under these optimal conditions, deoxyribonuclease gamma was shown to produce 3'-OH/5'-P ends of nucleosomal DNA fragments, while deoxyribonucleases alpha and beta both formed DNA fragments with 3'-P/5'-OH ends. The ends formed by cleavage with deoxyribonuclease gamma were the same as those produced in apoptotic rat thymocytes. On the basis of these results, it seems likely that deoxyribonuclease gamma is responsible for internucleosomal cleavage of chromatin during thymic apoptosis.
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PMID:Identification of an endonuclease responsible for apoptosis in rat thymocytes. 795 53

DNA topoisomerase I isolated from the lower eukaryote Neurospora crassa mitochondria was characterized. Molar mass of the enzyme in the native state is 120 kDa and 60-65 kDa when denatured. The pH optimum of the enzyme is 7.8 and the KCl optimum concentration is 40 mmol/L. This topoisomerase is independent of ATP and Mg2+. N-Ethylmaleimide, 4-chloromercuribenzoate, SDS, guanidinium chloride, polyethylene glycol, heparin and ethidium bromide inhibit its activity, while novobiocin, nalidixic acid, Triton X-100 and chloroquine do not. Polyamines and histone H1 stimulate the topoisomerase activity. We classify this DNA topoisomerase as type I and eukaryotic. Conversion of the topoisomerase to a nonspecific endonuclease at increased temperature is proposed.
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PMID:Characterization of mitochondrial DNA topoisomerase I from Neurospora crassa. 795 26

The major structural proteins of 13 temperate and one virulent Listeria typing bacteriophages were analysed and compared using isoelectric focusing in immobilized pH gradients (IPG), ultrathin-layer two-dimensional electrophoresis, amino acid analysis and N-terminal amino acid sequences of selected proteins. Isoelectric points for major capsid and tail proteins of the 12 members of the siphoviridae family included in this study ranged from 4.70 to 5.92, whereas one of the two myoviridae investigated (B054) showed structural proteins in the 6.1 to 6.3 range. In comparison to protein profiles from one-dimensional SDS gels, the IPG technique gave better resolution and improved discrimination of phage proteins. Combination of this technique and SDS gel electrophoresis made it possible to correlate M(r) and isoelectric points of major structural proteins. Tail polypeptides of all siphoviridae are smaller and, with one exception, more acidic than their corresponding capsid counterparts. We also determined the amino acid composition of capsid and tail proteins. When compared with an average protein, they were found to be fairly rich in acidic and short-chain hydrophobic amino acids, as well as in lysine. In addition, the N-terminal amino acid sequences of major capsid and tail proteins of four representative listeriaphages were compared. The base composition of listeriaphage DNAs was between 37% and 39% G + C, reflecting that of their bacterial hosts. Each phage had a distinct restriction endonuclease pattern, and genome sizes ranged from 35 to 116 kb. DNA-DNA hybridization permitted the identification of five DNA homology groups. The two myoviruses studied (A511 and B054) showed no DNA homology to other phages, confirming their unique nature. The 12 siphoviruses were classified into three DNA homology groups with little cross-homology. Furthermore, phage A006 was found to share little DNA homology with the other investigated members of species 2671. Therefore, a new species (A006) is proposed. With respect to phage classification and taxonomy, a good correlation between the various approaches was observed, mostly corresponding to particle morphology.
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PMID:Structural proteins and DNA characteristics of 14 Listeria typing bacteriophages. 815 Dec 88

An activity gel assay was developed for the detection of DNA helicases in crude extracts. The assay was based on the ability of DNA helicases to unwind radioactive fragments from single-stranded M13 circles that were immobilized in an SDS polyacrylamide gel. The displaced radioactive strands were detected by blotting them to a filter and visualizing the resulting bands by autoradiography. Experiments with purified proteins demonstrated that DNA helicases, endonucleases and exonucleases could produce activity bands. A one-dimensional gel assay was sufficiently sensitive to allow detection of DNA helicase I, DNA helicase II, DNA helicase IV, the RecQ helicase as well as 3 unidentified putative DNA helicases in crude extracts of Escherichia coli. Exonuclease and endonuclease activities from crude extracts could be distinguished from DNA helicase activities by their ATP-independence and from each other by their band morphologies.
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PMID:An activity gel assay for the detection of DNA helicases and nucleases from cell-free extracts. 820 62

We have purified a novel endonuclease from Escherichia coli that recognizes deoxyinosine, a deamination product of deoxyadenosine in DNA. This activity, which we named deoxyinosine 3' endonuclease, is different from the known hypoxanthine DNA N-glycosylases which have been partially characterized in E. coli and other organisms. The enzyme was purified 24,800-fold to apparent homogeneity. SDS- and activity PAGE analyses indicate that the enzyme has an apparent molecular mass of 25 kDa. Deoxyinosine 3' endonuclease recognized deoxyinosine in both single- and double-stranded DNA but exhibited a 4-fold preference for double stranded over single-stranded DNA. In addition to deoxyinosine, the enzyme recognized urea residues and AP sites. Deoxyinosine 3' endonuclease has an obligatory requirement for Mg2+, but other cations such as Co2+ and Mn2+ could partially replace Mg2+. The optimal pH for deoxyinosine 3' endonuclease was around 7.5. In contrast to most of the known repair enzymes, deoxyinosine 3' endonuclease makes an incision at the second phosphodiester bond 3' to a deoxyinosine or AP site, leaving behind the intact lesion on the nicked DNA. Therefore, deoxyinosine 3' endonuclease recognizes, but does not remove, the lesion from the DNA molecule. The biological significance of this novel activity is discussed with reference to other repair activities in E. coli.
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PMID:Purification and characterization of a novel deoxyinosine-specific enzyme, deoxyinosine 3' endonuclease, from Escherichia coli. 820 31

Out of 22 Enterobacter phages investigated, nine were found to be suitable for phage typing based on their different lytic spectra on 398 strains of Enterobacter spp. isolated from milk powder and other foods. These phages were compared on the basis of morphology, protein composition, restriction endonuclease patterns and DNA-DNA hybridization. Two phages (WS-EP19, WS-EP13) belonged to the Podoviridae family (morphotype C1), and three (WS-EP20, WS-EP26, WS-EP28) were classified as Siphoviridae (morphotype B1). The other four phages were Myoviridae of the morphological groups A1 (WS-EP57) and A2 (WS-EP32, WS-EP94, WS-EP96). SDS-PAGE revealed individual protein profiles for each phage, which corresponded to different restriction enzyme fragment patterns. DNA-DNA hybridization demonstrated the close relationship of phages WS-EP20 and WS-EP26, and of WS-EP94 and WS-EP96. In general, a good correlation was found between groupings obtained with the various methods. The nine phages could be attributed to existing enterobacterial phage species although some differences to the described type phages were observed.
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PMID:Isolation, classification and molecular characterization of bacteriophages for Enterobacter species. 827 46

Twelve reference and four Northern Ireland ovine Chlamydia psittaci isolates including ovine abortion, faecal, conjunctivitis and arthritis isolates were compared. Inclusion morphology was shown to provide a useful means of differentiating the abortion and the non-abortion isolates studied. Identical SDS-PAGE polypeptide profiles were produced by the ovine abortion isolates. The polypeptide profiles of the non-abortion isolates were similar to one another and clearly distinct from the abortion isolate profiles. The restriction endonuclease profiles of the abortion isolates were remarkably similar whereas different profiles were produced by most of the non-abortion isolates. Monoclonal antibodies were prepared and characterized. A number of these reacted with all the isolates of chlamydia tested. Three mAbs reacted exclusively with the ovine abortion isolates while four mAbs reacted exclusively with a number of the faecal isolates.
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PMID:Comparison of ovine abortion and non-abortion isolates of Chlamydia psittaci using inclusion morphology, polyacrylamide gel electrophoresis, restriction endonuclease analysis and reactivity with monoclonal antibodies. 836 94

A major event in apoptosis is the digestion of chromatin into oligonucleosomal fragments. However, the enzymes responsible for the DNA degradation have not been well characterized. Here we report the purification of an endonuclease from human spleen cell nuclei that is likely to be responsible for DNA digestion in apoptosis. Enzyme activity was measured by a sensitive fluorometric assay, which assesses the conversion of plasmid DNA from a supercoiled to an open form. The endonuclease was extracted from isolated nuclei with NaCl between 100 and 350 mM and was further purified by chromatography on columns of phosphocellulose, Superdex 75, and chelating Sepharose (Zn2+ form). By gel filtration, the apparent molecular mass was 22-26 kDa; on SDS-polyacrylamide gel electrophoresis, the purified enzyme showed a single 27-kDa band. The enzyme required both Mg2+ (optimum, 5 mM) and Ca2+ (optimum, 2 mM) for activity. It was inhibited by Zn2+ (100% inhibition at 50 microM) and by high (> 10 mM) concentrations of Ca2+. Aurintricarboxylic acid, spermine, p-(hydroxymercuri)benzoate, and N-ethylmaleimide were also endonuclease inhibitors. No inhibition was observed with iodoacetamide, G-actin, or nucleoside 3',5'-bisphosphates. An optimum pH of 8.0 was found. When added to human CCRF-CEM lymphoblast nuclei, that do not contain the endonuclease, the purified splenic enzyme digested the chromatin into the mono- and oligonucleosomal fragments that are characteristic of apoptosis. On the basis of this result, and the observation that the activators and inhibitors of the purified endonuclease closely parallel those that affect apoptosis, it seems likely that this enzyme is involved in the apoptotic degradation of DNA in human lymphocytes.
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PMID:Ca2+/Mg(2+)-dependent endonuclease from human spleen: purification, properties, and role in apoptosis. 839 24

Bovine herpesvirus 1 DNA has been isolated by SDS lysis of the virus purified from potassium tartrate (10-50%) density gradient centrifugation. The quality and quantity of viral DNA was checked by UV spectrophotometry and ethidium bromide stained agarose gel electrophoresis. The 0.4 kb Hin dIII'O' fragment of BHV-1 DNA was selectively cloned into Hin dIII cut pUC9 plasmid DNA (2.665 kb). Recombinants were screened by white/blue colonies as well as Hin dIII restriction enzyme analysis. On restriction endonuclease analysis of recombinant plasmid DNA (p-BH-0) with several restriction enzymes, viz., Sau 3A, Hin fI, Rsa I, Sal I, Dra I, Bgl I, Bgl II, Sma I, Hpa I, Stu I, Mlu I, Xho I, Kpn I, Hae III, Eco RI, Bam HI, Pst I, Pal I, revealed insert viral DNA having sites for Hin fI, Hae III, Rsa I, Sma I, only. Further, the partial restriction map of the recombinant plasmid DNA was constructed using above enzymes.
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PMID:Molecular cloning and restriction endonuclease analysis of 0.4 kb Hin dIII'O' fragment of bovine herpesvirus 1 DNA. 840 44


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