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:3.1.27.1 (RNase)
16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Clostridium thermocellum produces an extracellular multienzyme complex, termed the cellulosome, that allows efficient solubilization of crystalline cellulose. The complex is organized around a large noncatalytic protein subunit, termed CipA or scaffoldin, and is found either free in the supernatant or cell bound. The binding of the complex to the cell is mediated by three cell surface anchoring proteins, OlpB, Orf2p, and SdbA, that interact with the CipA scaffoldin. The transcriptional level of the olpB, orf2, sdbA, and cipA genes was determined quantitatively by RNase protection assays in batch and continuous cultures, under carbon and nitrogen limitation. The mRNA level of olpB, orf2, and cipA varied with growth rate, reaching 40 to 60 transcripts per cell under carbon limitation at a low growth rate of 0.04 h(-1) and 2 to 10 transcripts per cell at a growth rate of 0.35 h(-1) in batch culture. The mRNA level of sdbA was about three transcripts per cell and was not influenced by growth rate. Primer extension analysis revealed two major transcriptional start sites, at -81 and -50 bp, upstream of the translational start site of the cipA gene. The potential promoters exhibited homology to the known sigma factors sigma(A) and sigma(L) (sigma(54)) of Bacillus subtilis. Transcription from the sigma(L)-like promoter was found under all growth conditions, whereas transcription from the sigma(A)-like promoter was significant only under carbon limitation. The overall expression level obtained in the primer extension analysis was in good agreement with the results of the RNase-protection assays.
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PMID:Regulation of expression of scaffoldin-related genes in Clostridium thermocellum. 1292 83

Fresh anterior pituitary glands from beef and pig were separated by differential centrifugation into subcellular fractions. Nuclei and debris were obtained at 700 g for 15 minutes, secretory granules at 7000 g for 20 minutes, mitochondria at 34,000 g for 15 minutes, and microsomes at 78,000 g for 3 hours. Electron micrographs were taken of the individual fractions. Each fraction was analyzed for nitrogen, pentosenucleic acid (PNA), and phospholipide. Beef and pig anterior lobes were quite similar in their intracellular composition as seen in the subcellular fractions. Succinic dehydrogenase was localized in mitochondria, while alkaline phosphatase was concentrated in the microsomes. A proteinase with pH optimum at 8.2 was exclusively localized. in microsomal and supernatant fractions. Acid phosphatase, acid ribonuclease, and acid proteinase were distributed among the subcellular fractions in another pattern, indicating the presence of a particle type distinct from mitochondria and microsomes. The distribution of cytoplasmic PNA paralleled that of alkaline phosphatase.
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PMID:Cell fractionation of anterior pituitary glands from beef and pig. 1363 Sep 29

The contents of selected hydrolytic enzymes of oil-induced peritoneal, normal alveolar, and BCG-induced alveolar macrophages have been studied. On a per cell or nitrogen basis the normal alveolar cells contained considerably more acid phosphatase, cathepsin, acid ribonuclease, lysozyme, and lipase than peritoneal cells. The BCG-induced alveolar macrophage exhibited increased levels of acid phosphatase, lysozyme, and lipase as compared to alveolar macrophages from unstimulated rabbits. The morphological differences between these cells was discussed and electron micrographs of the BCG-induced macrophage presented. Fractionation of the BCG-induced macrophage by differential centrifugation showed that 60 to 80 per cent of the total cell content of acid phosphatase, cathepsin, beta glucuronidase, acid ribonuclease, acid deoxyribonuclease, aryl sulfatase, lysozyme, and lipase were localized in a postnuclear fraction which sedimented at 15,000 g. This fraction also contained the majority of the mitochondria as evidenced by its content of cytochrome oxidase. Non-specific esterase was not localized to this fraction. A separation of the hydrolase-containing particles and mitochondria was achieved by isopycnic sucrose gradient centrifugation. Under the conditions employed, the mitochondria distributed at densities of 1.19 to 1.20, whereas the hydrolase particles sedimented to a density of 1.26 to 1.27. Each of the hydrolases including acid phosphatase, beta glucuronidase, cathepsin, lysozyme, and acid ribonuclease exhibited maximum activities in the same gradient fraction. The isolated granules exhibited enzymatic latency, and activation could be achieved by cycles of freezing and thawing or surface active agents. The majority of each of the hydrolytic enzymes could be liberated in a non-particulate form by mechanical trauma. Macrophages which had been stained supravitally with neutral red were fractionated by differential and gradient centrifugation. More than 70 per cent of the dye could be recovered in the particulate hydrolase fraction. The isolated, stained granules resembled those seen in the intact cell.
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PMID:THE PARTICULATE HYDROLASES OF MACROPHAGES. I. COMPARATIVE ENZYMOLOGY, ISOLATION, AND PROPERTIES. 1411 77

Sakaguchi, Genji (National Institute of Health, Tokyo, Japan), Sumiko Sakaguchi, and Nobuko Imai. Comparative gel filtration of toxin grecursor and trypsin-activated toxin of Clostridium botulinum type E. J. Bacteriol. 87:401-407. 1964.-Precursor of type E botulinus toxin was highly purified from bacterial cells by extraction, ammonium sulfate precipitation, ribonuclease digestion, and chromatography on CM-Sephadex. The sample free from ribonucleic acid had a toxicity of 5.1 x 10(5)ld(50) per mg of nitrogen before activation and 8.3 x 10(7)ld(50) per mg of nitrogen after activation. This precursor and its activated product were subjected to gel filtration on a column of Sephadex G-200. No evidence for smaller fractions was obtained. Both precursor and trypsin-activated toxin were eluted in the void volume with 0.05 or 1 m acetate buffer (pH 6.0) or with 0.05 or 0.5 m phosphate buffer (pH 7.5). Intact trypsin and its degradation products were separated from toxin. The toxins eluted with the acetate buffers had potencies of 1.2 x 10(8) and 1.3 x 10(8)ld(50) per mg of N, while those eluted with the phosphate buffers showed lower toxicities. Possible mechanisms involved in the activation process are discussed.
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PMID:COMPARATIVE GEL FILTRATION OF TOXIN PRECURSOR AND TRYPSIN-ACTIVATED TOXIN OF CLOSTRIDIUM BOTULINUM TYPE E. 1415 Oct 63

Enhancement in oxygen uptake by high-cell-density cultivations has been achieved previously by expression of the bacterial hemoglobin gene from Vitreoscilla. The Vitreoscilla hemoglobin (VHb) gene was expressed in the yeast Yarrowia lipolytica to study the effect of expression in this commercially important yeast. The expression of VHb in this yeast was found to enhance growth, contrary to reported observations in wild-type Saccharomyces cerevisiae in which there was no significant growth enhancement. VHb-expressing Y. lipolytica exhibited higher specific growth rate, enhanced oxygen uptake rate, and higher respiratory activity. We report the beneficial effects of VHb expression on growth under microaerobic as well as under nonlimiting dissolved oxygen conditions. Earlier studies in Y. lipolytica have demonstrated inhibition of mycelia formation by respiratory inhibitors and poor nitrogen source, conditions poor for growth. VHb(+) Y. lipolytica cells were more efficient at forming mycelia, indicating better utilization of available oxygen as compared with the VHb(-) cells. Expression of VHb was also found to increase the levels of enzyme ribonuclease secreted into the medium, a property that may be beneficial for producing heterologous proteins in Y. lipolytica.
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PMID:Expression of vitreoscilla hemoglobin improves growth and levels of extracellular enzyme in Yarrowia lipolytica. 1459 78

The genome sequence of the genetically tractable, mesophilic, hydrogenotrophic methanogen Methanococcus maripaludis contains 1,722 protein-coding genes in a single circular chromosome of 1,661,137 bp. Of the protein-coding genes (open reading frames [ORFs]), 44% were assigned a function, 48% were conserved but had unknown or uncertain functions, and 7.5% (129 ORFs) were unique to M. maripaludis. Of the unique ORFs, 27 were confirmed to encode proteins by the mass spectrometric identification of unique peptides. Genes for most known functions and pathways were identified. For example, a full complement of hydrogenases and methanogenesis enzymes was identified, including eight selenocysteine-containing proteins, with each being paralogous to a cysteine-containing counterpart. At least 59 proteins were predicted to contain iron-sulfur centers, including ferredoxins, polyferredoxins, and subunits of enzymes with various redox functions. Unusual features included the absence of a Cdc6 homolog, implying a variation in replication initiation, and the presence of a bacterial-like RNase HI as well as an RNase HII typical of the Archaea. The presence of alanine dehydrogenase and alanine racemase, which are uniquely present among the Archaea, explained the ability of the organism to use L- and D-alanine as nitrogen sources. Features that contrasted with the related organism Methanocaldococcus jannaschii included the absence of inteins, even though close homologs of most intein-containing proteins were encoded. Although two-thirds of the ORFs had their highest Blastp hits in Methanocaldococcus jannaschii, lateral gene transfer or gene loss has apparently resulted in genes, which are often clustered, with top Blastp hits in more distantly related groups.
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PMID:Complete genome sequence of the genetically tractable hydrogenotrophic methanogen Methanococcus maripaludis. 1546 49

The activity of glutamate dehydrogenase (GDH), an important enzyme in carbon and nitrogen metabolism, is routinely assayed by photometry. The RNA synthetic activity of the enzyme provides new technologies for assaying its activity. The enzyme was made to synthesize RNAs in the absence of DNA and total RNA but with different mixes of the four nucleoside triphosphates (NTPs) in order to investigate the RNA characteristics. RNase VI (hydrolyzes base-paired residues) digested the poly (U,A) RNA completely because the U and A residues were evenly distributed to produce many base-paired regions. Therefore, the synthesis of RNA by GDH was by random addition of NTPs. The RNA synthetic activity of the enzyme was at least 50-fold more active in the deamination than in the amination direction, thus providing a robust technology for assay of the enzyme's activity. cDNAs prepared from the RNAs were subjected to restriction fragment differential display polymerase chain reaction analyses. Sequencing of the cDNA fragments showed that some of the RNA synthesized by GDH shared sequence homology with total RNA. Database searches showed that the RNA fragments shared sequence homologies with the G proteins, adenosine triphosphatase, calmodulin, phosphoenol pyruvate (PEP) carboxylase, and PEP carboxykinase, thus explaining the molecular mode of their functions in signal transduction.
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PMID:RNA synthetic activity of glutamate dehydrogenase: determination of enzyme purity, RNA characteristics, and deamination/amination ratio. 1559 15

We previously reported a genetic analysis of the growth-inhibitory effect caused by the overexpression of the Aspergillus oryzae rntA gene, encoding RNase T1 (Ribonuclease T1), in Saccharomyces cerevisiae. Subsequently, rns (ribonuclease T1 sensitive) mutants with mutations in the rns1 (DSL1), rns2 (UMP1), and rns3 (SEC17) genes, were identified. In the present study, rns4 (VPS32/SNF7) gene mutation was identified by complementation of tunicamycin sensitivity. While the rns4 mutant exhibited sensitivity to ambient stress conditions (200 mM CaCl(2), 1M NaCl and pH 8.0), genome-wide expression analysis revealed a similar pattern of genes up-regulated as was observed under nitrogen depletion condition by Gasch et al. [Mol. Biol. Cell 11 (2000) 4241]. Notably, the genes participating in autophagy (ATG4 and ATG8), the genes encoding a vacuolar protease (PRB1), vacuolar protease inhibitors (PAI3, PBI2 and TFS1) and YHR138c (a PBI2 homolog) were up-regulated in the rns4 mutant. Interestingly, the RNase T1*-GFP fusion protein (*inactive form) expressed in the rns4 mutant strain localized at the ER and vacuole under both stress or no-stress conditions. In contrast, the RNase T1*-GFP fusion protein expressed in the wild-type strain could not be detected under no-stress conditions, however, a stress-dependent localization of the fusion protein was observed at the vacuole. Since, the rns4 mutant exhibited a partial starvation-like response in spite of a rich ambient environment, leading to transportation of the secretory protein to the vacuole and accumulation in the endoplasmic reticulum, the present findings implicate a novel role for Rns4/Vps32 in proper response and adaptation to ambient conditions.
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PMID:Identification and characterization of rns4/vps32 mutation in the RNase T1 expression-sensitive strain of Saccharomyces cerevisiae: Evidence for altered ambient response resulting in transportation of the secretory protein to vacuoles. 1592 8

Carnivorous plants usually grow in nutrient-deficient habitats, and thus they partly depend on insects for nitrogen and phosphate needed for amino acid and nucleotide synthesis. We report that a sticky digestive liquid from a sundew, Drosera adelae, contains an abundant amount of an S-like ribonuclease (RNase) that shows high amino acid-sequence similarity to S-like RNases induced by phosphate starvation or wounding in normal plants. By giving leaves an RNase "coat", D. adelae seems to achieve two requirements simultaneously to adapt itself to its specific surroundings: it obtains phosphates from insects, and defends itself against pathogen attack.
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PMID:An S-like ribonuclease gene is used to generate a trap-leaf enzyme in the carnivorous plant Drosera adelae. 1622 72

Homogenates of leaflets of desiccated tomato plants show increased ribonuclease activity compared to homogenates of turgid controls. Much of this increase is independent of changes in translocation to and from the leaflet. Interruption of translocation through living cells by detachment of leaflets or steam damage to the petiolules produces increased ribonuclease activity, but this activity is increased further when excised leaflets are allowed to wilt. Increases in ribonuclease often parallel or precede increases in the soluble nitrogen content. Further increases in activity occur when excised leaves become yellow. Exposure of leaflets to CO(2)-free air has little effect on activity at low-light intensity (120 ft-c). These results suggest that water stress directly affected ribonuclease activity at the cellular level.
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PMID:Ribonuclease activity of stressed tomato leaflets. 1665 36


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