Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Circular dichroism (CD) in the 240-300-nm region was used to study the conformation of DNA and RNA complexed with proteins in isolated nucleoli form HeLa cells. Deoxyribonuclease or ribonuclease digestion was employed to obtain (1) the individual CD spectra of nucleolar DNA or RNA in complex form with proteins, or in free form; and (2) the experimental CD baseline correction to exclude contributions from nonnucleic acid sources such as light scattering artifacts and proteins. The CD spectrum of nucleolar DNA in DNA-protein complexes was highly reduced in ellipticity in comparison with protein-free DNA. It showed a positive peak at 283 nm with a molar ellipticity [theta]283 = 1200 deg cm2 dmol-1 and a crossover at 262 nm. Addition of sodium dodecylsulfate shifted the peak to 276 nm with [theta]276 8000 deg cm2 dmol-1 and a crossover at 254 nm. The CD spectrum of nucleolar RNA in RNA-protein complexes was also reduced in comparison with protein-free RNA, showing a peak at 269 nm ([theta]269 = 6900 deg cm2 dmol-1), and a crossover at 250 nm. Addition of sodium dodecyl sulfate shifted the peak to 265 nm with [theta]265 = 18 000 deg cm2 dmol-1 and a crossover at 246 nm. The low ellipticity of both nucleolar DNA and RNA when complexed with proteins was increased by treatment with sodium chloride, urea, or heparin. This suggests that some ionic, hydrophobic, and hydrogen bondings are involved in the nucleic acid-protein interaction in nucleolar chromatin similar to that observed in nuclear chromatin.
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PMID:Circular dichroic studies of the DNA and RNA of nucleoli. 94 79

1. Crude extracts of the extreme halophile Halobacterium cutirubrum contain separable DNA-dependent and RNA-dependent RNA polymerases. 2. The RNA-dependent enzyme has been purified about 2800-fold. 3. It requires RNA, preferably of high molecular weight, and all four ribonucleoside triphosphates to incorporate (14)C-labelled nucleoside triphosphate into an acid-insoluble, ribonuclease-sensitive product. 4. Both the stability and activity of the RNA polymerase are relatively insensitive to changes in potassium chloride or sodium chloride concentration, but incorporation is stimulated by both Mg(2+) and Mn(2+). 5. The molecular weight of the enzyme is about 17000-18000.
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PMID:Nucleic acid enzymology of extremely halophilic bacteria. Halobacterium cutirubrum ribonucleic acid-dependent ribonucleic acid polymerase. 511 74

1. The ;30s' and ;50s' ribosomes from ribonuclease-active (Escherichia coli B) and -inactive (Pseudomonas fluorescens and Escherichia coli MRE600) bacteria have been studied in the ultracentrifuge. Charge anomalies were largely overcome by using sodium chloride-magnesium chloride solution, I 0.16, made 0-50mm with respect to Mg(2+). 2. Differentiation of enzymic and physical breakdown at Mg(2+) concentrations less than 5mm was made by comparing the properties of E. coli B and P. fluorescens ribosomes. 3. Ribonuclease-active ribosomes alone showed a transformation of ;50s' into 40-43s components. This was combined with the release of a small amount of ;5s' material which may be covalently bound soluble RNA. Other transformations of the ;50s' into 34-37s components were observed in both ribonuclease-active and -inactive ribosomes at 1.0-2.5mm-Mg(2+), and also with E. coli MRE600 when EDTA (0.2mm) was added to a solution in 0.16m-sodium chloride. 4. Degradation of ribonuclease-active E. coli B ribosomes at Mg(2+) concentration 0.25mm or less was coincident with the formation of 16s and 21s ribonucleoprotein in P. fluorescens, and this suggested that complete dissociation of RNA from protein was not an essential prelude to breakdown of the RNA by the enzyme. 5. As high Cs(+)/Mg(2+) ratios cause ribosomal degradation great care is necessary in the interpretation of equilibrium-density-gradient experiments in which high concentrations of caesium chloride or similar salts are used. 6. The importance of the RNA moiety in understanding the response of ribosomes to their ionic environment is discussed.
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PMID:The sedimentation behaviour of ribonuclease-active and -inactive ribosomes from bacteria. 532 3

The distribution of ribonucleases among bacteria has been determined from the examination of a wide variety of species. Bacteria that had been growing rapidly on a solid medium were harvested, treated with acetone and incubated in the presence of EDTA between pH4 and pH9. The ribonuclease activity was determined from the rate at which acid-soluble nucleotides were released. Out of nearly 200 strains examined, about 30 did not contain a detectable ribonuclease. The pH optima of ribonucleases in the remainder were sufficiently distinctive to suggest a use in taxonomy. Escherichia coli B was examined in more detail to determine the factors responsible for variations in the ribonuclease content of this bacterium. Growth rate had little influence on ribonuclease content when a complex medium containing no readily assimilable carbohydrate was used; the addition of glucose resulted in a marked increase in ribonuclease and a dependence of enzyme content on growth rate. An increase in the concentration of sodium chloride in the medium decreased the ribonuclease content of bacteria growing on it.
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PMID:Magnesium ion-independent ribonucleic acid depolymerases in bacteria. 533 80

The pattern of the degradation of various double-stranded polyribonucleotides by several ribonucleases (bovine RNAase A and its cross-linked dimer, bovine seminal RNAase, and pike-whale pancreatic RNAase) has been studied as a function of ionic strength and pH. It appears that (1) there is no direct correlation between the secondary structure of double-stranded RNA and its resistance against enzymatic breakdown, i.e., the stability of the secondary structure of double-helical RNA is not the main variable in the process. (2) The acstivity responses of the enzymes examined to changes of ionic strength and pH suggest that enzymic degradation of double-stranded RNA is mainly controlled by ion concentration, and that the process may fall within the phenomena interpreted by the theory of the ionic control of biochemical reactions advanced by Douzou and Maurel (Douzou, P. and Maurel, P. (1977) Proc. Natl. Acad. Sci. U.S.A. 74, 1013--1015). (3) The activity curves of the enzyme studied show, at a given pH, a shift toward higher ionic strengths as a function of the basicity of the enzyme protein. This finding explains the already observed correlation between number and/or density of positive charges of a ribonuclease molecule and its ability to attack double-stranded RNA in 0.15 M sodium chloride/0.015 M sodium citrate (SSC). (4) A careful analysis of the influence of ionic strength and pH on the reaction appears to be necessary in order to characterize a ribonuclease which shows activity towards double-stranded RNAs, and to allow a meaningful comparison between different enzymes capable of attacking these substrates.
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PMID:Ionic control of enzymic degradation of double-stranded RNA. 625 Jun 14

Hantaan virus, the prototype virus of hemorrhagic fever with renal syndrome, was examined for nucleic acid characteristics which would support its previously proposed inclusion in the virus family Bunyaviridae. Nucleocapsid RNA from Hantaan virions and a control bunyavirus were examined for ribonuclease A (RNase A) sensitivity. Both viruses exhibited a similar accessibility of RNA within nucleocapsids to digestion by RNase A. Complete digestion of the RNA of both viruses was affected with high concentrations of ribonuclease. Evidence for negative strand RNA polarity was obtained by an in vitro transcriptase assay. RNA dependent RNA polymerase activity was associated with Hantaan virions. Polymerase activity required manganese and nucleoside triphosphates and was enhanced by magnesium, 2-mercaptoethanol, and sodium chloride. Oligonucleotide map analysis of the large (L), medium (M), and small (S) genome segments of Hantaan virus demonstrated that each RNA species was unique with respect to each other and was different from host cell ribosomal RNA. A common 3' terminal sequence of the three genome segments was determined to be 3' AUCAUCAUCUG. This sequence is different from those reported for viruses within the four recognized genera of the Bunyaviridae. Because all other data were consistent with nucleic acid characteristics of the Bunyaviridae, we propose a separate genus within the Bunyaviridae with Hantaan as its prototype virs.
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PMID:Analysis of Hantaan virus RNA: evidence for a new genus of bunyaviridae. 641 60

Part of the RNA synthesized from nucleoside triphosphate precursors by partially purified RNA synthetase, an enzyme induced in Escherichia coli by the RNA-containing phage MS 2, is resistant to hydrolysis by ribonuclease. Upon heating in 0.15M sodium chloride, 0.015M sodium citrate followed by fast cooling the material becomes ribonuclease-sensitive with a sharp transition at 102 degrees to 104 degrees C. The suggestion that the ribonuclease-resistant product is double-stranded RNA is reinforced by restoration of the ribonuclease resistance of the heat-denatured material by reannealing at temperatures just below the transition point and by its buoyant density in cesium sulfate. It is suggested that double-stranded RNA is the replicative form of MS 2 phage RNA.
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PMID:DOUBLE-STRANDED RIBONUCLEIC ACID FORMATION IN VITRO BY MS 2 PHAGE-INDUCED RNA SYNTHETASE. 1406 44

The interaction between Rnc1, an RNA interactive protein, and a Pmp1 mRNA was investigated by affinity capillary electrophoresis (ACE). Prior to the ACE experiments, the column performances of three capillaries (an untreated fused silica capillary, a polybrene-polyacrylic acid (PB-PAA) double layer coating capillary, and a carboxylated capillary with a covalent modification) were studied with model proteins including ribonuclease B (RNase B) and bovine serum albumin (BSA). Using an untreated fused silica and a PB-PAA double layer coating capillaries, both of the protein peaks were broad and tailing. However, using a carboxylated capillary, the protein peaks were sharp and symmetric, and migration times were repeatable (RSD<0.4%). Further, the proteins in human serum also gave sharp peaks and its repeatability was kept at a high level by pre-treatment of a capillary inner wall with 1M sodium chloride solution before each run. An Rnc1 protein was analyzed by ACE with background electrolytes containing various concentrations of Pmp1 sense mRNA using a carboxylated capillary. Increase in the concentration of the mRNA was found to delay the migration time of the protein. But the migration time of the protein was kept constant with increasing Pmp1 anti-sense mRNA instead of Pmp1 sense mRNA. A straight line (r=0.987) was obtained by plotting 1/(migration time shift) versus 1/(Pmp1 sense mRNA concentration) and the association constant of Rnc1 protein with Pmp1 sense mRNA could be estimated to be 4.15x10(6)M(-1). These results suggest that the association constants of proteins with mRNAs as ligands were easily determined by the proposed method.
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PMID:In vitro assay of the interaction between Rnc1 protein and Pmp1 mRNA by affinity capillary electrophoresis with a carboxylated capillary. 2069 17

The effects of sodium thiocyanate, sodium chloride, and sodium sulfate on the ribonuclease barnase were studied using differential scanning calorimetry (DSC) and NMR. Both measurements reveal specific and saturable binding at low anion concentrations (up to 250 mM), which produces localized conformational and energetic effects that are unrelated to the Hofmeister series. The binding of sulfate slows intramolecular motions, as revealed by peak broadening in 13C heteronuclear single quantum coherence spectroscopy. None of the anions shows significant binding to hydrophobic groups. Above 250 mM, the DSC results are consistent with the expected Hofmeister effects in that the chaotropic anion thiocyanate destabilizes barnase. In this higher concentration range, the anions have approximately linear effects on protein NMR chemical shifts, with no evidence for direct interaction of the anions with the protein surface. We conclude that the effects of the anions on barnase are mediated by solvent interactions. The results are not consistent with the predictions of the preferential interaction, preferential hydration, and excluded volume models commonly used to describe Hofmeister effects. Instead, they suggest that the Hofmeister anion effects on both stability and solubility of barnase are due to the way in which the protein interacts with water molecules, and in particular with water dipoles, which are more ordered around sulfate anions and less ordered around thiocyanate anions.
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PMID:Molecular Mechanism for the Hofmeister Effect Derived from NMR and DSC Measurements on Barnase. 3145 55