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)

The experiments described in this paper and the following one establish the sequence of the 3'-OH terminal 159 nucleotides of turnip yellow mosaic virus RNA. Uniformly 32P-labeled turnip yellow mosaic virus RNA was partially digested with T1 ribonuclease and the fragments were fractionated by polyacrylamide gel electrophoresis. Fragments originating from the 3'-OH end of the RNA molecule were identified by testing for the 3'-terminal oligonucleotide, C-COH, after total U2 ribonuclease hydrolysis. Once identified, the 3'-OH terminal fragments were sequenced by the methods of Sanger et al. The first 51 nucleotides of the longest of the sequenced fragments (158 nucleotides) extends into the 3'-terminal part of the coat protein cistron. The coat protein cistron is followed by a stretch of 108 untranslated nucleotides whose function, though still unknown, is probably linked to the tRNA-like properties which have been attributed to the 3'-OH extremity of this viral RNA. Two possible secondary structures are proposed for the sequence and the implications of the findings with regard to the tRNA-like properties of the extremity are discussed.
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PMID:Nucleotide sequence (n=159) of the amino-acid-accepting 3'-OH extremity of turnip-yellow-mosaic-virus RNA and the last portion of its coat-protein cistron. 83 24

Previous work has revealed that 4S RNA is the primary species of RNA in the axoplasm from the giant axons of the squid and Myxicola. This study shows that axoplasmic 4S RNA from the squid giant axon has the functional properties of tRNA. Axoplasmic RNA was charged with amino acids by aminoacyl-tRNA synthetases prepared from squid brain. Tthe aminoacylation was prevented by incubating the RNA with RNase prior to running the reaction. The amino acid-RNA complex was labile at pH 9, which is characteristic of the acyl linkage between an amino acid and its tRNA. Aminoacyl-tRNA synthetase activity was also present in the axoplasm, primarily in the soluble fraction.
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PMID:The presence of transfer RNA in the axoplasm of the squid giant axon. 87 79

1. Large-scale isolation of tRNA from barley embryos is described, involving: phenol extraction, RNA deproteinization with the chloroform-isoamyl alcohol mixture, batch sorption on DEAE-cellulose, NaCl gradient elution of tRNA from DEAE-cellulose, and deaminoacylation of tRNA in the presence of bentonite. The procedure yielded tRNA free of protein and RNase activity. 2. The amino acid acceptor activity of the crude barley tRNA, its melting profiles and chromatographic patterns on Sephadex G-100 and BD-cellulose were similar to those of tRNA from other sources.
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PMID:Large-scale isolation of tRNA from barley embryos. 93 83

The pH 5 supernatant fractions prepared from homogenates of tissues of normal and dystrophic mice were used to study the incorporation of [14C]phenylalanyl-tRNA into peptide. The incorpoation was markedly reduced using the muscle pH 5 supernatant fraction from dystrophic animals but no reduction was seen with brain, liver or heart preparations from dystrophic mice. The lower incorporation with dystrophic muscle pH 5 supernatant was not due to altered activity of ribonuclease, elongation factors, proteolytic enzymes, GTP or sulfhydryl reagents, but was attributable to the presence of activity that was inhibitory to protein synthesis.
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PMID:Protein synthesis in dystrophic muscle. Activity of the pH 5 supernatant fraction of muscle in dystrophic mice. 95 5

Arginine was transferred from arginyl-tRNA to the amino-terminal end of chromatin proteins by L-arginyl-transferase. The reaction was dependent on the presence of potassium ion and beta-mercaptoethanol and was sensitive to RNase and trypsin. Treatment with DNase partially inhibited the transfer of arginine from arginyl-tRNA suggesting that intact chromatin structure is necessary for modification of chromatin. The radioactivity incorporated into chromatin was sensitive to trypsin but not to DNase or RNase. Most of the incorporated radioactivity was recovered in the phenol fraction, supporting the notion that modification of chromatin takes place in proteins but not in nucleic acids of chromatin. Modification of the proteins by transfer of arginine from arginyl-tRNA takes place mainly in the nonhistone fraction of chromatin. Major portions of chromosomal proteins modified in this manner appear to be released from chromatin. Incubation of incorporated radioactive product with [12C]arginyl-tRNA did not alter the product, showing that incorporated arginine is stable and does not exchange with added arginine or arginyl-tRNA. These observations suggest that aminoacyl-transferase may function in the modification of chromosomal proteins and that modification of chromatin may alter the regulatory mechanisms of cellular functions.
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PMID:Amino-terminal arginylation of chromosomal proteins by arginyl-tRNA. 99 Feb 69

Foetal rat liver extracts were found to have higher tRNA methylene activities than corresponding extracts of adult liver. When the specific activities were expressed per mg of liver or per mg of protein, the foetal tRNA methylating enzymes were respectively 2.5 and 6 times higher than those of adult livers. The presence of an inhibitor in adult liver can be excluded, since the same recoveries of total tRNA methylase activity were obtained after partial purification of both adult and foetal liver extracts: yields were close to 100%. The apparent Km's for the substrates in the methylating reactions were the same when tRNA methylases from either adult or foetal liver were used: values were 0.2 muM for Escherichia coli tRNA and 2.1 muM for S-adenosyl-L-methionine. After T1-T2 ribonuclease digestion of an in vitro methylated tRNA, similar methyl nucleotide patterns were observed in foetal and adult enzymatic extracts. It is concluded that the same tRNA methylase pool is present in adult and foetal liver. In addition, it is hypothesized that the different reaction rates exhibited by these enzymes might be due to the tRNA functional requirements rather than to the presence of a tRNA methylase inhibitor.
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PMID:Transfer ribonucleic acid methylase activity in adult and foetal rat liver. 101 53

With the use of a precursor to Escherichia coli tRNA-Tyr as a substrate, we have detected and partially purified a novel endoribonuclease from the cytoplasm of human KB tissue culture cells. This activity, which we have called RNase NU, cleaves the tRNA precursor at two sites in that part of the molecule which is not included in the mature tRNA sequence and which is normally degraded in vivo. In keeping with this observation, we have found that, of a variety of substrates tested, only those which are unstable in vivo are attacked by RNase NU. RNase NU can be purified from the 0.2 M NH4Cl wash of ribosomes followed by ammonium sulfate fractionation and DEAE-Sephadex chromatography. RNase NU cleaves RNA to create 3'-phosphate-terminated oligonucleotides. It has a pH optimum near 8.0, requires either a monovalent cation (NH4+ is most efficient) or Ca-2+ for optimal activity, and is inhibited by 0.1 M PO4-3-. In the course of purifying RNase NU we have detected and studied the intracellular distribution of other ribonuclease activities in human KB cells.
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PMID:Partial purification and properties of an endoribonuclease isolated from human KB cells. 108 59

(1) By incubation in 0.1 M NaOH for 10 min at room temperature, it is possible to "saponify" some of the methyl carboxylate linkages in bulk yeast tRNA. By incubation with S-adenosyl(Me-14-C)methionine and either homologous (yeast) or heterologous (wheat-embryo) enzymes, it is then possible to "re-esterify" the "saponified" tRNA and thereby effect selective labelling at 5-carboxymethyluridine (Me-14-C)methyl ester residues. (2) There is also selective labelling at 2-thio-5-carboxymethyluridine (Me-14-C)methyl ester residues when "saponified" yeast tRNA is incubated with S-adenosyl(Me-14-C)methionine and homologous (but not heterologous) enzymes. (3) When selectively labelled yeast tRNA is hydrolyzed by RNase T-1, both 5-carboxymethyluridine (Me-14-C)methyl ester and its 2-thio-analogue are released as part of large oligonucleotides, each of which contains roughly 10 nucleotide residues. (4) There are at least three, and possibly four (Me-14-C)methyl ester-containing oligonucleotides released by RNase T-1 digestion of selectively labelled "saponified" yeast tRNA. A comparison of the chromatographic properties of the different (Me-14-C)oligonucleotides suggests that the same 5-carboxymethyluridine residues are probably targets for both homologous and heterologous enzymes. (5) The properties of the selectively labelled oligonucleotides are consistent with the view that some of them probably are derived from yeast tRNA-3-Glu, tRNA-2-Lys, and tRNA-3-Arg, all of which are known to contain 5-carboxymethyl methyl esters as part of their anticodon sequences.
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PMID:Selective labelling ot the methyl carboxylate substituents found in the anticodon sequences of some species of yeast transfer RNA. 109 33

RNAs synthesized in Escherichia coli infected with virulent phages T4, T5, T7 and BF23 were labelled with 32PO4 3- after phage infection. [32P]RNAs of low molecular weight were separated by two-dimensional polyacrylamide gel electrophoresis, in which electrophoresis was carried out in two dimensions at different concentrations of acrylamide. The fractionated RNAs were characterized by RNA-fingerprint patterns made after T1 ribonuclease digestion. The two-dimensional gel of 10% yields 20% acrylamide was suitable for RNA of less than 200 nucleotides, while that of 5% yields 10% was preferred for RNAs of about 150--400 nucleotides. With T4 phage, 16 RNA species were separable on a single slab gel. Among those, 11 were identified as the known RNA species, including eight T4 tRNAs, one tRNA precursor and two non-tRNA molecules. In the case of T5 and BF23, more than 20 RNA species were separated on a slab gel; 15 or more RNAs were found in the 4-S RNA region, and several in 5-S and 6-S region. The RNA-fingerprint patterns of many BF23 RNAs were very similar to those of corresponding RNAs of T5. Pseudouridine and ribosylthymidine, minor nucleosides generally present in tRNA, were found in several BF23 4-S RNAs tested. Possibility of those BF23 4-S RNAs as tRNAs is discussed. With phage T7, three RNAs were detected, two of which were much smaller than tRNAs.
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PMID:Two-dimensional polyacrylamide-gel electrophoresis for purification of small RNAs specified by virulent coliphages T4, T5, T7 and BF23. 109 84

The fluorescence properties of the Y base of yeast tRNA-Phe are known to be quite sensitive to the environment. The fluorescence lifetime of the Y base in yeast tRNA-Phe is identical in orthorhombic crystals and in the mother liquor from which these crystals are grown. It is 10% higher than the lifetime observed in dilute solutions of tRNA. This small change is a solvent effect due to isopropyl alcohol in the crystallization medium. Isopropyl alcohol does not change the accessibility of the chromophore of the Y base as measured by iodide quenching rates in solution. The accessibility in intact tRNA-Phe is much less than in a ribonuclease digest. Thus, within the limits of the sensitivity of the method, the Y chromophore occupies the same environment in solution and in the crystal and it must be at least partially buried.
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PMID:A comparison of the fluorescence of the Y base of yeast tRNA-Phe in solution and in crystals. 109 57


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