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)

Norepinephrine GABA, cystein and SH-glutathione evoke a considerable decrease in the activity of alkaline RNase in the postmitochondrial fraction of the rat brain homogenate where the complex of this enzyme with its natural cytoplasmic protein inhibitor is preliminarily disturbed by the addition of pCMB. However these substances have no effect on the activity of alkaline RNase and its cytoplasmic protein inhibitor each taken separately. Evidently, the studied preparations may favour the reduction of the native state of the inactive complex of the enzyme with its inhibitor which was preliminarily disturbed by the pCMB addition.
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PMID:[Effect of norepinephrine, GABA and cysteine on the complex of alkaline ribonuclease with its protein inhibitor]. 4 77

Polysomes consisting of two to eight monosomes were isolated from yeast mitochondria by lysing the mitochondria with Triton X-100 and centrifugation in a 20 to 40% linear sucrose gradient. When yeast spheroplasts were pulse-labeled with [3H]-Leucine in the presence of cycloheximide to block cytoplasmic protein synthesis, radioactivity which was trichloroacetic acid-precipitable was present mainly in the polysome region. Incorporation of leucine was blocked by erythromycin, a specific inhibitor of mitochondrial protein synthesis. Release of radioactivity to the top of the gradient resulted from treating labeled polysomes with either puromycin or ribonuclease (in the latter case with the breakdown of polysomes), indicating that the radioactivity was present in nascent polypeptide chains. Yeast cells were grown in chloramphenicol for 3 hours and in fresh medium for 1 hour and then pulse-labeled with either [3H]leucine or [14C]formate. Three parameters showed a 2-fold increase in cells grown in chloramphenicol prior to pulse labeling: the polysome to monosome ratio, the amount of labeled precursor incorporated into proteins, and the rate of polypeptide chain initiation as judged by the formation of fMet-puromycin. Conversely, these parameters were all decreased approximately 50% in cells treated with cycloheximide prior to pulse labeling. Mitochondria were also isolated from cells previously grown in chloramphenicol or cycloheximide and incubated in vitro with [3H]leucine under optimal conditions. Acid-precipitable radioactivity in the polysome region was increased 3-fold in mitochondria from cells grown previously in chloramphenicol and decreased 75% in those grown in cycloheximide. Furthermore, chain initiation was deomonstrated in the isolated mitochondria by formation of fMet-puromycin. The rate of chain initiation in vitro was increased 2-fold in mitochondria isolated from chloramphenicol-treated cells.
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PMID:Regulation of mitochondrial protein synthesis at the polyribosomal level. 110 23

The formation of hydrogen-bonded structure in the folding reaction of ubiquitin, a small cytoplasmic protein with an extended beta-sheet and an alpha-helix surrounding a pronounced hydrophobic core, has been investigated by hydrogen-deuterium exchange labeling in conjunction with rapid mixing methods and two-dimensional NMR analysis. The time course of protection from exchange has been measured for 26 back-bone amide protons that form stable hydrogen bonds upon refolding and exchange slowly under native conditions. Amide protons in the beta-sheet and the alpha-helix, as well as protons involved in hydrogen bonds at the helix/sheet interface, become 80% protected in an initial 8-ms folding phase, indicating that the two elements of secondary structure form and associate in a common cooperative folding event. Somewhat slower protection rates for residues 59, 61, and 69 provide evidence for the subsequent stabilization of a surface loop. Most probes also exhibit two minor phases with time constants of about 100 ms and 10 s. Only two of the observed residues, Gln-41 and Arg-42, display significant slow folding phases, with amplitudes of 37% and 22%, respectively, which can be attributed to native-like folding intermediates containing cis peptide bonds for Pro-37 and/or Pro-38. Compared with other proteins studied by pulse labeling, including cytochrome c, ribonuclease, and barnase, the initial formation of hydrogen-bonded structure in ubiquitin occurs at a more rapid rate and slow-folding species are less prominent.
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PMID:Early hydrogen-bonding events in the folding reaction of ubiquitin. 131 11

The ability of a reconstituted cell-free system to transport mRNA as a ribonucleoprotein particle has been examined. Poly(A) messenger ribonucleoproteins (mRNPs), UV cross-linked after release from isolated liver nuclei in a cell-free system, exhibited a buoyant density of 1.33 g/cm3 in cesium sulfate and 1.47 g/cm3 in cesium chloride, values identical to those of poly(A) mRNP isolated directly from liver polysomes. Furthermore, the in vivo and in vitro transported mRNP showed a similar degree of resistance to RNase digestion and had sedimentation coefficients approximately 2.5 times that of the isolated mRNA. Release of both total mRNA and alpha 2 mu-globulin mRNA was proportional to the concentration of a specific cytoplasmic protein. Removal of the transport proteins from the cytosol with streptomycin sulfate provided a basal system incapable of supporting the active transport of alpha 2 mu-globulin mRNA. Hybridization of released RNA with a recombinant probe specific for intron 6 of alpha 2 mu-globulin showed that intron sequences were retained within the nucleus under optimal alpha 2 mu-globulin mRNA transport conditions and that the transported alpha 2 mu-globulin mRNA was of mature size.
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PMID:Active transport of messenger ribonucleoprotein particles in a reconstituted cell-free system. 244 44

Gelsolin is an actin regulatory protein which is unique among vertebrates in that it is found as both an intrinsic cytoplasmic protein and as a secreted plasma protein. We demonstrate that plasma and cytoplasmic gelsolins are derived by alternative transcriptional initiation sites and message processing from a single gene 70 kb long, containing at least 14 exons. Their message and amino acid sequences are identical except at the 5' end/NH2 termini. The cytoplasmic-specific 5' sequence is derived from two exons that encode untranslated sequence, while the plasma message-specific 5' sequence is derived from a single exon that encodes untranslated sequence, the signal peptide, and the first 21 residues of the plasma protein. The two transcriptional initiation sites are separated by greater than or equal to 32 kb. Biosynthetic and RNase protection studies indicate that a number of cell types make both plasma and cytoplasmic gelsolin in widely varying amounts and ratios.
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PMID:Genomic organization and biosynthesis of secreted and cytoplasmic forms of gelsolin. 282 82

The primary structure of the ribonuclease inhibitor from pig liver has been determined by amino acid sequence analysis. The N alpha-acetylated polypeptide chain of 456 amino acids consists of 15 homologous leucine-rich repeats, characterized by leucyl residues at constant positions. Two types of alternating repeats occur, 29 (A) and 28 (B) residues long. The degree of identity between repeats of a given type ranged from 25 to 60%. Only one deletion in the B-repeat was necessary to perfectly align the leucyl residues between the two repeats. Leucine-rich repeats have previously been found in four membrane-bound proteins and one extracellular protein, and their amphiphilic character suggested that they could be involved in membrane binding. Ribonuclease inhibitor is the first example of a cytoplasmic protein containing this type of repeat. It seems likely, therefore, that leucine-rich repeats can have functions other than forming membrane binding structures.
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PMID:Amino acid sequence of the ribonuclease inhibitor from porcine liver reveals the presence of leucine-rich repeats. 321 61

Bovine pancreatic ribonuclease (RNase) A and S protein (enzymatically inactive proteolytic fragment of RNase A which contains RNA binding site) stimulate the activation, as evidenced by increasing DNA-cellulose binding, of highly purified rat hepatic glucocorticoid-receptor complexes. These effects are dose dependent with maximal stimulation of DNA-cellulose binding being detected at approximately 500 micrograms (50 units of RNase A/mL). RNase A and S protein do not enhance DNA-cellulose binding via their ability to interact directly with DNA or to increase nonspecific binding of receptors to cellulose. Neither S peptide (enzymatically inactive proteolytic fragment which lacks RNA binding site) nor cytochrome c, a nonspecific basic DNA binding protein, mimics these effects. RNase A and S protein do not stimulate the conformational change which is associated with activation and is reflected in a shift in the elution profile of receptor complexes from DEAE-cellulose. In contrast, these two proteins interact with previously heat-activated receptor complexes to further enhance their DNA-cellulose binding capacity and thus mimic the effects of an endogenous heat-stable cytoplasmic protein(s) which also function(s) during step 2 of in vitro activation [Schmidt, T. J., Miller-Diener, A., Webb, M. L., & Litwack, G. (1985) J. Biol. Chem. 260, 16255-16262]. Preadsorption of RNase A and S protein to an RNase affinity resin containing an inhibitory RNA analogue, or trypsin digestion of the RNA binding site within S protein, eliminates the subsequent ability of these two proteins to stimulate DNA-cellulose binding of the purified receptors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of bovine pancreatic ribonuclease A, S protein, and S peptide on activation of purified rat hepatic glucocorticoid-receptor complexes. 379 Apr 97

The fps/fes proto-oncogene encodes a cytoplasmic protein-tyrosine kinase known to be highly expressed in hematopoietic cells. To investigate fps/fes biological function, an activating mutation was introduced into the human fps/fes gene which directs amino-terminal myristylation of the Fps/Fes protein. This mutant, myristylated protein induced transformation of Rat-2 fibroblasts. The mutant fps/fes allele was incorporated into the mouse germ line and was found to be appropriately expressed in transgenic mice, in a tissue-specific pattern indistinguishable from that of the endogenous mouse gene. These mice displayed widespread hypervascularity, progressing to multifocal hemangiomas. High levels of both the transgenic human and endogenous murine fps/fes transcripts were detected in vascular tumors by using RNase protection, and fps/fes transcripts were localized to endothelial cells of both the vascular tumors and normal blood vessels by in situ RNA hybridization. Primary human umbilical vein endothelial cultures were also shown to express fps/fes transcripts and the Fps/Fes tyrosine kinase. These results indicate that fps/fes expression is intrinsic to cells of the vascular endothelial lineage and suggest a direct role of the Fps/Fes protein-tyrosine kinase in the regulation of angiogenesis.
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PMID:The Fps/Fes protein-tyrosine kinase promotes angiogenesis in transgenic mice. 752 58

The raf proto-oncogenes encode cytoplasmic protein serine/threonine kinases, which play a critical role in cell growth and development. One of these, A-raf-1 (human gene symbol, ARAF1), which is predominantly expressed in mouse urogenital tissues, has been mapped to an evolutionarily conserved linkage group composed of ARAF1, SYN1, TIMP, and properdin located at human chromosome Xp11.2. We have isolated human genomic DNA clones containing the expressed gene (ARAF1) on the X chromosome and a pseudogene (ARAF2) on chromosome 7p12-q11.21. Analysis of the nucleotide sequence from the ARAF1 genomic clones demonstrated that it consists of 16 exons encoded by minimally 10,776 nucleotides. The major transcriptional start site (+1) was determined by RNase protection and primer extension assays. Promoter activity was confirmed by functional assays using DNA fragments fused to a CAT reporter gene. The ARAF1 minimal promoter, located between nucleotides -59 and +93, has a low G + C content and lacks consensus TATA and Inr sequences but shows sequence similarity at position -1 to the E box that is known to interact with USF and TFII-I transcription factors.
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PMID:The complete sequence and promoter activity of the human A-raf-1 gene (ARAF1). 802 Sep 55

Ribonuclease inhibitor is a cytoplasmic protein that tightly binds and inhibits ribonucleases of the pancreatic ribonuclease superfamily. The primary sequence of this inhibitor contains leucine-rich repeats (LRRs); these motifs are present in many proteins that participate in protein-protein interactions and have different functions and cellular locations. In vivo, ribonuclease inhibitor may have a role in the regulation of RNA turnover in mammalian cells and in angiogenesis. To define the structural features of LRR proteins and to understand better the nature of the tight interaction of ribonuclease inhibitor with ribonucleases, we have determined the crystal structure of the porcine inhibitor. To our knowledge, this is the first three-dimensional structure of a protein containing LRRs and represents a new class of alpha/beta protein fold. Individual repeats constitute beta-alpha structural units that probably also occur in other proteins containing LRRs. The non-globular shape of the structure and the exposed face of the parallel beta-sheet may explain why LRRs are used to achieve strong protein-protein interactions. A possible ribonuclease-binding region incorporates the surface formed by the parallel beta-sheet and the beta alpha loops.
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PMID:Crystal structure of porcine ribonuclease inhibitor, a protein with leucine-rich repeats. 826 99


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