Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The nature of the interaction between the RNA and the protein component in the yeast 5 S rRNA-L1a complex was assessed using fluorescence and controlled proteolytic and RNase digestion. (a) Influence of L1a on the RNA conformation was monitored by ethidium fluorescence and controlled RNase T1 digestion. The complex was digested with alpha-chymotrypsin, Staphylococcus aureus protease V8, subtilisin, or trypsin. Both termini of L1a in the complex were readily accessible to proteases. Proteolytic digestion of the complex resulted in a reduction in fluorescence intensity if ethidium was added after proteolysis. No change was observed when ethidium was allowed to react with the complex prior to proteolysis. Neither the rate of proteolysis nor the resultant peptide pattern was affected by the presence of ethidium. T1 digestion of intact RNP and trypsin-treated RNP produced different oligonucleotide patterns. Both the fluorescence and the T1 digestion data suggest that the conformation of the RNA moiety was influenced by the protein. (b) Influence of the RNA molecule on L1a conformation in the complex was monitored by limited proteolysis. Whereas the protein in the complex was relatively sensitive to proteases, free protein was completely resistant to digestion under identical conditions. The trypsin sensitivity of L1a in complexes containing different truncated 5 S RNA molecules was studied also. Upon removal of residues 31-49 of the 5 S RNA molecule, L1a in the complex became resistant to proteolysis. These results are interpreted in a model in which specific regions of both the RNA and the protein are involved in the interaction.
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PMID:Probing the yeast 5 S RNA-protein complex by fluorescence and controlled proteolytic digestion. 240 92

During or immediately after transcription of chromatin the high molecular weight pre-mRNA is complexes with proteins and low molecular weight RNA (lmwRNA). In the presence of a cytosolic RNase inhibitor pre-mRNA-protein complexes, designated as polyparticles, can be isolated from rat liver nuclei. The polyparticles are characterized by a maximum of their sedimentation coefficient of around 90 S, a protein to RNA ratio of 4.1, and a density in CsCl of 1.4 g/cm3. A set of 6--10 basic proteins of molecular weights between 30 and 45 kd as well as a multitude of polypeptides of higher molecular weights is associated with the rapidly labeled, polydisperse, high molecular weight RNA and several lmwRNA species. In order to study the structure of these very complex nuclear RNP complexes, the polyparticles were incubated at various concentrations of sodium chloride, urea or proteinases of different specificities (trypsin, chymotrypsin, proteinase K), recentrifuged through a sucrose layer and analyzed with respect to their sedimentation behavior, their protein to RNA ratios and their protein- and RNA components. Rhe results of these experiments led us to the proposal of a structural model which is presented here.
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PMID:The structure of ribonucleoprotein particles from rat liver nuclei. 701 68

To cross-link the 3'-terminus of 5 S RNA to its neighbouring proteins, ribosomal 60 S subunits of rat liver were oxidized with sodium periodate and reduced with sodium borohydride. 5 S RNP was then isolated by EDTA treatment followed by sucrose density-gradient centrifugation and subjected to SDS-polyacrylamide gel electrophoresis. The protein with a slower mobility than the L5 protein, which was thought to be cross-linked 5 S RNP, was labeled with 125I, treated with RNAase, and analyzed by two-dimensional polyacrylamide gel electrophoresis, followed by radioautography. A radioactive spot located anodically from L5 protein was observed, suggesting that it is the L5 protein-oligonucleotide complex. When analyzed by SDS slab polyacrylamide gel electrophoresis followed by radioautography, the peptide pattern of the alpha-chymotrypsin digest of this 125I-labeled protein-oligonucleotide complex was similar to that of the digest of 125I-labeled L5 protein. The results indicate that L5 protein binds to the 3'-terminal region of 5 S RNA in rat liver 60 S subunits.
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PMID:Identification of the protein cross-linked to 3'-terminus of 5 S RNA in rat liver ribosomal 60 S subunits. 708 73