Showing papers on "Ribosomal protein published in 1976"
TL;DR: Three proteins of the 60 S ribosomal subunit are "exchangeable" in vivo, two of which are phosphoproteins, one of which is the very acidic protein possibly related to L7/L12 of E. coli.
249 citations
TL;DR: The observation that the Met-tRNAf binding factor is phosphorylated by PC2 supports the hypothesis that this initiation factor is a target for the action of the translational inhibitor activated in heme deficiency.
Abstract: A previous study demonstrated that the translational inhibitor from lysates of heme-deficient rabbit reticulocytes is associated with a protein kinase activity Chromatography of this inhibitor preparation on phosphocellulose yields two distinct protein kinase activities, PC1 and PC2 PC1, which consitutes about 90% of the activity in the unresolved preparation, does not inhibit protein synthesis in lysates, but actively phosporylates calf thymus histone II in a 3':5'-cyclic AMP-denpendent reaction PC2 contains the translational inhibitor, phosphorylates histone poorly, and is not cyclic AMP-dependent While [gamma-32P]ATP as the phosphate donor, the two kinase fractions were analyzed with the putative substrates, salt-washed 40S ribosomal subunits, and the initiation factor that mediates the binding of Met-tRNAf to the 40S subunit PC1 is inactive with the initiation factor, but phosphorylates 40S subunits at a single major site that migrates as a 31,000-dalton band in sodium dodecyl sulfate-acrylamide gels; phosphorylation requires cyclic AMP Similar phosphorylation of the reticulocyte 40S site (31,000 daltons) can be demonstrated with other cyclic AMP-dependent kinases from reticulocytes, rat liver, and bovine heart muscle PC2 phosphorylates the small subunit (38,000 daltons) but not the large subunit(s) of the initiation factor; the reaction does not require cyclic AMP PC2 does not phosphorylate 40S subunits In the presence of 40S subunits, the initiation factor appears to be rapidly bound in a manner that effectively blocks phosphorylation of the initiation factor by PC2; under the same conditions phosphorylation of the 40S subunit by PC1 is not affected The initiation factor has been shown to reverse the inhibitions of protein chain initiation induced in lysates by heme deficiency, double-stranded RNA, oxidized glutathione, or the purified translational inhibitor The observation that the Met-tRNAf binding factor is phosphorylated by PC2 supports the hypothesis that this initiation factor is a target for the action of the translational inhibitor activated in heme deficiency
187 citations
TL;DR: The results suggest that the synthesis of more than 40 ribosomal proteins is under coordinate control, and the coordinate regulation appears not to be influenced directly by the rate of transcription of Ribosomal precursor RNA.
Abstract: We have developed a method of r the direct measurement, in eukaryotic cells, of the synthesis of ribosomal proteins, irrespective of the synthesis of ribosomes. In this way the synthesis of ribosomal proteins has been examined in mutant strains of Saccharomyces cerevisiae, which are unable to synthesize ribosomes under nonpermissive conditions. The results suggest that the synthesis of more than 40 ribosomal proteins is under coordinate control. Under nonpermissive conditions,the synthesis of each h protein declines exponentially to a basal level which is 10-20% fo normal. The kinetics of that decline suggest that an early, if not primary, result of the nonpermissive conditions is the cessation of production of new mRNA for eac of the ribosomal proteins. The coordinate regulation appears not to be influenced directly by the rate of transcription of ribosomal precursor RNA.
172 citations
TL;DR: Acetone precipitation is a rapid and efficient method for concentrating ribosomal proteins and permits the elimination of sodium dodecylsulphate or urea from protein solutions containing these compounds.
Abstract: Acetone precipitation is a rapid and efficient method for concentrating ribosomal proteins. This procedure also permits the elimination of sodium dodecylsulphate or urea from protein solutions containing these compounds. Acetone-precipitated 30-S ribosomal proteins can be used for the reconstitution of active 30-S ribosomal subunits.
168 citations
TL;DR: The data persuade us that there is no unique protein species corresponding to L8 in the E. coli ribosome and the stability and specificity of the aggregate formed between L7/L12 and LlO suggest that these proteins are immediate neighbors bound to each other in the intact SOS subunit.
154 citations
TL;DR: Most ribosomal proteins on cytoplasmic ribosomes were found to have uniform, high stability as measured by comparing the short term (12-hour) to steady state (3-day) labeling ratios determined for each ribsomal protein.
148 citations
TL;DR: The complete amino acid sequence of ribosomal protein L34 has been established by improved micro techniques with 3 mg of the lyophilized protein by the combined micro dansyl-Edman technique.
Abstract: The complete amino acid sequence of ribosomal protein L34 has been established by improved micro techniques with 3 mg of the lyophilized protein. The protein was digested with trypsin, thermolysin and chymotrypsin and the resulting peptides were isolated from fingerprints performed on cellulose thin-layer plates. The amino acid sequences of the peptides were determined by the combined micro dansyl-Edman technique using 5 - 10 nmol per sample. Aspartic acid and glutamic acid were distinguished from their amides by use of the color reaction of ninhydrin with the respective amino acid phenylthiohydantoins.
123 citations
TL;DR: The results suggest that HF and possibly S1, through their interaction with the 3'-terminal region of Q beta RNA, are directly involved in the recognition of the 6' end of Qbeta RNA by Qbeta replicase.
119 citations
TL;DR: Initiation factor IF-E3 from rabbit reticulocytes was isolated from a high salf extract of ribosomes prepared according to the procedure of Schreier and Staehelin and bound stoichiometrically to 40S ribosomal subunits, but not to 60S or 80S Ribosomes.
Abstract: Initiation factor IF-E3 from rabbit reticulocytes was isolated from a high salf extract of ribosomes prepared according to the procedure of Schreier and Staehelin (J. Mol9 Biol, 73, 329-349, 1973). The factor was highly purified from the crude extract by ammonium sulfate fractionation, sucrose gradient centrifugation, salf gradient elution from DEAE-cellulose and phosphocellulose columns, and glycerol gradient centrifugation. IF-E3 stimulated cell-free protein synthesis dependent on an exogenous globin mRNA fraction 4- to 5-fold. The factor under nondenaturing conditions behaved as a large multipolypeptide complex, but was separated into 11 major protein components by two-dimensional polyacrylamide gel electrophoresis with urea and sodium dodecyl sulfate. The stoichiometry and molecular weights (range: 28,000-140,000) of the IF-E3 proteins were determined. None of the components corresponded to ribosomal proteins found in high salt-washed ribosomes. 14CH3-IF-E3 was prepared by reductive alkylation without detectable loss of its initiation factor activity, and bound stoichiometrically to 40S ribosomal subunits, but not to 60S or 80S ribosomes. 14CH3-IF-E3 isolated from the 40S complex contained only nine of the 11 original protein components.
119 citations
TL;DR: Almost 90% of the total number of proteins which theoretically can be encoded on the λdrifd18 have been identified on the two-dimensional Gel electrophoresis technique sensitive to changes in isoelectric point and molecular weight.
Abstract: The presence of EF-Tu, RNA polymerase subunit alpha, and EF-G on the lambdadfus-3 genome and EF-Tu, ribosomal proteins L7/L12, and RNA polymerase subunit beta on the lambdadrifd 18 genome has been confirmed using a two-dimensional gel electrophoresis technique sensitive to changes in isoelectric point and molecular weight. In this system two EF-Tu gene products could not be resolved. Following infection of ultraviolet light-irradiated Escherichia coli with either lambdadfus-3 or lambdadrifd18, the EF-Tu gene, tufA, near 65 minutes on the genetic map is expressed as 3-4 copies per EF-G molecule. The EF-Tu gene, tufB, near 79 minutes on the genetic map, is expressed at about one-third of this rate. alpha is expressed as 1 copy per EF-G molecule, beta as 0.14 per EF-G molecule and L7/L12 as 2.5 per EF-G. These figures compare well with the relative amounts found in exponentially-growing cells, in which the ratio of EF-Tu to EF-G is approximately 5. Almost 90% of the total number of proteins (calculated on a molecular weight basis) which theoretically can be encoded on the lambdadrifd18 have been identified on the two-dimensional gel.
94 citations
TL;DR: The Phosphorylation of Enzymes and Proteins: A Possible Basis for Cell Polarity and the Regulation of Cell Division is examined.
Abstract: Introduction 349 How Protein Phosphorylation Came to be Recognized as an Important Control Phenomenon 350 Phosphorylation of Enzymes . .. . 352 Phosphorylation of Nuclear Acidic Proteins: The Key to Genomic Control? 352 Histone Phosphorylation and the Regulation of Cell Division 355 Microtubule Phosphorylation and Aggregation 358 The Enigma of Ribosomal Protein Phosphorylation 359 Membrane Protein Phosphorylation: A Possible Basis for Cell Polarity . . . . . . . . . . . . . . . . . . 362 Phosphorylation of Organ-Specific Protei�s 365 Are Protein Kinases and Protein Phosphorylation Essential for Viral Infection? .... 366 Is there Cyclic AMP in Plants? 366
TL;DR: It can be shown that reversion to stringency in one of the relaxed mutants of Escherichia coli occurs simultaneously with a reversion of the L11 protein to its normal mobility.
Abstract: Relaxed mutants of Escherichia coli have been isolated which have an altered electrophoretic mobility of ribosomal protein L11. It can be shown that reversion to stringency in one of these mutants occurs simultaneously with a reversion of the L11 protein to its normal mobility. The L11 structural gene, rplK, maping near rif, is carried by the bacteriophage λcI857S7drifd18, and is most likely identical with relC.
TL;DR: A comparison has been made between the ribosomal proteins phosphorylated in intact cells and proteins isolated from Ribosomal subunits after modification in vitro by purified protein kinases and [gamma-32P]ATP.
Abstract: A comparison has been made between the ribosomal proteins phosphorylated in intact cells and proteins isolated from ribosomal subunits after modification in vitro by purified protein kinases and [gamma-32P]ATP. When intact reticulocytes were incubated for 2 h in a nutritional medium containing radioactive inorganic phosphate, one phosphorylated protein was identified as a 40S ribosomal component using two-dimensional polyacrylamide gel electrophoresis followed by electrophoresis in a third step containing sodium dodecyl sulfate. This protein, containing 99% of the total radioactivity associated with ribosomal proteins as observed by two-dimensional electrophoresis, is found in a nonphosphorylated form in addition to several phosphorylated states. These states differ by the number of phosphoryl group attached to the protein. The same 40S protein is modified in vitro by the three cAMP-regulated protein kinases from rabbit reticulocytes. Two additional proteins associated with the 40S subunit are phosphorylated in situ. These proteins migrate as a symmetrical doublet, and contain less than 1% of the radioactive phosphate in the 40S subunit. A number of phosphorylated proteins associated with 60S subunits are observed by disc gel electrophoresis after incubation of whole cells with labeled phosphate. These proteins do not migrate with previously identified ribosomal proteins and are not present in sufficient amounts to be identified as ribosomal structural proteins. Proteins in the large subunit are modified in vitro by cAMP-regulated protein kinases and ATP, and these modified proteins migrate with known ribosomal proteins. However, this phosphorylation has not been shown to occur in intact cells.
TL;DR: A large number of them (25 mutants) have mutations in protein S4 of the small subunit, while four mutants showed alterations in protein L6 of the large subunit that are important for structural and functional analyses of ribosomes.
Abstract: The ribosomal proteins of temperature-sensitive mutants of Escherichia coli isolated independently after mutagenesis with nitrosoguanidine were analyzed by two-dimensional gel electrophoresis. Out of 400 mutants analyzed, 60 mutants (15%) showed alterations in a total of 22 different ribosomal proteins. The proteins altered in these mutants are S2, S4, S6, S7, S8, S10, S15, S16, S18, L1, L3, L6, L10, L11, L14, L15, L17, L18, L19, L22, L23 and L24. A large number of them (25 mutants) have mutations in protein S4 of the small subunit, while four mutants showed alterations in protein L6 of the large subunit. The importance of these mutants for structural and functional analyses of ribosomes is discussed.
TL;DR: Experiments using inhibitors of protein synthesis showed that one of these protiens, S-4a (apparent M r =52,000), is synthesized inside the mitochondria, whereas all other mitochondrial ribosomal proteins are synthesized in the cytosol.
TL;DR: The phosphorylation of ribosomal proteins in HeLa cells infected with vaccinia virus is examined in the search for possible regulatory changes in the protein synthesising apparatus of virus-infected cells.
Abstract: MODIFICATION of ribosomal proteins has been suggested as a mechanism controlling protein biosynthesis1. In vivo and in vitro phosphorylation of eukaryotic ribosomal proteins has been described and its possible functional relevance discussed2–5. Two-dimensional polyacrylamide gel electrophoresis has shown that only one, small ribosomal subunit protein, S6, is phosphorylated in rat liver6. The number of phosphoserine residues in this protein increases by an order of magnitude during liver regeneration6 and also after administration of inhibitors of protein synthesis7. In addition, when Escherichia coli is infected with bacteriophage T7, various host cell proteins, including some ribosomal proteins, are phosphorylated8. In our search for possible regulatory changes in the protein synthesising apparatus of virus-infected cells, we have now examined the phosphorylation of ribosomal proteins in HeLa cells infected with vaccinia virus.
TL;DR: The proteins of the small subunit of rat liver ribosomes were separated into five groups by stepwise elution from carboxymethylcellulose with LiCl at pH 6.5; several proteins had no detectable contamination and the impurities in the others were no greater than 9%.
TL;DR: The total sum of these two components appears to be at least three and possibly four copies per ribosome and the fraction of L12 found varies from 25% to 85% during the growth cycle of the bacteria.
TL;DR: Ribosomal 30S protein S1 causes disruption of the secondary structure of certain pyrimidine-containing polynucleotides, which are stoichiometrically converted by S1 to structures indistinguishable from their partially or completely thermally denatured forms, as revealed by circular dichroism.
Abstract: Ribosomal 30S protein S1 causes disruption of the secondary structure of certain pyrimidine-containing polynucleotides. Helical poly(U), poly(C, U), and neutral and acidic poly(C) are stoichiometrically converted by S1 to structures indistinguishable from their partially or completely thermally denatured forms, as revealed by circular dichroism. Of the several double- and triple-stranded helical polynucleotides tested that contain one polypurine strand and at least one polypyrimidine strand, only the conformation of the DNA.RNA hybrid, poly(A)-poly(dT), is perturbed. In the presence of S1, this hybrid undergoes a transition to a new structure that has a circular dichroism spectrum unlike either the native or thermally denatured forms. Intercalated ethidium bromide is released from poly(A)-poly(dT) by S1, confirming the occurrence of a conformational rearrangement. The translation inhibitor, autintricarboxylic acid, completely inhibits the action of S1 on polypyrimidines, but has no effect on the conformational perturbation of poly(A(-poly(dT). The possible relation between these observations and the biological function of protein S1 is discussed.
TL;DR: The 30S ribosomal subunit of Bacillus stearothermophilus migrated as a single band when electrophoresed on agarose-acrylamide composite gels and the addition of the ribosome protein S1 purified from Escherichia coli resulted in the appearance of an additional band migrating more slowly; 14C-labeled S1 of E. coli was shown to be associated only with this form.
Abstract: The 30S ribosomal subunit of Bacillus stearothermophilus migrated as a single band when electrophoresed on agarose-acrylamide composite gels. The addition of the ribosomal protein S1 purified from Escherichia coli resulted in the appearance of an additional band migrating more slowly; 14C-labeled S1 of E. coli was shown to be associated only with this form. Antibody against E. coli protein S1 did not crossreact with either the total 30S ribosomal proteins or the postribosomal supernatant from B. stearothermophilus. These results indicate that B. stearothermophilus lacks a protein equivalent to E. coli S1 and may explain our previous finding [Eur. J. Biochem. 56, 15-22 (1975) that E. coli S1 greatly stimulated the translation by B. stearothermophilus ribosomes of f2 phage RNA.
TL;DR: The synthesis of the α and β subunits of RNA polymerase and several of the aminoacyl-tRNA synthetases is either not subject to the influence of the stringent control system, or is subject to additional regulatory constraints.
Abstract: The effects of a partial restriction of valyl-tRNA aminoacylation on the synthesis of aminoacyl-tRNA synthetases, ribosomal proteins, and other translation and transcription proteins were examined in otherwise isogenic stringent (relA+) and relaxed (relA1) derivatives of E. coli B. The synthesis of individual ribosomal proteins, elongation factor G, and to a lesser extent elongation factors Tu and Ts, and the valyl- and arginyl-tRNA synthetases was found to be subject to the influence of the stringent control system. The synthesis of the α and β subunits of RNA polymerase and several of the aminoacyl-tRNA synthetases, in contrast, is either not subject to the influence of the stringent control system, or is subject to additional regulatory constraints.
TL;DR: In this paper, a number of novel observations on ribosomal metabolism were made during gametic differentiation of Chlamydomonas reinhardi, and the amount of chloroplast and cytoplasmic ribosomes decreased steadily.
TL;DR: The proteins of the large subunit of rat liver ribosomes were separated into seven groups by stepwise elution from carboxymethylcellulose with LiCl at pH 6.5 and the amino acid composition was determined.
TL;DR: The phosphorylation of rat liver ribosomal protein was markedly increased by diabetes, and reduced towards the normal level by insulin administration, and the possibility that cyclic AMP is the mediator of the phosphorylated of S6 was considered.
Abstract: ONLY one rat liver ribosomal protein (S6) is phosphorylated in vivo1 During hepatic regeneration the phosphorylation of S6 is increased by an order of magnitude, and derivatives are generated (in some experiments as many as five) which contain increasing numbers of phosphoserine residues1 Very similar changes in the phosphorylation of S6 are caused by administration to animals of glucagon or cyclic AMP (AMG and IGW, unpublished) Indeed, a number of hormones including adrenocorticotrophic hormone (ACTH)2 and thyroid hormone3 increase the phosphorylation of ribosomal protein, although in the latter instances, the identity of the phosphoprotein has not been established These observations have led us to consider the possibility that cyclic AMP is the mediator of the phosphorylation of S6 (ref 4) The concentration of cyclic AMP in the liver is increased in diabetic animals and restored to normal by insulin5, although it is still moot whether the effect of the hormone on the level of the cyclic nucleotide accounts for all (or even any) of its actions on hepatic cells6 We have tested the effect of experimental diabetes and of insulin administration on the phosphorylation of rat liver ribosomal protein: the phosphorylation of S6 was markedly increased by diabetes, and reduced towards the normal level by insulin administration
TL;DR: The kinetics of appearance of newly formed 26-S and 17-S rRNA in mature ribosomes show that the maturation of the large ribosomal subunit takes about twice as much time as that of the small subunit.
TL;DR: Mutant VT, which was derived from A19, shows a novel type of streptomycin dependence and has an altered ribosomal protein S8, which probably are the result of the altered S8.
Abstract: A strain of E. coli K12 has been isolated which gives rise to mutations in a large number of ribosomal proteins. Mutant VT, which was derived from A19, shows a novel type of streptomycin dependence and has an altered ribosomal protein S8. Streptomycin-independent isolates from mutant VT contain a great variety of changed proteins on two-dimensional polyacrylamide gels. 120 revertants screened in this way have changes in thirteen 30S proteins and fifteen 50S proteins. Several mutants were found in which additional proteins are present on the ribosome. Further, there is one instance of a ribosomal protein (L1) being absent, and one of apparent doubling of a ribosomal protein (L7/12). The unique properties of mutant VT probably are the result of the altered S8.
TL;DR: It is shown that low concentrations of guanosine tetraphosphate specifically inhibit DNA-dependent r protein synthesis in this system, and that this inhibition takes place directly, rather than as a consequence of the inhibition of rRNA synthesis by ppGpp.
TL;DR: It was observed that methylation of ribosomal proteins occurs in both subunit proteins of HeLa cytoplasmic ribosome with N G , N G -dimethylarginine as the major methylated amino acid.
TL;DR: Proteins L7L12 are involved in several functions related to aminoacyl and peptidyl sites on the ribosome; the depletion and reconstitution experiments provide a direct possibility of correlating the changes in the fine structure of ribosomes with their biological function.
TL;DR: A specially designed apparatus and conditions are described for the rapid analysis of ribosomal proteins by two-dimensional gel electrophoresis on a micro scale, which is comparable to that obtained with other systems but because of miniaturization.
Abstract: A specially designed apparatus and conditions are described for the rapid analysis of ribosomal proteins by two-dimensional gel electrophoresis on a micro scale. The resolution of proteins in electropherograms is comparable to that obtained with other systems, but because of miniaturization, only 0.5 to 1 mug of each protein is required, and the entire procedure, including electrophoresis in both dimensions, and staining and destaining can be completed in 6 to 7 hours.