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E Gasior

Publications and source records attributed to E Gasior.

At least 37 records · Page 2Linked to original sources
PubMed1981

On the role of cyclic AMP-independent protein kinases in the modification of yeast ribosomal proteins in vivo.

Two proteins of yeast 40S ribosome subunit and four proteins of the 60S ribosome subunit were labelled in vivo with [32P]orthophosphate. Five of these proteins were phosphorylated by protein kinase 3, an enzyme which is cyclic AMP-independent and uses ATP and GTP as phosphoryl donors. Two proteins, belonging to the 60S ribosome subunit were phosphorylated by another, highly specific, cyclic AMP-independent protein kinase 1 B. Both in vivo and in vitro the most extensively phosphorylated protein species were acidic proteins, L44, L45 (according to the nomenclature of Kruiswijk & Planta, Molec. Biol. Rep., 1, 409-415, 1974) possibly corresponding to bacterial L7 and L12 proteins. The 40S ribosomal protein, S9, analogous to mammalian S6 protein, was phosphorylated in vivo but was not phosphorylated in vitro by either of the cyclic AMP-independent protein kinases. The obtained results clearly indicate that cyclic AMP-independent yeast protein kinases might be involved in the modification in vivo of some ribosomal proteins, in particular of the strongly acidic proteins of 60S ribosome subunit.

Cyclic AMP↗
PubMed1980

Evidence for a highly specific protein kinase phosphorylating two strongly acidic proteins of yeast 60 S ribosomal subunit.

Two distinct, cyclic AMP-independent protein kinase (ATP : protein photransferase, EC 2.7.1.37) from yeast have been isolated and highly purified. The first of the enzymes, protein kinase 1 A, phosphorylates casein and phosvitin, and its cellular protein substrate is unknown. The second enzyme, protein kinase 1 B, phosphorylates two strongly acidic proteins, L44 and L45, of the 60 S ribosomal subunit.

Adenosine Triphosphate↗
PubMed1979

The preparation and characterization of a cell-free system from Saccharomyces cerevisiae that translates natural messenger ribonucleic acid.

A cell-free protein-synthesizing system has been prepared from Saccharomyces cerevisiae by differential centrifugation of lysed spheroplasts. The preparation, a modified 100,000 x g supernatant fraction, contains ribosomes and monosomes, ribosomal subunits, translation factors, and aminoacyl-tRNA synthetases, but no polysomes. After removal of small amounts of remaining mRNA with micrococcal nuclease, protein synthesis is stringently dependent on the addition of mRNA, as well as amino acids and an energy-generating system. The 5'-cap analogue, 7-methylguanosine 5'-phosphate, inhibits translation of several natural mRNAs, but has no effect on chain elongation. Incubation of the polysome-free extract with natural mRNA leads to the formation of protein-synthesizing polysomes and eventually, to the release of protein; the molecular weight of the protein synthesized in the presence of BMV (brome mosaic virus) RNA is consistent with that of BMV coat protein.

Cations, Monovalent↗
PubMed1978

Isolation and properties of two protein kinases from yeast which phosphorylate casein and some ribosomal proteins.

Three fractions of protein kinase from postribosomal supernatant of Saccharomyces cerevisiae, active in phosphorylation of casein, were resolved on DEAE-cellulose. Two of these fractions: protein kinase 1 and protein kinase 3, were further purified about 1000 and 1800-fold respectively. The kinase 1 appeared to exist as a monomer with a molecular weight of 50 000 and utilized only ATP as phosphoryl donor. The protein kinase 3 was an aggregated form of enzyme with a molecular weight of above half a million and used both ATP and GTP for protein phosphorylation. Both isolated enzymes showed variations in respect to Michaelis constants, and inhibitory effects exerted by monovalent cations and nucleotide phosphates. The activity of the kinases was not affected by the presence of cAMP (adenosine 3':5'-monophosphate) or cGMP, however, only protein kinase 1 appeared to be a cAMP nucleotide-independent enzyme. Despite these differences both enzymes equally phosphorylated two strongly acidic proteins of the 60-S ribosome subunit, possibly related to L7, L12 of Escherichia coli.

Adenosine Triphosphate↗
PubMed1978

The effect of sulfhydryl reagents on the activity and stability of yeast ribosomes.

By titration with N-ethylmaleimide (MalNet) and p-chloromercuribenzoate (pCMB) of native yeast ribosomes, 40-43 SH groups were found, which represent about one third of the total SH groups present in these ribosomes. The reaction with pCMB proceeded fast, and that with MalNet was slow. The SH-blocking reaction led to inhibition of the ribosome activity. The activity of the MalNet-treated ribosomes in the polymerization reaction decreased concomitantly with the decrease of their activity in the enzymic and non-enzymic binding of phenylalanyl-tRNA and N-acetylphenylalanyl-tRNA. pCMB completely inactivated the ribosomes which seems to indicate that this reagent modified some SH groups which were not accessible to MalNet. The ribosome stability was affected by the blocking of the SH groups; in the buffered 0.5 M-KCl solution a significant portion of protein was detached from the modified ribosomes. Thus it appears that the SH groups of ribosomal proteins play some role in maintaining the ribosome structure.

Chloromercuribenzoates↗
PubMed1976

Ribosomal protein as substrate for a GTP-dependent protein kinase from yeast.

A protein kinase specific for casein and acidic ribosomal proteins was isolated and partly characterized. It was found that the enzyme utilizes GTP and ATP as phosphoryl donors. Its affinity for ATP was considerably higher than for GTP with the km values of 7.6 X 10(-6)M and 5.5 X 10(-5)M, respectively. Two-dimensional acrylamide gel electrophoresis revealed the phosphorylation of the same ribosomal proteins with either of the [gamma-32P] nucleotides used. It was also shown that one acidic protein (S1 or S2) of 40 S and two acidic proteins (L2 and L3) of 60 S ribosomal subunits were predominantly phosphorylated in vitro. The phosphorylated proteins: L2 and L3 seem to correspond to the proteins of L7 and L12 of E. coli ribosomes. The isolated kinase phosphorylated several basic ribosomal proteins though to a lower extent than the acidic ones.

Guanosine Triphosphate↗
PubMed1976

Effect of polaymines on yeast cell-free protein synthesizing system. I. Influence of spermine and spermidine on aminoacyl-tRNA transfer reaction.

Spermine and spermidine added to a Saccharomyces cerevisiae cell-free protein synthesizing system increased phenylalanine polymerization reaction several-fold at suboptimal concentration of Mg2+ and approximately two-fold at optimal amounts of Mg2+. The addition of polyamines greatly stimulated the enzymatic and nonenzymatic binding of phenylalanyl-tRNA and N-acetylphenylalanyl-tRNA to ribosomes. The binding of the acetylated derivative was higher than phenylalanyl-tRNA, however, as it was shown the former was bound exclusively to the A site of the ribosome. Contrary to the binding process, the puromycin reaction was not stimulated by spermine added at a concentration which enhanced the polyphenylalanine synthesis. These results indicate that polyamines have not only a sparing effect on the Mg2+ requirement for yeast protein synthesis in vitro and suggest that one of the possible sites of polyamines action might be the binding of aminoacyl-tRNA to ribosomes.

Cell-Free System↗
PubMed1976

Effect of polyamines on yeast cell-free protein synthesizing system. II. Increase stability of cell-free system in the presence of spermine.

The addition of spermine, at concentration which stimulates protein synthesis, to the yeast cell-free system significantly increases the thermal stability of the latter. Similar stabilizing effect of polyamine is observed for ribosome-poly U-ac-phe-tRNA complexes. These results suggest that the stimulatory effect of polyamines on the in vitro protein synthesis might be partly due to the increased stability of ribosomes and ribosome-peptydyl-tRNA complexes.

Cell-Free System↗
PubMed1976

Proteins of yeast ribosomal subunits: number and general properties.

1. Saccharomyces cerevisiae at the early stationary phase of growth accumulate 80 S ribosomes, easily dissociating into subunits, which retain full activity in phenylalanine polymerization in vitro. A simplified and efficient technique for large-scale preparation of yeast ribosomal subunits is proposed. 2. Presence of 34 proteins in 40 S subunit and 42 proteins in 60 S subunit was demonstrated by two-dimensional acrylamide-gel electrophoresis. Both ribosomal subunits contain acidic proteins: three in 60 S and six or seven in 40 S subunit. It seems that two of them correspond to prokaryotic proteins, L7 and L12. The total number of yeast ribosomal proteins is similar to those obtained for other Eukaryota.

Centrifugation, Zonal↗
PubMed1975

An in vivo and in vitro phosphorylation of yeast ribosomal proteins.

Phosphorylation of yeast ribosomal proteins has been demonstrated in vivo and in vitro. 32-P-labelled product represents an ester-linked class of phosphoprotein. Acrylamide-gel electrophoresis has shown that in both types of experiments radioactive proteins migrate similarly; this might indicate that closely related groups of proteins become phosphorylated in vivo and in vitro. In the presence of [32-P] ATP the amount of covalently bound phosphate was 1.0 - 1.2 moles/mole of ribosome. The phosphorylation of ribosomal proteins did not appreciably affect the activity of ribosomes in a cell-free protein-synthesizing system containing poly(U) and elongation factors.

Electrophoresis, Polyacrylamide Gel↗
PubMed1975

Isolation and some properties of colicin V preparations.

E. coli strain CLI(V) produces colicin V which can exist in two chemically different forms. A heat-stable, liposaccharide-protein complex is present as a main component of the cell wash. An intracellular colicin is a heat-labile and seems to be a simple protein. Preliminary experiments have shown that colicin V inhibits simultaneously synthesis of protein, RNA and DNA. Its mode of action is similar to colicins: E1, B, K and A.

Bacterial Proteins↗