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G Stöffler

Publications and source records attributed to G Stöffler.

At least 91 records · Page 5Linked to original sources
PubMed1981

Arrangement of the subunits in the ribosome of Escherichia coli: demonstration by immunoelectron microscopy.

The three-dimensional locations of Escherichia coli ribosomal proteins S13, L1, and L7/L12 on the surface of ribosomal subunits and 70S monomeric ribosomes were determined by electron microscopy of antibody-labeled ribosomal particles. A new approach to orient the subunits within 70S ribosomes was developed that used 30S.70S.50S triples that were prepared by simultaneous combination with one antibody directed against a 30S protein and another directed against a 50S protein. Electron microscope studies of triples obtained with the antibody combinations anti-S13/anti-L1 and anti-S13/anti-L7/L12 showed that, in 70S monomeric ribosomes, the head of the 30S subunit is proximate to protein L1 and the peptidyl transferase center but far from the rod-like appendage containing proteins L7 and L12.

Antibodies↗
PubMed1981

Localization of the puromycin binding site on the large ribosomal subunit of Escherichia coli by immunoelectron microscopy.

By using immunoelectron microscopy, we have localized the binding site on 50S Escherichia coli ribosomal subunits for puromycin, an antibiotic that interacts with the ribosomal peptidyltransferase center. This was achieved by affinity-labeling 50S subunits with N-bromoacetyl puromycin and treating the labeled subunits with an antibody specific for the N6,N6-dimethyladenosine moiety of puromycin. The position of the puromycin binding site was then revealed by localizing the attachment sites of the IgG molecules on the surfaces of the 50S subunits under the electron microscope: it was located at the interface between the subunits, on and around the wider lateral protuberance of the 50S subunit. This localizes directly the peptidyl transferase center on the surface of the large ribosomal subunit.

Binding Sites↗
PubMed1981

Localization of 3' ends of 5S and 23S rRNAs in reconstituted subunits of Escherichia coli ribosomes.

Periodate-oxidized 3' ends of 5S, 23S, and 16S rRNAs from Escherichia coli were allowed to react with fluorescein thiosemicarbazide, then labeled rRNAs were reconstituted into active ribosomal subunits. The fluorescein moiety on each of the rRNAs when reconstituted into ribosomal subunits was accessible to anti-fluorescein IgG as determined by fluorescence quenching and by sucrose gradient centrifugation. The region at which an antibody molecule bond to the labeled ribosomal subunits was determined by immunoelectron microscopy. The 3' end of the 5S RNA was localized on the central protuberance of the 50S subunit. The corresponding region for the 3' end of the 23S RNA was below the stalk on the noninterfacing surface. The 3' end of the 16S RNA was localized to the upper edge of the large lobe of 30S subunits, as reported previously.

Escherichia coli↗
PubMed1980

Mutants of Escherichia coli lacking ribosomal protein L11.

Three mutants with ribosomes apparently lacking Protein L11, AM68, AM76, and AM77, were investigated using a variety of immunological techniques to determine whether L11 was indeed lacking. Ouchterlony double diffusion, modified immunoelectrophoresis, and dimer formation on sucrose gradients all gave results indicating Protein L11 was missing from the ribosome in these mutants. Electron micrographs of ribosomes of the mutants were indistinguishable from those of wild type. Ribosomes of AM68, AM76, and AM77, did not bind the antibiotic thiostrepton, but binding was recovered upon reconstitution with wild type Protein L11.

Antigen-Antibody Complex↗
PubMed1980

The effect of antibodies against Escherichia coli small ribosomal subunit proteins on protein synthesis by rat liver ribosomes.

Monovalent Fab fragments from immunoglobulins, directed against Escherichia coli small ribosomal subunit proteins, were tested for their effect on poly(U)-directed synthesis of polyphenylalanine by rat liver ribosomes. Of the 18 Fabs tested, 3, anti-S10, anti-S12, and anti-S14, inhibited polyphenylalanine synthesis; antibodies against 3 of the 21 E. coli ribosomal proteins (S1, S16, and S17) were not tested. The others were either without any appreciable effect or, as in the case of anti-S11 and anti-S18, inhibited far less. Antibodies against S12 and S14 (but not against S10) inhibited elongation factor 1-dependent binding of [14C]Phe-tRNA to rat liver 80 S ribosomes. The presumption is that the prokaryotic (E. coli) ribosomal proteins, S10, S12, and S14, possess antigenic determinants also present in eukaryotic (rat liver) ribosomal proteins; the rat liver proteins have not yet been identified.

Animals↗
PubMed1980

Functional homology between E. coli ribosomal protein L11 and B. megaterium protein BM-L11.

Ribosomes from the thiostrepton-resistant mutant MJ1 of Bacillus megaterium completely lack a protein designated BM-L11. When assayed in vitro, such ribosomes show an impaired ability to hydrolyse GTP in the presence of the elongation factor EF-G and are unable to support the synthesis of (p)ppGpp in response to the stringent factor. Restoration of both these activities can be achieved by re-addition of either protein BM-L11 or its serological homologue from Escherichia coli, protein L11, implying that these two proteins are related functionally as well as immunologically.

Bacillus megaterium↗
PubMed1980

[Normal values for circulating thyroid hormones, T3 uptake and thyrotropin before and after TRH. Radioimmunoassay determinations on 182 euthyroid children (author's transl)].

Measurements of T4, T3, rT3, T3U, and TSH (before and after TRH stimulation) were performed by RIA. 182 children, apparently euthyroid, age 2/12--14 years, were investigated in a cross sectional study. Free T4RIA and free T3RIA Indices and the ratio rT3/T3 and T4/T3 were calculated. Statistical analysis showed the following results: 1. Geometric mean serum concentrations of T4, T3, rT3 and TSH (basal) show no age related differences; T4 showed a not significant negative slope with age.--2. The ratio rT3/T3 and T4/T3 remains constant.--3. TRH induced TSH release (indicating the activity of the regulatory system) is unchanged from 2/12 to 14 years. Geometric means values, standard deviations and normal ranges are given.

Adolescent↗
PubMed1979

Ribosomal protein alterations in thiostrepton- and Micrococcin-resistant mutants of Bacillus subtilis.

Ribosomal proteins of parental thiostrepton- and micrococcin-sensitive Bacillus subtilis cysA14 and thiostrepton-and micrococcin-resistant mutants were compared. Several electrophoretic and immunochemical techniques showed unambiguously that BS-L11 was not present on 50 S ribosomal subunits from the six thiostrepton-resistant mutants. Protein BS-L11 reappeared in all six revertants from thiostrepton resistance to thiostrepton sensitivity. No definitive protein alteration could be ascribed to the mutation from micrococcin sensitivity to resistance. It was also demonstrated that B. subtilis protein BS-L11 is homologous to Escherichia coli ribosomal protein L11. The finding that ribosomes from thiostrepton-resistant mutants do not contain protein L11 suggests that L11 not only is involved in binding of thiostrepton, but also, when mutationally altered, confers resistance to this antibiotic. Although the ribosomes of these strains do not contain protein L11, all thiostrepton-resistant mutants showed the same viability as the parental strain. Thus protein L11 cannot be obligatory for the structure and function of the ribosome.

Anti-Bacterial Agents↗
PubMed1978

Immunochemical analysis of the structure of eukaryotic ribosomes: antigenic properties of rat liver ribosomes and ribosomal proteins and characterization of the antisera.

Antibodies were prepared in rabbits and sheep to rat liver ribosomes, ribosomal subunits, and to mixtures of proteins from the particles. The antisera were characterized by quantitative immunoprecipitation, by passive hemagglutination, by immunodiffusion on Ouchterlony plates, and by immunoelectrophoresis. While all the antisera contained antibodies specific for ribosomal proteins, none had precipitating antibodies against ribosomal RNA. Rat liver ribosomal proteins were more immunogenic in sheep than rabbits, and the large ribosomal subunit and its proteins were more immunogenic than those of the 40S subparticle. Antisera specific for one or the other ribosomal subunit could be prepared; thus it is unlikely that there are antigenic determinants common to the proteins of the two subunits. When ribosomes, ribosomal subunits, or mixtures of proteins were used as antigens the sera contained antibodies directed against a large number of the ribosomal proteins.

Animals↗
PubMed1978

Immunological comparison of the proteins of chicken and rat liver ribosomes.

A comparison of the proteins of chicken and rat liver ribosomes using immunochemical techniques was undertaken. The procedures included quantitative precipitation, passive hemagglutination, and immunodiffusion on Ouchterlony plates. The results indicate that antisera specific for chicken or rat liver ribosomes recognize only about 20% of common determinants. While there are important reservations, the results suggest extensive differences in the proteins of rat and chicken liver ribosomes. Despite those differences, rat and chicken liver ribosomal proteins maintain some homologous sequences present in bacterial ribosomal proteins. An enriched antibody preparation against chicken 80 S ribosomes inhibited the poly(U)-directed synthesis of polyphenylalanine and the elongation factor G (EF-G)-catalyzed binding of [3H]GDP to Escherichia coli ribosomes. Thus, chicken liver ribosomes, like ribosomes from rat liver and yeast, must have proteins homologous with those of E. coli ribosomes.

Animals↗
PubMed1978

Ribosome structure.

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Amino Acid Sequence↗
PubMed1978

[Hemostasis in hereditary hemorrhagic telangiectasia (author's transl)].

The investigation of a girl aged 8 with hereditary hemorrhagic telangiectasia showed an abnormality of primary hemostasis. The bleeding time was at the upper end of normal and platelet adhesiveness was decreased to a variable extent. Platelet life span was shortened, presumably due to the telangiectatic lesions typical of this disease. Platelet aggregation and ADP-content were normal as was the plasma coagulation system.

Blood Coagulation↗
PubMed1977

Improved electrophoretic and immunochemical techniques for the identification and characterization of mutant proteins, applied to ribosomal protein S8 in Escherichia coli mutants.

The ribosomal proteins of 11 mutants which are sensitive to starvation at elevated temperature and of 36 transductants derived from them were studied with several electrophoretic, immunochemical and proteinchemical methods. The following results were obtained: (1) Ribosomal protein S8 is altered in three of these mutants. (2) The amino acid exchange in proteins S8 of mutant N4128 is Glu leads to Lys in position 59 of the protein chain. (3) Temperature sensitivity and inability to recover from starvation at elevated temperatures are caused by the same mutational event which is, however, unrelated to the alteration in protein S8. Several electrophoretic and immunological procedures were applied during the characterization of these mutants. A modified immunoelectrophoresis on cellulose acetate gels was developed, and proved to be the most applicable procedure for the detection of mutationally altered ribosomal proteins. This procedure may gain general importance for detecting mutational alterations in other proteins.

Amino Acid Sequence↗
PubMed1977

Accessibility of proteins in 50S ribosomal subunits of Escherichia coli to antibodies: an ultracentrifugation study.

The accessibility of each of the proteins on the 50S ribosomal subunit of Escherichia coli was investigated by establishing whether immunoglobulins (IgG), specific for each of the 34 proteins from the 50S subunit, were able to bind to the 50S subunit. The main criterion for accessibility was the formation of specific antibody-50S subunit complexes that could be detected by means of analytical ultracentrifugation. The proteins fell into two main groups. Immunoglobulins against proteins L1, L2, L3, L4, L5, L6, L7/L12, L8, L9, L10, L11, L14, L15, L16, L17, L18, L19, L20, L21, L22, L23, L25, L26, L27 and L30 gave large amounts of complex (20-100%) and, therefore, these proteins were considered to be accessible on the surface of the 50S ribosomal subunit. The antibodies against the remaining proteins L13, L24, L28, L29 and L31 to L34 produced small amounts of complexes (10-20%). Since their effects were unequivocably stronger than those obtained with IgG's from sera of non-immunized animals, the results indicate that these proteins are probably also accessible. Nonetheless, from the ultracentrifugation studies alone definite conclusions about the exposure of the latter group of proteins could not be drawn.

Antibody Specificity↗