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Biomedical subjects

H Weissbach

Publications and source records attributed to H Weissbach.

At least 145 records · Page 8Linked to original sources
PubMed1977

mRNA-dependent in vitro synthesis of ribosomal proteins L12 and L10 and elongation factor Tu.

RNA extracted from growing Escherichia coli can direct the in vitro synthesis of ribosomal proteins L12 and L10 and elongation factor Tu when an E. coli system is used. The synthesized L12 can be bound to L12-depleted ribosomes and the synthesized elongation factor Tu can form complexes with both elongation factor Ts and GDP. Guanosine 5'-diphosphate 3'-diphosphate has no effect on the synthesis of these proteins from an RNA template but inhibits their synthesis when a DNA template is used.

Cell-Free System↗
PubMed1977

DNA-directed synthesis in vitro of beta-galactosidase: requirement for a ribosome release factor.

The DNA-directed synthesis of beta-galactosidase in Escherichia coli extracts has been investigated in a partially fractionated system. A dependency was obtained for 3',5'-cyclic AMP receptor protein and also for a factor, from the salt wash of ribosomes, that has been purified to near homogeneity. This factor has been identified with a ribosome release factor previously purified from the supernatant fraction by A. Hirashima and A. Kaji [(1972) Biochemistry 11,4037-4044]. In the coupled transcription-translation system this factor stimulates beta-galactosidase synthesis and total protein synthesis 2- to 4-fold. It is thus clear that the ribosome release factor has a physiological function in translation. It may also affect transcription, because it stimulated total RNA synthesis up to 50% in this in vitro system.

Cross Reactions↗
PubMed1976

DNA-directed in vitro synthesis of elongation factor Tu.

The in vitro synthesis of EF-Tu was studied using the transducing phage lambdarifd18 DNA as template. The EF-Tu synthesized was identified by its immunological properties, gel analysis, and its ability to interact with GDP and EF-Ts. Two other unidentified polypeptides were also precipitated from the incubation mixture by EF-Tu antiserum. The synthesis of total EF-Tu immunoprecipitable material was depressed about one-half by guanosine-5'-diphosphate-3'-diphosphate which was shown to inhibit the transcription process.

Antibodies↗
PubMed1976

Synthesis of ribosomal proteins L7L12 in relaxed and stringent strains of Escherichia coli.

The control of the synthesis of ribosomal proteins L7L12 (which lack histidine) was examined during growth and histidine starvation of stringent and relaxed histidine mutants. Since no ribosomes are synthesized during starvation, these proteins, in both the stringent and relaxed organisms, accumulated in the supernatant and were shown to possess both biological and physical characteristics typical of normal L7L12. However, the rate and extent of synthesis of these proteins during starvation is greater in the relaxed strain than in the stringent. These data suggest that the regulation of the synthesis of these proteins, similar to that of ribosomal RNA is regulated by the stringent control system. It was also shown that during normal growth of both organisms, L7L12 is also found in the supernatant as well as on the ribosomes. The L7L12 found in the supernatant under these conditions, however, appears to be different than ribosomal L7L12.

Escherichia coli↗
PubMed1976

Elongation factor 1 from Artemia salina: properties and disaggregation of the enzyme.

Elongation factor 1 has been purified from undeveloped embryos of Artemia salina. The purified enzyme appears to be an aggregate (molecular weight approximately to 200 000) which on sodium dodecylsulfate gels shows the presence of two major protein bands whose estimated molecular weights are 52 000 and 47 000. Lipid material appears to be associated with the purified protein. In aminoacyl-tRNA binding to ribosomes, there is only a limited turnover of the enzyme, but the protein acts catalytically in amino acid polymerization. The enzyme is disaggregated by a partially purified phospholipase C preparation, elastase and under certain conditions, by guanosine nucleotides. The significance of these results is discussed with respect to the overall role of elongation faction 1 in aminoacyl-tRNA binding to ribosomes.

Amino Acids↗
PubMed1976

DNA dependent synthesis of protein L12 from escherichia coli ribosomes, in vitro.

The in vitro synthesis of ribosomal protein L12 has been obtained in a coupled system with DNA extracted from the transducing phage lambdarifd18 as template. In addition, a second protein (molecular weight of 16,000) with immunological, chemical, and ribosome-binding characteristics similar to L12 is formed in this in vitro system. The synthesis of both proteins is depressed by one-half when guanosine-5'-diphosphate-3'-diphosphate is added to the reaction mixture.

Bacterial Proteins↗
PubMed1975

Polyanion-induced release of polyribosomes from HeLa cell nuclei.

Intact detergent-washed HeLa nuclei contain a population of polyribisomes that were released by exposure to polyanions such as RNA or poly(U). The released material appeared by electron microscopic examination to be particles averaging about 200 to 300 angstroms in diameter. Sedimentation velocity analysis of the released particles indicated that the particles had S20,w values of 75 and 110. The particles stimulated amino acid incorporation in an ascites S-30 or S-100 extract at 2.5 mM Mg2+. Studies with a variety of antibiotics indicated that these polyribosomes were capable of elongating but not initiating protein synthesis. Although these polyribosomes may be of cytoplasmic origin, they appear unique in that agents thought to disperse chromatin are required for their release from the nucleus.

Aminoacylation↗