Identification and quantitation of elongation factor EF-P in Escherichia coli cell-free extracts

1980 ◽  
Vol 58 (11) ◽  
pp. 1312-1314 ◽  
Author(s):  
Gynheung An ◽  
Bernard R. Glick ◽  
James D. Friesen ◽  
M. Clelia Ganoza
Keyword(s):  
Escherichia Coli ◽  
Molecular Weight ◽  
Protein Synthesis ◽  
Gel Electrophoresis ◽  
Ribosomal Proteins ◽  
Elongation Factor ◽  
Peptide Bond ◽  
Two Dimensional ◽  
Two Dimensional Gel Electrophoresis

EF-P, an elongation factor that stimulates peptide bond synthesis in vitro with some aminoacyl-tRNAs, has been identified by two-dimensional gel electrophoresis and the cellular content at three points in the growth curve has been measured. The molecular weight of EF-P is estimated to be 21 000. EF-P is a slightly acidic protein whose isoelectric point is close to RNA polymerase subunit α. The amount of EF-P present in Escherichia coli is about [Formula: see text]that of EF-G and the level is independent of the stage of cell growth; there is about one EF-P per 10 ribosomes. It is also shown that a highly purified preparation of EF-P is free of all known protein synthesis factors and ribosomal proteins.

scholarly journals Multiple forms of tubulin in the cytoskeletal and flagellar microtubules of polytomella

1981 ◽  
Vol 91 (2) ◽  
pp. 352-360 ◽  
Author(s):  
TW McKeithan ◽  
JL Rosenbaum
Keyword(s):  
Protein Synthesis ◽  
Gel Electrophoresis ◽  
Cold Temperature ◽  
Two Dimensional ◽  
Multiple Forms ◽  
Cytoplasmic Fraction ◽  
Two Dimensional Gel Electrophoresis ◽  
Brain Tubulin ◽  
Β Tubulin

The alga polytomella contains several organelles composed of microtubules, including four flagella and hundreds of cytoskeletal microtubules. Brown and co-workers have shown (1976. J. Cell Biol. 69:6-125; 1978, Exp. Cell Res. 117: 313-324) that the flagella could be removed and the cytoskeletans dissociated, and that both structures could partially regenerate in the absence of protein synthesis. Because of this, and because both the flagella and the cytoskeletons can be isolated intact, this organism is particularly suitable for studying tubulin heterogeneity and the incorporation of specific tubulins into different microtubule-containing organelles in the same cell. In order to define the different species of tubulin in polytonella cytoplasm, a (35)S- labeled cytoplasmic fraction was subjected to two cycles of assembly and disassembly in the presence of unlabeled brain tubulin. Comparison of the labeled polytomella cytoplasmic tubulin obtained by this procedure with the tubulin of isolated polytomella flagella by two-dimensional gel electrophoresis showed that, whereas the β-tubulin from both cytoplasmic and flagellar tubulin samples comigrated, the two α-tubulins had distinctly different isoelectic points. As a second method of isolating tubulin from the cytoplasm, cells were gently lysed with detergent and intact cytoskeletons obtained. When these cytoskeletons were exposed to cold temperature, the proteins that were released were found to be highly enriched in tubulin; this tubulin, by itself, could be assembled into microtubules in vitro. The predominant α-tubulin of this in vitro- assembled cytoskeletal tubulin corresponded to the major cytoplasmic α-tubulin obtained by coassembly of labeled polytomella cytoplasmic extract with brain tubulin and was quite distinct from the α-tubulin of purified flagella. These results clearly show that two different microtubule-containing organelles from the same cell are composed of distinct tubulins.

Protein Synthesis During Oxygen Deprivation in Cotton

1996 ◽  
Vol 23 (3) ◽  
pp. 341 ◽  
Author(s):  
AA Millar ◽  
ES Dennis
Keyword(s):  
Molecular Weight ◽  
Protein Synthesis ◽  
Gel Electrophoresis ◽  
Major Part ◽  
Oxygen Deprivation ◽  
Two Dimensional ◽  
Root Tips ◽  
Two Dimensional Gel Electrophoresis ◽  
Molecular Masses ◽  
Adh Activity

The alteration of protein synthesis induced by oxygen deprivation has been examined in the root tips of cotton (Gossypium hirsutum cv. Siokra), a plant that is intolerant to anoxia. Using [35S]methionine labelling and two-dimensional gel electrophoresis it was demonstrated that 14 major polypeptides are being selectively synthesised during oxygen deprivation. These polypeptides have been designated the cotton anaerobic polypeptides (ANPs), and have estimated molecular masses that correspond to molecular masses of ANPs from other plant species. However, compared to maize, several of the major molecular weight classes are absent, suggesting that the response to oxygen deprivation in cotton is simpler than that of maize. Alcohol dehydrogenase (ADH) activity is induced by oxygen deprivation. Using western analysis we have determined that this increase in activity is correlated with the accumulation of the ADH polypeptide and that three of the major cotton ANPs are ADH, including the most intensely labelled ANP, demonstrating that the synthesis of ADH constitutes a major part of the response in cotton.

Fibrin-I Degradation Products with a Molecular Weight Higher than That of Fibrinogen

1973 ◽  
Vol 29 (01) ◽  
pp. 122-129 ◽  
Author(s):  
René von Hugo ◽  
Henner Graeff
Keyword(s):  
Molecular Weight ◽  
Gel Electrophoresis ◽  
Degradation Products ◽  
Gel Filtration ◽  
Agarose Gel ◽  
Two Dimensional ◽  
Plasma Clot ◽  
Two Dimensional Gel Electrophoresis ◽  
Parent Molecule

SummaryThe observation of intravascular lysis of fibrin deposits and of fibrinogen derivatives with a molecular weight higher than the parent molecule in human cases of disseminated intravascular coagulation (DIC) initiated the following in vitro study. Following streptokinase induced plasma clot solubilization fibrinogen derivatives were investigated after ß-alanine precipitation of the plasma samples by polyacrylamide (PAA) gel electrophoresis, intra gel immunoprecipitation, two dimensional gel electrophoresis and by agarose gel filtration. Three fibrin-i degradation products were observed and characterized according to their relative electrophoretic mobility in 5% PAA gel: 0.23, 0.35, 0.46 (fibrinogen: 0.43) x 10-5 cm2/V x sec. They could also be demonstrated after electrophoresis in the presence of 5 M urea. Agarose gel filtration yielded one peak at 180 ml of effluent volume. The 0.23 derivative was eluted in the peak fractions, whilst the 0.35 and 0.46 derivatives were eluted together at approximately 201 ml of the effluent volume (fibrinogen: 225 ml). This indicates, that the three fibrin-i degradation products described are molecular entities with molecular weights higher than fibrinogen and, that the 0.46 derivative has an increased charge/molecular size ratio in comparison with fibrinogen. Corresponding data were obtained by two dimensional gel electrophoresis in gels of different pore size.

In vitro translation of mRNA for arginine esterase, the major secretory protein of dog prostate, and in vitro processing of the translation product

1985 ◽  
Vol 63 (7) ◽  
pp. 705-710 ◽  
Author(s):  
Pierre Chapdelaine ◽  
Jean Y. Dubé ◽  
Gilles Frenette ◽  
Roland R. Tremblay
Keyword(s):  
Molecular Weight ◽  
Signal Peptide ◽  
Seminal Plasma ◽  
Gel Electrophoresis ◽  
In Vitro Translation ◽  
Translation Product ◽  
Two Dimensional ◽  
Single Chain ◽  
Two Dimensional Gel Electrophoresis

Poly(A)+ rich RNA was isolated from prostate of adult dogs and translated in the rabbit reticulocyte lysate cell-free protein-synthesizing system. Two-dimensional gel electrophoresis of the translation products showed that a protein with a molecular weight of 31 000 was predominantly synthesized. This protein was immunoprecipitated with antibodies directed against purified arginine esterase from dog seminal plasma. mRNA isolated from the prostate of animals castrated for 1 or 2 weeks was unable to direct the synthesis of arginine esterase. However, the synthesis of the enzyme could be stimulated by androgens in castrated animals, presumably by increasing prostatic concentrations of arginine esterase mRNA. The single chain translation product could be further processed in vitro by the addition of dog pancreas microsomes and purified arginine esterase. This procedure yielded split chains of arginine esterase which had identical electrophoretic mobilities as seminal plasma enzyme by two-dimensional gel electrophoresis. When prostatic tissue slices were incubated with tunicamycin, the unglycosylated arginine esterase obtained had a lower molecular weight than the in vitro translation product, suggesting that a signal peptide had been removed in the living cells. These results indicate that arginine esterase processing may include the following steps: removal of a signal peptide, glycosylation, and splitting of the polypeptide chain by active arginine esterase in the secretory granules or outside the cell.

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