scholarly journals Synthesis time of β-galactosidase in Escherichia coli B/r as a function of growth rate

1975 ◽  
Vol 150 (1) ◽  
pp. 13-20 ◽  
Author(s):  
D G Dalbow ◽  
R Young
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Growth Rate ◽  
Peptide Chain ◽  
Chain Elongation ◽  
Chain Growth ◽  
Synthesis Time ◽  
Fast Growing ◽  
Kinetics Of ◽  
Escherichia Coli B

By analysing the kinetics of β-galactosidase accumulation after induction, the synthesis time of β-galactosidase in Escherichia coli B/r was found to be 75s in rapidly growing cells (1.36 and 2.1 doublings/h), and 90s in slowly growing cells (0.63 doubling/h). These values correspond to peptide-chain-elongation rates of 16 and 13 amino acids/s respectively, in agreement with previous findings, indicating that the peptide-chain growth rate is constant (presumably maximal) in fast-growing bacteria, but decreased in slowly growing bacteria [Forchhammer & Lindahl (1971) J. Mol. Biol. 55, 563-568].

scholarly journals Polypeptide-chain-elongation rate in Escherichia coli B/r as a function of growth rate

1976 ◽  
Vol 160 (2) ◽  
pp. 185-194 ◽  
Author(s):  
R Young ◽  
H Bremer
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Growth Rate ◽  
Growth Rates ◽  
Elongation Rate ◽  
Peptide Chain ◽  
Chain Elongation ◽  
Slow Growing ◽  
Kinetics Of ◽  
Escherichia Coli B

By evaluating the kinetics of radioactive labelling of nascent and finished polypeptides, the peptide-chain elongation rate for Escherichia coli B/r at three different growth rates (mu) was determined to be 17 amino acids/s for the fast-growing cells (mu equals 1.3 and 2.0 doublings/h) and 12 amino acids/s for slow-growing cells (mu equals 0.67 doublings/h). The results agree with the growth-rate-dependence of the rate of peptide-chain elongation found for the translation of newly induced β-galactosidase messenger in this strain and under these conditions of growth [Dalbow & Young (1975) Biochem. J. 150, 13-20]. Together with the previously observed ribosome efficiency at these growth rates [Dennis & Bremer (1974) J. Mol. Biol. 84, 407-422] the results indicate that the fraction of ribosomes engaged in protein synthesis is about 0.8 at all three growth rates.

scholarly journals Effect of Temperature on In Vivo Protein Synthetic Capacity in Escherichia coli

1998 ◽  
Vol 180 (17) ◽  
pp. 4704-4710 ◽  
Author(s):  
Anne Farewell ◽  
Frederick C. Neidhardt
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
High Temperature ◽  
Low Temperature ◽  
Protein Degradation ◽  
Elongation Rate ◽  
Peptide Chain ◽  
Chain Elongation ◽  
Effect Of Temperature ◽  
Synthetic Capacity

ABSTRACT In this report, we examine the effect of temperature on protein synthesis. The rate of protein accumulation is determined by three factors: the number of working ribosomes, the rate at which ribosomes are working, and the rate of protein degradation. Measurements of RNA/protein ratios and the levels of individual ribosomal proteins and rRNA show that the cellular amount of ribosomal machinery in Escherichia coli is constant between 25 and 37°C. Within this range, in a given medium, temperature affects ribosomal function the same as it affects overall growth. Two independent methodologies show that the peptide chain elongation rate increases as a function of temperature identically to growth rate up to 37°C. Unlike the growth rate, however, the elongation rate continues to increase up to 44°C at the same rate as between 25 and 37°C. Our results show that the peptide elongation rate is not rate limiting for growth at high temperature. Taking into consideration the number of ribosomes per unit of cell mass, there is an apparent excess of protein synthetic capacity in these cells, indicating a dramatic increase in protein degradation at high temperature. Temperature shift experiments show that peptide chain elongation rate increases immediately, which supports a mechanism of heat shock response induction in which an increase in unfolded, newly translated protein induces this response. In addition, we find that at low temperature (15°C), cells contain a pool of nontranslating ribosomes which do not contribute to cell growth, supporting the idea that there is a defect in initiation at low temperature.

scholarly journals Wachstumsgeschwindigkeit der Peptidkette im Tabakmosaikvirus

1967 ◽  
Vol 22 (12) ◽  
pp. 1280-1291 ◽  
Author(s):  
H. Diringer ◽  
F. A. Anderer ◽  
G. Schramm
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Protein Synthesis ◽  
Peptide Chain ◽  
Cell Protein ◽  
Virus Protein ◽  
Animal Cells ◽  
Tobacco Leaves ◽  
Soluble Cell ◽  
C Terminus

The rate of incorporation of labelled amino acids into the complete tobacco mosaic virus (TMV), into soluble virus protein and into soluble cell proteins has been determined in discs of infected and healthy tobacco leaves. The rate of overall protein synthesis is increased by 50% in the infected leaves. At least 60% of the increase derives from the synthesis of virus-specific proteins and the synthesis of cellular proteins is not inhibited. The virus protein synthesis is strongly temperature dependent and shows a maximum at 28 °C.The exchange of free labelled amino acids between the external medium and the inner cellular pool reaches equilibrium within ten minutes. The influence of the exchange rate on the measurement of the kinetics of peptide chain synthesis is discussed in detail.Discs from infected leaves were incubated for short periods at low temperatures in media containing 3H-tyrosine or 3H-proline. Peptides isolated after 5 minutes incubation at 15 °C were found to be uniformly labelled with no apparent gradient of radioactivity from the N- to the C-terminus. The results indicate that the growth rate of the peptide chain at 15 °C is probably higher than 2 - 3 amino acids/sec and at 28 °C higher than 20 amino acids/sec. These values are higher than those for animal cells and similar to those for protein synthesis in Escherichia coli.Comparison of the growth rate of TMV protein with rate of total protein synthesis and the number of ribosomes in the tobacco leaves indicate that only a small portion of the ribosomes takes part in cell protein synthesis.

Propriétés physiques et chimiques des tryptophanases de cinq espèces d'Entérobactériaceae

1975 ◽  
Vol 21 (6) ◽  
pp. 828-833 ◽  
Author(s):  
C. Simard ◽  
A. Mardini ◽  
L. M. Bordeleau
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Molecular Weight ◽  
Sedimentation Coefficient ◽  
Species Differentiation ◽  
Proteus Vulgaris ◽  
Amino Acids Composition ◽  
Propriétés Physiques ◽  
Tryptophan Content ◽  
Escherichia Coli B

The molecular weight, sedimentation coefficient, and amino acids composition were determined on five tryptophanases (TPases) from Escherichia coli B and E. aurescens, Shigella alkalescens, and Proteus vulgaris and P. morganii. These TPases have identical sedimentation profile and coefficient (9.6 S), and the same molecular weight (220 000). Each enzyme is constituted of four identical subunits having a molecular weight of 55 000. The amino acids composition of these TPases is very similar, with the exception of P. morganii and P. vulgaris TPases which present significative variations in basic amino acids and tryptophan content. The species differentiation of the coli group cannot be made on their TPase characteristics only, contrary to P. morganii and P. vulgaris which can be differentiated between them and from the coli group. [Journal translation]

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