Defective 30S ribosomal particles in a polyamine auxotroph of Escherichia coli

Echandi, G; Algranati, Israel D.

doi:10.1016/0006-291x(75)90798-6

Cited by 61 publications

(37 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The lack of polyamine may be critical only when the basal error rate is unusually high, or for certain base pairs or contexts. The effect of polyamine omission on in vivo misreading, described here, might be due to the direct participation of these substances in the translational process or could be the result of physiological changes promoted by polyamine starvation, such as defective 3 0 s ribosomal subunits [52] or decreased growth rate. More studies to distinguish among these possibilities as well as to observe misreading at different codons in other proteins would allow a more general conclusion about the effect of polyamines on the fidelity of in vivo translation.…”

Section: Discussionmentioning

confidence: 85%

Effect of polyamines on translation fidelity in vivo

McMurry

Algranati

1986

European Journal of Biochemistry

View full text Add to dashboard Cite

Polyamines, when added to cell-free protein-synthesizing systems, have been shown either to reduce mistranslation or to increase it depending upon the composition of the reaction mixture. To study this question under conditions as natural as possible we investigated the effects of polyamines on the fidelity of protein synthesis in intact Escherichiu coli bacterial cells, using strains which were auxotrophic for polyamine synthesis. Error was measured in two ways: (a) the incorporation of [3H]histidine into coat protein of bacteriophage MS2, the gene of which does not code for histidine, and (b) the synthesis of a basic variant of MS2 coat protein in which a lysine erroneously replaces an asparagine, causing a change in isoelectric point. We found that when cell cultures were supplemented with polyamines there was no effect on the first type of error and the second type decreased twofold. The measured errors occurred at the level of translation because their frequency increased in the presence of streptomycin and decreased in cells bearing a streptomycin-resistance mutation known to lower the occurrence of translational misreading. The average erroneous incorporation per mol coat protein in the presence of polyamines was 1.43 ? 0.59 mmol histidine and 25 -34 mmol lysine/asparagine substitution. The reason for the different effect of polyamines on the two types of error is not known but could be related to the difference between their corresponding frequencies or to codon-specific effects.Polyamines are widely distributed organic cations which appear to have many roles, especially in processes involving nucleic acids, such as DNA replication, transcription and translation [I -51. Studies carried out with cell-free systems have demonstrated that polyamines can replace part of the magnesium requirement of protein synthesis and at the same time cause overall stimulation [6 -81. Polyamines have also been shown to have a qualitative effect on the proteins synthesized. Adenovirus proteins made in vitro in the presence of polyamines resembled more closely those synthesized in vivo, both in size and quantity [9]. Polypeptides of higher molecular mass were found in smaller amounts in the absence of polyamines in vitro [lo, 111 and in vivo [12]. These observations had suggested that polyamines might prevent premature peptide termination or otherwise affect the fidelity of translation. It was subsequently reported that polyamines, particularly spermidine, decreased the misincorporation of leucine for phenylalanine severalfold in a polyuridylic-acid-dependent in vitro translation system [13-151. However, in these studies the error determinations in presence of polyamines were done at lower Mg concentrations than those in the absence of polyamines because the Mg optimum for polyphenylalanine synthesis was higher under the latter conditions than in the presence of polyamines. In one study, other changes besides polyamine addition were made [16]. At some concentrations of Mg, however, the error was no different or [18] that when...

show abstract

Section: Discussionmentioning

confidence: 85%

Effect of polyamines on translation fidelity in vivo

McMurry

Algranati

1986

European Journal of Biochemistry

View full text Add to dashboard Cite

show abstract

“…They can bind to nucleic acids, stabilize membranes, and stimulate the activity of several enzymes, such as RNA polymerase (1,31,34). Found in the ribosomal fraction, polyamines enhance the synthesis of several proteins and stimulate the in vivo assembly of the Escherichia coli 30S ribosomal subunit (7,13,21,35).Although intracellular polyamine is required for optimal growth, polyamine accumulation can lead to inhibition of cellular growth (11,25,26,33). The addition of spermidine to cell cultures of mouse FM3A cells results in a decrease in cell growth accompanied by inhibition of protein synthesis (11).…”

mentioning

confidence: 99%

Spermidine Acetyltransferase Is Required To Prevent Spermidine Toxicity at Low Temperatures in Escherichia coli

Limsuwun

Jones

2000

J Bacteriol

View full text Add to dashboard Cite

Polyamines are required for optimal growth in most cells; however, polyamine accumulation leads to inhibition of cellular growth. To reduce intracellular polyamine levels, spermidine is monoacetylated in both prokaryotes and eukaryotes. In Escherichia coli, the speG gene encodes the spermidine acetyltransferase, which transfers the acetyl group to either the N-1 or N-8 position. In addition to polyamine accumulation, stress conditions, such as cold shock, cause an increase in the level of spermidine acetylation, suggesting an adaptive role for reduced polyamine levels under stressful growth conditions. The effect of spermidine accumulation on the growth of E. coli at low temperature was examined using a speG mutant. At 37°C, growth of the speG mutant was normal in the presence of 0.5 or 1 mM spermidine. However, following a shift to 7°C, the addition of 0.5 or 1 mM spermidine resulted in inhibition of cellular growth or cell lysis, respectively. Furthermore, at 7°C, spermidine accumulation resulted in a decrease in total protein synthesis accompanied by an increase in the synthesis of the major cold shock proteins CspA, CspB, and CspG. However, the addition of 50 mM Mg Polyamines, such as spermidine and putrescine, are present in virtually all cells (25, 33). These polycations have pleiotropic properties, which can influence several cellular processes. They can bind to nucleic acids, stabilize membranes, and stimulate the activity of several enzymes, such as RNA polymerase (1,31,34). Found in the ribosomal fraction, polyamines enhance the synthesis of several proteins and stimulate the in vivo assembly of the Escherichia coli 30S ribosomal subunit (7,13,21,35).Although intracellular polyamine is required for optimal growth, polyamine accumulation can lead to inhibition of cellular growth (11,25,26,33). The addition of spermidine to cell cultures of mouse FM3A cells results in a decrease in cell growth accompanied by inhibition of protein synthesis (11). To prevent polyamine toxicity in eukaryotes, polyamine catabolism is initiated by the monoacetylation of spermidine and spermine catalyzed by spermidine/spermine N 1 -acetyltransferase (SSAT) (4). The acetylpolyamines are then either further oxidized by polyamine oxidase or excreted from the cell.In E. coli, the speG gene encodes spermidine acetyltransferase (SAT), which transfers the acetyl group to either the N-1 or N-8 position of the polyamine (2,8,20). SAT is required to reduce the spermidine level, since the addition of exogenous spermidine to a speG mutant results in intracellular accumulation of spermidine (9). Furthermore, the excess spermidine causes decreased protein synthesis and cell viability during the stationary phase of growth (9). Acetylation serves to convert the polyamine to a physiologically inert form; acetylpolyamines cannot substitute for polyamines in RNA binding, in the enhancement of growth of an E. coli polyamine-deficient mutant, or in the stimulation of in vitro translation (18). Neither spermidine-deacetylating activity nor polyamin...

show abstract

“…We previously reported that polyamines can stimulate some kinds of protein synthesis in both prokaryotic and eukaryotic cell-free systems (2,3) and in vivo (4,5). Furthermore, it has been reported that assembly of 30 S ribosomal subunits is stimulated by polyamines (6,7) and the fidelity of protein synthesis is increased by polyamines (8,9). We also found that most polyamines exist as a polyamine-RNA complex in cells, and that the amount of polyamines (spermidine plus spermine) bound to RNA in rat liver is about 2 mol/100 mol of phosphate of RNA (10).…”

mentioning

confidence: 99%