Growth phase and growth rate dependence of ribosomal peptidyltransferase activity status in Escherichia coli

Kalpaxis, Dimitrios L.; Karahalios, Panagiotis; Papapetropoulou, M.

doi:10.1016/0300-9084(95)80009-3

Cited by 7 publications

(19 citation statements)

References 35 publications

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“…The L7:L12 ratio of 1:1 occurring in the exponential growth phase and very similar trends in the stationary phase have been reported. 10,15,16 However, our data show that we can monitor the precise ratio of L7/L12 throughout the different phases of cell growth with unprecedented detail.…”

Section: N-acetylation Of L12 Varies With Cell Growth and Nutrient Dementioning

confidence: 79%

“…While S18 and S5 are always found in their Nacetylated form, the ratio of L12 and L7 is known to change throughout the growth phase. [10][11][12][13][14][15][16] The L7:L12 ratio has been shown to increase as cells go from logarithmic to stationary growth phase. Similarly, the proportion of L7 is higher in ribosomes from E. coli cells grown in minimal medium, 12 indicating that increasing acetylation of L12 takes place as nutrients become depleted.…”

Section: Introductionmentioning

confidence: 99%

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Acetylation of L12 Increases Interactions in the Escherichia coli Ribosomal Stalk Complex

Gordiyenko

Deroo

Zhou

et al. 2008

Journal of Molecular Biology

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Section: N-acetylation Of L12 Varies With Cell Growth and Nutrient Dementioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Acetylation of L12 Increases Interactions in the Escherichia coli Ribosomal Stalk Complex

Gordiyenko

Deroo

Zhou

et al. 2008

Journal of Molecular Biology

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“…All of the model building and refinement were carried out using the programs O (29) and CNS (30). Details of the refined structures are reported in In E. coli and Salmonella, the ratio of L12/L7 was found to vary with growth where the proportion as L12 was highest during logarithmic growth (12)(13)(14). To generate L12 substrate, cells expressing L12…”

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

“…This is due to the interaction of the C-terminal domains of L12/L7 with both elongation factors EF-Tu and EF-G and the promotion of GTP hydrolysis by these two elongation factors (10, 11). Finally, whereas S18 and S5 are always found in their N ␣ -acetylated form, the relative proportions of L12 and L7 are correlated with the rate of growth and the cell cycle (12)(13)(14).Although cotranslational N ␣ -acetylation appears to be critical to the function and stability of numerous eukaryotic proteins (15), no known function has been ascribed to the acetylation of prokaryotic ribosomal proteins. Knock-out mutants lacking a functional RimL, RimI, or RimJ exhibit no distinguishable phenotype compared with wild type (16 -18), and the L12/L7 ratio has not been found to affect ribosomal function (19 -21).…”

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confidence: 99%

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A Novel Dimeric Structure of the RimL Nα-acetyltransferase from Salmonella typhimurium

Vetting

Carvalho

Roderick

et al. 2005

Journal of Biological Chemistry

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RimL is responsible for converting the prokaryotic ribosomal protein from L12 to L7 by acetylation of its N-terminal amino group. We demonstrate that purified RimL is capable of posttranslationally acetylating L12, exhibiting a V max of 21 min ؊1 . We have also determined the apostructure of RimL from Salmonella typhimurium and its complex with coenzyme A, revealing a homodimeric oligomer with structural similarity to other Gcn5-related N-acetyltransferase superfamily members. A large central trough located at the dimer interface provides sufficient room to bind both L12 N-terminal helices. Structural and biochemical analysis indicates that RimL proceeds by single-step transfer rather than a covalent-enzyme intermediate. This is the first structure of a Gcn5-related N-acetyltransferase family member with demonstrated activity toward a protein N ␣ -amino group and is a first step toward understanding the molecular basis for N ␣ acetylation and its function in cellular regulation.The posttranslational acetylation of N ␣ -protein termini is a common occurrence in eukaryotic proteins where between 50 and 90% of proteins are N ␣ -acetylated (1). However, in prokaryotes, N ␣ -protein acetylation is limited to four known examples. The early secreted antigenic target (ESAT-6) of Mycobacterium tuberculosis is N ␣ -acetylated, and its acetylation has been shown to alter its interaction with the 10-kDa culture filtrate protein (CFP10) (2). The three other examples are the prokaryotic ribosomal proteins S18, S5, and L12, which are N ␣ -acetylated by the Rim proteins, RimI, RimJ, and RimL, respectively (3, 4). L12 and its N ␣ -acetylated derivative, L7, have garnered the most interest because of its interesting physical and biological properties. L12 lacks tryptophan, tyrosine, cysteine, and histidine residues and is the most acidic Escherichia coli ribosomal protein (5). The dimeric L12/L7 complex is the only protein found in more than one copy in the ribosome (6) and is the only ribosomal protein that has no direct contact with rRNA, instead interacting indirectly via formation of a complex with the L10 protein (7). In addition, the efficiency of protein translation is correlated with the number of L12/L7 dimers bound with maximum efficiency occurring at a ratio of two dimers per ribosome (8,9). This is due to the interaction of the C-terminal domains of L12/L7 with both elongation factors EF-Tu and EF-G and the promotion of GTP hydrolysis by these two elongation factors (10, 11). Finally, whereas S18 and S5 are always found in their N ␣ -acetylated form, the relative proportions of L12 and L7 are correlated with the rate of growth and the cell cycle (12)(13)(14).Although cotranslational N ␣ -acetylation appears to be critical to the function and stability of numerous eukaryotic proteins (15), no known function has been ascribed to the acetylation of prokaryotic ribosomal proteins. Knock-out mutants lacking a functional RimL, RimI, or RimJ exhibit no distinguishable phenotype compared with wild type (16 -18), and the L12/L...

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Changes in Ribosomal Activity of Escherichia coli Cells during Prolonged Culture in Sea Salts Medium

1998

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The activity of ribosomes from a clinical isolate ofEscherichia coli, exposed to starvation for 7 days in sea salts medium, was investigated by measuring the kinetic parameters of ribosomal peptidyltransferase, by using the puromycin reaction as a model reaction. No alterations in the extent of peptide bond formation were observed during starvation. In contrast, a 50% reduction in thek max/Ks ratio could be seen after 24 h of starvation; an additional 6 days of starvation resulted in a progressive but less abrupt decline in thek max/Ks value. {k max is the apparent catalytic rate constant of peptidyl transferase, and Ks is the dissociation constant of the encounter complex between acetyl (Ac)[3H]Phe-tRNA-poly(U)-ribosome and puromycin.} Although the distribution of ribosomal particles remained constant, a substantial decrease in the number of ribosomes per starved cell and a clear decline in the ability of ribosomes to bind AcPhe-tRNA were observed, particularly during the first day of starvation. Further analysis indicated that rRNA in general, but especially 23S rRNA, was rapidly degraded during the starvation period. In addition, the L12/L7 molar ratio decreased from 1.5 to 1 during the initial phase of starvation (up to 24 h) but remained constant during the subsequent starvation period. Ribosomes isolated from 24-h-starved cells, when artificially depleted of L7/L12 protein and reconstituted with L7/L12 protein from mid-logarithmic-phase cells, regenerated an L12/L7 molar ratio of 1.5 and restored the peptidyltransferase activity to a substantial level. An analogous effect of reconstitution on the efficiency of ribosomes in binding AcPhe-tRNA was evident not only during the initial phase but throughout the starvation period.

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Growth phase and growth rate dependence of ribosomal peptidyltransferase activity status in Escherichia coli

Cited by 7 publications

References 35 publications

Acetylation of L12 Increases Interactions in the Escherichia coli Ribosomal Stalk Complex

Acetylation of L12 Increases Interactions in the Escherichia coli Ribosomal Stalk Complex

A Novel Dimeric Structure of the RimL Nα-acetyltransferase from Salmonella typhimurium

Changes in Ribosomal Activity of Escherichia coli Cells during Prolonged Culture in Sea Salts Medium

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