Mistranslation in E. coli

Edelmann, Patricia L.; Gallant, Jonathan

doi:10.1016/0092-8674(77)90147-7

Cited by 280 publications

(139 citation statements)

References 15 publications

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“…As shown in Table II, the error frequency of the wild-type strain YKS99-2A was 26 errors every 10 4 codons. This error rate is almost identical to that reported recently for 2D-J809, another wild-type strain (21) and it is within the range reported in the literature (36,37).…”

Section: A Mutant Strain Carrying Deletions Of Five 60 S Ribosomal Prsupporting

confidence: 77%

A Dispensable Yeast Ribosomal Protein Optimizes Peptidyltransferase Activity and Affects Translocation

Dresios

Panopoulos

Suzuki³

et al. 2003

Journal of Biological Chemistry

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Yeast ribosomal protein L41 is dispensable in the yeast. Its absence had no effect on polyphenylalanine synthesis activity, and a limited effect on growth, translational accuracy, or the resistance toward the antibiotic paromomycin. Removal of L41 did not affect the 60:40 S ratio, but it reduced the amount of 80 S, suggesting that L41 is involved in ribosomal subunit association. However, the two most important effects of L41 were on peptidyltransferase activity and translocation. Peptidyltransferase activity was measured as a secondorder rate constant (k cat /K s ) corresponding to the rate of peptide bond formation; this k cat /K s was lowered 3-fold to 1.15 min ؊1 mM ؊1 in the L41 mutant compared with 3.46 min ؊1 mM ؊1 in the wild type. Translocation was also affected by L41. Elongation factor 2 (EF2)-dependent (enzymatic) translocation of Ac-Phe-tRNA from the A-to P-site was more efficient in the absence of L41, because 50% translocation was achieved at only 0.004 M EF2 compared with 0.02 M for the wild type. Furthermore, the EF2-dependent translocation was inhibited by 50% at 2.5 M of the translocation inhibitor cycloheximide in the L41 mutant compared with 1.2 M in the wild type. Finally, the rate of EF2-independent (spontaneous) translocation was increased in the absence of L41.The ribosome is a large macromolecular machine that consists of a large number of proteins and several molecules of ribosomal RNA (rRNA). The ribosome is responsible for the translation of the genetic message, which results in protein synthesis.The crystal structures of the 30 S (1, 2) and 50 S (3, 4) ribosomal subunits, and the intact 70 S ribosome (5) are contributing to a better understanding of ribosomal function. It has now been confirmed that rRNA plays the major role in ribosomal structure and function, including the two most important activities of the ribosome: the decoding process and the peptidyltransferase activity. The 16 S rRNA of the small ribosomal subunit is responsible for the decoding process, the selection of the cognate tRNA (6). The central loop of domain V of 23 S rRNA of the large ribosomal subunit is responsible for the catalytic activity of the ribosome (7, 8). The search is still underway to identify a critical site or nucleotide(s) of 23 S rRNA involved in the catalysis of peptide bond formation (9 -13). It is still possible that the rate of peptide bond formation is influenced by structural rearrangements of RNA in the peptidyltransferase center that would affect the positioning of the substrates (14).Ribosomal proteins offer structural support to the ribosome by stabilizing and orienting the ribosomal RNA into a specific, active structure (15). Also, they are crucial for the assembly of functional ribosomes (16). Several ribosomal proteins of the small subunit (17-20) and at least one of the large subunit (21) appear to affect the decoding process. Moreover, some ribosomal proteins appear to influence the peptidyltransferase activity of the ribosome (22-24).Yeast ribosomal protein L41 is the smallest a...

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Section: A Mutant Strain Carrying Deletions Of Five 60 S Ribosomal Prsupporting

confidence: 77%

A Dispensable Yeast Ribosomal Protein Optimizes Peptidyltransferase Activity and Affects Translocation

Dresios

Panopoulos

Suzuki³

et al. 2003

Journal of Biological Chemistry

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“…The difference between the results obtained with the trp operon and those obtained with the ilv operon appear even more paradoxical when it is recalled that the arginine codon in the trp leader (CGC) is one that can be misread (13) and therefore could be less effective in ribosome stalling, whereas that in the ilv leader (CGA) is one for which the tRNA is less efficiently charged (21). The effect of arginine starvation on trp operon expression had been measured by formation of hybridizable message, i.e., a measure of functional transcription beyond the attenuator.…”

Section: Discussionmentioning

confidence: 96%

Specificity of attenuation control in the ilvGMEDA operon of Escherichia coli K-12

1991

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Three different approaches were used to examine the regulatory effects of the amino acids specified by the peptide-coding region of the leader transcript of the ilvGMEDA operon of Escherichia coli K-12. Gene expression was examined in strains carrying an ilvGMED'-lac operon fusion. In one approach, auxotrophic derivatives were starved of single amino acids for brief periods, and the burst of j-galactosidase synthesis upon adding the missing amino acid was determined. Auxotrophic derivatives were also grown for brief periods with a limited supply of one amino acid (derepression experiments). Finally, prototrophic strains were grown in minimal medium supplemented with single and multiple supplements of the chosen amino acids. Although codons for arginine, serine, and proline are interspersed among the codons for the three branched-chain (regulatory) amino acids, they appeared to have no effect when added in excess to prototrophs or when supplied in restricted amounts to auxotrophs. Deletions removing the terminator stem from the leader removed all ilvspecific control, indicating that the attenuation mechanism is the sole mechanism for ilv-specific control.The specific control of expression of the ilvGMEDA operon in the enteric bacteria is characterized by repression of the operon when the three branched-chain amino acids are in ample supply but derepression when the supply of any one of the three is limited (14,30). This ilv-specific regulation appears to be exclusively a consequence of an attenuation mechanism ( Fig. 1) (4,32,38). In principle, the attenuation mechanism controlling the ilv operon appears to be quite similar to that found to control operons involved in tryptophan (35), leucine (19), phenylalanine (61), histidine (3), and threonine (17) biosynthesis: the leader region specifies a short peptide containing a disproportionate frequency of the amino acids that are found to regulate the operon. Thus, the rate at which the leader can be translated serves to sense whether the regulatory amino acid is in short or ample supply.As emphasized by Landick and Yanofsky (31), an important feature of the attenuation mechanism is the pausing of RNA polymerase at a certain site in the leader region. The pause allows time for the ribosome to initiate translation, and as translation proceeds, the base pairing in the protector (1:2 stem, Fig. 2) is progressively disrupted. Should ribosome movement be retarded, presumably by stalling at a regulatory codon, long enough for the bases in the upstream arm of the terminator (bases 157 to 164) to emerge on the nascent transcript, these bases can pair with those in the downstream arm of the protector (bases 98 to 105) in the antiterminator (2:3 stem, Fig. 3). It is assumed that, in the absence of ribosome stalling (repressing conditions), translation proceeds rapidly enough that the bases in the downstream arm of the protector will also be covered by the ribosome or otherwise be sterically prevented from antiterminator formation and the terminator will be formed instead. Altho...

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“…The apparent error frequency for protein synthesis in vivo is close to 10-4 mistakes/amino acid residue [1,2]. Such a high fidelity of translation is substantially greater than the specificity of codonanticodon recognition which would be expected from the known energetics of base-pairing in solution [3,4].…”

Section: Introductionmentioning

confidence: 99%

A stereospecific mechanism for the aminoacyl‐tRNA selection at the ribosome

Потапов¹

1982

FEBS Letters

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Mistranslation in E. coli

Cited by 280 publications

References 15 publications

A Dispensable Yeast Ribosomal Protein Optimizes Peptidyltransferase Activity and Affects Translocation

A Dispensable Yeast Ribosomal Protein Optimizes Peptidyltransferase Activity and Affects Translocation

Specificity of attenuation control in the ilvGMEDA operon of Escherichia coli K-12

A stereospecific mechanism for the aminoacyl‐tRNA selection at the ribosome

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