lep operon proximal gene is not required for growth or secretion by Escherichia coli

Dibb, Nick J.; Wolfe, P B

doi:10.1128/jb.166.1.83-87.1986

Cited by 45 publications

(40 citation statements)

References 27 publications

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“…Like bipA, lepA is highly conserved but is dispensable, and a lepA deletion yields no observable phenotype (12). However, an exciting recent publication described a unique function for LepA (36).…”

mentioning

confidence: 99%

Suppression of ΔbipAPhenotypes inEscherichia coliby Abolishment of Pseudouridylation at Specific Sites on the 23S rRNA

Krishnan

Flower

2008

J Bacteriol

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The BipA protein of Escherichia coli has intriguing similarities to the elongation factor subfamily of GTPases, including EF-Tu, EF-G, and LepA. In addition, phenotypes of a bipA deletion mutant suggest that BipA is involved in regulation of a variety of pathways. These two points have led to speculation that BipA may be a novel regulatory protein that affects efficient translation of target genes through direct interaction with the ribosome. We isolated and characterized suppressors of the cold-sensitive growth phenotype exhibited by ⌬bipA strains and identified insertion mutations in rluC. The rluC gene encodes a pseudouridine synthase responsible for pseudouridine modification of 23S rRNA at three sites, all located near the peptidyl transferase center. Deletion of rluC not only suppressed cold sensitivity but also alleviated the decrease in capsule synthesis exhibited by bipA mutants, suggesting that the phenotypic effects of BipA are manifested through an effect on the ribosome. The suppressor effect is specific to rluC, as deletion of other rlu genes did not relieve cold sensitivity, and further, more than a single pseudouridine residue is involved, as alteration of single residues did not produce suppressors. These results are consistent with a role for BipA in either the structure or the function of the ribosome and imply that wild-type ribosomes are dependent on BipA for efficient expression of target mRNAs and that the lack of pseudouridylation at these three sites renders the ribosomes BipA independent.

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confidence: 99%

Suppression of ΔbipAPhenotypes inEscherichia coliby Abolishment of Pseudouridylation at Specific Sites on the 23S rRNA

Krishnan

Flower

2008

J Bacteriol

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“…Four of these trGTPases are omnipresent in bacterial lineages-IF2, EF-Tu, EF-G, and LepA (1). Despite such high conservation, the gene encoding LepA can be deleted with no obvious phenotype in Escherichia coli (2).…”

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confidence: 99%

Conserved GTPase LepA (Elongation Factor 4) functions in biogenesis of the 30S subunit of the 70S ribosome

Gibbs

Moon

Chen

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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The physiological role of LepA, a paralog of EF-G found in all bacteria, has been a mystery for decades. Here, we show that LepA functions in ribosome biogenesis. In cells lacking LepA, immature 30S particles accumulate. Four proteins are specifically underrepresented in these particles—S3, S10, S14, and S21—all of which bind late in the assembly process and contribute to the folding of the 3′ domain of 16S rRNA. Processing of 16S rRNA is also delayed in the mutant strain, as indicated by increased levels of precursor 17S rRNA in assembly intermediates. MutationΔlepAconfers a synthetic growth phenotype in absence of RsgA, another GTPase, well known to act in 30S subunit assembly. Analysis of theΔrsgAstrain reveals accumulation of intermediates that resemble those seen in the absence of LepA. These data suggest that RsgA and LepA play partially redundant roles to ensure efficient 30S assembly.

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“…Although ΔEF4 cells grown in rich medium have no phenotype (13), recent results have demonstrated that EF4 can improve the yield of functional protein synthesis (6) and that, under certain stress conditions, including high salt, low pH, and low temperatures, a ΔEF4 strain is overgrown by wild-type bacterial cells (14). In addition, bacterial ΔEF4 strains have been shown to be hypersensitive to potassium tellurite and to penicillin [Escherichia coli (8)] and to have increased levels of the calcium-dependent antibiotic nonribosomal peptide synthetases [Streptomyces coelicor (15)].…”

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confidence: 99%

The conserved protein EF4 (LepA) modulates the elongation cycle of protein synthesis

Liu

Chen

Zhang

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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EF4 (LepA), a strongly conserved protein, is important for bacterial growth and functional protein biosynthesis under certain conditions and is quite similar structurally to the translocase EF-G. The elongation cycle in protein synthesis is characterized by ribosome oscillation between pretranslocation (PRE) and posttranslocation (POST) complexes. Here, using ensemble single turnover and equilibrium experiments, as well as single molecule FRET measurements, we demonstrate that EF4 can compete with EF-G for binding to the PRE complex. Such EF4 binding results in formation of a complex, denoted X 3 , that effectively sequesters a catalytically active ribosome, leading to a transient inhibition of elongation that provides a mechanism for optimization of functional protein synthesis. Earlier [Liu H, et al. (2010) J Mol Biol 396:1043-1052 we demonstrated that EF4 also reacts with POST complex, leading to the formation of a complex, I 3 , that appears to be identical with X 3 . Our present results strongly suggest that PRE complex is the principal target of EF4 action on translation, rather than POST complex as had been previously supposed.

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lep operon proximal gene is not required for growth or secretion by Escherichia coli

Cited by 45 publications

References 27 publications

Suppression of ΔbipAPhenotypes inEscherichia coliby Abolishment of Pseudouridylation at Specific Sites on the 23S rRNA

Suppression of ΔbipAPhenotypes inEscherichia coliby Abolishment of Pseudouridylation at Specific Sites on the 23S rRNA

Conserved GTPase LepA (Elongation Factor 4) functions in biogenesis of the 30S subunit of the 70S ribosome

The conserved protein EF4 (LepA) modulates the elongation cycle of protein synthesis

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