Ribosomal Protein S1: An Important Trans-Translational Factor

Wower, Iwona K.; Jahan, Nusrat; Zwieb, Christian W; Wower, Jacek

doi:10.4172/2168-9652.s2-001

Cited by 4 publications

(1 citation statement)

References 41 publications

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“…EF-Tu binds to the T-arm of the TLD precisely as observed in canonical aminoacyl-tRNAs [ 7 , 8 ]. Protein S1 was found in E. coli tmRNA:ribosome complexes that were assembled in vivo [ 9 ]. S1 has been shown to bind to free tmRNAs and tmRNA:SmpB complexes by contacting the MLR, pk2 and pk3 [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

Requirements for resuming translation in chimeric transfer-messenger RNAs of Escherichia coli and Mycobacterium tuberculosis

2014

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BackgroundTrans-translation is catalyzed by ribonucleprotein complexes composed of SmpB protein and transfer-messenger RNA. They release stalled ribosomes from truncated mRNAs and tag defective proteins for proteolytic degradation. Comparative sequence analysis of bacterial tmRNAs provides considerable insights into their secondary structures in which a tRNA-like domain and an mRNA-like region are connected by a variable number of pseudoknots. Progress toward understanding the molecular mechanism of trans-translation is hampered by our limited knowledge about the structure of tmRNA:SmpB complexes.ResultsComplexes consisting of M. tuberculosis tmRNA and E. coli SmpB tag truncated proteins poorly in E. coli. In contrast, the tagging activity of E. coli tmRNA is well supported by M. tuberculosis SmpB that is expressed in E. coli. To investigate this incompatibility, we constructed 12 chimeric tmRNA molecules composed of structural features derived from both E. coli and M. tuberculosis. Our studies demonstrate that replacing the hp5-pk2-pk3-pk4 segment of E. coli tmRNA with the equivalent segment of M. tuberculosis tmRNA has no significant effect on the tagging efficiency of chimeric tmRNAs in the presence of E. coli SmpB. Replacing either helices 2b-2d, the single-stranded part of the ORF, pk1, or residues 79–89 of E. coli tmRNA with the equivalent features of M. tuberculosis tmRNA yields chimeric tmRNAs that are tagged at 68 to 88 percent of what is observed with E. coli tmRNA. Exchanging segments composed of either pk1 and the single-stranded segment upstream of the ORF or helices 2b-2d and pk1 results in markedly impaired tagging activity.ConclusionOur observations demonstrate the existence of functionally important but as yet uncharacterized structural constraints in the segment of tmRNA that connects its TLD to the ORF used for resuming translation. As trans-translation is important for the survival of M. tuberculosis, our work provides a new target for pharmacological intervention against multidrug-resistant tuberculosis.

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Section: Introductionmentioning

confidence: 99%

Requirements for resuming translation in chimeric transfer-messenger RNAs of Escherichia coli and Mycobacterium tuberculosis

2014

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Mycobacterium tuberculosis ribosomal protein S1 (RpsA) and variants with truncated C-terminal end show absence of interaction with pyrazinoic acid

Vallejos-Sánchez

López

Antiparra

et al. 2020

Sci Rep

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Pyrazinamide (PZA) is an antibiotic used in first- and second-line tuberculosis treatment regimens. Approximately 50% of multidrug-resistant tuberculosis and over 90% of extensively drug-resistant tuberculosis strains are also PZA resistant. Despite the key role played by PZA, its mechanisms of action are not yet fully understood. It has been postulated that pyrazinoic acid (POA), the hydrolyzed product of PZA, could inhibit trans-translation by binding to Ribosomal protein S1 (RpsA) and competing with tmRNA, the natural cofactor of RpsA. Subsequent data, however, indicate that these early findings resulted from experimental artifact. Hence, in this study we assess the capacity of POA to compete with tmRNA for RpsA. We evaluated RpsA wild type (WT), RpsA ∆A438, and RpsA ∆A438 variants with truncations towards the carboxy terminal end. Interactions were measured using Nuclear Magnetic Resonance spectroscopy (NMR), Isothermal Titration Calorimetry (ITC), Microscale Thermophoresis (MST), and Electrophoretic Mobility Shift Assay (EMSA). We found no measurable binding between POA and RpsA (WT or variants). This suggests that RpsA may not be involved in the mechanism of action of PZA in Mycobacterium tuberculosis, as previously thought. Interactions observed between tmRNA and RpsA WT, RpsA ∆A438, and each of the truncated variants of RpsA ∆A438, are reported.

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Influence of increased nutrient supply on Microcystis aeruginosa at cellular and proteomic levels

Jiang

Liu

2020

Aquat. Microb. Ecol.

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Various studies have observed that increased nutrient supply promotes the growth of bloom-forming cyanobacteria, but only a limited number of studies have investigated the influence of increased nutrient supply on bloom-forming cyanobacteria at the proteomic level. We investigated the cellular and proteomic responses of Microcystis aeruginosa to elevated nitrogen and phosphorus supply. Increased supply of both nutrients significantly promoted the growth of M. aeruginosa and the synthesis of chlorophyll a, protein, and microcystins. The release of microcystins and the synthesis of polysaccharides negatively correlated with the growth of M. aeruginosa under high nutrient levels. Overexpressed proteins related to photosynthesis, and amino acid synthesis, were responsible for the stimulatory effects of increased nutrient supply in M. aeruginosa. Increased nitrogen supply directly promoted cyanobacterial growth by inducing the overexpression of the cell division regulatory protein FtsZ. NtcA, that regulates gene transcription related to both nitrogen assimilation and microcystin synthesis, was overexpressed under the high nitrogen condition, which consequently induced overexpression of 2 microcystin synthetases (McyC and McyF) and promoted microcystin synthesis. Elevated nitrogen supply induced the overexpression of proteins involved in gas vesicle organization (GvpC and GvpW), which may increase the buoyancy of M. aeruginosa. Increased phosphorus level indirectly affected growth and the synthesis of cellular substances in M. aeruginosa through the mediation of differentially expressed proteins related to carbon and phosphorus metabolism. This study provides a comprehensive description of changes in the proteome of M. aeruginosa in response to an increased supply of 2 key nutrients.

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Ribosomal Protein S1: An Important Trans-Translational Factor

Cited by 4 publications

References 41 publications

Requirements for resuming translation in chimeric transfer-messenger RNAs of Escherichia coli and Mycobacterium tuberculosis

Requirements for resuming translation in chimeric transfer-messenger RNAs of Escherichia coli and Mycobacterium tuberculosis

Mycobacterium tuberculosis ribosomal protein S1 (RpsA) and variants with truncated C-terminal end show absence of interaction with pyrazinoic acid

Influence of increased nutrient supply on Microcystis aeruginosa at cellular and proteomic levels

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