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Judd HNG, Martínez AK, Klepacki D, Vázquez-Laslop N, Sachs MS, Cruz-Vera LR. Functional domains of a ribosome arresting peptide are affected by surrounding nonconserved residues. J Biol Chem 2024; 300:105780. [PMID: 38395310 PMCID: PMC10941005 DOI: 10.1016/j.jbc.2024.105780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 02/12/2024] [Accepted: 02/15/2024] [Indexed: 02/25/2024] Open
Abstract
Expression of the Escherichia coli tnaCAB operon, responsible for L-tryptophan (L-Trp) transport and catabolism, is regulated by L-Trp-directed translation arrest and the ribosome arresting peptide TnaC. The function of TnaC relies on conserved residues distributed throughout the peptide, which are involved in forming an L-Trp binding site at the ribosome exit tunnel and inhibiting the ribosome function. We aimed to understand whether nonconserved amino acids surrounding these critical conserved residues play a functional role in TnaC-mediated ribosome arrest. We have isolated two intragenic suppressor mutations that restore arrest function of TnaC mutants; one of these mutations is located near the L-Trp binding site, while the other mutation is located near the ribosome active site. We used reporter gene fusions to show that both suppressor mutations have similar effects on TnaC mutants at the conserved residues involved in forming a free L-Trp binding site. However, they diverge in suppressing loss-of-function mutations in a conserved TnaC residue at the ribosome active site. With ribosome toeprinting assays, we determined that both suppressor mutations generate TnaC peptides, which are highly sensitive to L-Trp. Puromycin-challenge assays with isolated arrested ribosomes indicate that both TnaC suppressor mutants are resistant to peptidyl-tRNA cleavage by puromycin in the presence of L-Trp; however, they differ in their resistance to puromycin in the absence of L-Trp. We propose that the TnaC peptide two functionally distinct segments, a sensor domain and a stalling domain, and that the functional versatility of these domains is fine-tuned by the nature of their surrounding nonconserved residues.
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Affiliation(s)
- Heather N G Judd
- Department of Biological Sciences, University of Alabama in Huntsville, Huntsville, Alabama, USA
| | - Allyson K Martínez
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Dorota Klepacki
- Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, Illinois, USA; Center for Biomolecular Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Nora Vázquez-Laslop
- Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, Illinois, USA; Center for Biomolecular Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Matthew S Sachs
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Luis R Cruz-Vera
- Department of Biological Sciences, University of Alabama in Huntsville, Huntsville, Alabama, USA.
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2
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Fostier CR, Ousalem F, Leroy EC, Ngo S, Soufari H, Innis CA, Hashem Y, Boël G. Regulation of the macrolide resistance ABC-F translation factor MsrD. Nat Commun 2023; 14:3891. [PMID: 37393329 PMCID: PMC10314930 DOI: 10.1038/s41467-023-39553-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 06/19/2023] [Indexed: 07/03/2023] Open
Abstract
Antibiotic resistance ABC-Fs (ARE ABC-Fs) are translation factors that provide resistance against clinically important ribosome-targeting antibiotics which are proliferating among pathogens. Here, we combine genetic and structural approaches to determine the regulation of streptococcal ARE ABC-F gene msrD in response to macrolide exposure. We show that binding of cladinose-containing macrolides to the ribosome prompts insertion of the leader peptide MsrDL into a crevice of the ribosomal exit tunnel, which is conserved throughout bacteria and eukaryotes. This leads to a local rearrangement of the 23 S rRNA that prevents peptide bond formation and accommodation of release factors. The stalled ribosome obstructs the formation of a Rho-independent terminator structure that prevents msrD transcriptional attenuation. Erythromycin induction of msrD expression via MsrDL, is suppressed by ectopic expression of mrsD, but not by mutants which do not provide antibiotic resistance, showing correlation between MsrD function in antibiotic resistance and its action on this stalled complex.
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Affiliation(s)
- Corentin R Fostier
- Expression Génétique Microbienne, CNRS, Université Paris Cité, Institut de Biologie Physico-Chimique, 75005, Paris, France
| | - Farès Ousalem
- Expression Génétique Microbienne, CNRS, Université Paris Cité, Institut de Biologie Physico-Chimique, 75005, Paris, France
| | - Elodie C Leroy
- ARNA Laboratory, UMR 5320, U1212, Institut Européen de Chimie et Biologie, Univ. Bordeaux, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, 33607, Pessac, France
| | - Saravuth Ngo
- Expression Génétique Microbienne, CNRS, Université Paris Cité, Institut de Biologie Physico-Chimique, 75005, Paris, France
| | - Heddy Soufari
- ARNA Laboratory, UMR 5320, U1212, Institut Européen de Chimie et Biologie, Univ. Bordeaux, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, 33607, Pessac, France
- SPT Labtech Ltd., SG8 6HB, Melbourn, United Kingdom
| | - C Axel Innis
- ARNA Laboratory, UMR 5320, U1212, Institut Européen de Chimie et Biologie, Univ. Bordeaux, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, 33607, Pessac, France
| | - Yaser Hashem
- ARNA Laboratory, UMR 5320, U1212, Institut Européen de Chimie et Biologie, Univ. Bordeaux, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, 33607, Pessac, France.
| | - Grégory Boël
- Expression Génétique Microbienne, CNRS, Université Paris Cité, Institut de Biologie Physico-Chimique, 75005, Paris, France.
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3
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Ojima-Kato T, Nishikawa Y, Furukawa Y, Kojima T, Nakano H. Nascent MSKIK Peptide Cancels Ribosomal Stalling by Arrest Peptides in Escherichia coli. J Biol Chem 2023; 299:104676. [PMID: 37028767 DOI: 10.1016/j.jbc.2023.104676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 03/22/2023] [Accepted: 03/24/2023] [Indexed: 04/09/2023] Open
Abstract
The insertion of the DNA sequence encoding SKIK peptide adjacent to the M start codon of a difficult-to-express protein enhances protein production in Escherichia coli. In this report, we reveal that the increased production of the SKIK-tagged protein is not due to codon usage of the SKIK sequence. Furthermore, we found that insertion of SKIK or MSKIK just before the SecM arrest peptide (FSTPVWISQAQGIRAGP), which causes ribosomal stalling on mRNA, greatly increased the production of the protein containing the SecM arrest peptide in the E. coli reconstituted cell-free protein synthesis system (PURE system). A similar translation enhancement phenomenon by MSKIK was observed for the CmlA leader peptide, a ribosome arrest peptide, whose arrest is induced by chloramphenicol. These results strongly suggest that the nascent MSKIK peptide prevents or releases ribosomal stalling immediately following its generation during the translation process, resulting in an increase of protein production.
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Affiliation(s)
- Teruyo Ojima-Kato
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
| | - Yuma Nishikawa
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Yuki Furukawa
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Takaaki Kojima
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Hideo Nakano
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
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4
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Su T, Kudva R, Becker T, Buschauer R, Komar T, Berninghausen O, von Heijne G, Cheng J, Beckmann R. Structural basis of l-tryptophan-dependent inhibition of release factor 2 by the TnaC arrest peptide. Nucleic Acids Res 2021; 49:9539-9547. [PMID: 34403461 PMCID: PMC8450073 DOI: 10.1093/nar/gkab665] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 07/13/2021] [Accepted: 08/14/2021] [Indexed: 12/20/2022] Open
Abstract
In Escherichia coli, elevated levels of free l-tryptophan (l-Trp) promote translational arrest of the TnaC peptide by inhibiting its termination. However, the mechanism by which translation-termination by the UGA-specific decoding release factor 2 (RF2) is inhibited at the UGA stop codon of stalled TnaC-ribosome-nascent chain complexes has so far been ambiguous. This study presents cryo-EM structures for ribosomes stalled by TnaC in the absence and presence of RF2 at average resolutions of 2.9 and 3.5 Å, respectively. Stalled TnaC assumes a distinct conformation composed of two small α-helices that act together with residues in the peptide exit tunnel (PET) to coordinate a single L-Trp molecule. In addition, while the peptidyl-transferase center (PTC) is locked in a conformation that allows RF2 to adopt its canonical position in the ribosome, it prevents the conserved and catalytically essential GGQ motif of RF2 from adopting its active conformation in the PTC. This explains how translation of the TnaC peptide effectively allows the ribosome to function as a L-Trp-specific small-molecule sensor that regulates the tnaCAB operon.
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Affiliation(s)
- Ting Su
- Gene Center Munich, Department of Biochemistry, University of Munich, Munich 81377, Germany
| | - Renuka Kudva
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm SE-10691, Sweden.,Science for Life Laboratories, Solna 17165, Sweden
| | - Thomas Becker
- Gene Center Munich, Department of Biochemistry, University of Munich, Munich 81377, Germany
| | - Robert Buschauer
- Gene Center Munich, Department of Biochemistry, University of Munich, Munich 81377, Germany
| | - Tobias Komar
- Gene Center Munich, Department of Biochemistry, University of Munich, Munich 81377, Germany
| | - Otto Berninghausen
- Gene Center Munich, Department of Biochemistry, University of Munich, Munich 81377, Germany
| | - Gunnar von Heijne
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm SE-10691, Sweden.,Science for Life Laboratories, Solna 17165, Sweden
| | - Jingdong Cheng
- Gene Center Munich, Department of Biochemistry, University of Munich, Munich 81377, Germany
| | - Roland Beckmann
- Gene Center Munich, Department of Biochemistry, University of Munich, Munich 81377, Germany
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5
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Structural basis for the tryptophan sensitivity of TnaC-mediated ribosome stalling. Nat Commun 2021; 12:5340. [PMID: 34504068 PMCID: PMC8429421 DOI: 10.1038/s41467-021-25663-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 08/24/2021] [Indexed: 02/07/2023] Open
Abstract
Free L-tryptophan (L-Trp) stalls ribosomes engaged in the synthesis of TnaC, a leader peptide controlling the expression of the Escherichia coli tryptophanase operon. Despite extensive characterization, the molecular mechanism underlying the recognition and response to L-Trp by the TnaC-ribosome complex remains unknown. Here, we use a combined biochemical and structural approach to characterize a TnaC variant (R23F) with greatly enhanced sensitivity for L-Trp. We show that the TnaC-ribosome complex captures a single L-Trp molecule to undergo termination arrest and that nascent TnaC prevents the catalytic GGQ loop of release factor 2 from adopting an active conformation at the peptidyl transferase center. Importantly, the L-Trp binding site is not altered by the R23F mutation, suggesting that the relative rates of L-Trp binding and peptidyl-tRNA cleavage determine the tryptophan sensitivity of each variant. Thus, our study reveals a strategy whereby a nascent peptide assists the ribosome in detecting a small metabolite.
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6
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Sherman MW, Sandeep S, Contreras LM. The Tryptophan-Induced tnaC Ribosome Stalling Sequence Exposes High Amino Acid Cross-Talk That Can Be Mitigated by Removal of NusB for Higher Orthogonality. ACS Synth Biol 2021; 10:1024-1038. [PMID: 33835775 DOI: 10.1021/acssynbio.0c00547] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A growing number of engineered synthetic circuits have employed biological parts coupling transcription and translation in bacterial systems to control downstream gene expression. One such example, the leader sequence of the tryptophanase (tna) operon, is a transcription-translation system commonly employed as an l-tryptophan inducible circuit controlled by ribosome stalling. While induction of the tna operon has been well-characterized in response to l-tryptophan, cross-talk of this modular component with other metabolites in the cell, such as other naturally occurring amino acids, has been less explored. In this study, we investigated the impact of natural metabolites and E. coli host factors on induction of the tna leader sequence. To do so, we constructed and biochemically validated an experimental assay using the tna operon leader sequence to assess differential regulation of transcription elongation and translation in response to l-tryptophan. Operon induction was then assessed following addition of each of the 20 naturally occurring amino acids to discover that several additional amino acids (e.g., l-alanine, l-cysteine, l-glycine, l-methionine, and l-threonine) also induce expression of the tna leader sequence. Following characterization of dose-dependent induction by l-cysteine relative to l-tryptophan, the effect on induction by single gene knockouts of protein factors associated with transcription and/or translation were interrogated. Our results implicate the endogenous cellular protein, NusB, as an important factor associated with induction of the operon by the alternative amino acids. As such, removal of the nusB gene from strains intended for tryptophan-sensing utilizing the tna leader region reduces amino acid cross-talk, resulting in enhanced orthogonal control of this commonly used synthetic system.
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Affiliation(s)
- Mark W. Sherman
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas 78714, United States
| | - Sanjna Sandeep
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78714, United States
| | - Lydia M. Contreras
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78714, United States
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7
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Dever TE, Ivanov IP, Sachs MS. Conserved Upstream Open Reading Frame Nascent Peptides That Control Translation. Annu Rev Genet 2020; 54:237-264. [PMID: 32870728 DOI: 10.1146/annurev-genet-112618-043822] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cells utilize transcriptional and posttranscriptional mechanisms to alter gene expression in response to environmental cues. Gene-specific controls, including changing the translation of specific messenger RNAs (mRNAs), provide a rapid means to respond precisely to different conditions. Upstream open reading frames (uORFs) are known to control the translation of mRNAs. Recent studies in bacteria and eukaryotes have revealed the functions of evolutionarily conserved uORF-encoded peptides. Some of these uORF-encoded nascent peptides enable responses to specific metabolites to modulate the translation of their mRNAs by stalling ribosomes and through ribosome stalling may also modulate the level of their mRNAs. In this review, we highlight several examples of conserved uORF nascent peptides that stall ribosomes to regulate gene expression in response to specific metabolites in bacteria, fungi, mammals, and plants.
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Affiliation(s)
- Thomas E Dever
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA; ,
| | - Ivaylo P Ivanov
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA; ,
| | - Matthew S Sachs
- Department of Biology, Texas A&M University, College Station, Texas 77843, USA;
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