1
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Hinnu M, Putrinš M, Kogermann K, Kaldalu N, Tenson T. Fluorescent reporters give new insights into antibiotics-induced nonsense and frameshift mistranslation. Sci Rep 2024; 14:6883. [PMID: 38519558 PMCID: PMC10959953 DOI: 10.1038/s41598-024-57597-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 03/20/2024] [Indexed: 03/25/2024] Open
Abstract
We developed a reporter system based on simultaneous expression of two fluorescent proteins: GFP as a reporter of the capacity of protein synthesis and mutated mScarlet-I as a reporter of translational errors. Because of the unique stop codons or frameshift mutations introduced into the mScarlet-I gene, red fluorescence was produced only after a mistranslation event. These reporters allowed us to estimate mistranslation at a single cell level using either flow cytometry or fluorescence microscopy. We found that laboratory strains of Escherichia coli are more prone to mistranslation compared to the clinical isolates. As relevant for uropathogenic E. coli, growth in human urine elevated translational frameshifting compared to standard laboratory media, whereas different standard media had a small effect on translational fidelity. Antibiotic-induced mistranslation was studied by using amikacin (aminoglycoside family) and azithromycin (macrolide family). Bactericidal amikacin induced preferably stop-codon readthrough at a moderate level. Bacteriostatic azithromycin on the other hand induced both frameshifting and stop-codon readthrough at much higher level. Single cell analysis revealed that fluorescent reporter-protein signal can be lost due to leakage from a fraction of bacteria in the presence of antibiotics, demonstrating the complexity of the antimicrobial activity.
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Affiliation(s)
- Mariliis Hinnu
- Institute of Technology, University of Tartu, 50411, Tartu, Estonia.
| | - Marta Putrinš
- Institute of Technology, University of Tartu, 50411, Tartu, Estonia
- Institute of Pharmacy, University of Tartu, 50411, Tartu, Estonia
| | - Karin Kogermann
- Institute of Pharmacy, University of Tartu, 50411, Tartu, Estonia
| | - Niilo Kaldalu
- Institute of Technology, University of Tartu, 50411, Tartu, Estonia
| | - Tanel Tenson
- Institute of Technology, University of Tartu, 50411, Tartu, Estonia
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2
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Aseev LV, Koledinskaya LS, Boni IV. Extraribosomal Functions of Bacterial Ribosomal Proteins-An Update, 2023. Int J Mol Sci 2024; 25:2957. [PMID: 38474204 DOI: 10.3390/ijms25052957] [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: 01/19/2024] [Revised: 02/19/2024] [Accepted: 02/21/2024] [Indexed: 03/14/2024] Open
Abstract
Ribosomal proteins (r-proteins) are abundant, highly conserved, and multifaceted cellular proteins in all domains of life. Most r-proteins have RNA-binding properties and can form protein-protein contacts. Bacterial r-proteins govern the co-transcriptional rRNA folding during ribosome assembly and participate in the formation of the ribosome functional sites, such as the mRNA-binding site, tRNA-binding sites, the peptidyl transferase center, and the protein exit tunnel. In addition to their primary role in a cell as integral components of the protein synthesis machinery, many r-proteins can function beyond the ribosome (the phenomenon known as moonlighting), acting either as individual regulatory proteins or in complexes with various cellular components. The extraribosomal activities of r-proteins have been studied over the decades. In the past decade, our understanding of r-protein functions has advanced significantly due to intensive studies on ribosomes and gene expression mechanisms not only in model bacteria like Escherichia coli or Bacillus subtilis but also in little-explored bacterial species from various phyla. The aim of this review is to update information on the multiple functions of r-proteins in bacteria.
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Affiliation(s)
- Leonid V Aseev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997 Moscow, Russia
| | | | - Irina V Boni
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997 Moscow, Russia
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3
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Catalanotto C, Barbato C, Cogoni C, Benelli D. The RNA-Binding Function of Ribosomal Proteins and Ribosome Biogenesis Factors in Human Health and Disease. Biomedicines 2023; 11:2969. [PMID: 38001969 PMCID: PMC10669870 DOI: 10.3390/biomedicines11112969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/26/2023] Open
Abstract
The ribosome is a macromolecular complex composed of RNA and proteins that interact through an integrated and interconnected network to preserve its ancient core activities. In this review, we emphasize the pivotal role played by RNA-binding proteins as a driving force in the evolution of the current form of the ribosome, underscoring their importance in ensuring accurate protein synthesis. This category of proteins includes both ribosomal proteins and ribosome biogenesis factors. Impairment of their RNA-binding activity can also lead to ribosomopathies, which is a group of disorders characterized by defects in ribosome biogenesis that are detrimental to protein synthesis and cellular homeostasis. A comprehensive understanding of these intricate processes is essential for elucidating the mechanisms underlying the resulting diseases and advancing potential therapeutic interventions.
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Affiliation(s)
- Caterina Catalanotto
- Department of Molecular Medicine, Sapienza University of Rome, 00185 Rome, Italy; (C.C.); (C.C.)
| | - Christian Barbato
- National Research Council (CNR), Department of Sense Organs DOS, Institute of Biochemistry and Cell Biology (IBBC), Sapienza University of Rome, 00185 Rome, Italy;
| | - Carlo Cogoni
- Department of Molecular Medicine, Sapienza University of Rome, 00185 Rome, Italy; (C.C.); (C.C.)
| | - Dario Benelli
- Department of Molecular Medicine, Sapienza University of Rome, 00185 Rome, Italy; (C.C.); (C.C.)
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4
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Landry-Voyer AM, Mir Hassani Z, Avino M, Bachand F. Ribosomal Protein uS5 and Friends: Protein-Protein Interactions Involved in Ribosome Assembly and Beyond. Biomolecules 2023; 13:biom13050853. [PMID: 37238722 DOI: 10.3390/biom13050853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/15/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
Ribosomal proteins are fundamental components of the ribosomes in all living cells. The ribosomal protein uS5 (Rps2) is a stable component of the small ribosomal subunit within all three domains of life. In addition to its interactions with proximal ribosomal proteins and rRNA inside the ribosome, uS5 has a surprisingly complex network of evolutionarily conserved non-ribosome-associated proteins. In this review, we focus on a set of four conserved uS5-associated proteins: the protein arginine methyltransferase 3 (PRMT3), the programmed cell death 2 (PDCD2) and its PDCD2-like (PDCD2L) paralog, and the zinc finger protein, ZNF277. We discuss recent work that presents PDCD2 and homologs as a dedicated uS5 chaperone and PDCD2L as a potential adaptor protein for the nuclear export of pre-40S subunits. Although the functional significance of the PRMT3-uS5 and ZNF277-uS5 interactions remain elusive, we reflect on the potential roles of uS5 arginine methylation by PRMT3 and on data indicating that ZNF277 and PRMT3 compete for uS5 binding. Together, these discussions highlight the complex and conserved regulatory network responsible for monitoring the availability and the folding of uS5 for the formation of 40S ribosomal subunits and/or the role of uS5 in potential extra-ribosomal functions.
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Affiliation(s)
- Anne-Marie Landry-Voyer
- Dept of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Zabih Mir Hassani
- Dept of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Mariano Avino
- Dept of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - François Bachand
- Dept of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
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5
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Radford F, Rinehart J, Isaacs FJ. Mapping the in vivo fitness landscape of a tethered ribosome. SCIENCE ADVANCES 2023; 9:eade8934. [PMID: 37115918 PMCID: PMC10146877 DOI: 10.1126/sciadv.ade8934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Fitness landscapes are models of the sequence space of a genetic element that map how each sequence corresponds to its activity and can be used to guide laboratory evolution. The ribosome is a macromolecular machine that is essential for protein synthesis in all organisms. Because of the prevalence of dominant lethal mutations, a comprehensive fitness landscape of the ribosomal peptidyl transfer center (PTC) has not yet been attained. Here, we develop a method to functionally map an orthogonal tethered ribosome (oRiboT), which permits complete mutagenesis of nucleotides located in the PTC and the resulting epistatic interactions. We found that most nucleotides studied showed flexibility to mutation, and identified epistatic interactions between them, which compensate for deleterious mutations. This work provides a basis for a deeper understanding of ribosome function and malleability and could be used to inform design of engineered ribosomes with applications to synthesize next-generation biomaterials and therapeutics.
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Affiliation(s)
- Felix Radford
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA
- Systems Biology Institute, Yale University, West Haven, CT 06516, USA
| | - Jesse Rinehart
- Systems Biology Institute, Yale University, West Haven, CT 06516, USA
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Farren J. Isaacs
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA
- Systems Biology Institute, Yale University, West Haven, CT 06516, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA
- Corresponding author.
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6
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Lyu Z, Wilson C, Ling J. Translational Fidelity during Bacterial Stresses and Host Interactions. Pathogens 2023; 12:383. [PMID: 36986305 PMCID: PMC10057733 DOI: 10.3390/pathogens12030383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/22/2023] [Accepted: 02/24/2023] [Indexed: 03/05/2023] Open
Abstract
Translational fidelity refers to accuracy during protein synthesis and is maintained in all three domains of life. Translational errors occur at base levels during normal conditions and may rise due to mutations or stress conditions. In this article, we review our current understanding of how translational fidelity is perturbed by various environmental stresses that bacterial pathogens encounter during host interactions. We discuss how oxidative stress, metabolic stresses, and antibiotics affect various types of translational errors and the resulting effects on stress adaption and fitness. We also discuss the roles of translational fidelity during pathogen-host interactions and the underlying mechanisms. Many of the studies covered in this review will be based on work with Salmonella enterica and Escherichia coli, but other bacterial pathogens will also be discussed.
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Affiliation(s)
| | | | - Jiqiang Ling
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
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7
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Liu F, Bratulić S, Costello A, Miettinen TP, Badran AH. Directed evolution of rRNA improves translation kinetics and recombinant protein yield. Nat Commun 2021; 12:5638. [PMID: 34561441 PMCID: PMC8463689 DOI: 10.1038/s41467-021-25852-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 09/03/2021] [Indexed: 11/09/2022] Open
Abstract
In bacteria, ribosome kinetics are considered rate-limiting for protein synthesis and cell growth. Enhanced ribosome kinetics may augment bacterial growth and biomanufacturing through improvements to overall protein yield, but whether this can be achieved by ribosome-specific modifications remains unknown. Here, we evolve 16S ribosomal RNAs (rRNAs) from Escherichia coli, Pseudomonas aeruginosa, and Vibrio cholerae towards enhanced protein synthesis rates. We find that rRNA sequence origin significantly impacted evolutionary trajectory and generated rRNA mutants with augmented protein synthesis rates in both natural and engineered contexts, including the incorporation of noncanonical amino acids. Moreover, discovered consensus mutations can be ported onto phylogenetically divergent rRNAs, imparting improved translational activities. Finally, we show that increased translation rates in vivo coincide with only moderately reduced translational fidelity, but do not enhance bacterial population growth. Together, these findings provide a versatile platform for development of unnatural ribosomal functions in vivo.
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MESH Headings
- Base Sequence
- Directed Molecular Evolution/methods
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Kinetics
- Mass Spectrometry/methods
- Models, Molecular
- Mutation
- Nucleic Acid Conformation
- Protein Biosynthesis
- Proteome/metabolism
- RNA, Ribosomal/chemistry
- RNA, Ribosomal/genetics
- RNA, Ribosomal/metabolism
- RNA, Ribosomal, 16S/chemistry
- RNA, Ribosomal, 16S/genetics
- RNA, Ribosomal, 16S/metabolism
- Recombinant Proteins/metabolism
- Ribosomal Proteins/genetics
- Ribosomal Proteins/metabolism
- Ribosomes/genetics
- Ribosomes/metabolism
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Affiliation(s)
- Fan Liu
- The Broad Institute of MIT & Harvard University, Cambridge, MA, 02142, USA
| | - Siniša Bratulić
- The Broad Institute of MIT & Harvard University, Cambridge, MA, 02142, USA
- Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96, Göteborg, Sweden
| | - Alan Costello
- The Broad Institute of MIT & Harvard University, Cambridge, MA, 02142, USA
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Teemu P Miettinen
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, 02142, USA
| | - Ahmed H Badran
- The Broad Institute of MIT & Harvard University, Cambridge, MA, 02142, USA.
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, 92037, USA.
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8
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Calles J, Justice I, Brinkley D, Garcia A, Endy D. Fail-safe genetic codes designed to intrinsically contain engineered organisms. Nucleic Acids Res 2019; 47:10439-10451. [PMID: 31511890 PMCID: PMC6821295 DOI: 10.1093/nar/gkz745] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/13/2019] [Accepted: 08/19/2019] [Indexed: 11/24/2022] Open
Abstract
One challenge in engineering organisms is taking responsibility for their behavior over many generations. Spontaneous mutations arising before or during use can impact heterologous genetic functions, disrupt system integration, or change organism phenotype. Here, we propose restructuring the genetic code itself such that point mutations in protein-coding sequences are selected against. Synthetic genetic systems so-encoded should fail more safely in response to most spontaneous mutations. We designed fail-safe codes and simulated their expected effects on the evolution of so-encoded proteins. We predict fail-safe codes supporting expression of 20 or 15 amino acids could slow protein evolution to ∼30% or 0% the rate of standard-encoded proteins, respectively. We also designed quadruplet-codon codes that should ensure all single point mutations in protein-coding sequences are selected against while maintaining expression of 20 or more amino acids. We demonstrate experimentally that a reduced set of 21 tRNAs is capable of expressing a protein encoded by only 20 sense codons, whereas a standard 64-codon encoding is not expressed. Our work suggests that biological systems using rationally depleted but otherwise natural translation systems should evolve more slowly and that such hypoevolvable organisms may be less likely to invade new niches or outcompete native populations.
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Affiliation(s)
- Jonathan Calles
- Bioengineering Department, Stanford University, Stanford, CA 94305, USA
| | - Isaac Justice
- Bioengineering Department, Stanford University, Stanford, CA 94305, USA
| | - Detravious Brinkley
- Department of Mathematics and Computer Science, Claflin University, Orangeburg, SC 29115, USA
| | - Alexa Garcia
- Bioengineering Department, Stanford University, Stanford, CA 94305, USA
| | - Drew Endy
- Bioengineering Department, Stanford University, Stanford, CA 94305, USA
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9
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Hoffer ED, Maehigashi T, Fredrick K, Dunham CM. Ribosomal ambiguity (ram) mutations promote the open (off) to closed (on) transition and thereby increase miscoding. Nucleic Acids Res 2019; 47:1557-1563. [PMID: 30476222 PMCID: PMC6379664 DOI: 10.1093/nar/gky1178] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 10/31/2018] [Accepted: 11/05/2018] [Indexed: 01/18/2023] Open
Abstract
Decoding is thought to be governed by a conformational transition in the ribosome—open (off) to closed (on)—that occurs upon codon–anticodon pairing in the A site. Ribosomal ambiguity (ram) mutations increase miscoding and map to disparate regions, consistent with a role for ribosome dynamics in decoding, yet precisely how these mutations act has been unclear. Here, we solved crystal structures of 70S ribosomes harboring 16S ram mutations G299A and G347U in the absence A-site tRNA (A-tRNA) and in the presence of a near-cognate anticodon stem-loop (ASL). In the absence of an A-tRNA, each of the mutant ribosomes exhibits a partially closed (on) state. In the 70S-G347U structure, the 30S shoulder is rotated inward and intersubunit bridge B8 is disrupted. In the 70S-G299A structure, the 30S shoulder is rotated inward and decoding nucleotide G530 flips into the anti conformation. Both of these mutant ribosomes adopt the fully closed (on) conformation in the presence of near-cognate A-tRNA, just as they do with cognate A-tRNA. Thus, these ram mutations act by promoting the open (off) to closed (on) transition, albeit in somewhat distinct ways. This work reveals the functional importance of 30S shoulder rotation for productive aminoacylated-tRNA incorporation.
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Affiliation(s)
- Eric D Hoffer
- Department of Biochemistry and Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Tatsuya Maehigashi
- Department of Biochemistry and Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Kurt Fredrick
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
- Correspondence may also be addressed to Kurt Fredrick. Tel: +1 614 292 6679; Fax: +1 614 292 8120;
| | - Christine M Dunham
- Department of Biochemistry and Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, GA 30322, USA
- To whom correspondence should be addressed. Tel: +1 404 712 1756; Fax: +1 404 727 2738; E-mail:
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10
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Fan Y, Thompson L, Lyu Z, Cameron TA, De Lay NR, Krachler AM, Ling J. Optimal translational fidelity is critical for Salmonella virulence and host interactions. Nucleic Acids Res 2019; 47:5356-5367. [PMID: 30941426 PMCID: PMC6547416 DOI: 10.1093/nar/gkz229] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/19/2019] [Accepted: 03/24/2019] [Indexed: 01/09/2023] Open
Abstract
Translational fidelity is required for accurate flow of genetic information, but is frequently altered by genetic changes and environmental stresses. To date, little is known about how translational fidelity affects the virulence and host interactions of bacterial pathogens. Here we show that surprisingly, either decreasing or increasing translational fidelity impairs the interactions of the enteric pathogen Salmonella Typhimurium with host cells and its fitness in zebrafish. Host interactions are mediated by Salmonella pathogenicity island 1 (SPI-1). Our RNA sequencing and quantitative RT-PCR results demonstrate that SPI-1 genes are among the most down-regulated when translational fidelity is either increased or decreased. Further, this down-regulation of SPI-1 genes depends on the master regulator HilD, and altering translational fidelity destabilizes HilD protein via enhanced degradation by Lon protease. Our work thus reveals that optimal translational fidelity is pivotal for adaptation of Salmonella to the host environment, and provides important mechanistic insights into this process.
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Affiliation(s)
- Yongqiang Fan
- College of Life and Health Sciences, Northeastern University, Shenyang 110819, People's Republic of China
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
- Shenyang National Laboratory for Materials Science, Northeastern University, Shenyang 110819, People's Republic of China
| | - Laurel Thompson
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Zhihui Lyu
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
| | - Todd A Cameron
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Nicholas R De Lay
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Anne Marie Krachler
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Jiqiang Ling
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
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11
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Kamath D, Allgeyer BB, Gregory ST, Bielski MC, Roelofsz DM, Sabapathypillai SL, Vaid N, O'Connor M. The C-terminus of ribosomal protein uS4 contributes to small ribosomal subunit biogenesis and the fidelity of translation. Biochimie 2017; 138:194-201. [PMID: 28483689 DOI: 10.1016/j.biochi.2017.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 05/04/2017] [Indexed: 01/28/2023]
Abstract
Ribosomal protein uS4 is an essential ribosomal component involved in multiple functions, including mRNA decoding. Structural analyses indicate that during decoding, the interface between the C-terminus of uS4 and protein uS5 is disrupted and in agreement with this, C-terminal uS4 truncation mutants are readily isolated on the basis of their increased miscoding phenotypes. The same mutants can also display defects in small subunit assembly and 16S rRNA processing and some are temperature sensitive for growth. Starting with one such temperature sensitive Escherichia coli uS4 mutant, we have isolated temperature insensitive derivatives carrying additional, intragenic mutations that restore the C-terminus and ameliorate the ribosomal defects. At least one of these suppressors has no detectable ribosome biogenesis phenotype, yet still miscodes, suggesting that the C-terminal requirements for ribosome assembly are less rigid than for mRNA decoding. In contrast to the uS4 C-terminal mutants that increase miscoding, two Salmonella enterica uS4 mutants with altered C-termini have been reported as being error-restrictive. Here, reconstruction experiments demonstrate that contrary to the previous reports, these mutants have a distinct error-prone, increased misreading phenotype, consistent with the behavior of the equivalent E. coli mutants and their likely structural effects on uS4-uS5 interactions.
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Affiliation(s)
- Divya Kamath
- School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Benjamin B Allgeyer
- School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Steven T Gregory
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, RI, USA; Department of Cell and Molecular Biology, University of Rhode Island, Kingston, RI, USA
| | - Margaret C Bielski
- School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO, USA
| | - David M Roelofsz
- Program in Medicine, School of Medicine, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Sharon L Sabapathypillai
- Program in Medicine, School of Medicine, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Nikhil Vaid
- School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Michael O'Connor
- School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO, USA.
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12
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Maddamsetti R, Hatcher PJ, Green AG, Williams BL, Marks DS, Lenski RE. Core Genes Evolve Rapidly in the Long-Term Evolution Experiment with Escherichia coli. Genome Biol Evol 2017; 9:1072-1083. [PMID: 28379360 PMCID: PMC5406848 DOI: 10.1093/gbe/evx064] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/03/2017] [Indexed: 12/22/2022] Open
Abstract
Bacteria can evolve rapidly under positive selection owing to their vast numbers, allowing their genes to diversify by adapting to different environments. We asked whether the same genes that evolve rapidly in the long-term evolution experiment (LTEE) with Escherichia coli have also diversified extensively in nature. To make this comparison, we identified ∼2000 core genes shared among 60 E. coli strains. During the LTEE, core genes accumulated significantly more nonsynonymous mutations than flexible (i.e., noncore) genes. Furthermore, core genes under positive selection in the LTEE are more conserved in nature than the average core gene. In some cases, adaptive mutations appear to modify protein functions, rather than merely knocking them out. The LTEE conditions are novel for E. coli, at least in relation to its evolutionary history in nature. The constancy and simplicity of the environment likely favor the complete loss of some unused functions and the fine-tuning of others.
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Affiliation(s)
- Rohan Maddamsetti
- Ecology, Evolutionary Biology, and Behavior Program, Michigan State University, East Lansing, MI.,BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI.,Department of Systems Biology, Harvard Medical School, Boston, MA
| | - Philip J Hatcher
- Department of Computer Science, University of New Hampshire, Durham, NH
| | - Anna G Green
- Department of Systems Biology, Harvard Medical School, Boston, MA
| | - Barry L Williams
- Ecology, Evolutionary Biology, and Behavior Program, Michigan State University, East Lansing, MI
| | - Debora S Marks
- Department of Systems Biology, Harvard Medical School, Boston, MA
| | - Richard E Lenski
- Ecology, Evolutionary Biology, and Behavior Program, Michigan State University, East Lansing, MI.,BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI
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13
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The Loop 2 Region of Ribosomal Protein uS5 Influences Spectinomycin Sensitivity, Translational Fidelity, and Ribosome Biogenesis. Antimicrob Agents Chemother 2017; 61:AAC.01186-16. [PMID: 27855073 DOI: 10.1128/aac.01186-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 11/07/2016] [Indexed: 12/24/2022] Open
Abstract
Ribosomal protein uS5 is an essential component of the small ribosomal subunit that is involved in subunit assembly, maintenance of translational fidelity, and the ribosome's response to the antibiotic spectinomycin. While many of the characterized uS5 mutations that affect decoding map to its interface with uS4, more recent work has shown that residues distant from the uS4-uS5 interface can also affect the decoding process. We targeted one such interface-remote area, the loop 2 region (residues 20 to 31), for mutagenesis in Escherichia. coli and generated 21 unique mutants. A majority of the loop 2 alterations confer resistance to spectinomycin and affect the fidelity of translation. However, only a minority show altered rRNA processing or ribosome biogenesis defects.
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14
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Ying L, Fredrick K. Epistasis analysis of 16S rRNA ram mutations helps define the conformational dynamics of the ribosome that influence decoding. RNA (NEW YORK, N.Y.) 2016; 22:499-505. [PMID: 26873598 PMCID: PMC4793206 DOI: 10.1261/rna.054486.115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 01/14/2016] [Indexed: 06/05/2023]
Abstract
The ribosome actively participates in decoding, with a tRNA-dependent rearrangement of the 30S A site playing a key role. Ribosomal ambiguity (ram) mutations have mapped not only to the A site but also to the h12/S4/S5 region and intersubunit bridge B8, implicating other conformational changes such as 30S shoulder rotation and B8 disruption in the mechanism of decoding. Recent crystallographic data have revealed that mutation G299A in helix h12 allosterically promotes B8 disruption, raising the question of whether G299A and/or other ram mutations act mainly via B8. Here, we compared the effects of each of several ram mutations in the absence and presence of mutation h8Δ2, which effectively takes out bridge B8. The data obtained suggest that a subset of mutations including G299A act in part via B8 but predominantly through another mechanism. We also found that G299A in h12 and G347U in h14 each stabilize tRNA in the A site. Collectively, these data support a model in which rearrangement of the 30S A site, inward shoulder rotation, and bridge B8 disruption are loosely coupled events, all of which promote progression along the productive pathway toward peptide bond formation.
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Affiliation(s)
- Lanqing Ying
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Kurt Fredrick
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
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15
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Liu Q, Fredrick K. Intersubunit Bridges of the Bacterial Ribosome. J Mol Biol 2016; 428:2146-64. [PMID: 26880335 DOI: 10.1016/j.jmb.2016.02.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 01/29/2016] [Accepted: 02/05/2016] [Indexed: 02/02/2023]
Abstract
The ribosome is a large two-subunit ribonucleoprotein machine that translates the genetic code in all cells, synthesizing proteins according to the sequence of the mRNA template. During translation, the primary substrates, transfer RNAs, pass through binding sites formed between the two subunits. Multiple interactions between the ribosomal subunits, termed intersubunit bridges, keep the ribosome intact and at the same time govern dynamics that facilitate the various steps of translation such as transfer RNA-mRNA movement. Here, we review the molecular nature of these intersubunit bridges, how they change conformation during translation, and their functional roles in the process.
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Affiliation(s)
- Qi Liu
- Ohio State Biochemistry Program, Department of Microbiology, and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Kurt Fredrick
- Ohio State Biochemistry Program, Department of Microbiology, and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.
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16
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Another look at mutations in ribosomal protein S4 lends strong support to the domain closure model. J Bacteriol 2014; 197:1014-6. [PMID: 25548248 DOI: 10.1128/jb.02579-14] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Ribosomes employ a "kinetic discrimination" mechanism, in which correct substrates are incorporated more rapidly than incorrect ones. The structural basis of this mechanism may involve 30S domain closure, a global conformational change that coincides with codon recognition. In a direct screen for fidelity-altering mutations, Agarwal and coworkers (D. Agarwal, D. Kamath, S. T. Gregory, and M. O'Connor, J Bacteriol 197:1017-1025, 2015, doi:10.1128/JB.02485-14) isolated mutations that progressively truncate the C terminus of S4. All of these promote miscoding and undoubtedly destabilize the S4-S5 interface, consistent with the domain closure model.
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