1
|
Zafar H, Hassan AH, Demo G. Translation machinery captured in motion. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1792. [PMID: 37132456 DOI: 10.1002/wrna.1792] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 03/14/2023] [Accepted: 04/17/2023] [Indexed: 05/04/2023]
Abstract
Translation accuracy is one of the most critical factors for protein synthesis. It is regulated by the ribosome and its dynamic behavior, along with translation factors that direct ribosome rearrangements to make translation a uniform process. Earlier structural studies of the ribosome complex with arrested translation factors laid the foundation for an understanding of ribosome dynamics and the translation process as such. Recent technological advances in time-resolved and ensemble cryo-EM have made it possible to study translation in real time at high resolution. These methods provided a detailed view of translation in bacteria for all three phases: initiation, elongation, and termination. In this review, we focus on translation factors (in some cases GTP activation) and their ability to monitor and respond to ribosome organization to enable efficient and accurate translation. This article is categorized under: Translation > Ribosome Structure/Function Translation > Mechanisms.
Collapse
Affiliation(s)
- Hassan Zafar
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Ahmed H Hassan
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Gabriel Demo
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| |
Collapse
|
2
|
Balasanyants SM, Aleksandrova EV, Polikanov YS. The Role of Release Factors in the Hydrolysis of Ester Bond in Peptidyl-tRNA. BIOCHEMISTRY (MOSCOW) 2021; 86:1122-1127. [PMID: 34565315 DOI: 10.1134/s0006297921090078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Class I release factors (RFs) recognize stop codons in the sequences of mRNAs and are required for the hydrolysis of peptidyl-tRNA in the ribosomal P site during the final step of protein synthesis in bacteria, resulting in the release of a complete polypeptide chain from the ribosome. A key role in this process belongs to the highly conserved GGQ motif in RFs. Mutations in this motif can reduce the hydrolysis rate or even completely inhibit the reaction. Previously, it was hypothesized that the amino acid residues of GGQ (especially glutamine) are essential for the proper coordination of the water molecule for subsequent hydrolysis of the ester bond. However, available structures of the 70S ribosome termination complex do not allow unambiguous identification of the exact orientation of the carbonyl group in peptidyl-tRNA relative to the GGQ, as well as of the position of the catalytic water molecule in the peptidyl transferase center (PTC). This mini-review summarizes key facts and hypotheses on the role of GGQ in the catalysis of peptide release, as well as suggests and discusses future experiments aimed to produce high-quality structural data for deciphering the precise mechanism of RF-mediated catalysis.
Collapse
Affiliation(s)
- Samson M Balasanyants
- Department of Biological Sciences, College of Liberal Arts and Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Elena V Aleksandrova
- Department of Biological Sciences, College of Liberal Arts and Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Yury S Polikanov
- Department of Biological Sciences, College of Liberal Arts and Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA.
| |
Collapse
|
3
|
Korostelev AA. Diversity and Similarity of Termination and Ribosome Rescue in Bacterial, Mitochondrial, and Cytoplasmic Translation. BIOCHEMISTRY (MOSCOW) 2021; 86:1107-1121. [PMID: 34565314 DOI: 10.1134/s0006297921090066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
When a ribosome encounters the stop codon of an mRNA, it terminates translation, releases the newly made protein, and is recycled to initiate translation on a new mRNA. Termination is a highly dynamic process in which release factors (RF1 and RF2 in bacteria; eRF1•eRF3•GTP in eukaryotes) coordinate peptide release with large-scale molecular rearrangements of the ribosome. Ribosomes stalled on aberrant mRNAs are rescued and recycled by diverse bacterial, mitochondrial, or cytoplasmic quality control mechanisms. These are catalyzed by rescue factors with peptidyl-tRNA hydrolase activity (bacterial ArfA•RF2 and ArfB, mitochondrial ICT1 and mtRF-R, and cytoplasmic Vms1), that are distinct from each other and from release factors. Nevertheless, recent structural studies demonstrate a remarkable similarity between translation termination and ribosome rescue mechanisms. This review describes how these pathways rely on inherent ribosome dynamics, emphasizing the active role of the ribosome in all translation steps.
Collapse
Affiliation(s)
- Andrei A Korostelev
- RNA Therapeutics Institute, Department of Biochemistry and Molecular Pharmacology, UMass Medical School, Worcester, MA, USA.
| |
Collapse
|
4
|
Müller C, Crowe-McAuliffe C, Wilson DN. Ribosome Rescue Pathways in Bacteria. Front Microbiol 2021; 12:652980. [PMID: 33815344 PMCID: PMC8012679 DOI: 10.3389/fmicb.2021.652980] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 02/23/2021] [Indexed: 12/18/2022] Open
Abstract
Ribosomes that become stalled on truncated or damaged mRNAs during protein synthesis must be rescued for the cell to survive. Bacteria have evolved a diverse array of rescue pathways to remove the stalled ribosomes from the aberrant mRNA and return them to the free pool of actively translating ribosomes. In addition, some of these pathways target the damaged mRNA and the incomplete nascent polypeptide chain for degradation. This review highlights the recent developments in our mechanistic understanding of bacterial ribosomal rescue systems, including drop-off, trans-translation mediated by transfer-messenger RNA and small protein B, ribosome rescue by the alternative rescue factors ArfA and ArfB, as well as Bacillus ribosome rescue factor A, an additional rescue system found in some Gram-positive bacteria, such as Bacillus subtilis. Finally, we discuss the recent findings of ribosome-associated quality control in particular bacterial lineages mediated by RqcH and RqcP. The importance of rescue pathways for bacterial survival suggests they may represent novel targets for the development of new antimicrobial agents against multi-drug resistant pathogenic bacteria.
Collapse
Affiliation(s)
| | | | - Daniel N. Wilson
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany
| |
Collapse
|
5
|
Ayyub SA, Gao F, Lightowlers RN, Chrzanowska-Lightowlers ZM. Rescuing stalled mammalian mitoribosomes - what can we learn from bacteria? J Cell Sci 2020; 133:133/1/jcs231811. [PMID: 31896602 DOI: 10.1242/jcs.231811] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
In the canonical process of translation, newly completed proteins escape from the ribosome following cleavage of the ester bond that anchors the polypeptide to the P-site tRNA, after which the ribosome can be recycled to initiate a new round of translation. Not all protein synthesis runs to completion as various factors can impede the progression of ribosomes. Rescuing of stalled ribosomes in mammalian mitochondria, however, does not share the same mechanisms that many bacteria use. The classic method for rescuing bacterial ribosomes is trans-translation. The key components of this system are absent from mammalian mitochondria; however, four members of a translation termination factor family are present, with some evidence of homology to members of a bacterial back-up rescue system. To date, there is no definitive demonstration of any other member of this family functioning in mitoribosome rescue. Here, we provide an overview of the processes and key players of canonical translation termination in both bacteria and mammalian mitochondria, followed by a perspective of the bacterial systems used to rescue stalled ribosomes. We highlight any similarities or differences with the mitochondrial translation release factors, and suggest potential roles for these proteins in ribosome rescue in mammalian mitochondria.
Collapse
Affiliation(s)
- Shreya Ahana Ayyub
- The Wellcome Centre for Mitochondrial Research, Newcastle University, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Fei Gao
- The Wellcome Centre for Mitochondrial Research, Newcastle University, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Robert N Lightowlers
- The Wellcome Centre for Mitochondrial Research, Newcastle University, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Zofia M Chrzanowska-Lightowlers
- The Wellcome Centre for Mitochondrial Research, Newcastle University, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| |
Collapse
|
6
|
Release factor-dependent ribosome rescue by BrfA in the Gram-positive bacterium Bacillus subtilis. Nat Commun 2019; 10:5397. [PMID: 31776341 PMCID: PMC6881298 DOI: 10.1038/s41467-019-13408-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 11/07/2019] [Indexed: 12/14/2022] Open
Abstract
Rescue of the ribosomes from dead-end translation complexes, such as those on truncated (non-stop) mRNA, is essential for the cell. Whereas bacteria use trans-translation for ribosome rescue, some Gram-negative species possess alternative and release factor (RF)-dependent rescue factors, which enable an RF to catalyze stop-codon-independent polypeptide release. We now discover that the Gram-positive Bacillus subtilis has an evolutionarily distinct ribosome rescue factor named BrfA. Genetic analysis shows that B. subtilis requires the function of either trans-translation or BrfA for growth, even in the absence of proteotoxic stresses. Biochemical and cryo-electron microscopy (cryo-EM) characterization demonstrates that BrfA binds to non-stop stalled ribosomes, recruits homologous RF2, but not RF1, and induces its transition into an open active conformation. Although BrfA is distinct from E. coli ArfA, they use convergent strategies in terms of mode of action and expression regulation, indicating that many bacteria may have evolved as yet unidentified ribosome rescue systems. In bacteria, the conserved trans-translation system serves as the primary pathway of ribosome rescue, but many species can also use alternative rescue pathways. Here the authors report that in B. subtilis, the rescue factor BrfA binds to non-stop stalled ribosomes, recruits RF2 but not RF1, and induces transition of the ribosome into an open active conformation.
Collapse
|
7
|
Ge X, Oliveira A, Hjort K, Bergfors T, Gutiérrez-de-Terán H, Andersson DI, Sanyal S, Åqvist J. Inhibition of translation termination by small molecules targeting ribosomal release factors. Sci Rep 2019; 9:15424. [PMID: 31659219 PMCID: PMC6817905 DOI: 10.1038/s41598-019-51977-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 10/10/2019] [Indexed: 11/18/2022] Open
Abstract
The bacterial ribosome is an important drug target for antibiotics that can inhibit different stages of protein synthesis. Among the various classes of compounds that impair translation there are, however, no known small-molecule inhibitors that specifically target ribosomal release factors (RFs). The class I RFs are essential for correct termination of translation and they differ considerably between bacteria and eukaryotes, making them potential targets for inhibiting bacterial protein synthesis. We carried out virtual screening of a large compound library against 3D structures of free and ribosome-bound RFs in order to search for small molecules that could potentially inhibit termination by binding to the RFs. Here, we report identification of two such compounds which are found both to bind free RFs in solution and to inhibit peptide release on the ribosome, without affecting peptide bond formation.
Collapse
Affiliation(s)
- Xueliang Ge
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, SE-75124, Uppsala, Sweden
| | - Ana Oliveira
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, SE-75124, Uppsala, Sweden
| | - Karin Hjort
- Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, SE-75124, Uppsala, Sweden
| | - Terese Bergfors
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, SE-75124, Uppsala, Sweden
| | - Hugo Gutiérrez-de-Terán
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, SE-75124, Uppsala, Sweden
| | - Dan I Andersson
- Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, SE-75124, Uppsala, Sweden
| | - Suparna Sanyal
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, SE-75124, Uppsala, Sweden
| | - Johan Åqvist
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, SE-75124, Uppsala, Sweden.
| |
Collapse
|
8
|
Svidritskiy E, Demo G, Loveland AB, Xu C, Korostelev AA. Extensive ribosome and RF2 rearrangements during translation termination. eLife 2019; 8:46850. [PMID: 31513010 PMCID: PMC6742477 DOI: 10.7554/elife.46850] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 08/28/2019] [Indexed: 12/31/2022] Open
Abstract
Protein synthesis ends when a ribosome reaches an mRNA stop codon. Release factors (RFs) decode the stop codon, hydrolyze peptidyl-tRNA to release the nascent protein, and then dissociate to allow ribosome recycling. To visualize termination by RF2, we resolved a cryo-EM ensemble of E. coli 70S•RF2 structures at up to 3.3 Å in a single sample. Five structures suggest a highly dynamic termination pathway. Upon peptidyl-tRNA hydrolysis, the CCA end of deacyl-tRNA departs from the peptidyl transferase center. The catalytic GGQ loop of RF2 is rearranged into a long β-hairpin that plugs the peptide tunnel, biasing a nascent protein toward the ribosome exit. Ribosomal intersubunit rotation destabilizes the catalytic RF2 domain on the 50S subunit and disassembles the central intersubunit bridge B2a, resulting in RF2 departure. Our structures visualize how local rearrangements and spontaneous inter-subunit rotation poise the newly-made protein and RF2 to dissociate in preparation for ribosome recycling.
Collapse
Affiliation(s)
- Egor Svidritskiy
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States
| | - Gabriel Demo
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States
| | - Anna B Loveland
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States
| | - Chen Xu
- Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, United States
| | - Andrei A Korostelev
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States.,Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, United States
| |
Collapse
|
9
|
The structural basis for release-factor activation during translation termination revealed by time-resolved cryogenic electron microscopy. Nat Commun 2019; 10:2579. [PMID: 31189921 PMCID: PMC6561943 DOI: 10.1038/s41467-019-10608-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 05/14/2019] [Indexed: 11/08/2022] Open
Abstract
When the ribosome encounters a stop codon, it recruits a release factor (RF) to hydrolyze the ester bond between the peptide chain and tRNA. RFs have structural motifs that recognize stop codons in the decoding center and a GGQ motif for induction of hydrolysis in the peptidyl transfer center 70 Å away. Surprisingly, free RF2 is compact, with only 20 Å between its codon-reading and GGQ motifs. Cryo-EM showed that ribosome-bound RFs have extended structures, suggesting that RFs are compact when entering the ribosome and then extend their structures upon stop codon recognition. Here we use time-resolved cryo-EM to visualize transient compact forms of RF1 and RF2 at 3.5 and 4 Å resolution, respectively, in the codon-recognizing ribosome complex on the native pathway. About 25% of complexes have RFs in the compact state at 24 ms reaction time, and within 60 ms virtually all ribosome-bound RFs are transformed to their extended forms. Translation termination is under strong selection pressure for high speed and accuracy. Here the authors provide a 3D view of the dynamics of a translating bacterial ribosome as it recruits a class-1 release factor (RF1 or RF2) upon encountering a stop codon, and propose a structure-based kinetic model for the early steps in bacterial translation termination.
Collapse
|
10
|
Svidritskiy E, Korostelev AA. Mechanism of Inhibition of Translation Termination by Blasticidin S. J Mol Biol 2019; 430:591-593. [PMID: 29366636 DOI: 10.1016/j.jmb.2018.01.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 12/13/2017] [Accepted: 01/05/2018] [Indexed: 01/25/2023]
Abstract
Understanding the mechanisms of inhibitors of translation termination may inform development of new antibacterials and therapeutics for premature termination diseases. We report the crystal structure of the potent termination inhibitor blasticidin S bound to the ribosomal 70S•release factor 1 (RF1) termination complex. Blasticidin S shifts the catalytic domain 3 of RF1 and restructures the peptidyl transferase center. Universally conserved uridine 2585 in the peptidyl transferase center occludes the catalytic backbone of the GGQ motif of RF1, explaining the structural mechanism of inhibition. Rearrangement of domain 3 relative to the codon-recognition domain 2 provides insight into the dynamics of RF1 implicated in termination accuracy.
Collapse
Affiliation(s)
- Egor Svidritskiy
- RNA Therapeutics Institute, University of Massachusetts Medical School, 368 Plantation St., Worcester, MA 01605, USA
| | - Andrei A Korostelev
- RNA Therapeutics Institute, University of Massachusetts Medical School, 368 Plantation St., Worcester, MA 01605, USA.
| |
Collapse
|
11
|
Abstract
Ribosomes are biological nanomachine that synthesise all proteins within a cell. It took decades to reveal the architecture of this essential cellular component. To understand the structure -function relationship of this nanomachine needed the utilisisation of different biochemical, biophysical and structural techniques. Structural studies combined with mutagenesis of the different ribosomal complexes comprising various RNAs and proteins enabled us to understand how this machine works inside a cell. Nowadays quite a number of ribosomal structures were published that confirmed biochemical studies on particular steps of protein synthesis by the ribosome . Four major steps were identified: initiation , elongation, termination and recycling. These steps lead us to the important question how the ribosome function can be regulated. Advances in technology for cryo electron microscopy: sample preparations, image recording, developments in algorithms for image analysis and processing significantly helped in revelation of structural details of the ribosome . We now have a library of ribosome structures from prokaryotes to eukaryotes that enable us to understand the complex mechanics of this nanomachine. As this structural library continues to grow, we gradually improve our understanding of this process and how it can be regulated and how the specific ribosomes can be stalled or activated, or completely disabled. This article provides a comprehensive overview of ribosomal structures that represent structural snapshots of the ribosome at its different functional states. Better understanding rises more particular questions that have to be addressed by determination structures of more complexes.Synopsis: Structural biology of the ribosome.
Collapse
Affiliation(s)
- Abid Javed
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, Malet Street, London, WC1E 7HX, UK
| | - Elena V Orlova
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, Malet Street, London, WC1E 7HX, UK.
| |
Collapse
|
12
|
Abstract
This review summarizes our current understanding of translation in prokaryotes, focusing on the mechanistic and structural aspects of each phase of translation: initiation, elongation, termination, and ribosome recycling. The assembly of the initiation complex provides multiple checkpoints for messenger RNA (mRNA) and start-site selection. Correct codon-anticodon interaction during the decoding phase of elongation results in major conformational changes of the small ribosomal subunit and shapes the reaction pathway of guanosine triphosphate (GTP) hydrolysis. The ribosome orchestrates proton transfer during peptide bond formation, but requires the help of elongation factor P (EF-P) when two or more consecutive Pro residues are to be incorporated. Understanding the choreography of transfer RNA (tRNA) and mRNA movements during translocation helps to place the available structures of translocation intermediates onto the time axis of the reaction pathway. The nascent protein begins to fold cotranslationally, in the constrained space of the polypeptide exit tunnel of the ribosome. When a stop codon is reached at the end of the coding sequence, the ribosome, assisted by termination factors, hydrolyzes the ester bond of the peptidyl-tRNA, thereby releasing the nascent protein. Following termination, the ribosome is dissociated into subunits and recycled into another round of initiation. At each step of translation, the ribosome undergoes dynamic fluctuations between different conformation states. The aim of this article is to show the link between ribosome structure, dynamics, and function.
Collapse
Affiliation(s)
- Marina V Rodnina
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Goettingen 37077, Germany
| |
Collapse
|
13
|
Ray S, Widom JR, Walter NG. Life under the Microscope: Single-Molecule Fluorescence Highlights the RNA World. Chem Rev 2018; 118:4120-4155. [PMID: 29363314 PMCID: PMC5918467 DOI: 10.1021/acs.chemrev.7b00519] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The emergence of single-molecule (SM) fluorescence techniques has opened up a vast new toolbox for exploring the molecular basis of life. The ability to monitor individual biomolecules in real time enables complex, dynamic folding pathways to be interrogated without the averaging effect of ensemble measurements. In parallel, modern biology has been revolutionized by our emerging understanding of the many functions of RNA. In this comprehensive review, we survey SM fluorescence approaches and discuss how the application of these tools to RNA and RNA-containing macromolecular complexes in vitro has yielded significant insights into the underlying biology. Topics covered include the three-dimensional folding landscapes of a plethora of isolated RNA molecules, their assembly and interactions in RNA-protein complexes, and the relation of these properties to their biological functions. In all of these examples, the use of SM fluorescence methods has revealed critical information beyond the reach of ensemble averages.
Collapse
Affiliation(s)
| | | | - Nils G. Walter
- Department of Chemistry, Single Molecule Analysis Group, University of Michigan, Ann Arbor, MI 48109, USA
| |
Collapse
|
14
|
Casy W, Prater AR, Cornish PV. Operative Binding of Class I Release Factors and YaeJ Stabilizes the Ribosome in the Nonrotated State. Biochemistry 2018; 57:1954-1966. [PMID: 29499110 DOI: 10.1021/acs.biochem.7b00824] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
During translation, the small subunit of the ribosome rotates with respect to the large subunit primarily between two states as mRNA is being translated into a protein. At the termination of bacterial translation, class I release factors (RFs) bind to a stop codon in the A-site and catalyze the release of the peptide chain from the ribosome. Periodically, mRNA is truncated prematurely, and the translating ribosome stalls at the end of the mRNA forming a nonstop complex requiring one of several ribosome rescue factors to intervene. One factor, YaeJ, is structurally homologous with the catalytic region of RFs but differs by binding to the ribosome directly through its C-terminal tail. Structures of the ribosome show that the ribosome adopts the nonrotated state conformation when these factors are bound. However, these studies do not elucidate the influence of binding to cognate or noncognate codons on the dynamics of intersubunit rotation. Here, we investigate the effects of wild-type and mutant forms of RF1, RF2, and YaeJ binding on ribosome intersubunit rotation using single-molecule Förster resonance energy transfer. We show that both RF1 binding and RF2 binding are sufficient to shift the population of posthydrolysis ribosome complexes from primarily the rotated to the nonrotated state only when a cognate stop codon is present in the A-site. Similarly, YaeJ binding stabilizes nonstop ribosomal complexes in the nonrotated state. Along with previous studies, these results are consistent with the idea that directed conformational changes and binding of subsequent factors to the ribosome are requisite for efficient termination and ribosome recycling.
Collapse
Affiliation(s)
- Widler Casy
- Department of Biochemistry , University of Missouri , Columbia , Missouri 65211 , United States
| | - Austin R Prater
- Department of Biochemistry , University of Missouri , Columbia , Missouri 65211 , United States
| | - Peter V Cornish
- Department of Biochemistry , University of Missouri , Columbia , Missouri 65211 , United States
| |
Collapse
|
15
|
Hoernes TP, Clementi N, Juen MA, Shi X, Faserl K, Willi J, Gasser C, Kreutz C, Joseph S, Lindner H, Hüttenhofer A, Erlacher MD. Atomic mutagenesis of stop codon nucleotides reveals the chemical prerequisites for release factor-mediated peptide release. Proc Natl Acad Sci U S A 2018; 115:E382-E389. [PMID: 29298914 PMCID: PMC5776981 DOI: 10.1073/pnas.1714554115] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Termination of protein synthesis is triggered by the recognition of a stop codon at the ribosomal A site and is mediated by class I release factors (RFs). Whereas in bacteria, RF1 and RF2 promote termination at UAA/UAG and UAA/UGA stop codons, respectively, eukaryotes only depend on one RF (eRF1) to initiate peptide release at all three stop codons. Based on several structural as well as biochemical studies, interactions between mRNA, tRNA, and rRNA have been proposed to be required for stop codon recognition. In this study, the influence of these interactions was investigated by using chemically modified stop codons. Single functional groups within stop codon nucleotides were substituted to weaken or completely eliminate specific interactions between the respective mRNA and RFs. Our findings provide detailed insight into the recognition mode of bacterial and eukaryotic RFs, thereby revealing the chemical groups of nucleotides that define the identity of stop codons and provide the means to discriminate against noncognate stop codons or UGG sense codons.
Collapse
Affiliation(s)
- Thomas Philipp Hoernes
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Nina Clementi
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Michael Andreas Juen
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | - Xinying Shi
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0314
| | - Klaus Faserl
- Division of Clinical Biochemistry, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Jessica Willi
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Catherina Gasser
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | - Christoph Kreutz
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | - Simpson Joseph
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0314
| | - Herbert Lindner
- Division of Clinical Biochemistry, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Alexander Hüttenhofer
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Matthias David Erlacher
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria;
| |
Collapse
|
16
|
Pierson WE, Hoffer ED, Keedy HE, Simms CL, Dunham CM, Zaher HS. Uniformity of Peptide Release Is Maintained by Methylation of Release Factors. Cell Rep 2017; 17:11-18. [PMID: 27681416 DOI: 10.1016/j.celrep.2016.08.085] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 06/30/2016] [Accepted: 08/24/2016] [Indexed: 10/20/2022] Open
Abstract
Termination of protein synthesis on the ribosome is catalyzed by release factors (RFs), which share a conserved glycine-glycine-glutamine (GGQ) motif. The glutamine residue is methylated in vivo, but a mechanistic understanding of its contribution to hydrolysis is lacking. Here, we show that the modification, apart from increasing the overall rate of termination on all dipeptides, substantially increases the rate of peptide release on a subset of amino acids. In the presence of unmethylated RFs, we measure rates of hydrolysis that are exceptionally slow on proline and glycine residues and approximately two orders of magnitude faster in the presence of the methylated factors. Structures of 70S ribosomes bound to methylated RF1 and RF2 reveal that the glutamine side-chain methylation packs against 23S rRNA nucleotide 2451, stabilizing the GGQ motif and placing the side-chain amide of the glutamine toward tRNA. These data provide a framework for understanding how release factor modifications impact termination.
Collapse
Affiliation(s)
- William E Pierson
- Department of Biology, Washington University in St. Louis, Campus Box 1137, 1 Brookings Drive, St. Louis, MO 63130, USA
| | - Eric D Hoffer
- Biochemistry, Cell and Developmental Biology Graduate Program, Emory University School of Medicine, 1510 Clifton Road NE, Room G223, Atlanta, GA 30322, USA; Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road NE, Room G223, Atlanta, GA 30322, USA
| | - Hannah E Keedy
- Department of Biology, Washington University in St. Louis, Campus Box 1137, 1 Brookings Drive, St. Louis, MO 63130, USA
| | - Carrie L Simms
- Department of Biology, Washington University in St. Louis, Campus Box 1137, 1 Brookings Drive, St. Louis, MO 63130, USA
| | - Christine M Dunham
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road NE, Room G223, Atlanta, GA 30322, USA.
| | - Hani S Zaher
- Department of Biology, Washington University in St. Louis, Campus Box 1137, 1 Brookings Drive, St. Louis, MO 63130, USA.
| |
Collapse
|
17
|
Demo G, Svidritskiy E, Madireddy R, Diaz-Avalos R, Grant T, Grigorieff N, Sousa D, Korostelev AA. Mechanism of ribosome rescue by ArfA and RF2. eLife 2017; 6. [PMID: 28300532 PMCID: PMC5378476 DOI: 10.7554/elife.23687] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Accepted: 03/14/2017] [Indexed: 11/13/2022] Open
Abstract
ArfA rescues ribosomes stalled on truncated mRNAs by recruiting release factor RF2, which normally binds stop codons to catalyze peptide release. We report two 3.2 Å resolution cryo-EM structures – determined from a single sample – of the 70S ribosome with ArfA•RF2 in the A site. In both states, the ArfA C-terminus occupies the mRNA tunnel downstream of the A site. One state contains a compact inactive RF2 conformation. Ordering of the ArfA N-terminus in the second state rearranges RF2 into an extended conformation that docks the catalytic GGQ motif into the peptidyl-transferase center. Our work thus reveals the structural dynamics of ribosome rescue. The structures demonstrate how ArfA ‘senses’ the vacant mRNA tunnel and activates RF2 to mediate peptide release without a stop codon, allowing stalled ribosomes to be recycled. DOI:http://dx.doi.org/10.7554/eLife.23687.001
Collapse
Affiliation(s)
- Gabriel Demo
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States
| | - Egor Svidritskiy
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States
| | - Rohini Madireddy
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, United States
| | - Ruben Diaz-Avalos
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Timothy Grant
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Nikolaus Grigorieff
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Duncan Sousa
- Department of Biological Science, Florida State University, Tallahassee, United States
| | - Andrei A Korostelev
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States.,Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, United States
| |
Collapse
|
18
|
Mechanistic insights into the alternative translation termination by ArfA and RF2. Nature 2016; 541:550-553. [PMID: 27906160 DOI: 10.1038/nature20822] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 11/25/2016] [Indexed: 01/07/2023]
Abstract
During cellular translation of messenger RNAs by ribosomes, the translation apparatus sometimes pauses or stalls at the elongation and termination steps. With the exception of programmed stalling, which is usually used by cells for regulatory purposes, ribosomes stalled on mRNAs need to be terminated and recycled to maintain adequate translation capacity. Much ribosome stalling originates in aberrant mRNAs that lack a stop codon. Transcriptional errors, misprocessing of primary transcripts, and undesired mRNA cleavage all contribute to the formation of non-stop mRNAs. Ribosomes stalled at the 3' end of non-stop mRNAs do not undergo normal termination owing to the lack of specific stop-codon recognition by canonical peptide release factors at the A-site decoding centre. In bacteria, the transfer-messenger RNA (tmRNA)-SmpB-mediated trans-translation rescue system reroutes stalled ribosomes to the normal elongation cycle and translation termination. Two additional rescue systems, ArfA-RF2 (refs 13, 14, 15, 16) and ArfB (formerly known as YaeJ), are also present in many bacterial species, but their mechanisms are not fully understood. Here, using cryo-electron microscopy, we characterize the structure of the Escherichia coli 70S ribosome bound with ArfA, the release factor RF2, a short non-stop mRNA and a cognate P-site tRNA. The C-terminal loop of ArfA occupies the mRNA entry channel on the 30S subunit, whereas its N terminus is sandwiched between the decoding centre and the switch loop of RF2, leading to marked conformational changes in both the decoding centre and RF2. Despite the distinct conformation of RF2, its conserved catalytic GGQ motif is precisely positioned next to the CCA-end of the P-site tRNA. These data illustrate a stop-codon surrogate mechanism for ArfA in facilitating the termination of non-stop ribosomal complexes by RF2.
Collapse
|
19
|
Svidritskiy E, Madireddy R, Korostelev AA. Structural Basis for Translation Termination on a Pseudouridylated Stop Codon. J Mol Biol 2016; 428:2228-36. [PMID: 27107638 DOI: 10.1016/j.jmb.2016.04.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 04/06/2016] [Accepted: 04/11/2016] [Indexed: 12/27/2022]
Abstract
Pseudouridylation of messenger RNA emerges as an abundant modification involved in gene expression regulation. Pseudouridylation of stop codons in eukaryotic and bacterial cells results in stop-codon read through. The structural mechanism of this phenomenon is not known. Here we present a 3.1-Å crystal structure of Escherichia coli release factor 1 (RF1) bound to the 70S ribosome in response to the ΨAA codon. The structure reveals that recognition of a modified stop codon does not differ from that of a canonical stop codon. Our in vitro biochemical results support this finding by yielding nearly identical rates for peptide release from E. coli ribosomes programmed with pseudouridylated and canonical stop codons. The crystal structure also brings insight into E. coli RF1-specific interactions and suggests involvement of L27 in bacterial translation termination. Our results are consistent with a mechanism in which read through of a pseudouridylated stop codon in bacteria results from increased decoding by near-cognate tRNAs (miscoding) rather than from decreased efficiency of termination.
Collapse
Affiliation(s)
- Egor Svidritskiy
- RNA Therapeutics Institute, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation St., Worcester, MA 01605, USA
| | - Rohini Madireddy
- RNA Therapeutics Institute, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation St., Worcester, MA 01605, USA
| | - Andrei A Korostelev
- RNA Therapeutics Institute, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation St., Worcester, MA 01605, USA.
| |
Collapse
|
20
|
Zeng F, Jin H. Peptide release promoted by methylated RF2 and ArfA in nonstop translation is achieved by an induced-fit mechanism. RNA (NEW YORK, N.Y.) 2016; 22:49-60. [PMID: 26554029 PMCID: PMC4691834 DOI: 10.1261/rna.053082.115] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 10/01/2015] [Indexed: 05/27/2023]
Abstract
Here we report that the specificity of peptide release in the ribosome on a nonstop mRNA by ArfA and RF2 is achieved by an induced-fit mechanism. Using RF2 that is methylated on the glutamine of its GGQ motif (RF2(m)), we show that methylation substantially increases the rate of ArfA/RF2-catalyzed peptide release on a nonstop mRNA that does not occupy the ribosomal A site, but has only a modest effect on k(cat) by the same proteins on longer nonstop mRNAs occupying the A site of the mRNA channel in the ribosome. Our data suggest that enhancement in the kcat of peptide release by ArfA and RF2 under the cognate decoding condition is the result of favorable conformational changes in the nonstop complex. We demonstrate a shared mechanism between canonical and nonstop termination, supported by similarities in the kinetic mechanisms in antibiotic inhibition and methylation-correlated enhancement in the rate of peptide release. Despite these similarities, our data suggest that nonstop termination differs from canonical pathway in the downstream event of recycling.
Collapse
Affiliation(s)
- Fuxing Zeng
- Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Hong Jin
- Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| |
Collapse
|
21
|
|
22
|
Indrisiunaite G, Pavlov MY, Heurgué-Hamard V, Ehrenberg M. On the pH dependence of class-1 RF-dependent termination of mRNA translation. J Mol Biol 2015; 427:1848-60. [PMID: 25619162 DOI: 10.1016/j.jmb.2015.01.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 01/05/2015] [Accepted: 01/09/2015] [Indexed: 10/24/2022]
Abstract
We have studied the pH dependence of the rate of termination of bacterial protein synthesis catalyzed by a class-1 release factor (RF1 or RF2). We used a classical quench-flow technique and a newly developed stopped-flow technique that relies on the use of fluorescently labeled peptides. We found the termination rate to increase with increasing pH and, eventually, to saturate at about 70 s(-1) with an apparent pKa value of about 7.6. From our data, we suggest that class-1 RF termination is rate limited by the chemistry of ester bond hydrolysis at low pH and by a stop-codon-dependent and pH-independent conformational change of RFs at high pH. We propose that RF-dependent termination depends on the participation of a hydroxide ion rather than a water molecule in the hydrolysis of the ester bond between the P-site tRNA and its peptide chain. We provide a simple explanation for why the rate of termination saturated at high pH in our experiments but not in those of others.
Collapse
Affiliation(s)
- Gabriele Indrisiunaite
- Department of Cell and Molecular Biology, Uppsala University, Biomedicinskt Centrum, Box 596, 75124 Uppsala, Sweden
| | - Michael Y Pavlov
- Department of Cell and Molecular Biology, Uppsala University, Biomedicinskt Centrum, Box 596, 75124 Uppsala, Sweden
| | - Valérie Heurgué-Hamard
- Centre National de la Recherche Scientifique, FRE3630, University Paris Diderot Sorbonne Paris Cité Institut de Biologie Physico-Chimique, 13 Rue Pierre et Marie Curie, 75005 Paris, France
| | - Måns Ehrenberg
- Department of Cell and Molecular Biology, Uppsala University, Biomedicinskt Centrum, Box 596, 75124 Uppsala, Sweden.
| |
Collapse
|
23
|
Karijolich J, Yu YT. Therapeutic suppression of premature termination codons: mechanisms and clinical considerations (review). Int J Mol Med 2014; 34:355-62. [PMID: 24939317 PMCID: PMC4094583 DOI: 10.3892/ijmm.2014.1809] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 06/06/2014] [Indexed: 12/22/2022] Open
Abstract
An estimated one-third of genetic disorders are the result of mutations that generate premature termination codons (PTCs) within protein coding genes. These disorders are phenotypically diverse and consist of diseases that affect both young and old individuals. Various small molecules have been identified that are capable of modulating the efficiency of translation termination, including select antibiotics of the aminoglycoside family and multiple novel synthetic molecules, including PTC124. Several of these agents have proved their effectiveness at promoting nonsense suppression in preclinical animal models, as well as in clinical trials. In addition, it has recently been shown that box H/ACA RNA-guided peudouridylation, when directed to modify PTCs, can also promote nonsense suppression. In this review, we summarize our current understanding of eukaryotic translation termination and discuss various methods for promoting the read-through of disease-causing PTCs, as well as the current obstacles that stand in the way of using the discussed agents broadly in clinical practice.
Collapse
Affiliation(s)
- John Karijolich
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Yi-Tao Yu
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| |
Collapse
|
24
|
des Georges A, Hashem Y, Unbehaun A, Grassucci RA, Taylor D, Hellen CUT, Pestova TV, Frank J. Structure of the mammalian ribosomal pre-termination complex associated with eRF1.eRF3.GDPNP. Nucleic Acids Res 2013; 42:3409-18. [PMID: 24335085 PMCID: PMC3950680 DOI: 10.1093/nar/gkt1279] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Eukaryotic translation termination results from the complex functional interplay between two release factors, eRF1 and eRF3, in which GTP hydrolysis by eRF3 couples codon recognition with peptidyl-tRNA hydrolysis by eRF1. Here, we present a cryo-electron microscopy structure of pre-termination complexes associated with eRF1•eRF3•GDPNP at 9.7 -Å resolution, which corresponds to the initial pre-GTP hydrolysis stage of factor attachment and stop codon recognition. It reveals the ribosomal positions of eRFs and provides insights into the mechanisms of stop codon recognition and triggering of eRF3's GTPase activity.
Collapse
Affiliation(s)
- Amédée des Georges
- Howard Hughes Medical Institute, Chevy Chase, MD, USA, Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA, Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY, USA, Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA and Department of Biological Sciences, Columbia University, New York, NY, USA
| | | | | | | | | | | | | | | |
Collapse
|
25
|
Chojnowski G, Walen T, Bujnicki JM. RNA Bricks--a database of RNA 3D motifs and their interactions. Nucleic Acids Res 2013; 42:D123-31. [PMID: 24220091 PMCID: PMC3965019 DOI: 10.1093/nar/gkt1084] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The RNA Bricks database (http://iimcb.genesilico.pl/rnabricks), stores information about recurrent RNA 3D motifs and their interactions, found in experimentally determined RNA structures and in RNA–protein complexes. In contrast to other similar tools (RNA 3D Motif Atlas, RNA Frabase, Rloom) RNA motifs, i.e. ‘RNA bricks’ are presented in the molecular environment, in which they were determined, including RNA, protein, metal ions, water molecules and ligands. All nucleotide residues in RNA bricks are annotated with structural quality scores that describe real-space correlation coefficients with the electron density data (if available), backbone geometry and possible steric conflicts, which can be used to identify poorly modeled residues. The database is also equipped with an algorithm for 3D motif search and comparison. The algorithm compares spatial positions of backbone atoms of the user-provided query structure and of stored RNA motifs, without relying on sequence or secondary structure information. This enables the identification of local structural similarities among evolutionarily related and unrelated RNA molecules. Besides, the search utility enables searching ‘RNA bricks’ according to sequence similarity, and makes it possible to identify motifs with modified ribonucleotide residues at specific positions.
Collapse
Affiliation(s)
- Grzegorz Chojnowski
- International Institute of Molecular and Cell Biology, Trojdena 4, 02-109 Warsaw, Poland, Faculty of Mathematics, Informatics, and Mechanics, University of Warsaw, Banacha 2, 02-097 Warsaw, Poland and Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | | | | |
Collapse
|