1
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Smart A, Lancaster L, Donohue JP, Niblett D, Noller H. Implication of nucleotides near the 3' end of 16S rRNA in guarding the translational reading frame. Nucleic Acids Res 2024; 52:5950-5958. [PMID: 38452198 PMCID: PMC11162774 DOI: 10.1093/nar/gkae143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 01/24/2024] [Accepted: 03/04/2024] [Indexed: 03/09/2024] Open
Abstract
Loss of the translational reading frame leads to misincorporation and premature termination, which can have lethal consequences. Based on structural evidence that A1503 of 16S rRNA intercalates between specific mRNA bases, we tested the possibility that it plays a role in maintenance of the reading frame by constructing ribosomes with an abasic nucleotide at position 1503. This was done by specific cleavage of 16S rRNA at position 1493 using the colicin E3 endonuclease and replacing the resulting 3'-terminal 49mer fragment with a synthetic oligonucleotide containing the abasic site using a novel splinted RNA ligation method. Ribosomes reconstituted from the abasic 1503 16S rRNA were highly active in protein synthesis but showed elevated levels of spontaneous frameshifting into the -1 reading frame. We then asked whether the residual frameshifting persisting in control ribosomes containing an intact A1503 is due to the absence of the N6-dimethyladenosine modifications at positions 1518 and 1519. Indeed, this frameshifting was rescued by site-specific methylation in vitro by the ksgA methylase. These findings thus implicate two different sites near the 3' end of 16S rRNA in maintenance of the translational reading frame, providing yet another example of a functional role for ribosomal RNA in protein synthesis.
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Affiliation(s)
- Alexandria Smart
- Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, CA, USA
| | - Laura Lancaster
- Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, CA, USA
| | - John Paul Donohue
- Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, CA, USA
| | - Dustin Niblett
- Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, CA, USA
| | - Harry F Noller
- Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, CA, USA
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2
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Fang N, Wu L, Duan S, Li J. The Structural and Molecular Mechanisms of Mycobacterium tuberculosis Translational Elongation Factor Proteins. Molecules 2024; 29:2058. [PMID: 38731549 PMCID: PMC11085428 DOI: 10.3390/molecules29092058] [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: 03/04/2024] [Revised: 04/19/2024] [Accepted: 04/24/2024] [Indexed: 05/13/2024] Open
Abstract
Targeting translation factor proteins holds promise for developing innovative anti-tuberculosis drugs. During protein translation, many factors cause ribosomes to stall at messenger RNA (mRNA). To maintain protein homeostasis, bacteria have evolved various ribosome rescue mechanisms, including the predominant trans-translation process, to release stalled ribosomes and remove aberrant mRNAs. The rescue systems require the participation of translation elongation factor proteins (EFs) and are essential for bacterial physiology and reproduction. However, they disappear during eukaryotic evolution, which makes the essential proteins and translation elongation factors promising antimicrobial drug targets. Here, we review the structural and molecular mechanisms of the translation elongation factors EF-Tu, EF-Ts, and EF-G, which play essential roles in the normal translation and ribosome rescue mechanisms of Mycobacterium tuberculosis (Mtb). We also briefly describe the structure-based, computer-assisted study of anti-tuberculosis drugs.
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Affiliation(s)
- Ning Fang
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Shanghai Engineering Research Center of Industrial Microorganisms, Fudan University, Shanghai 200438, China; (N.F.); (L.W.)
| | - Lingyun Wu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Shanghai Engineering Research Center of Industrial Microorganisms, Fudan University, Shanghai 200438, China; (N.F.); (L.W.)
| | - Shuyan Duan
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Shanghai Engineering Research Center of Industrial Microorganisms, Fudan University, Shanghai 200438, China; (N.F.); (L.W.)
- College of Food Science and Pharmaceutical Engineering, Zaozhuang University, Zaozhuang 277160, China
| | - Jixi Li
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Shanghai Engineering Research Center of Industrial Microorganisms, Fudan University, Shanghai 200438, China; (N.F.); (L.W.)
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3
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Johnson JL, Steele JH, Lin R, Stepanov VG, Gavriliuc MN, Wang Y. Multi-Channel smFRET study reveals a Compact conformation of EF-G on the Ribosome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.27.577133. [PMID: 38328191 PMCID: PMC10849647 DOI: 10.1101/2024.01.27.577133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
While elongation factor G (EF-G) is crucial for ribosome translocation, the role of its GTP hydrolysis remains ambiguous. EF-G's indispensability is further exemplified by the phosphorylation of human eukaryotic elongation factor 2 (eEF2) at Thr56, which inhibits protein synthesis globally, but its exact mechanism is not clear. In this study, we developed a multi-channel single-molecule FRET (smFRET) microscopy methodology to examine the conformational changes of E. coli EF-G induced by mutations that closely aligned with eEF2's Thr56 residue. We utilized Alexa 488/594 double-labeled EF-G to catalyze the translocation of fMet-Phe-tRNAPhe-Cy3 inside Cy5-L27 labeled ribosomes, allowing us to probe both processes within the same complex. Our findings indicate that in the presence of either GTP or GDPCP, wild-type EF-G undergoes a conformational extension upon binding to the ribosome to promote normal translocation. On the other hand, T48E and T48V mutations did not affect GTP/GDP binding or GTP hydrolysis, but impeded Poly(Phe) synthesis and caused EF-G to adopt a unique compact conformation, which wasn't observed when the mutants interact solely with the sarcin/ricin loop. This study provides new insights into EF-G's adaptability and sheds light on the modification mechanism of human eEF2.
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Affiliation(s)
- Jordan L Johnson
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Jacob H Steele
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Ran Lin
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Victor G Stepanov
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Miriam N Gavriliuc
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Yuhong Wang
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
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4
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Milicevic N, Jenner L, Myasnikov A, Yusupov M, Yusupova G. mRNA reading frame maintenance during eukaryotic ribosome translocation. Nature 2024; 625:393-400. [PMID: 38030725 DOI: 10.1038/s41586-023-06780-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 10/24/2023] [Indexed: 12/01/2023]
Abstract
One of the most critical steps of protein synthesis is coupled translocation of messenger RNA (mRNA) and transfer RNAs (tRNAs) required to advance the mRNA reading frame by one codon. In eukaryotes, translocation is accelerated and its fidelity is maintained by elongation factor 2 (eEF2)1,2. At present, only a few snapshots of eukaryotic ribosome translocation have been reported3-5. Here we report ten high-resolution cryogenic-electron microscopy (cryo-EM) structures of the elongating eukaryotic ribosome bound to the full translocation module consisting of mRNA, peptidyl-tRNA and deacylated tRNA, seven of which also contained ribosome-bound, naturally modified eEF2. This study recapitulates mRNA-tRNA2-growing peptide module progression through the ribosome, from the earliest states of eEF2 translocase accommodation until the very late stages of the process, and shows an intricate network of interactions preventing the slippage of the translational reading frame. We demonstrate how the accuracy of eukaryotic translocation relies on eukaryote-specific elements of the 80S ribosome, eEF2 and tRNAs. Our findings shed light on the mechanism of translation arrest by the anti-fungal eEF2-binding inhibitor, sordarin. We also propose that the sterically constrained environment imposed by diphthamide, a conserved eukaryotic posttranslational modification in eEF2, not only stabilizes correct Watson-Crick codon-anticodon interactions but may also uncover erroneous peptidyl-tRNA, and therefore contribute to higher accuracy of protein synthesis in eukaryotes.
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Affiliation(s)
- Nemanja Milicevic
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), CNRS UMR7104, INSERM U1258, University of Strasbourg, Strasbourg, France
| | - Lasse Jenner
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), CNRS UMR7104, INSERM U1258, University of Strasbourg, Strasbourg, France
| | | | - Marat Yusupov
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), CNRS UMR7104, INSERM U1258, University of Strasbourg, Strasbourg, France
| | - Gulnara Yusupova
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), CNRS UMR7104, INSERM U1258, University of Strasbourg, Strasbourg, France.
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5
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Das A, Bao C, Ermolenko DN. Comparing FRET Pairs that Report on Intersubunit Rotation in Bacterial Ribosomes. J Mol Biol 2023; 435:168185. [PMID: 37348753 PMCID: PMC10528089 DOI: 10.1016/j.jmb.2023.168185] [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: 02/01/2023] [Revised: 05/03/2023] [Accepted: 06/14/2023] [Indexed: 06/24/2023]
Abstract
Mediated by elongation factor G (EF-G), ribosome translocation along mRNA is accompanied by rotational movement between ribosomal subunits. Here, we reassess whether the intersubunit rotation requires GTP hydrolysis by EF-G or can occur spontaneously. To that end, we employ two independent FRET assays, which are based on labeling either ribosomal proteins (bS6 and bL9) or rRNAs (h44 of 16S and H101 of 23S rRNA). Both FRET pairs reveal three FRET states, corresponding to the non-rotated, rotated and semi-rotated conformations of the ribosome. Both FRET assays show that in the absence of EF-G, pre-translocation ribosomes containing deacylated P-site tRNA undergo spontaneous intersubunit rotations between non-rotated and rotated conformations. While the two FRET pairs exhibit largely similar behavior, they substantially differ in the fraction of ribosomes showing spontaneous fluctuations. Nevertheless, instead of being an invariable intrinsic property of each FRET pair, the fraction of spontaneously fluctuating molecules changes in both FRET assays depending on experimental conditions. Our results underscore importance of using multiple FRET pairs in studies of ribosome dynamics and highlight the role of thermally-driven large-scale ribosome rearrangements in translation.
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Affiliation(s)
- Ananya Das
- Department of Biochemistry & Biophysics, School of Medicine and Dentistry, and Center for RNA Biology, University of Rochester, Rochester, NY 14642, United States
| | - Chen Bao
- Department of Biochemistry & Biophysics, School of Medicine and Dentistry, and Center for RNA Biology, University of Rochester, Rochester, NY 14642, United States
| | - Dmitri N Ermolenko
- Department of Biochemistry & Biophysics, School of Medicine and Dentistry, and Center for RNA Biology, University of Rochester, Rochester, NY 14642, United States.
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6
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Poulis P, Peske F, Rodnina MV. The many faces of ribosome translocation along the mRNA: reading frame maintenance, ribosome frameshifting and translational bypassing. Biol Chem 2023; 404:755-767. [PMID: 37077160 DOI: 10.1515/hsz-2023-0142] [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: 02/21/2023] [Accepted: 03/22/2023] [Indexed: 04/21/2023]
Abstract
In each round of translation elongation, the ribosome translocates along the mRNA by precisely one codon. Translocation is promoted by elongation factor G (EF-G) in bacteria (eEF2 in eukaryotes) and entails a number of precisely-timed large-scale structural rearrangements. As a rule, the movements of the ribosome, tRNAs, mRNA and EF-G are orchestrated to maintain the exact codon-wise step size. However, signals in the mRNA, as well as environmental cues, can change the timing and dynamics of the key rearrangements leading to recoding of the mRNA into production of trans-frame peptides from the same mRNA. In this review, we discuss recent advances on the mechanics of translocation and reading frame maintenance. Furthermore, we describe the mechanisms and biological relevance of non-canonical translocation pathways, such as hungry and programmed frameshifting and translational bypassing, and their link to disease and infection.
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Affiliation(s)
- Panagiotis Poulis
- Department of Physical Biochemistry, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany
| | - Frank Peske
- Department of Physical Biochemistry, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany
| | - Marina V Rodnina
- Department of Physical Biochemistry, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany
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7
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Das A, Bao C, Ermolenko DN. Comparing FRET pairs that report on intersubunit rotation in bacterial ribosomes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.09.540051. [PMID: 37214817 PMCID: PMC10197640 DOI: 10.1101/2023.05.09.540051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Mediated by elongation factor G (EF-G), ribosome translocation along mRNA is accompanied by rotational movement between ribosomal subunits. Here, we reassess whether the intersubunit rotation requires GTP hydrolysis by EF-G or can occur spontaneously. To that end, we employ two independent FRET assays, which are based on labeling either ribosomal proteins (bS6 and bL9) or rRNAs (h44 of 16S and H101 of 23S rRNA). Both FRET pairs reveal three FRET states, corresponding to the non-rotated, rotated and semi-rotated conformations of the ribosome. Both FRET assays show that in the absence of EF-G, pre-translocation ribosomes containing deacylated P-site tRNA undergo spontaneous intersubunit rotations between non-rotated and rotated conformations. While the two FRET pairs exhibit largely similar behavior, they substantially differ in the fraction of ribosomes showing spontaneous fluctuations. Nevertheless, instead of being an invariable intrinsic property of each FRET pair, the fraction of spontaneously fluctuating molecules changes in both FRET assays depending on experimental conditions. Our results underscore importance of using multiple FRET pairs in studies of ribosome dynamics and highlight the role of thermally-driven large-scale ribosome rearrangements in translation.
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8
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Das A, Adiletta N, Ermolenko DN. Interplay between Inter-Subunit Rotation of the Ribosome and Binding of Translational GTPases. Int J Mol Sci 2023; 24:ijms24086878. [PMID: 37108045 PMCID: PMC10138997 DOI: 10.3390/ijms24086878] [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: 02/28/2023] [Revised: 03/31/2023] [Accepted: 04/03/2023] [Indexed: 04/29/2023] Open
Abstract
Translational G proteins, whose release from the ribosome is triggered by GTP hydrolysis, regulate protein synthesis. Concomitantly with binding and dissociation of protein factors, translation is accompanied by forward and reverse rotation between ribosomal subunits. Using single-molecule measurements, we explore the ways in which the binding of translational GTPases affects inter-subunit rotation of the ribosome. We demonstrate that the highly conserved translation factor LepA, whose function remains debated, shifts the equilibrium toward the non-rotated conformation of the ribosome. By contrast, the catalyst of ribosome translocation, elongation factor G (EF-G), favors the rotated conformation of the ribosome. Nevertheless, the presence of P-site peptidyl-tRNA and antibiotics, which stabilize the non-rotated conformation of the ribosome, only moderately reduces EF-G binding. These results support the model suggesting that EF-G interacts with both the non-rotated and rotated conformations of the ribosome during mRNA translocation. Our results provide new insights into the molecular mechanisms of LepA and EF-G action and underscore the role of ribosome structural dynamics in translation.
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Affiliation(s)
- Ananya Das
- Department of Biochemistry & Biophysics, School of Medicine and Dentistry & Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
| | - Nichole Adiletta
- Department of Biochemistry & Biophysics, School of Medicine and Dentistry & Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
| | - Dmitri N Ermolenko
- Department of Biochemistry & Biophysics, School of Medicine and Dentistry & Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
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9
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Hassan A, Byju S, Freitas F, Roc C, Pender N, Nguyen K, Kimbrough E, Mattingly J, Gonzalez Jr. R, de Oliveira R, Dunham C, Whitford P. Ratchet, swivel, tilt and roll: a complete description of subunit rotation in the ribosome. Nucleic Acids Res 2022; 51:919-934. [PMID: 36583339 PMCID: PMC9881166 DOI: 10.1093/nar/gkac1211] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 12/01/2022] [Accepted: 12/06/2022] [Indexed: 12/31/2022] Open
Abstract
Protein synthesis by the ribosome requires large-scale rearrangements of the 'small' subunit (SSU; ∼1 MDa), including inter- and intra-subunit rotational motions. However, with nearly 2000 structures of ribosomes and ribosomal subunits now publicly available, it is exceedingly difficult to design experiments based on analysis of all known rotation states. To overcome this, we developed an approach where the orientation of each SSU head and body is described in terms of three angular coordinates (rotation, tilt and tilt direction) and a single translation. By considering the entire RCSB PDB database, we describe 1208 fully-assembled ribosome complexes and 334 isolated small subunits, which span >50 species. This reveals aspects of subunit rearrangements that are universal, and others that are organism/domain-specific. For example, we show that tilt-like rearrangements of the SSU body (i.e. 'rolling') are pervasive in both prokaryotic and eukaryotic (cytosolic and mitochondrial) ribosomes. As another example, domain orientations associated with frameshifting in bacteria are similar to those found in eukaryotic ribosomes. Together, this study establishes a common foundation with which structural, simulation, single-molecule and biochemical efforts can more precisely interrogate the dynamics of this prototypical molecular machine.
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Affiliation(s)
| | | | | | - Claude Roc
- Department of Physics, Northeastern University, Dana Research Center 111, 360 Huntington Ave, Boston, MA 02115, USA
| | - Nisaa Pender
- Department of Physics, Northeastern University, Dana Research Center 111, 360 Huntington Ave, Boston, MA 02115, USA
| | - Kien Nguyen
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Evelyn M Kimbrough
- Department of Biochemistry, Emory University, Rollins Research Center 4027, 1510 Clifton Rd NE, Atlanta, GA 30322, USA,Department of Chemistry, Emory University, 1515 Dickey Dr, Atlanta, GA 30322, USA
| | - Jacob M Mattingly
- Department of Biochemistry, Emory University, Rollins Research Center 4027, 1510 Clifton Rd NE, Atlanta, GA 30322, USA
| | | | - Ronaldo Junio de Oliveira
- Laboratório de Biofísica Teórica, Departamento de Física, Instituto de Ciências Exatas, Naturais e Educação, Universidade Federal do Triângulo Mineiro, Uberaba, MG 38064-200, Brazil
| | - Christine M Dunham
- Department of Biochemistry, Emory University, Rollins Research Center 4027, 1510 Clifton Rd NE, Atlanta, GA 30322, USA
| | - Paul C Whitford
- To whom correspondence should be addressed. Tel: +1 617 373 2952;
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