1
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Pati AK, Kilic Z, Martin MI, Terry DS, Borgia A, Bar S, Jockusch S, Kiselev R, Altman RB, Blanchard SC. Recovering true FRET efficiencies from smFRET investigations requires triplet state mitigation. Nat Methods 2024; 21:1222-1230. [PMID: 38877317 DOI: 10.1038/s41592-024-02293-8] [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: 03/29/2023] [Accepted: 04/25/2024] [Indexed: 06/16/2024]
Abstract
Single-molecule fluorescence resonance energy transfer (smFRET) methods employed to quantify time-dependent compositional and conformational changes within biomolecules require elevated illumination intensities to recover robust photon emission streams from individual fluorophores. Here we show that outside the weak-excitation limit, and in regimes where fluorophores must undergo many rapid cycles of excitation and relaxation, non-fluorescing, excitation-induced triplet states with lifetimes orders of magnitude longer lived than photon-emitting singlet states degrade photon emission streams from both donor and acceptor fluorophores resulting in illumination-intensity-dependent changes in FRET efficiency. These changes are not commonly taken into consideration; therefore, robust strategies to suppress excited state accumulations are required to recover accurate and precise FRET efficiency, and thus distance, estimates. We propose both robust triplet state suppression and data correction strategies that enable the recovery of FRET efficiencies more closely approximating true values, thereby extending the spatial and temporal resolution of smFRET.
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Affiliation(s)
- Avik K Pati
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
- Department of Chemistry, Birla Institute of Technology and Science, Pilani, Rajasthan, India
| | - Zeliha Kilic
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Maxwell I Martin
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Daniel S Terry
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Alessandro Borgia
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Sukanta Bar
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Steffen Jockusch
- Center for Photochemical Sciences and Department of Chemistry, Bowling Green State University, Bowling Green, OH, USA
| | - Roman Kiselev
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Roger B Altman
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Scott C Blanchard
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA.
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA.
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2
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Chowdhury AR, Sapkota D, Girodat D. Conformational changes of ribosomes during translation elongation resolved by molecular dynamics simulations. Curr Opin Struct Biol 2024; 86:102804. [PMID: 38569462 DOI: 10.1016/j.sbi.2024.102804] [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: 10/02/2023] [Revised: 02/06/2024] [Accepted: 03/04/2024] [Indexed: 04/05/2024]
Abstract
Molecular dynamics simulations have emerged as a powerful set of tools to unravel the intricate dynamics of ribosomes during protein synthesis. Recent advancements in this field have enabled simulations to delve deep into the conformational rearrangements of ribosomes and associated factors, providing invaluable insights into the intricacies of translation. Emphasis on simulations has recently been on translation elongation, such as tRNA selection, translocation, and ribosomal head-swivel motions. These studies have offered crucial structural interpretations of how genetic information is faithfully translated into proteins. This review outlines recent discoveries concerning ribosome conformational changes occurring during translation elongation, as elucidated through molecular dynamics simulations.
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Affiliation(s)
- Anuradha Rai Chowdhury
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, 72701, USA. https://twitter.com/atomcellplankl
| | - Divya Sapkota
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, 72701, USA; Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Dylan Girodat
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, 72701, USA.
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3
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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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4
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Ide NA, Gentry RC, Rudbach MA, Yoo K, Velez PK, Comunale VM, Hartwick EW, Kinz-Thompson CD, Gonzalez RL, Aitken CE. A dynamic compositional equilibrium governs mRNA recognition by eIF3. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.25.581977. [PMID: 38712078 PMCID: PMC11071631 DOI: 10.1101/2024.04.25.581977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Eukaryotic translation initiation factor (eIF) 3 is a multi-subunit protein complex that binds both ribosomes and messenger RNAs (mRNAs) in order to drive a diverse set of mechanistic steps during translation. Despite its importance, a unifying framework explaining how eIF3 performs these numerous activities is lacking. Using single-molecule light scattering microscopy, we demonstrate that Saccharomyces cerevisiae eIF3 is an equilibrium mixture of the full complex, subcomplexes, and subunits. By extending our microscopy approach to an in vitro reconstituted eIF3 and complementing it with biochemical assays, we define the subspecies comprising this equilibrium and show that, rather than being driven by the full complex, mRNA binding by eIF3 is instead driven by the eIF3a subunit within eIF3a-containing subcomplexes. Our findings provide a mechanistic model for the role of eIF3 in the mRNA recruitment step of translation initiation and establish a mechanistic framework for explaining and investigating the other activities of eIF3.
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5
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Landerer C, Poehls J, Toth-Petroczy A. Fitness Effects of Phenotypic Mutations at Proteome-Scale Reveal Optimality of Translation Machinery. Mol Biol Evol 2024; 41:msae048. [PMID: 38421032 PMCID: PMC10939442 DOI: 10.1093/molbev/msae048] [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: 09/04/2023] [Revised: 01/30/2024] [Accepted: 02/23/2024] [Indexed: 03/02/2024] Open
Abstract
Errors in protein translation can lead to non-genetic, phenotypic mutations, including amino acid misincorporations. While phenotypic mutations can increase protein diversity, the systematic characterization of their proteome-wide frequencies and their evolutionary impact has been lacking. Here, we developed a mechanistic model of translation errors to investigate how selection acts on protein populations produced by amino acid misincorporations. We fitted the model to empirical observations of misincorporations obtained from over a hundred mass spectrometry datasets of E. coli and S. cerevisiae. We found that on average 20% to 23% of proteins synthesized in the cell are expected to harbor at least one amino acid misincorporation, and that deleterious misincorporations are less likely to occur. Combining misincorporation probabilities and the estimated fitness effects of amino acid substitutions in a population genetics framework, we found 74% of mistranslation events in E. coli and 94% in S. cerevisiae to be neutral. We further show that the set of available synonymous tRNAs is subject to evolutionary pressure, as the presence of missing tRNAs would increase codon-anticodon cross-reactivity and misincorporation error rates. Overall, we find that the translation machinery is likely optimal in E. coli and S. cerevisiae and that both local solutions at the level of codons and a global solution such as the tRNA pool can mitigate the impact of translation errors. We provide a framework to study the evolutionary impact of codon-specific translation errors and a method for their proteome-wide detection across organisms and conditions.
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Affiliation(s)
- Cedric Landerer
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
- Center for Systems Biology Dresden, 01307 Dresden, Germany
| | - Jonas Poehls
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
- Center for Systems Biology Dresden, 01307 Dresden, Germany
| | - Agnes Toth-Petroczy
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
- Center for Systems Biology Dresden, 01307 Dresden, Germany
- Cluster of Excellence Physics of Life, TU Dresden, 01062 Dresden, Germany
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6
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Gentry RC, Ide NA, Comunale VM, Hartwick EW, Kinz-Thompson CD, Gonzalez RL. The mechanism of mRNA activation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.15.567265. [PMID: 38014128 PMCID: PMC10680758 DOI: 10.1101/2023.11.15.567265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
During translation initiation, messenger RNA molecules must be identified and activated for loading into a ribosome. In this rate-limiting step, the heterotrimeric protein eukaryotic initiation factor eIF4F must recognize and productively interact with the 7-methylguanosine cap at the 5' end of the messenger RNA and subsequently activate the message. Despite its fundamental, regulatory role in gene expression, the molecular events underlying cap recognition and messenger RNA activation remain mysterious. Here, we generate a unique, single-molecule fluorescence imaging system to interrogate the dynamics with which eIF4F discriminates productive and non-productive locations on full-length, native messenger RNA molecules. At the single-molecule level, we observe stochastic sampling of eIF4F along the length of the messenger RNA and identify allosteric communication between the eIF4F subunits which ultimately drive cap-recognition and subsequent activation of the message. Our experiments uncover novel functions for each subunit of eIF4F and we conclude by presenting a model for messenger RNA activation which precisely defines the composition of the activated message. This model provides a general framework for understanding how messenger RNA molecules may be discriminated from one another, and how other RNA-binding proteins may control the efficiency of translation initiation.
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Affiliation(s)
- Riley C Gentry
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Nicholas A Ide
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | | | - Erik W Hartwick
- Department of Chemistry, Columbia University, New York, NY, USA
- Current Address: BioChemistry Krios Electron Microscopy Facility, Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Colin D Kinz-Thompson
- Department of Chemistry, Columbia University, New York, NY, USA
- Current Address: Department of Chemistry, Rutgers University-Newark, Newark, NJ 07102
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7
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Han Z, Moore GA, Mitter R, Lopez Martinez D, Wan L, Dirac Svejstrup AB, Rueda DS, Svejstrup JQ. DNA-directed termination of RNA polymerase II transcription. Mol Cell 2023; 83:3253-3267.e7. [PMID: 37683646 PMCID: PMC7615648 DOI: 10.1016/j.molcel.2023.08.007] [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: 03/23/2023] [Revised: 06/27/2023] [Accepted: 08/09/2023] [Indexed: 09/10/2023]
Abstract
RNA polymerase II (RNAPII) transcription involves initiation from a promoter, transcriptional elongation through the gene, and termination in the terminator region. In bacteria, terminators often contain specific DNA elements provoking polymerase dissociation, but RNAPII transcription termination is thought to be driven entirely by protein co-factors. We used biochemical reconstitution, single-molecule studies, and genome-wide analysis in yeast to study RNAPII termination. Transcription into natural terminators by pure RNAPII results in spontaneous termination at specific sequences containing T-tracts. Single-molecule analysis indicates that termination involves pausing without backtracking. The "torpedo" Rat1-Rai1 exonuclease (XRN2 in humans) greatly stimulates spontaneous termination but is ineffectual on other paused RNAPIIs. By contrast, elongation factor Spt4-Spt5 (DSIF) suppresses termination. Genome-wide analysis further indicates that termination occurs by transcript cleavage at the poly(A) site exposing a new 5' RNA-end that allows Rat1-Rai1 loading, which then catches up with destabilized RNAPII at specific termination sites to end transcription.
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Affiliation(s)
- Zhong Han
- Department of Cellular and Molecular Medicine, Panum Institute, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark; Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - George A Moore
- Single Molecule Imaging group, MRC-London Institute of Medical Sciences, and Section of Virology, Department of Infectious Disease, Faculty of Medicine, Imperial College London, London W12 0NN, UK
| | - Richard Mitter
- Bioinformatics and Biostatistics, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - David Lopez Martinez
- Department of Cellular and Molecular Medicine, Panum Institute, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark; Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Li Wan
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - A Barbara Dirac Svejstrup
- Department of Cellular and Molecular Medicine, Panum Institute, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark; Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - David S Rueda
- Single Molecule Imaging group, MRC-London Institute of Medical Sciences, and Section of Virology, Department of Infectious Disease, Faculty of Medicine, Imperial College London, London W12 0NN, UK
| | - Jesper Q Svejstrup
- Department of Cellular and Molecular Medicine, Panum Institute, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark; Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
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8
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Girodat D, Wieden HJ, Blanchard SC, Sanbonmatsu KY. Geometric alignment of aminoacyl-tRNA relative to catalytic centers of the ribosome underpins accurate mRNA decoding. Nat Commun 2023; 14:5582. [PMID: 37696823 PMCID: PMC10495418 DOI: 10.1038/s41467-023-40404-9] [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: 08/23/2022] [Accepted: 07/27/2023] [Indexed: 09/13/2023] Open
Abstract
Accurate protein synthesis is determined by the two-subunit ribosome's capacity to selectively incorporate cognate aminoacyl-tRNA for each mRNA codon. The molecular basis of tRNA selection accuracy, and how fidelity can be affected by antibiotics, remains incompletely understood. Using molecular simulations, we find that cognate and near-cognate tRNAs delivered to the ribosome by Elongation Factor Tu (EF-Tu) can follow divergent pathways of motion into the ribosome during both initial selection and proofreading. Consequently, cognate aa-tRNAs follow pathways aligned with the catalytic GTPase and peptidyltransferase centers of the large subunit, while near-cognate aa-tRNAs follow pathways that are misaligned. These findings suggest that differences in mRNA codon-tRNA anticodon interactions within the small subunit decoding center, where codon-anticodon interactions occur, are geometrically amplified over distance, as a result of this site's physical separation from the large ribosomal subunit catalytic centers. These insights posit that the physical size of both tRNA and ribosome are key determinants of the tRNA selection fidelity mechanism.
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Affiliation(s)
- Dylan Girodat
- Theoretical Biology and Biophysics, Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Hans-Joachim Wieden
- Department of Microbiology, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Scott C Blanchard
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
| | - Karissa Y Sanbonmatsu
- Theoretical Biology and Biophysics, Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
- New Mexico Consortium, Los Alamos, NM, 87545, USA.
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9
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Livingston NM, Kwon J, Valera O, Saba JA, Sinha NK, Reddy P, Nelson B, Wolfe C, Ha T, Green R, Liu J, Wu B. Bursting translation on single mRNAs in live cells. Mol Cell 2023; 83:2276-2289.e11. [PMID: 37329884 PMCID: PMC10330622 DOI: 10.1016/j.molcel.2023.05.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 03/27/2023] [Accepted: 05/14/2023] [Indexed: 06/19/2023]
Abstract
Stochasticity has emerged as a mechanism of gene regulation. Much of this so-called "noise" has been attributed to bursting transcription. Although bursting transcription has been studied extensively, the role of stochasticity in translation has not been fully investigated due to the lack of enabling imaging technology. In this study, we developed techniques to track single mRNAs and their translation in live cells for hours, allowing the measurement of previously uncharacterized translation dynamics. We applied genetic and pharmacological perturbations to control translation kinetics and found that, like transcription, translation is not a constitutive process but instead cycles between inactive and active states, or "bursts." However, unlike transcription, which is largely frequency-modulated, complex structures in the 5'-untranslated region alter burst amplitudes. Bursting frequency can be controlled through cap-proximal sequences and trans-acting factors such as eIF4F. We coupled single-molecule imaging with stochastic modeling to quantitatively determine the kinetic parameters of translational bursting.
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Affiliation(s)
- Nathan M Livingston
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jiwoong Kwon
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Oliver Valera
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - James A Saba
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Niladri K Sinha
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Pranav Reddy
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Blake Nelson
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Clara Wolfe
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Rachel Green
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Jian Liu
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Bin Wu
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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10
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Prabhakar A, Pavlov MY, Zhang J, Indrisiunaite G, Wang J, Lawson M, Ehrenberg M, Puglisi JD. Dynamics of release factor recycling during translation termination in bacteria. Nucleic Acids Res 2023; 51:5774-5790. [PMID: 37102635 PMCID: PMC10287982 DOI: 10.1093/nar/gkad286] [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: 07/02/2022] [Revised: 04/05/2023] [Accepted: 04/09/2023] [Indexed: 04/28/2023] Open
Abstract
In bacteria, release of newly synthesized proteins from ribosomes during translation termination is catalyzed by class-I release factors (RFs) RF1 or RF2, reading UAA and UAG or UAA and UGA codons, respectively. Class-I RFs are recycled from the post-termination ribosome by a class-II RF, the GTPase RF3, which accelerates ribosome intersubunit rotation and class-I RF dissociation. How conformational states of the ribosome are coupled to the binding and dissociation of the RFs remains unclear and the importance of ribosome-catalyzed guanine nucleotide exchange on RF3 for RF3 recycling in vivo has been disputed. Here, we profile these molecular events using a single-molecule fluorescence assay to clarify the timings of RF3 binding and ribosome intersubunit rotation that trigger class-I RF dissociation, GTP hydrolysis, and RF3 dissociation. These findings in conjunction with quantitative modeling of intracellular termination flows reveal rapid ribosome-dependent guanine nucleotide exchange to be crucial for RF3 action in vivo.
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Affiliation(s)
- Arjun Prabhakar
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA
- Program in Biophysics, Stanford University, Stanford, CA 94305-5126, USA
| | - Michael Y Pavlov
- Department of Cell and Molecular Biology, Biomedical Center, Box 596, Uppsala University, Uppsala, Sweden
| | - Jingji Zhang
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA
| | - Gabriele Indrisiunaite
- Department of Cell and Molecular Biology, Biomedical Center, Box 596, Uppsala University, Uppsala, Sweden
| | - Jinfan Wang
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA
| | - Michael R Lawson
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA
| | - Måns Ehrenberg
- Department of Cell and Molecular Biology, Biomedical Center, Box 596, Uppsala University, Uppsala, Sweden
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA
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11
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Holm M, Natchiar SK, Rundlet EJ, Myasnikov AG, Watson ZL, Altman RB, Wang HY, Taunton J, Blanchard SC. mRNA decoding in human is kinetically and structurally distinct from bacteria. Nature 2023; 617:200-207. [PMID: 37020024 PMCID: PMC10156603 DOI: 10.1038/s41586-023-05908-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 03/01/2023] [Indexed: 04/07/2023]
Abstract
In all species, ribosomes synthesize proteins by faithfully decoding messenger RNA (mRNA) nucleotide sequences using aminoacyl-tRNA substrates. Current knowledge of the decoding mechanism derives principally from studies on bacterial systems1. Although key features are conserved across evolution2, eukaryotes achieve higher-fidelity mRNA decoding than bacteria3. In human, changes in decoding fidelity are linked to ageing and disease and represent a potential point of therapeutic intervention in both viral and cancer treatment4-6. Here we combine single-molecule imaging and cryogenic electron microscopy methods to examine the molecular basis of human ribosome fidelity to reveal that the decoding mechanism is both kinetically and structurally distinct from that of bacteria. Although decoding is globally analogous in both species, the reaction coordinate of aminoacyl-tRNA movement is altered on the human ribosome and the process is an order of magnitude slower. These distinctions arise from eukaryote-specific structural elements in the human ribosome and in the elongation factor eukaryotic elongation factor 1A (eEF1A) that together coordinate faithful tRNA incorporation at each mRNA codon. The distinct nature and timing of conformational changes within the ribosome and eEF1A rationalize how increased decoding fidelity is achieved and potentially regulated in eukaryotic species.
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Affiliation(s)
- Mikael Holm
- Department of Structural Biology, St Jude Children's Research Hospital, Memphis, TN, USA
| | - S Kundhavai Natchiar
- Department of Structural Biology, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Emily J Rundlet
- Department of Structural Biology, St Jude Children's Research Hospital, Memphis, TN, USA
- Tri-Institutional PhD Program in Chemical Biology, Weill Cornell Medicine, New York, NY, USA
| | - Alexander G Myasnikov
- Department of Structural Biology, St Jude Children's Research Hospital, Memphis, TN, USA
- Dubochet Center for Imaging (DCI), EPFL, Lausanne, Switzerland
| | - Zoe L Watson
- Department of Structural Biology, St Jude Children's Research Hospital, Memphis, TN, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
| | - Roger B Altman
- Department of Structural Biology, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Hao-Yuan Wang
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA, USA
| | - Jack Taunton
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA, USA
| | - Scott C Blanchard
- Department of Structural Biology, St Jude Children's Research Hospital, Memphis, TN, USA.
- Chemical Biology & Therapeutics, St Jude Children's Research Hospital, Memphis, TN, USA.
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12
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Lomakin IB, Devarkar SC, Patel S, Grada A, Bunick C. Sarecycline inhibits protein translation in Cutibacterium acnes 70S ribosome using a two-site mechanism. Nucleic Acids Res 2023; 51:2915-2930. [PMID: 36864821 PMCID: PMC10085706 DOI: 10.1093/nar/gkad103] [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: 10/12/2022] [Revised: 02/01/2023] [Accepted: 02/07/2023] [Indexed: 03/04/2023] Open
Abstract
Acne vulgaris is a chronic disfiguring skin disease affecting ∼1 billion people worldwide, often having persistent negative effects on physical and mental health. The Gram-positive anaerobe, Cutibacterium acnes is implicated in acne pathogenesis and is, therefore, a main target for antibiotic-based acne therapy. We determined a 2.8-Å resolution structure of the 70S ribosome of Cutibacterium acnes by cryogenic electron microscopy and discovered that sarecycline, a narrow-spectrum antibiotic against Cutibacterium acnes, may inhibit two active sites of this bacterium's ribosome in contrast to the one site detected previously on the model ribosome of Thermus thermophilus. Apart from the canonical binding site at the mRNA decoding center, the second binding site for sarecycline exists at the nascent peptide exit tunnel, reminiscent of the macrolides class of antibiotics. The structure also revealed Cutibacterium acnes-specific features of the ribosomal RNA and proteins. Unlike the ribosome of the Gram-negative bacterium Escherichia coli, Cutibacterium acnes ribosome has two additional proteins, bS22 and bL37, which are also present in the ribosomes of Mycobacterium smegmatis and Mycobacterium tuberculosis. We show that bS22 and bL37 have antimicrobial properties and may be involved in maintaining the healthy homeostasis of the human skin microbiome.
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Affiliation(s)
- Ivan B Lomakin
- Department of Dermatology, Yale University School of Medicine, New Haven, CT06520, USA
| | - Swapnil C Devarkar
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06520, USA
| | - Shivali Patel
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06520, USA
| | - Ayman Grada
- Department of Dermatology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Christopher G Bunick
- Department of Dermatology, Yale University School of Medicine, New Haven, CT06520, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06520, USA
- Program in Translational Biomedicine, Yale University School of Medicine, New Haven, CT 06520, USA
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13
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Chrzanowska-Lightowlers ZM, Lightowlers RN. Translation in Mitochondrial Ribosomes. Methods Mol Biol 2023; 2661:53-72. [PMID: 37166631 DOI: 10.1007/978-1-0716-3171-3_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Mitochondrial protein synthesis is essential for the life of aerobic eukaryotes. Without it, oxidative phosphorylation cannot be coupled. Evolution has shaped a battery of factors and machinery that are key to production of just a handful of critical proteins. In this general concept chapter, we attempt to briefly summarize our current knowledge of the overall process in mitochondria from a variety of species, breaking this down to the four parts of translation: initiation, elongation, termination, and recycling. Where appropriate, we highlight differences between species and emphasize gaps in our understanding. Excitingly, with the current revolution in cryoelectron microscopy and mitochondrial genome editing, it is highly likely that many of these gaps will be resolved in the near future. However, the absence of a faithful in vitro reconstituted system to study mitochondrial translation is still problematic.
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Affiliation(s)
- Zofia M Chrzanowska-Lightowlers
- Wellcome Centre for Mitochondrial Research, Newcastle University Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne, UK.
| | - Robert N Lightowlers
- Wellcome Centre for Mitochondrial Research, Newcastle University Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne, UK
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14
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Martin MI, Pati AK, Abeywickrama CS, Bar S, Kilic Z, Altman RB, Blanchard SC. Leveraging Baird aromaticity for advancement of bioimaging applications. J PHYS ORG CHEM 2023; 36:e4449. [PMID: 36590885 PMCID: PMC9799245 DOI: 10.1002/poc.4449] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 10/03/2022] [Accepted: 10/04/2022] [Indexed: 02/01/2023]
Abstract
In this perspective, we highlight the recent progress in utilizing Baird aromatic species to improve fluorophore performance in microscopy and imaging applications. We specifically focus on the origins of the use of Baird aromaticity in fluorescence applications, the development of “self‐healing” fluorophores leveraging cyclooctatetraene’ Baird aromaticity, and where developments need to occur to optimize this technology.
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Affiliation(s)
- Maxwell I. Martin
- Department of Structural BiologySt. Jude Children's Research HospitalMemphisTNUSA
- Department of Chemical Biology & TherapeuticsSt. Jude Children's Research HospitalMemphisTNUSA
| | - Avik K. Pati
- Department of Structural BiologySt. Jude Children's Research HospitalMemphisTNUSA
| | - Chathura S. Abeywickrama
- Department of Structural BiologySt. Jude Children's Research HospitalMemphisTNUSA
- Department of Chemical Biology & TherapeuticsSt. Jude Children's Research HospitalMemphisTNUSA
| | - Sukanta Bar
- Department of Structural BiologySt. Jude Children's Research HospitalMemphisTNUSA
- Department of Chemical Biology & TherapeuticsSt. Jude Children's Research HospitalMemphisTNUSA
| | - Zeliha Kilic
- Department of Structural BiologySt. Jude Children's Research HospitalMemphisTNUSA
| | - Roger B. Altman
- Department of Structural BiologySt. Jude Children's Research HospitalMemphisTNUSA
- Department of Chemical Biology & TherapeuticsSt. Jude Children's Research HospitalMemphisTNUSA
| | - Scott C. Blanchard
- Department of Structural BiologySt. Jude Children's Research HospitalMemphisTNUSA
- Department of Chemical Biology & TherapeuticsSt. Jude Children's Research HospitalMemphisTNUSA
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15
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Hassan A, Whitford PC. Identifying Strategies to Experimentally Probe Multidimensional Dynamics in the Ribosome. J Phys Chem B 2022; 126:8460-8471. [PMID: 36256879 DOI: 10.1021/acs.jpcb.2c05706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The ribosome is a complex biomolecular machine that utilizes large-scale conformational rearrangements to synthesize proteins. For example, during the elongation cycle, the "head" domain of the ribosomal small subunit (SSU) is known to undergo transient rotation events that allow for movement of tRNA molecules (i.e., translocation). While the head may exhibit rigid-body-like properties, the precise relationship between experimentally accessible probes and multidimensional rotations has yet to be established. To address this gap, we perform molecular dynamics simulations of the translocation step of the elongation cycle in the ribosome, where the SSU head spontaneously undergoes rotation and tilt-like motions. With this data set (1250 simulated events), we used statistical and information-theory-based measures to identify possible single-molecule probes that can isolate SSU head rotation and head tilting. This analysis provides a molecular interpretation for previous single-molecule measurements, while establishing a framework for the design of next-generation experiments that may precisely probe the mechanistic and kinetic aspects of the ribosome.
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Affiliation(s)
- Asem Hassan
- Department of Physics, Northeastern University, Dana Research Center 111, 360 Huntington Avenue, Boston, Massachusetts02115, United States.,Center for Theoretical Biological Physics, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts02115, United States
| | - Paul C Whitford
- Department of Physics, Northeastern University, Dana Research Center 111, 360 Huntington Avenue, Boston, Massachusetts02115, United States.,Center for Theoretical Biological Physics, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts02115, United States
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16
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Juette MF, Carelli JD, Rundlet EJ, Brown A, Shao S, Ferguson A, Wasserman MR, Holm M, Taunton J, Blanchard SC. Didemnin B and ternatin-4 differentially inhibit conformational changes in eEF1A required for aminoacyl-tRNA accommodation into mammalian ribosomes. eLife 2022; 11:e81608. [PMID: 36264623 PMCID: PMC9584604 DOI: 10.7554/elife.81608] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 10/03/2022] [Indexed: 12/11/2022] Open
Abstract
Rapid and accurate mRNA translation requires efficient codon-dependent delivery of the correct aminoacyl-tRNA (aa-tRNA) to the ribosomal A site. In mammals, this fidelity-determining reaction is facilitated by the GTPase elongation factor-1 alpha (eEF1A), which escorts aa-tRNA as an eEF1A(GTP)-aa-tRNA ternary complex into the ribosome. The structurally unrelated cyclic peptides didemnin B and ternatin-4 bind to the eEF1A(GTP)-aa-tRNA ternary complex and inhibit translation but have different effects on protein synthesis in vitro and in vivo. Here, we employ single-molecule fluorescence imaging and cryogenic electron microscopy to determine how these natural products inhibit translational elongation on mammalian ribosomes. By binding to a common site on eEF1A, didemnin B and ternatin-4 trap eEF1A in an intermediate state of aa-tRNA selection, preventing eEF1A release and aa-tRNA accommodation on the ribosome. We also show that didemnin B and ternatin-4 exhibit distinct effects on the dynamics of aa-tRNA selection that inform on observed disparities in their inhibition efficacies and physiological impacts. These integrated findings underscore the value of dynamics measurements in assessing the mechanism of small-molecule inhibition and highlight potential of single-molecule methods to reveal how distinct natural products differentially impact the human translation mechanism.
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Affiliation(s)
- Manuel F Juette
- Department of Physiology and Biophysics, Weill Cornell MedicineNew YorkUnited States
| | - Jordan D Carelli
- Chemistry and Chemical Biology Graduate Program, University of California, San FranciscoSan FranciscoUnited States
| | - Emily J Rundlet
- Department of Physiology and Biophysics, Weill Cornell MedicineNew YorkUnited States
- Department of Structural Biology, St. Jude Children's Research HospitalMemphisUnited States
- Tri-Institutional PhD Program in Chemical Biology, Weill Cornell MedicineNew YorkUnited States
| | - Alan Brown
- MRC-LMB, Francis Crick AvenueCambridgeUnited Kingdom
| | - Sichen Shao
- MRC-LMB, Francis Crick AvenueCambridgeUnited Kingdom
| | - Angelica Ferguson
- Department of Physiology and Biophysics, Weill Cornell MedicineNew YorkUnited States
| | - Michael R Wasserman
- Department of Physiology and Biophysics, Weill Cornell MedicineNew YorkUnited States
| | - Mikael Holm
- Department of Physiology and Biophysics, Weill Cornell MedicineNew YorkUnited States
- Department of Structural Biology, St. Jude Children's Research HospitalMemphisUnited States
| | - Jack Taunton
- Chemistry and Chemical Biology Graduate Program, University of California, San FranciscoSan FranciscoUnited States
| | - Scott C Blanchard
- Department of Physiology and Biophysics, Weill Cornell MedicineNew YorkUnited States
- Department of Structural Biology, St. Jude Children's Research HospitalMemphisUnited States
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17
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Milstein JN, Nino DF, Zhou X, Gradinaru CC. Single-molecule counting applied to the study of GPCR oligomerization. Biophys J 2022; 121:3175-3187. [PMID: 35927960 PMCID: PMC9463696 DOI: 10.1016/j.bpj.2022.07.034] [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: 05/31/2022] [Revised: 06/29/2022] [Accepted: 07/28/2022] [Indexed: 11/24/2022] Open
Abstract
Single-molecule counting techniques enable a precise determination of the intracellular abundance and stoichiometry of proteins and macromolecular complexes. These details are often challenging to quantitatively assess yet are essential for our understanding of cellular function. Consider G-protein-coupled receptors-an expansive class of transmembrane signaling proteins that participate in many vital physiological functions making them a popular target for drug development. While early evidence for the role of oligomerization in receptor signaling came from ensemble biochemical and biophysical assays, innovations in single-molecule measurements are now driving a paradigm shift in our understanding of its relevance. Here, we review recent developments in single-molecule counting with a focus on photobleaching step counting and the emerging technique of quantitative single-molecule localization microscopy-with a particular emphasis on the potential for these techniques to advance our understanding of the role of oligomerization in G-protein-coupled receptor signaling.
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Affiliation(s)
- Joshua N Milstein
- Department of Physics, University of Toronto, Toronto, Ontario, Canada; Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, Canada.
| | - Daniel F Nino
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Xiaohan Zhou
- Department of Physics, University of Toronto, Toronto, Ontario, Canada; Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Claudiu C Gradinaru
- Department of Physics, University of Toronto, Toronto, Ontario, Canada; Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, Canada.
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18
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Hansen SR, White DS, Scalf M, Corrêa IR, Smith LM, Hoskins AA. Multi-step recognition of potential 5' splice sites by the Saccharomyces cerevisiae U1 snRNP. eLife 2022; 11:70534. [PMID: 35959885 PMCID: PMC9436412 DOI: 10.7554/elife.70534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 08/11/2022] [Indexed: 11/13/2022] Open
Abstract
In eukaryotes, splice sites define the introns of pre-mRNAs and must be recognized and excised with nucleotide precision by the spliceosome to make the correct mRNA product. In one of the earliest steps of spliceosome assembly, the U1 small nuclear ribonucleoprotein (snRNP) recognizes the 5' splice site (5' SS) through a combination of base pairing, protein-RNA contacts, and interactions with other splicing factors. Previous studies investigating the mechanisms of 5' SS recognition have largely been done in vivo or in cellular extracts where the U1/5' SS interaction is difficult to deconvolute from the effects of trans-acting factors or RNA structure. In this work we used colocalization single-molecule spectroscopy (CoSMoS) to elucidate the pathway of 5' SS selection by purified yeast U1 snRNP. We determined that U1 reversibly selects 5' SS in a sequence-dependent, two-step mechanism. A kinetic selection scheme enforces pairing at particular positions rather than overall duplex stability to achieve long-lived U1 binding. Our results provide a kinetic basis for how U1 may rapidly surveil nascent transcripts for 5' SS and preferentially accumulate at these sequences rather than on close cognates.
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Affiliation(s)
- Sarah R Hansen
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
| | - David S White
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
| | - Mark Scalf
- Department of Chemistry, University of Wisconsin-Madison, Madison, United States
| | | | - Lloyd M Smith
- Department of Chemistry, University of Wisconsin-Madison, Madison, United States
| | - Aaron A Hoskins
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
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19
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Lombardi S, Testa MF, Pinotti M, Branchini A. Translation termination codons in protein synthesis and disease. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2022; 132:1-48. [PMID: 36088072 DOI: 10.1016/bs.apcsb.2022.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Fidelity of protein synthesis, a process shaped by several mechanisms involving specialized ribosome regions and external factors, ensures the precise reading of sense as well as stop codons (UGA, UAG, UAA), which are usually localized at the 3' of mRNA and drive the release of the polypeptide chain. However, either natural (NTCs) or premature (PTCs) termination codons, the latter arising from nucleotide changes, can undergo a recoding process named ribosome or translational readthrough, which insert specific amino acids (NTCs) or subset(s) depending on the stop codon type (PTCs). This process is particularly relevant for nonsense mutations, a relatively frequent cause of genetic disorders, which impair gene expression at different levels by potentially leading to mRNA degradation and/or synthesis of truncated proteins. As a matter of fact, many efforts have been made to develop efficient and safe readthrough-inducing compounds, which have been challenged in several models of human disease to provide with a therapy. In this view, the dissection of the molecular determinants shaping the outcome of readthrough, namely nucleotide and protein contexts as well as their interplay and impact on protein structure/function, is crucial to identify responsive nonsense mutations resulting in functional full-length proteins. The interpretation of experimental and mechanistic findings is also important to define a possibly clear picture of potential readthrough-favorable features useful to achieve rescue profiles compatible with therapeutic thresholds typical of each targeted disorder, which is of primary importance for the potential translatability of readthrough into a personalized and mutation-specific, and thus patient-oriented, therapeutic strategy.
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Affiliation(s)
- Silvia Lombardi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Maria Francesca Testa
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Mirko Pinotti
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Alessio Branchini
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy.
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20
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Asher WB, Terry DS, Gregorio GGA, Kahsai AW, Borgia A, Xie B, Modak A, Zhu Y, Jang W, Govindaraju A, Huang LY, Inoue A, Lambert NA, Gurevich VV, Shi L, Lefkowitz RJ, Blanchard SC, Javitch JA. GPCR-mediated β-arrestin activation deconvoluted with single-molecule precision. Cell 2022; 185:1661-1675.e16. [PMID: 35483373 PMCID: PMC9191627 DOI: 10.1016/j.cell.2022.03.042] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 02/11/2022] [Accepted: 03/29/2022] [Indexed: 01/14/2023]
Abstract
β-arrestins bind G protein-coupled receptors to terminate G protein signaling and to facilitate other downstream signaling pathways. Using single-molecule fluorescence resonance energy transfer imaging, we show that β-arrestin is strongly autoinhibited in its basal state. Its engagement with a phosphopeptide mimicking phosphorylated receptor tail efficiently releases the β-arrestin tail from its N domain to assume distinct conformations. Unexpectedly, we find that β-arrestin binding to phosphorylated receptor, with a phosphorylation barcode identical to the isolated phosphopeptide, is highly inefficient and that agonist-promoted receptor activation is required for β-arrestin activation, consistent with the release of a sequestered receptor C tail. These findings, together with focused cellular investigations, reveal that agonism and receptor C-tail release are specific determinants of the rate and efficiency of β-arrestin activation by phosphorylated receptor. We infer that receptor phosphorylation patterns, in combination with receptor agonism, synergistically establish the strength and specificity with which diverse, downstream β-arrestin-mediated events are directed.
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Affiliation(s)
- Wesley B Asher
- Department of Psychiatry, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Daniel S Terry
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - G Glenn A Gregorio
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065, USA
| | - Alem W Kahsai
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA; Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Alessandro Borgia
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Bing Xie
- Computational Chemistry and Molecular Biophysics Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | - Arnab Modak
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Ying Zhu
- Department of Psychiatry, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Wonjo Jang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Alekhya Govindaraju
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Li-Yin Huang
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA; Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | | | - Lei Shi
- Computational Chemistry and Molecular Biophysics Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | - Robert J Lefkowitz
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA; Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA; Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Scott C Blanchard
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065, USA.
| | - Jonathan A Javitch
- Department of Psychiatry, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA; Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
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21
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Abstract
Biochemistry and molecular biology rely on the recognition of structural complementarity between molecules. Molecular interactions must be both quickly reversible, i.e., tenuous, and specific. How the cell reconciles these conflicting demands is the subject of this article. The problem and its theoretical solution are discussed within the wider theoretical context of the thermodynamics of stochastic processes (stochastic thermodynamics). The solution-an irreversible reaction cycle that decreases internal error at the expense of entropy export into the environment-is shown to be widely employed by biological processes that transmit genetic and regulatory information. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Hinrich Boeger
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California;
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22
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Abstract
Accurate protein synthesis (translation) relies on translation factors that rectify ribosome fluctuations into a unidirectional process. Understanding this process requires structural characterization of the ribosome and translation-factor dynamics. In the 2000s, crystallographic studies determined high-resolution structures of ribosomes stalled with translation factors, providing a starting point for visualizing translation. Recent progress in single-particle cryogenic electron microscopy (cryo-EM) has enabled near-atomic resolution of numerous structures sampled in heterogeneous complexes (ensembles). Ensemble and time-resolved cryo-EM have now revealed unprecedented views of ribosome transitions in the three principal stages of translation: initiation, elongation, and termination. This review focuses on how translation factors help achieve high accuracy and efficiency of translation by monitoring distinct ribosome conformations and by differentially shifting the equilibria of ribosome rearrangements for cognate and near-cognate substrates. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Andrei A Korostelev
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA;
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23
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Iizuka R, Yamazaki H, Uemura S. Zero-mode waveguides and nanopore-based sequencing technologies accelerate single-molecule studies. Biophys Physicobiol 2022; 19:e190032. [DOI: 10.2142/biophysico.bppb-v19.0032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 08/26/2022] [Indexed: 12/01/2022] Open
Affiliation(s)
- Ryo Iizuka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo
| | - Hirohito Yamazaki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo
| | - Sotaro Uemura
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo
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24
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Moreno S, Brunner M, Delazer I, Rieder D, Lusser A, Micura R. Synthesis of 4-thiouridines with prodrug functionalization for RNA metabolic labeling. RSC Chem Biol 2022; 3:447-455. [PMID: 35441143 PMCID: PMC8985182 DOI: 10.1039/d2cb00001f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 02/18/2022] [Indexed: 12/22/2022] Open
Abstract
Metabolic labeling has emerged as a powerful tool to endow RNA with reactive handles allowing for subsequent chemical derivatization and processing. Recently, thiolated nucleosides, such as 4-thiouridine (4sU), have attracted great interest in metabolic labeling-based RNA sequencing approaches (TUC-seq, SLAM-seq, TimeLapse-seq) to study cellular RNA expression and decay dynamics. For these and other applications (e.g. PAR-CLIP), thus far only the naked nucleoside 4sU has been applied. Here we examined the concept of derivatizing 4sU into a 5′-monophosphate prodrug that would allow for cell permeation and potentially improve labeling efficiency by bypassing the rate-limiting first step of 5′ phosphorylation of the nucleoside into the ultimately bioactive 4sU triphosphate (4sUTP). To this end, we developed robust synthetic routes towards diverse 4sU monophosphate prodrugs. Using metabolic labeling assays, we found that most of the newly introduced 4sU prodrugs were well tolerated by the cells. One derivative, the bis(4-acetyloxybenzyl) 5′-monophosphate of 4sU, was also efficiently incorporated into nascent RNA. Synthetic access to 4-thiouridine (4sU) derivatives with monophosphate prodrug patterns creates additional possibilities for metabolic labeling of RNA for different applications.![]()
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Affiliation(s)
- Sarah Moreno
- Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Melanie Brunner
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Isabel Delazer
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Dietmar Rieder
- Institute of Bioinformatics, Biocenter, Medical University of Innsbruck, Innrain 82, 6020 Innsbruck, Austria
| | - Alexandra Lusser
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
| | - Ronald Micura
- Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria
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25
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Shirokikh NE. Translation complex stabilization on messenger RNA and footprint profiling to study the RNA responses and dynamics of protein biosynthesis in the cells. Crit Rev Biochem Mol Biol 2021; 57:261-304. [PMID: 34852690 DOI: 10.1080/10409238.2021.2006599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
During protein biosynthesis, ribosomes bind to messenger (m)RNA, locate its protein-coding information, and translate the nucleotide triplets sequentially as codons into the corresponding sequence of amino acids, forming proteins. Non-coding mRNA features, such as 5' and 3' untranslated regions (UTRs), start sites or stop codons of different efficiency, stretches of slower or faster code and nascent polypeptide interactions can alter the translation rates transcript-wise. Most of the homeostatic and signal response pathways of the cells converge on individual mRNA control, as well as alter the global translation output. Among the multitude of approaches to study translational control, one of the most powerful is to infer the locations of translational complexes on mRNA based on the mRNA fragments protected by these complexes from endonucleolytic hydrolysis, or footprints. Translation complex profiling by high-throughput sequencing of the footprints allows to quantify the transcript-wise, as well as global, alterations of translation, and uncover the underlying control mechanisms by attributing footprint locations and sizes to different configurations of the translational complexes. The accuracy of all footprint profiling approaches critically depends on the fidelity of footprint generation and many methods have emerged to preserve certain or multiple configurations of the translational complexes, often in challenging biological material. In this review, a systematic summary of approaches to stabilize translational complexes on mRNA for footprinting is presented and major findings are discussed. Future directions of translation footprint profiling are outlined, focusing on the fidelity and accuracy of inference of the native in vivo translation complex distribution on mRNA.
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Affiliation(s)
- Nikolay E Shirokikh
- Division of Genome Sciences and Cancer, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
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Barrenechea V, Vargas-Reyes M, Quiliano M, Milón P. A Complementary Mechanism of Bacterial mRNA Translation Inhibition by Tetracyclines. Front Microbiol 2021; 12:682682. [PMID: 34262544 PMCID: PMC8273347 DOI: 10.3389/fmicb.2021.682682] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/10/2021] [Indexed: 11/26/2022] Open
Abstract
Tetracycline has positively impacted human health as well as the farming and animal industries. Its extensive usage and versatility led to the spread of resistance mechanisms followed by the development of new variants of the antibiotic. Tetracyclines inhibit bacterial growth by impeding the binding of elongator tRNAs to the ribosome. However, a small number of reports indicated that Tetracyclines could also inhibit translation initiation, yet the molecular mechanism remained unknown. Here, we use biochemical and computational methods to study how Oxytetracycline (Otc), Demeclocycline (Dem), and Tigecycline (Tig) affect the translation initiation phase of protein synthesis. Our results show that all three Tetracyclines induce Initiation Factor IF3 to adopt a compact conformation on the 30S ribosomal subunit, similar to that induced by Initiation Factor IF1. This compaction was faster for Tig than Dem or Otc. Furthermore, all three tested tetracyclines affected IF1-bound 30S complexes. The dissociation rate constant of IF1 in early 30S complexes was 14-fold slower for Tig than Dem or Otc. Late 30S initiation complexes (30S pre-IC or IC) exhibited greater IF1 stabilization by Tig than for Dem and Otc. Tig and Otc delayed 50S joining to 30S initiation complexes (30S ICs). Remarkably, the presence of Tig considerably slowed the progression to translation elongation and retained IF1 in the resulting 70S initiation complex (70S IC). Molecular modeling of Tetracyclines bound to the 30S pre-IC and 30S IC indicated that the antibiotics binding site topography fluctuates along the initiation pathway. Mainly, 30S complexes show potential contacts between Dem or Tig with IF1, providing a structural rationale for the enhanced affinity of the antibiotics in the presence of the factor. Altogether, our data indicate that Tetracyclines inhibit translation initiation by allosterically perturbing the IF3 layout on the 30S, retaining IF1 during 70S IC formation, and slowing the transition toward translation elongation. Thus, this study describes a new complementary mechanism by which Tetracyclines may inhibit bacterial protein synthesis.
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Affiliation(s)
- Victor Barrenechea
- Faculty of Health Sciences, Centre for Research and Innovation, Universidad Peruana de Ciencias Aplicadas (UPC), Lima, Peru.,Postgraduate Unit, Medicine Faculty, Universidad Nacional Mayor de San Marcos, Lima, Peru
| | - Maryhory Vargas-Reyes
- Faculty of Health Sciences, Centre for Research and Innovation, Universidad Peruana de Ciencias Aplicadas (UPC), Lima, Peru
| | - Miguel Quiliano
- Faculty of Health Sciences, Centre for Research and Innovation, Universidad Peruana de Ciencias Aplicadas (UPC), Lima, Peru
| | - Pohl Milón
- Faculty of Health Sciences, Centre for Research and Innovation, Universidad Peruana de Ciencias Aplicadas (UPC), Lima, Peru
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27
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Abstract
Over the past decade, harnessing the cellular protein synthesis machinery to incorporate non-canonical amino acids (ncAAs) into tailor-made peptides has significantly advanced many aspects of molecular science. More recently, groundbreaking progress in our ability to engineer this machinery for improved ncAA incorporation has led to significant enhancements of this powerful tool for biology and chemistry. By revealing the molecular basis for the poor or improved incorporation of ncAAs, mechanistic studies of ncAA incorporation by the protein synthesis machinery have tremendous potential for informing and directing such engineering efforts. In this chapter, we describe a set of complementary biochemical and single-molecule fluorescence assays that we have adapted for mechanistic studies of ncAA incorporation. Collectively, these assays provide data that can guide engineering of the protein synthesis machinery to expand the range of ncAAs that can be incorporated into peptides and increase the efficiency with which they can be incorporated, thereby enabling the full potential of ncAA mutagenesis technology to be realized.
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28
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Bhaskar V, Graff-Meyer A, Schenk AD, Cavadini S, von Loeffelholz O, Natchiar SK, Artus-Revel CG, Hotz HR, Bretones G, Klaholz BP, Chao JA. Dynamics of uS19 C-Terminal Tail during the Translation Elongation Cycle in Human Ribosomes. Cell Rep 2021; 31:107473. [PMID: 32268098 DOI: 10.1016/j.celrep.2020.03.037] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 12/06/2019] [Accepted: 03/12/2020] [Indexed: 01/08/2023] Open
Abstract
Ribosomes undergo multiple conformational transitions during translation elongation. Here, we report the high-resolution cryoelectron microscopy (cryo-EM) structure of the human 80S ribosome in the post-decoding pre-translocation state (classical-PRE) at 3.3-Å resolution along with the rotated (hybrid-PRE) and the post-translocation states (POST). The classical-PRE state ribosome structure reveals a previously unobserved interaction between the C-terminal region of the conserved ribosomal protein uS19 and the A- and P-site tRNAs and the mRNA in the decoding site. In addition to changes in the inter-subunit bridges, analysis of different ribosomal conformations reveals the dynamic nature of this domain and suggests a role in tRNA accommodation and translocation during elongation. Furthermore, we show that disease-associated mutations in uS19 result in increased frameshifting. Together, this structure-function analysis provides mechanistic insights into the role of the uS19 C-terminal tail in the context of mammalian ribosomes.
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Affiliation(s)
- Varun Bhaskar
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | | | - Andreas D Schenk
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Simone Cavadini
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Ottilie von Loeffelholz
- Centre for Integrative Biology (CBI), Department of Integrated Structural Biology, IGBMC, CNRS, INSERM, Université de Strasbourg, 1 rue Laurent Fries, 67404 Illkirch, France; Institute of Genetics and of Molecular and Cellular Biology (IGBMC), 1 rue Laurent Fries, Illkirch, France; Centre National de la Recherche Scientifique (CNRS), UMR 7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale (INSERM), U964, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - S Kundhavai Natchiar
- Centre for Integrative Biology (CBI), Department of Integrated Structural Biology, IGBMC, CNRS, INSERM, Université de Strasbourg, 1 rue Laurent Fries, 67404 Illkirch, France; Institute of Genetics and of Molecular and Cellular Biology (IGBMC), 1 rue Laurent Fries, Illkirch, France; Centre National de la Recherche Scientifique (CNRS), UMR 7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale (INSERM), U964, Illkirch, France; Université de Strasbourg, Illkirch, France
| | | | - Hans-Rudolf Hotz
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Gabriel Bretones
- Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Universidad de Oviedo, 33006 Oviedo, Spain
| | - Bruno P Klaholz
- Centre for Integrative Biology (CBI), Department of Integrated Structural Biology, IGBMC, CNRS, INSERM, Université de Strasbourg, 1 rue Laurent Fries, 67404 Illkirch, France; Institute of Genetics and of Molecular and Cellular Biology (IGBMC), 1 rue Laurent Fries, Illkirch, France; Centre National de la Recherche Scientifique (CNRS), UMR 7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale (INSERM), U964, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Jeffrey A Chao
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland.
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29
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Song Y, Hyeon C. Thermodynamic uncertainty relation to assess biological processes. J Chem Phys 2021; 154:130901. [PMID: 33832251 DOI: 10.1063/5.0043671] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
We review the trade-offs between speed, fluctuations, and thermodynamic cost involved with biological processes in nonequilibrium states and discuss how optimal these processes are in light of the universal bound set by the thermodynamic uncertainty relation (TUR). The values of the uncertainty product Q of TUR, which can be used as a measure of the precision of enzymatic processes realized for a given thermodynamic cost, are suboptimal when the substrate concentration is at the Michaelis constant, and some of the key biological processes are found to work around this condition. We illustrate the utility of Q in assessing how close the molecular motors and biomass producing machineries are to the TUR bound, and for the cases of biomass production (or biological copying processes), we discuss how their optimality quantified in terms of Q is balanced with the error rate in the information transfer process. We also touch upon the trade-offs in other error-minimizing processes in biology, such as gene regulation and chaperone-assisted protein folding. A spectrum of Q recapitulating the biological processes surveyed here provides glimpses into how biological systems are evolved to optimize and balance the conflicting functional requirements.
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Affiliation(s)
- Yonghyun Song
- Korea Institute for Advanced Study, Seoul 02455, South Korea
| | - Changbong Hyeon
- Korea Institute for Advanced Study, Seoul 02455, South Korea
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30
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Ciftci D, Huysmans GHM, Wang X, He C, Terry D, Zhou Z, Fitzgerald G, Blanchard SC, Boudker O. FRET-based Microscopy Assay to Measure Activity of Membrane Amino Acid Transporters with Single-transporter Resolution. Bio Protoc 2021; 11:e3970. [PMID: 33889664 DOI: 10.21769/bioprotoc.3970] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/21/2021] [Accepted: 02/01/2021] [Indexed: 01/05/2023] Open
Abstract
Secondary active transporters reside in cell membranes transporting polar solutes like amino acids against steep concentration gradients, using electrochemical gradients of ions as energy sources. Commonly, ensemble-based measurements of radiolabeled substrate uptakes or transport currents inform on kinetic parameters of transporters. Here we describe a fluorescence-based functional assay for glutamate and aspartate transporters that provides single-transporter, single-transport cycle resolution using an archaeal elevator-type sodium and aspartate symporter GltPh as a model system. We prepare proteo-liposomes containing reconstituted purified GltPh transporters and an encapsulated periplasmic glutamate/aspartate-binding protein, PEB1a, labeled with donor and acceptor fluorophores. We then surface-immobilize the proteo-liposomes and measure transport-dependent Fluorescence Resonance Energy Transfer (FRET) efficiency changes over time using single-molecule Total Internal Reflection Fluorescence (TIRF) microscopy. The assay provides a 10-100 fold increase in temporal resolution compared to radioligand uptake assays. It also allows kinetic characterization of different transport cycle steps and discerns kinetic heterogeneities within the transporter population.
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Affiliation(s)
- Didar Ciftci
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, USA.,Tri-Institutional Training Program in Chemical Biology, New York, USA
| | - Gerard H M Huysmans
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, USA
| | - Xiaoyu Wang
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, USA
| | - Changhao He
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, USA
| | - Daniel Terry
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, USA
| | - Zhou Zhou
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, USA
| | - Gabriel Fitzgerald
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, USA
| | - Scott C Blanchard
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, USA.,Tri-Institutional Training Program in Chemical Biology, New York, USA
| | - Olga Boudker
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, USA.,Tri-Institutional Training Program in Chemical Biology, New York, USA.,Howard Hughes Medical Institute, New York, USA
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31
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Lerner E, Barth A, Hendrix J, Ambrose B, Birkedal V, Blanchard SC, Börner R, Sung Chung H, Cordes T, Craggs TD, Deniz AA, Diao J, Fei J, Gonzalez RL, Gopich IV, Ha T, Hanke CA, Haran G, Hatzakis NS, Hohng S, Hong SC, Hugel T, Ingargiola A, Joo C, Kapanidis AN, Kim HD, Laurence T, Lee NK, Lee TH, Lemke EA, Margeat E, Michaelis J, Michalet X, Myong S, Nettels D, Peulen TO, Ploetz E, Razvag Y, Robb NC, Schuler B, Soleimaninejad H, Tang C, Vafabakhsh R, Lamb DC, Seidel CAM, Weiss S. FRET-based dynamic structural biology: Challenges, perspectives and an appeal for open-science practices. eLife 2021; 10:e60416. [PMID: 33779550 PMCID: PMC8007216 DOI: 10.7554/elife.60416] [Citation(s) in RCA: 125] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 02/09/2021] [Indexed: 12/18/2022] Open
Abstract
Single-molecule FRET (smFRET) has become a mainstream technique for studying biomolecular structural dynamics. The rapid and wide adoption of smFRET experiments by an ever-increasing number of groups has generated significant progress in sample preparation, measurement procedures, data analysis, algorithms and documentation. Several labs that employ smFRET approaches have joined forces to inform the smFRET community about streamlining how to perform experiments and analyze results for obtaining quantitative information on biomolecular structure and dynamics. The recent efforts include blind tests to assess the accuracy and the precision of smFRET experiments among different labs using various procedures. These multi-lab studies have led to the development of smFRET procedures and documentation, which are important when submitting entries into the archiving system for integrative structure models, PDB-Dev. This position paper describes the current 'state of the art' from different perspectives, points to unresolved methodological issues for quantitative structural studies, provides a set of 'soft recommendations' about which an emerging consensus exists, and lists openly available resources for newcomers and seasoned practitioners. To make further progress, we strongly encourage 'open science' practices.
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Affiliation(s)
- Eitan Lerner
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, and The Center for Nanoscience and Nanotechnology, Faculty of Mathematics & Science, The Edmond J. Safra Campus, The Hebrew University of JerusalemJerusalemIsrael
| | - Anders Barth
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-UniversitätDüsseldorfGermany
| | - Jelle Hendrix
- Dynamic Bioimaging Lab, Advanced Optical Microscopy Centre and Biomedical Research Institute (BIOMED), Hasselt UniversityDiepenbeekBelgium
| | - Benjamin Ambrose
- Department of Chemistry, University of SheffieldSheffieldUnited Kingdom
| | - Victoria Birkedal
- Department of Chemistry and iNANO center, Aarhus UniversityAarhusDenmark
| | - Scott C Blanchard
- Department of Structural Biology, St. Jude Children's Research HospitalMemphisUnited States
| | - Richard Börner
- Laserinstitut HS Mittweida, University of Applied Science MittweidaMittweidaGermany
| | - Hoi Sung Chung
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesdaUnited States
| | - Thorben Cordes
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität MünchenPlanegg-MartinsriedGermany
| | - Timothy D Craggs
- Department of Chemistry, University of SheffieldSheffieldUnited Kingdom
| | - Ashok A Deniz
- Department of Integrative Structural and Computational Biology, The Scripps Research InstituteLa JollaUnited States
| | - Jiajie Diao
- Department of Cancer Biology, University of Cincinnati School of MedicineCincinnatiUnited States
| | - Jingyi Fei
- Department of Biochemistry and Molecular Biology and The Institute for Biophysical Dynamics, University of ChicagoChicagoUnited States
| | - Ruben L Gonzalez
- Department of Chemistry, Columbia UniversityNew YorkUnited States
| | - Irina V Gopich
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesdaUnited States
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Howard Hughes Medical InstituteBaltimoreUnited States
| | - Christian A Hanke
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-UniversitätDüsseldorfGermany
| | - Gilad Haran
- Department of Chemical and Biological Physics, Weizmann Institute of ScienceRehovotIsrael
| | - Nikos S Hatzakis
- Department of Chemistry & Nanoscience Centre, University of CopenhagenCopenhagenDenmark
- Denmark Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of CopenhagenCopenhagenDenmark
| | - Sungchul Hohng
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National UniversitySeoulRepublic of Korea
| | - Seok-Cheol Hong
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science and Department of Physics, Korea UniversitySeoulRepublic of Korea
| | - Thorsten Hugel
- Institute of Physical Chemistry and Signalling Research Centres BIOSS and CIBSS, University of FreiburgFreiburgGermany
| | - Antonino Ingargiola
- Department of Chemistry and Biochemistry, and Department of Physiology, University of California, Los AngelesLos AngelesUnited States
| | - Chirlmin Joo
- Department of BioNanoScience, Kavli Institute of Nanoscience, Delft University of TechnologyDelftNetherlands
| | - Achillefs N Kapanidis
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of OxfordOxfordUnited Kingdom
| | - Harold D Kim
- School of Physics, Georgia Institute of TechnologyAtlantaUnited States
| | - Ted Laurence
- Physical and Life Sciences Directorate, Lawrence Livermore National LaboratoryLivermoreUnited States
| | - Nam Ki Lee
- School of Chemistry, Seoul National UniversitySeoulRepublic of Korea
| | - Tae-Hee Lee
- Department of Chemistry, Pennsylvania State UniversityUniversity ParkUnited States
| | - Edward A Lemke
- Departments of Biology and Chemistry, Johannes Gutenberg UniversityMainzGermany
- Institute of Molecular Biology (IMB)MainzGermany
| | - Emmanuel Margeat
- Centre de Biologie Structurale (CBS), CNRS, INSERM, Universitié de MontpellierMontpellierFrance
| | | | - Xavier Michalet
- Department of Chemistry and Biochemistry, and Department of Physiology, University of California, Los AngelesLos AngelesUnited States
| | - Sua Myong
- Department of Biophysics, Johns Hopkins UniversityBaltimoreUnited States
| | - Daniel Nettels
- Department of Biochemistry and Department of Physics, University of ZurichZurichSwitzerland
| | - Thomas-Otavio Peulen
- Department of Bioengineering and Therapeutic Sciences, University of California, San FranciscoSan FranciscoUnited States
| | - Evelyn Ploetz
- Physical Chemistry, Department of Chemistry, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-UniversitätMünchenGermany
| | - Yair Razvag
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, and The Center for Nanoscience and Nanotechnology, Faculty of Mathematics & Science, The Edmond J. Safra Campus, The Hebrew University of JerusalemJerusalemIsrael
| | - Nicole C Robb
- Warwick Medical School, University of WarwickCoventryUnited Kingdom
| | - Benjamin Schuler
- Department of Biochemistry and Department of Physics, University of ZurichZurichSwitzerland
| | - Hamid Soleimaninejad
- Biological Optical Microscopy Platform (BOMP), University of MelbourneParkvilleAustralia
| | - Chun Tang
- College of Chemistry and Molecular Engineering, PKU-Tsinghua Center for Life Sciences, Beijing National Laboratory for Molecular Sciences, Peking UniversityBeijingChina
| | - Reza Vafabakhsh
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
| | - Don C Lamb
- Physical Chemistry, Department of Chemistry, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-UniversitätMünchenGermany
| | - Claus AM Seidel
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-UniversitätDüsseldorfGermany
| | - Shimon Weiss
- Department of Chemistry and Biochemistry, and Department of Physiology, University of California, Los AngelesLos AngelesUnited States
- Department of Physiology, CaliforniaNanoSystems Institute, University of California, Los AngelesLos AngelesUnited States
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32
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Ieong KW, Indrisiunaite G, Prabhakar A, Puglisi JD, Ehrenberg M. N 6-Methyladenosines in mRNAs reduce the accuracy of codon reading by transfer RNAs and peptide release factors. Nucleic Acids Res 2021; 49:2684-2699. [PMID: 33561188 PMCID: PMC7969026 DOI: 10.1093/nar/gkab033] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/09/2021] [Accepted: 02/03/2021] [Indexed: 11/15/2022] Open
Abstract
We used quench flow to study how N6-methylated adenosines (m6A) affect the accuracy ratio between kcat/Km (i.e. association rate constant (ka) times probability (Pp) of product formation after enzyme-substrate complex formation) for cognate and near-cognate substrate for mRNA reading by tRNAs and peptide release factors 1 and 2 (RFs) during translation with purified Escherichia coli components. We estimated kcat/Km for Glu-tRNAGlu, EF-Tu and GTP forming ternary complex (T3) reading cognate (GAA and Gm6AA) or near-cognate (GAU and Gm6AU) codons. ka decreased 10-fold by m6A introduction in cognate and near-cognate cases alike, while Pp for peptidyl transfer remained unaltered in cognate but increased 10-fold in near-cognate case leading to 10-fold amino acid substitution error increase. We estimated kcat/Km for ester bond hydrolysis of P-site bound peptidyl-tRNA by RF2 reading cognate (UAA and Um6AA) and near-cognate (UAG and Um6AG) stop codons to decrease 6-fold or 3-fold by m6A introduction, respectively. This 6-fold effect on UAA reading was also observed in a single-molecule termination assay. Thus, m6A reduces both sense and stop codon reading accuracy by decreasing cognate significantly more than near-cognate kcat/Km, in contrast to most error inducing agents and mutations, which increase near-cognate at unaltered cognate kcat/Km.
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Affiliation(s)
- Ka-Weng Ieong
- Department of Cell and Molecular Biology, Biomedical Center, Box 596, Uppsala University, Uppsala, Sweden
| | - Gabriele Indrisiunaite
- Department of Cell and Molecular Biology, Biomedical Center, Box 596, Uppsala University, Uppsala, Sweden
| | - Arjun Prabhakar
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA.,Program in Biophysics, Stanford University, Stanford, CA 94305, USA
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA
| | - Måns Ehrenberg
- Department of Cell and Molecular Biology, Biomedical Center, Box 596, Uppsala University, Uppsala, Sweden
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33
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Site-Specific Fluorescent Labeling of RNA Interior Positions. Molecules 2021; 26:molecules26051341. [PMID: 33802273 PMCID: PMC7959133 DOI: 10.3390/molecules26051341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/26/2021] [Accepted: 03/01/2021] [Indexed: 02/08/2023] Open
Abstract
The introduction of fluorophores into RNA for both in vitro and in cellulo studies of RNA function and cellular distribution is a subject of great current interest. Here I briefly review methods, some well-established and others newly developed, which have been successfully exploited to site-specifically fluorescently label interior positions of RNAs, as a guide to investigators seeking to apply this approach to their studies. Most of these methods can be applied directly to intact RNAs, including (1) the exploitation of natural posttranslational modifications, (2) the repurposing of enzymatic transferase reactions, and (3) the nucleic acid-assisted labeling of intact RNAs. In addition, several methods are described in which specifically labeled RNAs are prepared de novo.
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34
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Abstract
Peptide-chain elongation during protein synthesis entails sequential aminoacyl-tRNA selection and translocation reactions that proceed rapidly (2-20 per second) and with a low error rate (around 10-3 to 10-5 at each step) over thousands of cycles1. The cadence and fidelity of ribosome transit through mRNA templates in discrete codon increments is a paradigm for movement in biological systems that must hold for diverse mRNA and tRNA substrates across domains of life. Here we use single-molecule fluorescence methods to guide the capture of structures of early translocation events on the bacterial ribosome. Our findings reveal that the bacterial GTPase elongation factor G specifically engages spontaneously achieved ribosome conformations while in an active, GTP-bound conformation to unlock and initiate peptidyl-tRNA translocation. These findings suggest that processes intrinsic to the pre-translocation ribosome complex can regulate the rate of protein synthesis, and that energy expenditure is used later in the translocation mechanism than previously proposed.
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35
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Molecular Insights into Determinants of Translational Readthrough and Implications for Nonsense Suppression Approaches. Int J Mol Sci 2020; 21:ijms21249449. [PMID: 33322589 PMCID: PMC7764779 DOI: 10.3390/ijms21249449] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 11/27/2020] [Accepted: 12/05/2020] [Indexed: 02/07/2023] Open
Abstract
The fidelity of protein synthesis, a process shaped by several mechanisms involving specialized ribosome regions and external factors, ensures the precise reading of sense and stop codons. However, premature termination codons (PTCs) arising from mutations may, at low frequency, be misrecognized and result in PTC suppression, named ribosome readthrough, with production of full-length proteins through the insertion of a subset of amino acids. Since some drugs have been identified as readthrough inducers, this fidelity drawback has been explored as a therapeutic approach in several models of human diseases caused by nonsense mutations. Here, we focus on the mechanisms driving translation in normal and aberrant conditions, the potential fates of mRNA in the presence of a PTC, as well as on the results obtained in the research of efficient readthrough-inducing compounds. In particular, we describe the molecular determinants shaping the outcome of readthrough, namely the nucleotide and protein context, with the latter being pivotal to produce functional full-length proteins. Through the interpretation of experimental and mechanistic findings, mainly obtained in lysosomal and coagulation disorders, we also propose a scenario of potential readthrough-favorable features to achieve relevant rescue profiles, representing the main issue for the potential translatability of readthrough as a therapeutic strategy.
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36
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Girodat D, Pati AK, Terry DS, Blanchard SC, Sanbonmatsu KY. Quantitative comparison between sub-millisecond time resolution single-molecule FRET measurements and 10-second molecular simulations of a biosensor protein. PLoS Comput Biol 2020; 16:e1008293. [PMID: 33151943 PMCID: PMC7643941 DOI: 10.1371/journal.pcbi.1008293] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/27/2020] [Indexed: 12/15/2022] Open
Abstract
Molecular Dynamics (MD) simulations seek to provide atomic-level insights into conformationally dynamic biological systems at experimentally relevant time resolutions, such as those afforded by single-molecule fluorescence measurements. However, limitations in the time scales of MD simulations and the time resolution of single-molecule measurements have challenged efforts to obtain overlapping temporal regimes required for close quantitative comparisons. Achieving such overlap has the potential to provide novel theories, hypotheses, and interpretations that can inform idealized experimental designs that maximize the detection of the desired reaction coordinate. Here, we report MD simulations at time scales overlapping with in vitro single-molecule Förster (fluorescence) resonance energy transfer (smFRET) measurements of the amino acid binding protein LIV-BPSS at sub-millisecond resolution. Computationally efficient all-atom structure-based simulations, calibrated against explicit solvent simulations, were employed for sampling multiple cycles of LIV-BPSS clamshell-like conformational changes on the time scale of seconds, examining the relationship between these events and those observed by smFRET. The MD simulations agree with the smFRET measurements and provide valuable information on local dynamics of fluorophores at their sites of attachment on LIV-BPSS and the correlations between fluorophore motions and large-scale conformational changes between LIV-BPSS domains. We further utilize the MD simulations to inform the interpretation of smFRET data, including Förster radius (R0) and fluorophore orientation factor (κ2) determinations. The approach we describe can be readily extended to distinct biochemical systems, allowing for the interpretation of any FRET system conjugated to protein or ribonucleoprotein complexes, including those with more conformational processes, as well as those implementing multi-color smFRET. Förster (fluorescence) resonance energy transfer (FRET) has been used extensively by biophysicists as a molecular-scale ruler that yields fundamental structural and kinetic insights into transient processes including complex formation and conformational rearrangements required for biological function. FRET techniques require the identification of informative fluorophore labeling sites, spaced at defined distances to inform on a reaction coordinate of interest and consideration of noise sources that have the potential to obscure quantitative interpretations. Here, we describe an approach to leverage advancements in computationally efficient all-atom structure-based molecular dynamics simulations in which structural dynamics observed via FRET can be interpreted in full atomistic detail on commensurate time scales. We demonstrate the potential of this approach using a model FRET system, the amino acid binding protein LIV-BPSS conjugated to self-healing organic fluorophores. LIV-BPSS exhibits large scale, sub-millisecond clamshell-like conformational changes between open and closed conformations associated with ligand unbinding and binding, respectively. Our findings inform on the molecular basis of the dynamics observed by smFRET and on strategies to optimize fluorophore labeling sites, the manner of fluorophore attachment, and fluorophore composition.
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Affiliation(s)
- Dylan Girodat
- Theoretical Biology and Biophysics, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Avik K Pati
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Daniel S Terry
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Scott C Blanchard
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Karissa Y Sanbonmatsu
- Theoretical Biology and Biophysics, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America.,New Mexico Consortium, Los Alamos, New Mexico, United States of America
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37
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Sarecycline interferes with tRNA accommodation and tethers mRNA to the 70S ribosome. Proc Natl Acad Sci U S A 2020; 117:20530-20537. [PMID: 32817463 PMCID: PMC7456112 DOI: 10.1073/pnas.2008671117] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Sarecycline is the first narrow-spectrum tetracycline-class antibiotic that was recently approved by the FDA for the clinical treatment of acne vulgaris. In this work, we determined two (2.8-Å and 3.0-Å) X-ray crystal structures of sarecycline bound to the initiation complex of the bacterial 70S ribosome and found that this antibiotic inhibits bacterial ribosome in part using a mechanism of direct mRNA contact, which has not been reported for any other tetracyclines so far. Moreover, our structural analysis rationalizes why sarecycline is able to overcome one of the most common mechanisms of resistance to tetracyclines among pathogenic bacteria. Thus, this work provides mechanistic insights into the function of the tetracycline class of antibiotics on the ribosome with direct clinical relevance. Sarecycline is a new narrow-spectrum tetracycline-class antibiotic approved for the treatment of acne vulgaris. Tetracyclines share a common four-ring naphthacene core and inhibit protein synthesis by interacting with the 70S bacterial ribosome. Sarecycline is distinguished chemically from other tetracyclines because it has a 7-[[methoxy(methyl)amino]methyl] group attached at the C7 position of ring D. To investigate the functional role of this C7 moiety, we determined the X-ray crystal structure of sarecycline bound to the Thermus thermophilus 70S ribosome. Our 2.8-Å resolution structure revealed that sarecycline binds at the canonical tetracycline binding site located in the decoding center of the small ribosomal subunit. Importantly, unlike other tetracyclines, the unique C7 extension of sarecycline extends into the messenger RNA (mRNA) channel to form a direct interaction with the A-site codon to possibly interfere with mRNA movement through the channel and/or disrupt A-site codon–anticodon interaction. Based on our biochemical studies, sarecycline appears to be a more potent initiation inhibitor compared to other tetracyclines, possibly due to drug interactions with the mRNA, thereby blocking accommodation of the first aminoacyl transfer RNA (tRNA) into the A site. Overall, our structural and biochemical findings rationalize the role of the unique C7 moiety of sarecycline in antibiotic action.
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38
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Park SR, Hauver J, Zhang Y, Revyakin A, Coleman RA, Tjian R, Chu S, Pertsinidis A. A Single-Molecule Surface-Based Platform to Detect the Assembly and Function of the Human RNA Polymerase II Transcription Machinery. Structure 2020; 28:1337-1343.e4. [PMID: 32763141 DOI: 10.1016/j.str.2020.07.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/08/2020] [Accepted: 07/21/2020] [Indexed: 01/28/2023]
Abstract
Single-molecule detection and manipulation is a powerful tool for unraveling dynamic biological processes. Unfortunately, success in such experiments is often challenged by tethering the biomolecule(s) of interest to a biocompatible surface. Here, we describe a robust surface passivation method by dense polymer brush grafting, based on optimized polyethylene glycol (PEG) deposition conditions, exactly at the lower critical point of an aqueous biphasic PEG-salt system. The increased biocompatibility achieved, compared with PEG deposition in sub-optimal conditions away from the critical point, allowed us to successfully detect the assembly and function of a large macromolecular machine, a fluorescent-labeled multi-subunit, human RNA Polymerase II Transcription Pre-Initiation Complex, on single, promoter-containing, surface-immobilized DNA molecules. This platform will enable probing the complex biochemistry and dynamics of large, multi-subunit macromolecular assemblies, such as during the initiation of human RNA Pol II transcription, at the single-molecule level.
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Affiliation(s)
- Sang Ryul Park
- California Institute for Quantitative Biosciences (QB3), University of California at Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Jesse Hauver
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Tri-Institutional Training Program in Chemical Biology, New York, NY 10065, USA
| | - Yunxiang Zhang
- Departments of Physics and Molecular and Cellular Physiology, Stanford University, Stanford CA 94305, USA
| | - Andrey Revyakin
- California Institute for Quantitative Biosciences (QB3), University of California at Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Robert A Coleman
- Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Robert Tjian
- Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Steven Chu
- Departments of Physics and Molecular and Cellular Physiology, Stanford University, Stanford CA 94305, USA.
| | - Alexandros Pertsinidis
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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39
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Abstract
The aminoacyl-tRNA synthetases are an essential and universally distributed family of enzymes that plays a critical role in protein synthesis, pairing tRNAs with their cognate amino acids for decoding mRNAs according to the genetic code. Synthetases help to ensure accurate translation of the genetic code by using both highly accurate cognate substrate recognition and stringent proofreading of noncognate products. While alterations in the quality control mechanisms of synthetases are generally detrimental to cellular viability, recent studies suggest that in some instances such changes facilitate adaption to stress conditions. Beyond their central role in translation, synthetases are also emerging as key players in an increasing number of other cellular processes, with far-reaching consequences in health and disease. The biochemical versatility of the synthetases has also proven pivotal in efforts to expand the genetic code, further emphasizing the wide-ranging roles of the aminoacyl-tRNA synthetase family in synthetic and natural biology.
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Affiliation(s)
- Miguel Angel Rubio Gomez
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA Department of Microbiology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Michael Ibba
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA Department of Microbiology, The Ohio State University, Columbus, Ohio 43210, USA
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40
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Multiplexed genomic encoding of non-canonical amino acids for labeling large complexes. Nat Chem Biol 2020; 16:1129-1135. [PMID: 32690942 PMCID: PMC7982790 DOI: 10.1038/s41589-020-0599-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 06/23/2020] [Indexed: 12/21/2022]
Abstract
Stunning advances in the structural biology of multicomponent biomolecular complexes (MBCs) have ushered in an era of intense, structure-guided mechanistic and functional studies of these complexes. Nonetheless, existing methods to site-specifically conjugate MBCs with biochemical and biophysical labels are notoriously impracticable and/or significantly perturb MBC assembly and function. To overcome these limitations, we have developed a general, multiplexed method in which we genomically encode non-canonical amino acids (ncAAs) into multiple, structure-informed, individual sites within a target MBC; select for ncAA-containing MBC variants that assemble and function like the wildtype MBC; and site-specifically conjugate biochemical or biophysical labels to these ncAAs. As a proof-of-principle, we have used this method to generate unique single-molecule fluorescence resonance energy transfer (smFRET) signals reporting on ribosome structural dynamics that have thus far remained inaccessible to smFRET studies of translation.
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41
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Grabe M, Zuckerman DM, Rosenberg JM. EmrE reminds us to expect the unexpected in membrane transport. J Gen Physiol 2020; 152:132728. [PMID: 31816640 PMCID: PMC7034101 DOI: 10.1085/jgp.201912467] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Grabe et al. celebrate a new mathematical model of the multidrug transporter EmrE, constructed from NMR and stop flow kinetic data.
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Affiliation(s)
- Michael Grabe
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA
| | - Daniel M Zuckerman
- Oregon Health & Science University Center for Spatial Systems, Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR
| | - John M Rosenberg
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA
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42
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Bao C, Loerch S, Ling C, Korostelev AA, Grigorieff N, Ermolenko DN. mRNA stem-loops can pause the ribosome by hindering A-site tRNA binding. eLife 2020; 9:e55799. [PMID: 32427100 PMCID: PMC7282821 DOI: 10.7554/elife.55799] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 05/18/2020] [Indexed: 12/27/2022] Open
Abstract
Although the elongating ribosome is an efficient helicase, certain mRNA stem-loop structures are known to impede ribosome movement along mRNA and stimulate programmed ribosome frameshifting via mechanisms that are not well understood. Using biochemical and single-molecule Förster resonance energy transfer (smFRET) experiments, we studied how frameshift-inducing stem-loops from E. coli dnaX mRNA and the gag-pol transcript of Human Immunodeficiency Virus (HIV) perturb translation elongation. We find that upon encountering the ribosome, the stem-loops strongly inhibit A-site tRNA binding and ribosome intersubunit rotation that accompanies translation elongation. Electron cryo-microscopy (cryo-EM) reveals that the HIV stem-loop docks into the A site of the ribosome. Our results suggest that mRNA stem-loops can transiently escape the ribosome helicase by binding to the A site. Thus, the stem-loops can modulate gene expression by sterically hindering tRNA binding and inhibiting translation elongation.
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Affiliation(s)
- Chen Bao
- Department of Biochemistry and Biophysics at School of Medicine and Dentistry and Center for RNA Biology, University of RochesterRochesterUnited States
| | - Sarah Loerch
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Clarence Ling
- Department of Biochemistry and Biophysics at School of Medicine and Dentistry and Center for RNA Biology, University of RochesterRochesterUnited States
| | - Andrei A Korostelev
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical SchoolWorcesterUnited States
- RNA Therapeutics Institute, University of Massachusetts Medical SchoolWorcesterUnited States
| | - Nikolaus Grigorieff
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
- RNA Therapeutics Institute, University of Massachusetts Medical SchoolWorcesterUnited States
| | - Dmitri N Ermolenko
- Department of Biochemistry and Biophysics at School of Medicine and Dentistry and Center for RNA Biology, University of RochesterRochesterUnited States
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43
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Barulin A, Wenger J. Ultraviolet Photostability Improvement for Autofluorescence Correlation Spectroscopy on Label-Free Proteins. J Phys Chem Lett 2020; 11:2027-2035. [PMID: 32083877 DOI: 10.1021/acs.jpclett.0c00209] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The poor photostability and low brightness of protein autofluorescence have been major limitations preventing the detection of label-free proteins at the single-molecule level. Overcoming these issues, we report here a strategy to promote the photostability of proteins and use their natural tryptophan autofluorescence in the ultraviolet (UV) for fluorescence correlation spectroscopy (FCS). Combining enzymatic oxygen scavengers with antioxidants and triplet-state quenchers greatly promotes the protein photostability, reduces the photobleaching probability, and improves the net autofluorescence detection rate. Our results show that the underlying photochemical concepts initially derived for organic visible fluorescent dyes are quite general. Using this approach, we achieved UV fluorescence correlation spectroscopy on label-free streptavidin proteins containing only 24 tryptophan residues, 6.5× fewer than the current state-of-the-art. This strategy greatly extends the possibility of detecting single label-free proteins with the versatility of single-molecule fluorescence without requiring the presence of a potentially disturbing external fluorescent marker. It also opens new perspectives to improve the UV durability of organic devices.
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Affiliation(s)
- Aleksandr Barulin
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, 13013 Marseille, France
| | - Jérôme Wenger
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, 13013 Marseille, France
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44
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Elongation factor-Tu can repetitively engage aminoacyl-tRNA within the ribosome during the proofreading stage of tRNA selection. Proc Natl Acad Sci U S A 2020; 117:3610-3620. [PMID: 32024753 PMCID: PMC7035488 DOI: 10.1073/pnas.1904469117] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Elongation factor Tu (EF-Tu) facilitates rapid and accurate selection of aminoacyl-tRNA (aa-tRNA) by the bacterial ribosome during protein synthesis. We show that EF-Tu dissociates from the ribosome as aa-tRNA navigates the accommodation corridor en route to peptide bond formation. We find that EF-Tu’s release from the ribosome during aa-tRNA selection can be reversible. We also demonstrate that new ternary complex formation, accompanied by futile cycles of GTP hydrolysis, can occur on aa-tRNA bound within the ribosome. These findings inform on the decoding mechanism, the contributions of EF-Tu to the fidelity of translation, and the potential consequences of reduced rates of peptide bond formation on cellular physiology. The substrate for ribosomes actively engaged in protein synthesis is a ternary complex of elongation factor Tu (EF-Tu), aminoacyl-tRNA (aa-tRNA), and GTP. EF-Tu plays a critical role in mRNA decoding by increasing the rate and fidelity of aa-tRNA selection at each mRNA codon. Here, using three-color single-molecule fluorescence resonance energy transfer imaging and molecular dynamics simulations, we examine the timing and role of conformational events that mediate the release of aa-tRNA from EF-Tu and EF-Tu from the ribosome after GTP hydrolysis. Our investigations reveal that conformational changes in EF-Tu coordinate the rate-limiting passage of aa-tRNA through the accommodation corridor en route to the peptidyl transferase center of the large ribosomal subunit. Experiments using distinct inhibitors of the accommodation process further show that aa-tRNA must at least partially transit the accommodation corridor for EF-Tu⋅GDP to release. aa-tRNAs failing to undergo peptide bond formation at the end of accommodation corridor passage after EF-Tu release can be reengaged by EF-Tu⋅GTP from solution, coupled to GTP hydrolysis. These observations suggest that additional rounds of ternary complex formation can occur on the ribosome during proofreading, particularly when peptide bond formation is slow, which may serve to increase both the rate and fidelity of protein synthesis at the expense of GTP hydrolysis.
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45
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Kurylo CM, Parks MM, Juette MF, Zinshteyn B, Altman RB, Thibado JK, Vincent CT, Blanchard SC. Endogenous rRNA Sequence Variation Can Regulate Stress Response Gene Expression and Phenotype. Cell Rep 2020; 25:236-248.e6. [PMID: 30282032 PMCID: PMC6312700 DOI: 10.1016/j.celrep.2018.08.093] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 08/16/2018] [Accepted: 08/30/2018] [Indexed: 11/30/2022] Open
Abstract
Prevailing dogma holds that ribosomes are uniform in composition and function. Here, we show that nutrient limitation-induced stress in E. coli changes the relative expression of rDNA operons to alter the rRNA composition within the actively translating ribosome pool. The most upregulated operon encodes the unique 16S rRNA, rrsH, distinguished by conserved sequence variation within the small ribosomal subunit. rrsH-bearing ribosomes affect the expression of functionally coherent gene sets and alter the levels of the RpoS sigma factor, the master regulator of the general stress response. These impacts are associated with phenotypic changes in antibiotic sensitivity, biofilm formation, and cell motility and are regulated by stress response proteins, RelA and RelE, as well as the metabolic enzyme and virulence-associated protein, AdhE. These findings establish that endogenously encoded, naturally occurring rRNA sequence variation can modulate ribosome function, central aspects of gene expression regulation, and cellular physiology. Most organisms encode multiple, distinct copies of rRNA genes, rendering the composition of the ribosome pool intrinsically heterogeneous. Here, Kurylo et al. show that nutrient limitation in E. coli upregulates the expression of ribosomes bearing conserved sequence variation in 16S rRNA that can regulate gene expression and phenotype.
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Affiliation(s)
- Chad M Kurylo
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Matthew M Parks
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Manuel F Juette
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Boris Zinshteyn
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Roger B Altman
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Jordana K Thibado
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - C Theresa Vincent
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Scott C Blanchard
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA; Tri-Institutional Training Program in Chemical Biology, Weill Cornell Medicine, New York, NY, USA.
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46
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Choi J, O’Loughlin S, Atkins JF, Puglisi JD. The energy landscape of -1 ribosomal frameshifting. SCIENCE ADVANCES 2020; 6:eaax6969. [PMID: 31911945 PMCID: PMC6938710 DOI: 10.1126/sciadv.aax6969] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 11/04/2019] [Indexed: 05/02/2023]
Abstract
Maintenance of translational reading frame ensures the fidelity of information transfer during protein synthesis. Yet, programmed ribosomal frameshifting sequences within the coding region promote a high rate of reading frame change at predetermined sites thus enriching genomic information density. Frameshifting is typically stimulated by the presence of 3' messenger RNA (mRNA) structures, but how these mRNA structures enhance -1 frameshifting remains debatable. Here, we apply single-molecule and ensemble approaches to formulate a mechanistic model of ribosomal -1 frameshifting. Our model suggests that the ribosome is intrinsically susceptible to frameshift before its translocation and this transient state is prolonged by the presence of a precisely positioned downstream mRNA structure. We challenged this model using temperature variation in vivo, which followed the prediction made based on in vitro results. Our results provide a quantitative framework for analyzing other frameshifting enhancers and a potential approach to control gene expression dynamically using programmed frameshifting.
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Affiliation(s)
- Junhong Choi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA
- Department of Applied Physics, Stanford University, Stanford, CA 94305-4090, USA
| | - Sinéad O’Loughlin
- Schools of Biochemistry and Microbiology, University College Cork, Western Gateway Building, Western Road, Cork, Ireland
| | - John F. Atkins
- Schools of Biochemistry and Microbiology, University College Cork, Western Gateway Building, Western Road, Cork, Ireland
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112-5330, USA
| | - Joseph D. Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA
- Corresponding author.
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47
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Abstract
Kinetic proofreading is an error correction mechanism present in the processes of the central dogma and beyond and typically requires the free energy of nucleotide hydrolysis for its operation. Though the molecular players of many biological proofreading schemes are known, our understanding of how energy consumption is managed to promote fidelity remains incomplete. In our work, we introduce an alternative conceptual scheme called "the piston model of proofreading" in which enzyme activation through hydrolysis is replaced with allosteric activation achieved through mechanical work performed by a piston on regulatory ligands. Inspired by Feynman's ratchet and pawl mechanism, we consider a mechanical engine designed to drive the piston actions powered by a lowering weight, whose function is analogous to that of ATP synthase in cells. Thanks to its mechanical design, the piston model allows us to tune the "knobs" of the driving engine and probe the graded changes and trade-offs between speed, fidelity, and energy dissipation. It provides an intuitive explanation of the conditions necessary for optimal proofreading and reveals the unexpected capability of allosteric molecules to beat the Hopfield limit of fidelity by leveraging the diversity of states available to them. The framework that we have built for the piston model can also serve as a basis for additional studies of driven biochemical systems.
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Affiliation(s)
- Vahe Galstyan
- Biochemistry and Molecular Biophysics Option , California Institute of Technology , Pasadena , California 91125 , United States
| | - Rob Phillips
- Department of Physics , California Institute of Technology , Pasadena , California 91125 , United States.,Department of Applied Physics , California Institute of Technology , Pasadena , California 91125 , United States.,Division of Biology and Biological Engineering , California Institute of Technology , Pasadena , California 91125 , United States
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48
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Dynamics of the context-specific translation arrest by chloramphenicol and linezolid. Nat Chem Biol 2019; 16:310-317. [PMID: 31844301 PMCID: PMC7036023 DOI: 10.1038/s41589-019-0423-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 10/30/2019] [Indexed: 12/14/2022]
Abstract
Chloramphenicol (CHL) and linezolid (LZD) are antibiotics that inhibit translation. Both were thought to block peptide bond formation between all combinations of amino acids. Yet recently, a strong nascent peptide context-dependency of CHL- and LZD-induced translation arrest was discovered. Here, we probed the mechanism of action of CHL and LZD by using single-molecule Förster resonance energy transfer spectroscopy (smFRET) to monitor translation arrest induced by antibiotics. The presence of CHL or LZD does not significantly alter dynamics of protein synthesis until the arrest-motif of the nascent peptide is generated. Inhibition of peptide-bond formation compels the fully accommodated A-site tRNA to undergo repeated rounds of dissociation and non-productive rebinding. The glycyl amino-acid moiety on the A-site Gly-tRNA manages to overcome the arrest by CHL. Our results illuminate the mechanism of CHL and LZD action through their interactions with the ribosome, the nascent peptide and the incoming amino acid, perturbing elongation dynamics.
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49
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Yang H, Bandarkar P, Horne R, Leite VBP, Chahine J, Whitford PC. Diffusion of tRNA inside the ribosome is position-dependent. J Chem Phys 2019; 151:085102. [PMID: 31470725 DOI: 10.1063/1.5113814] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In recent years, there has been a growing interest to quantify the energy landscape that governs ribosome dynamics. However, in order to quantitatively integrate theoretical predictions and experimental measurements, it is essential that one has a detailed understanding of the associated diffusive properties. Here, all-atom explicit-solvent simulations (50 μs of aggregate sampling) predict that the diffusion coefficient of a tRNA molecule will depend on its position within the ribosome. Specifically, during aa-tRNA accommodation (i.e., the process by which tRNA enters the ribosome), the apparent diffusion coefficient decreases by approximately an order of magnitude. By comparing these to values obtained with an energetically "smooth" model, we show that the observed nonuniform behavior likely arises from electrostatic and solvation interactions between the tRNA and ribosome. These calculations also reveal the hierarchical character of ribosomal energetics, where steric interactions induce a large-scale free-energy barrier, and short-scale roughness determines the rate of diffusive movement across the landscape.
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Affiliation(s)
- Huan Yang
- Department of Physics, Northeastern University, Dana Research Center 111, 360 Huntington Ave., Boston, Massachusetts 02115, USA
| | - Prasad Bandarkar
- Department of Physics, Northeastern University, Dana Research Center 111, 360 Huntington Ave., Boston, Massachusetts 02115, USA
| | - Ransom Horne
- Department of Physics, Northeastern University, Dana Research Center 111, 360 Huntington Ave., Boston, Massachusetts 02115, USA
| | - Vitor B P Leite
- São Paulo State University (UNESP), IBILCE, São José do Rio Preto, Brazil
| | - Jorge Chahine
- São Paulo State University (UNESP), IBILCE, São José do Rio Preto, Brazil
| | - Paul C Whitford
- Department of Physics, Northeastern University, Dana Research Center 111, 360 Huntington Ave., Boston, Massachusetts 02115, USA
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50
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Sych TS, Polyanichko AM, Ramazanov RR, Kononov AI. tRNA as a stabilizing matrix for fluorescent silver clusters: photophysical properties and IR study. NANOSCALE ADVANCES 2019; 1:3579-3583. [PMID: 36133554 PMCID: PMC9418588 DOI: 10.1039/c9na00112c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 07/22/2019] [Indexed: 06/16/2023]
Abstract
In this experimental study fluorescent silver clusters on a tRNA matrix were synthesized for the first time. Two types of fluorescent complexes emitting in the green (550 nm) and red (635 nm) regions of the visible spectrum were obtained. Using FTIR spectroscopy, we identified possible binding sites for the clusters, which appeared to be within the helical regions of tRNA. It was also shown that tRNA retained its double helical structure after the cluster formation, which is essential for its functionality.
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Affiliation(s)
- Tomash S Sych
- Saint Petersburg State University Saint-Petersburg 199034 Russia
| | | | | | - Alexei I Kononov
- Saint Petersburg State University Saint-Petersburg 199034 Russia
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