1
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Hong HJ, Zhang AL, Conn AB, Blaha G, O'Leary SE. Single-molecule tracking reveals dynamic regulation of ribosomal scanning. SCIENCE ADVANCES 2024; 10:eadm9801. [PMID: 39356761 PMCID: PMC11446271 DOI: 10.1126/sciadv.adm9801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 08/26/2024] [Indexed: 10/04/2024]
Abstract
How eukaryotic ribosomes traverse messenger RNA (mRNA) leader sequences to search for protein-synthesis start sites remains one of the most mysterious aspects of translation and its regulation. While the search process is conventionally described by a linear "scanning" model, its exquisitely dynamic nature has restricted detailed mechanistic study. Here, we observed single Saccharomyces cerevisiae ribosomal scanning complexes in real time, finding that they scan diverse mRNA leaders at a rate of 10 to 20 nt s-1. We show that specific binding of a protein to its mRNA leader sequence substantially arrests scanning. Conversely, impairing scanning-complex guanosine 5'-triphosphate hydrolysis results in native start-site bypass. Our results illustrate an mRNA-centric, kinetically controlled regulatory model where the ribosomal pre-initiation complex amplifies a nuanced energetic landscape to regulate scanning and start-site selection fidelity.
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Affiliation(s)
- Hea Jin Hong
- Department of Biochemistry, University of California Riverside, Riverside, CA 92521, USA
| | - Antonia L Zhang
- Department of Biochemistry, University of California Riverside, Riverside, CA 92521, USA
| | - Adam B Conn
- Department of Biochemistry, University of California Riverside, Riverside, CA 92521, USA
| | - Gregor Blaha
- Department of Biochemistry, University of California Riverside, Riverside, CA 92521, USA
- Center for RNA Biology and Medicine, University of California Riverside, Riverside, CA 92521, USA
| | - Seán E O'Leary
- Department of Biochemistry, University of California Riverside, Riverside, CA 92521, USA
- Center for RNA Biology and Medicine, University of California Riverside, Riverside, CA 92521, USA
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2
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Herkert EK, Lau L, Pons Lanau R, Garcia-Parajo MF. Hexagonal Plasmonic Arrays for High-Throughput Multicolor Single-Molecule Studies. ACS APPLIED MATERIALS & INTERFACES 2024; 16:41271-41280. [PMID: 39041362 PMCID: PMC11310910 DOI: 10.1021/acsami.4c04744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 07/03/2024] [Accepted: 07/08/2024] [Indexed: 07/24/2024]
Abstract
Nanophotonic biosensors offer exceptional sensitivity in the presence of strong background signals by enhancing and confining light in subwavelength volumes. In the field of nanophotonic biosensors, antenna-in-box (AiB) designs consisting of a nanoantenna within a nanoaperture have demonstrated remarkable single-molecule fluorescence detection sensitivities under physiologically relevant conditions. However, their full potential has not yet been exploited as current designs prohibit insightful correlative multicolor single-molecule studies and are limited in terms of throughput. Here, we overcome these constraints by introducing aluminum-based hexagonal close-packed AiB (HCP-AiB) arrays. Our approach enables the parallel readout of over 1000 HCP-AiBs with multicolor single-molecule sensitivity up to micromolar concentrations using an alternating three-color excitation scheme and epi-fluorescence detection. Notably, the high-density HCP-AiB arrays not only enable high-throughput studies at micromolar concentrations but also offer high single-molecule detection probabilities in the nanomolar range. We demonstrate that robust and alignment-free correlative multicolor studies are possible using optical fiducial markers even when imaging in the low millisecond range. These advancements pave the way for the use of HCP-AiB arrays as biosensor architectures for high-throughput multicolor studies on single-molecule dynamics.
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Affiliation(s)
- Ediz Kaan Herkert
- ICFO
- Institut de Ciencies Fotoniques, The Barcelona
Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - Lukas Lau
- ICFO
- Institut de Ciencies Fotoniques, The Barcelona
Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - Roger Pons Lanau
- ICFO
- Institut de Ciencies Fotoniques, The Barcelona
Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
| | - Maria F. Garcia-Parajo
- ICFO
- Institut de Ciencies Fotoniques, The Barcelona
Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain
- ICREA, 08010 Barcelona, Spain
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3
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Grosely R, Alvarado C, Ivanov IP, Nicholson OB, Puglisi JD, Dever TE, Lapointe CP. eIF1 and eIF5 dynamically control translation start site fidelity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.10.602410. [PMID: 39026837 PMCID: PMC11257575 DOI: 10.1101/2024.07.10.602410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Translation initiation defines the identity of a synthesized protein through selection of a translation start site on a messenger RNA. This process is essential to well-controlled protein synthesis, modulated by stress responses, and dysregulated in many human diseases. The eukaryotic initiation factors eIF1 and eIF5 interact with the initiator methionyl-tRNAi Met on the 40S ribosomal subunit to coordinate start site selection. Here, using single-molecule analysis of in vitro reconstituted human initiation combined with translation assays in cells, we examine eIF1 and eIF5 function. During translation initiation on a panel of RNAs, we monitored both proteins directly and in real time using single-molecule fluorescence. As expected, eIF1 loaded onto mRNAs as a component of the 43S initiation complex. Rapid (~ 2 s) eIF1 departure required a translation start site and was delayed by alternative start sites and a longer 5' untranslated region (5'UTR). After its initial departure, eIF1 rapidly and transiently sampled initiation complexes, with more prolonged sampling events on alternative start sites. By contrast, eIF5 only transiently bound initiation complexes late in initiation immediately prior to association of eIF5B, which allowed joining of the 60S ribosomal subunit. eIF5 association required the presence of a translation start site and was inhibited and destabilized by alternative start sites. Using both knockdown and overexpression experiments in human cells, we validated that eIF1 and eIF5 have opposing roles during initiation. Collectively, our findings demonstrate how multiple eIF1 and eIF5 binding events control start-site selection fidelity throughout initiation, which is tuned in response to changes in the levels of both proteins.
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Affiliation(s)
- Rosslyn Grosely
- Dept. of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Carlos Alvarado
- Dept. of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Ivaylo P. Ivanov
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | | | - Joseph D. Puglisi
- Dept. of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Thomas E. Dever
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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4
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Wang F, Holmes MJ, Hong HJ, Thaprawat P, Kannan G, Huynh MH, Schultz TL, Licon MH, Lourido S, Dong W, Brito Querido J, Sullivan WJ, O'Leary SE, Carruthers VB. Translation initiation factor eIF1.2 promotes Toxoplasma stage conversion by regulating levels of key differentiation factors. Nat Commun 2024; 15:4385. [PMID: 38782906 PMCID: PMC11116398 DOI: 10.1038/s41467-024-48685-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 05/07/2024] [Indexed: 05/25/2024] Open
Abstract
The parasite Toxoplasma gondii persists in its hosts by converting from replicating tachyzoites to latent bradyzoites housed in tissue cysts. The molecular mechanisms that mediate T. gondii differentiation remain poorly understood. Through a mutagenesis screen, we identified translation initiation factor eIF1.2 as a critical factor for T. gondii differentiation. A F97L mutation in eIF1.2 or the genetic ablation of eIF1.2 (∆eif1.2) markedly impeded bradyzoite cyst formation in vitro and in vivo. We demonstrated, at single-molecule level, that the eIF1.2 F97L mutation impacts the scanning process of the ribosome preinitiation complex on a model mRNA. RNA sequencing and ribosome profiling experiments unveiled that ∆eif1.2 parasites are defective in upregulating bradyzoite induction factors BFD1 and BFD2 during stress-induced differentiation. Forced expression of BFD1 or BFD2 significantly restored differentiation in ∆eif1.2 parasites. Together, our findings suggest that eIF1.2 functions by regulating the translation of key differentiation factors necessary to establish chronic toxoplasmosis.
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Affiliation(s)
- Fengrong Wang
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Michael J Holmes
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Hea Jin Hong
- Department of Biochemistry, University of California Riverside, Riverside, CA, 92521, USA
| | - Pariyamon Thaprawat
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
- Medical Scientist Training Program, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Geetha Kannan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - My-Hang Huynh
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Tracey L Schultz
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | | | - Sebastian Lourido
- Whitehead Institute, Cambridge, MA, 02142, USA
- Biology Department, Massachusetts Institute of Technology, Cambridge, MA, 02142, USA
| | - Wenzhao Dong
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA
- Center for RNA Biomedicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jailson Brito Querido
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA
- Center for RNA Biomedicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | - William J Sullivan
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
- Department of Microbiology & Immunology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Seán E O'Leary
- Department of Biochemistry, University of California Riverside, Riverside, CA, 92521, USA
- Center for RNA Biology and Medicine, University of California Riverside, Riverside, CA, 92521, USA
| | - Vern B Carruthers
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
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5
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Wang F, Holmes MJ, Hong HJ, Thaprawat P, Kannan G, Huynh MH, Schultz TL, Licon MH, Lourido S, Dong W, Querido JB, Sullivan WJ, O'Leary SE, Carruthers VB. Translation initiation factor eIF1.2 promotes Toxoplasma stage conversion by regulating levels of key differentiation factors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.03.565545. [PMID: 37961607 PMCID: PMC10635126 DOI: 10.1101/2023.11.03.565545] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The parasite Toxoplasma gondii persists in its hosts by converting from replicating tachyzoites to latent bradyzoites housed in tissue cysts. The molecular mechanisms that mediate T. gondii differentiation remain poorly understood. Through a mutagenesis screen, we identified translation initiation factor eIF1.2 as a critical factor for T. gondii differentiation. A F97L mutation in eIF1.2 or the genetic ablation of eIF1.2 (Δ eif1.2 ) markedly impeded bradyzoite cyst formation in vitro and in vivo . We demonstrated, at single-molecule level, that the eIF1.2 F97L mutation impacts the scanning process of the ribosome preinitiation complex on a model mRNA. RNA sequencing and ribosome profiling experiments unveiled that Δ eif1.2 parasites are defective in upregulating bradyzoite induction factors BFD1 and BFD2 during stress-induced differentiation. Forced expression of BFD1 or BFD2 significantly restored differentiation in Δ eif1.2 parasites. Together, our findings suggest that eIF1.2 functions by regulating the translation of key differentiation factors necessary to establish chronic toxoplasmosis.
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6
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Guca E, Alarcon R, Palo MZ, Santos L, Alonso-Gil S, Davyt M, de Lima LHF, Boissier F, Das S, Zagrovic B, Puglisi JD, Hashem Y, Ignatova Z. N 6-methyladenosine in 5' UTR does not promote translation initiation. Mol Cell 2024; 84:584-595.e6. [PMID: 38244546 PMCID: PMC10909339 DOI: 10.1016/j.molcel.2023.12.028] [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: 06/05/2023] [Revised: 10/19/2023] [Accepted: 12/16/2023] [Indexed: 01/22/2024]
Abstract
The most abundant N6-methyladenosine (m6A) modification on mRNAs is installed non-stoichiometrically across transcripts, with 5' untranslated regions (5' UTRs) being the least conductive. 5' UTRs are essential for translation initiation, yet the molecular mechanisms orchestrated by m6A remain poorly understood. Here, we combined structural, biochemical, and single-molecule approaches and show that at the most common position, a single m6A does not affect translation yields, the kinetics of translation initiation complex assembly, or start codon recognition both under permissive growth and following exposure to oxidative stress. Cryoelectron microscopy (cryo-EM) structures of the late preinitiation complex reveal that m6A purine ring established stacking interactions with an arginine side chain of the initiation factor eIF2α, although with only a marginal energy contribution, as estimated computationally. These findings provide molecular insights into m6A interactions with the initiation complex and suggest that the subtle stabilization is unlikely to affect the translation dynamics under homeostatic conditions or stress.
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Affiliation(s)
- Ewelina Guca
- INSERM U1212 Acides nucléiques: Régulations Naturelle et Artificielle (ARNA), Institut Européen de Chimie et Biologie, Université de Bordeaux, Pessac 33607, France
| | - Rodrigo Alarcon
- Institute of Biochemistry and Molecular Biology, University of Hamburg, 20146 Hamburg, Germany
| | - Michael Z Palo
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94304, USA
| | - Leonardo Santos
- Institute of Biochemistry and Molecular Biology, University of Hamburg, 20146 Hamburg, Germany
| | - Santiago Alonso-Gil
- Department of Structural and Computational Biology, Center for Molecular Biology, University of Vienna, 1030, Vienna, Austria; Max Perutz Labs, Vienna Biocenter Campus (VBC), 1030, Vienna, Austria
| | - Marcos Davyt
- Institute of Biochemistry and Molecular Biology, University of Hamburg, 20146 Hamburg, Germany
| | - Leonardo H F de Lima
- INSERM U1212 Acides nucléiques: Régulations Naturelle et Artificielle (ARNA), Institut Européen de Chimie et Biologie, Université de Bordeaux, Pessac 33607, France; Department of Exact and Biological Sciences, Federal University of São João Del Rei, Sete Lagoas Campus, Sete Lagoas 35701-970, Minas Gerais, Brazil
| | - Fanny Boissier
- INSERM U1212 Acides nucléiques: Régulations Naturelle et Artificielle (ARNA), Institut Européen de Chimie et Biologie, Université de Bordeaux, Pessac 33607, France
| | - Sarada Das
- Institute of Biochemistry and Molecular Biology, University of Hamburg, 20146 Hamburg, Germany
| | - Bojan Zagrovic
- Department of Structural and Computational Biology, Center for Molecular Biology, University of Vienna, 1030, Vienna, Austria; Max Perutz Labs, Vienna Biocenter Campus (VBC), 1030, Vienna, Austria
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94304, USA
| | - Yaser Hashem
- INSERM U1212 Acides nucléiques: Régulations Naturelle et Artificielle (ARNA), Institut Européen de Chimie et Biologie, Université de Bordeaux, Pessac 33607, France.
| | - Zoya Ignatova
- Institute of Biochemistry and Molecular Biology, University of Hamburg, 20146 Hamburg, Germany.
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7
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Vermeer B, van Ossenbruggen J, Schmid S. Single-Molecule FRET-Resolved Protein Dynamics - from Plasmid to Data in Six Steps. Methods Mol Biol 2024; 2694:267-291. [PMID: 37824009 DOI: 10.1007/978-1-0716-3377-9_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Single-molecule Förster resonance energy transfer (smFRET) is a powerful technique for the detection of conformational dynamics of biomolecules. While many smFRET experiments are performed using dye-labeled DNA, here we describe a comprehensive protocol to resolve the conformational dynamics of a protein system - notably from plasmid to data. Using the example of the heat-shock protein Hsp90, we describe the protein production and threefold site-specific bioconjugation, the smFRET measurement using total internal reflection fluorescence microscopy (TIRFM), and raw data processing to reveal time-resolved protein dynamics. The described smFRET approach is readily transferrable to the study of many more all-protein systems and their conformational energy landscape.
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Affiliation(s)
- Benjamin Vermeer
- Laboratory of Biophysics, Wageningen University & Research, Wageningen, The Netherlands
| | | | - Sonja Schmid
- Laboratory of Biophysics, Wageningen University & Research, Wageningen, The Netherlands.
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8
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Yun WS, Cho H, Jeon SI, Lim DK, Kim K. Fluorescence-Based Mono- and Multimodal Imaging for In Vivo Tracking of Mesenchymal Stem Cells. Biomolecules 2023; 13:1787. [PMID: 38136656 PMCID: PMC10742164 DOI: 10.3390/biom13121787] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/01/2023] [Accepted: 12/11/2023] [Indexed: 12/24/2023] Open
Abstract
The advancement of stem cell therapy has offered transformative therapeutic outcomes for a wide array of diseases over the past decades. Consequently, stem cell tracking has become significant in revealing the mechanisms of action and ensuring safe and effective treatments. Fluorescence stands out as a promising choice for stem cell tracking due to its myriad advantages, including high resolution, real-time monitoring, and multi-fluorescence detection. Furthermore, combining fluorescence with other tracking modalities-such as bioluminescence imaging (BLI), positron emission tomography (PET), photoacoustic (PA), computed tomography (CT), and magnetic resonance (MR)-can address the limitations of single fluorescence detection. This review initially introduces stem cell tracking using fluorescence imaging, detailing various labeling strategies such as green fluorescence protein (GFP) tagging, fluorescence dye labeling, and nanoparticle uptake. Subsequently, we present several combinations of strategies for efficient and precise detection.
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Affiliation(s)
- Wan Su Yun
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Republic of Korea; (W.S.Y.); (D.-K.L.)
| | - Hanhee Cho
- Graduate School of Pharmaceutical Sciences, College of Pharmacy, Ewha Woman’s University, Seoul 03760, Republic of Korea; (H.C.); (S.I.J.)
| | - Seong Ik Jeon
- Graduate School of Pharmaceutical Sciences, College of Pharmacy, Ewha Woman’s University, Seoul 03760, Republic of Korea; (H.C.); (S.I.J.)
| | - Dong-Kwon Lim
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Republic of Korea; (W.S.Y.); (D.-K.L.)
| | - Kwangmeyung Kim
- Graduate School of Pharmaceutical Sciences, College of Pharmacy, Ewha Woman’s University, Seoul 03760, Republic of Korea; (H.C.); (S.I.J.)
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9
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Huang T, Choi J, Prabhakar A, Puglisi JD, Petrov A. Partial spontaneous intersubunit rotations in pretranslocation ribosomes. Proc Natl Acad Sci U S A 2023; 120:e2114979120. [PMID: 37801472 PMCID: PMC10576065 DOI: 10.1073/pnas.2114979120] [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: 08/17/2021] [Accepted: 08/29/2023] [Indexed: 10/08/2023] Open
Abstract
The two main steps of translation, peptidyl transfer, and translocation are accompanied by counterclockwise and clockwise rotations of the large and small ribosomal subunits with respect to each other. Upon peptidyl transfer, the small ribosomal subunit rotates counterclockwise relative to the large subunit, placing the ribosome into the rotated conformation. Simultaneously, tRNAs move into the hybrid conformation, and the L1 stalk moves inward toward the P-site tRNA. The conformational dynamics of pretranslocation ribosomes were extensively studied by ensemble and single-molecule methods. Different experimental modalities tracking ribosomal subunits, tRNAs, and the L1 stalk showed that pretranslocation ribosomes undergo spontaneous conformational transitions. Thus, peptidyl transfer unlocks the ribosome and decreases an energy barrier for the reverse ribosome rotation during translocation. However, the tracking of translation with ribosomes labeled at rRNA helices h44 and H101 showed a lack of spontaneous rotations in pretranslocation complexes. Therefore, reverse intersubunit rotations occur during EF-G catalyzed translocation. To reconcile these views, we used high-speed single-molecule microscopy to follow translation in real time. We showed spontaneous rotations in puromycin-released h44-H101 dye-labeled ribosomes. During elongation, the h44-H101 ribosomes undergo partial spontaneous rotations. Spontaneous rotations in h44-H101-labeled ribosomes are restricted prior to aminoacyl-tRNA binding. The pretranslocation h44-H101 ribosomes spontaneously exchanged between three different rotational states. This demonstrates that peptidyl transfer unlocks spontaneous rotations and pretranslocation ribosomes can adopt several thermally accessible conformations, thus supporting the Brownian model of translocation.
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Affiliation(s)
- Tianhan Huang
- Department of Biological Sciences, Auburn University, Auburn, AL36849
| | - Junhong Choi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA94305
| | - Arjun Prabhakar
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA94305
| | - Joseph D. Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA94305
| | - Alexey Petrov
- Department of Biological Sciences, Auburn University, Auburn, AL36849
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10
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Schubert K, Karousis ED, Ban I, Lapointe CP, Leibundgut M, Bäumlin E, Kummerant E, Scaiola A, Schönhut T, Ziegelmüller J, Puglisi JD, Mühlemann O, Ban N. Universal features of Nsp1-mediated translational shutdown by coronaviruses. Mol Cell 2023; 83:3546-3557.e8. [PMID: 37802027 PMCID: PMC10575594 DOI: 10.1016/j.molcel.2023.09.002] [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: 02/03/2023] [Revised: 05/16/2023] [Accepted: 09/06/2023] [Indexed: 10/08/2023]
Abstract
Nonstructural protein 1 (Nsp1) produced by coronaviruses inhibits host protein synthesis. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Nsp1 C-terminal domain was shown to bind the ribosomal mRNA channel to inhibit translation, but it is unclear whether this mechanism is broadly used by coronaviruses, whether the Nsp1 N-terminal domain binds the ribosome, or how Nsp1 allows viral RNAs to be translated. Here, we investigated Nsp1 from SARS-CoV-2, Middle East respiratory syndrome coronavirus (MERS-CoV), and Bat-Hp-CoV coronaviruses using structural, biophysical, and biochemical experiments, revealing a conserved role for the C-terminal domain. Additionally, the N-terminal domain of Bat-Hp-CoV Nsp1 binds to the decoding center of the 40S subunit, where it would prevent mRNA and eIF1A accommodation. Structure-based experiments demonstrated the importance of decoding center interactions in all three coronaviruses and showed that the same regions of Nsp1 are necessary for the selective translation of viral RNAs. Our results provide a mechanistic framework to understand how Nsp1 controls preferential translation of viral RNAs.
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Affiliation(s)
- Katharina Schubert
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich 8049, Switzerland
| | - Evangelos D Karousis
- Department of Chemistry and Biochemistry, University of Bern, Bern 3012, Switzerland; Multidisciplinary Center for Infectious Diseases, University of Bern, Bern 3012, Switzerland.
| | - Ivo Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich 8049, Switzerland
| | - Christopher P Lapointe
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Marc Leibundgut
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich 8049, Switzerland
| | - Emilie Bäumlin
- Department of Chemistry and Biochemistry, University of Bern, Bern 3012, Switzerland; Multidisciplinary Center for Infectious Diseases, University of Bern, Bern 3012, Switzerland
| | - Eric Kummerant
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich 8049, Switzerland
| | - Alain Scaiola
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich 8049, Switzerland
| | - Tanja Schönhut
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich 8049, Switzerland
| | - Jana Ziegelmüller
- Department of Chemistry and Biochemistry, University of Bern, Bern 3012, Switzerland
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Oliver Mühlemann
- Department of Chemistry and Biochemistry, University of Bern, Bern 3012, Switzerland
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich 8049, Switzerland.
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11
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Hentschel J, Badstübner M, Choi J, Bagshaw CR, Lapointe CP, Wang J, Jansson LI, Puglisi JD, Stone MD. Real-time detection of human telomerase DNA synthesis by multiplexed single-molecule FRET. Biophys J 2023; 122:3447-3457. [PMID: 37515327 PMCID: PMC10502476 DOI: 10.1016/j.bpj.2023.07.019] [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: 05/20/2022] [Revised: 02/28/2023] [Accepted: 07/25/2023] [Indexed: 07/30/2023] Open
Abstract
Genomic stability in proliferating cells critically depends on telomere maintenance by telomerase reverse transcriptase. Here we report the development and proof-of-concept results of a single-molecule approach to monitor the catalytic activity of human telomerase in real time and with single-nucleotide resolution. Using zero-mode waveguides and multicolor FRET, we recorded the processive addition of multiple telomeric repeats to individual DNA primers. Unlike existing biophysical and biochemical tools, the novel approach enables the quantification of nucleotide-binding kinetics before nucleotide incorporation. Moreover, it provides a means to dissect the unique translocation dynamics that telomerase must undergo after synthesis of each hexameric DNA repeat. We observed an unexpectedly prolonged binding dwell time of dGTP in the enzyme active site at the start of each repeat synthesis cycle, suggesting that telomerase translocation is composed of multiple rate-contributing sub-steps that evade classical biochemical analysis.
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Affiliation(s)
- Jendrik Hentschel
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California; Department of Structural Biology, Stanford University School of Medicine, Stanford, California
| | - Mareike Badstübner
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California
| | - Junhong Choi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California
| | - Clive R Bagshaw
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California
| | - Christopher P Lapointe
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California
| | - Jinfan Wang
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California
| | - Linnea I Jansson
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California
| | - Michael D Stone
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California.
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12
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White D, Smith MA, Chanda B, Goldsmith RH. Strategies for Overcoming the Single-Molecule Concentration Barrier. ACS MEASUREMENT SCIENCE AU 2023; 3:239-257. [PMID: 37600457 PMCID: PMC10436376 DOI: 10.1021/acsmeasuresciau.3c00002] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 04/21/2023] [Accepted: 04/24/2023] [Indexed: 08/22/2023]
Abstract
Fluorescence-based single-molecule approaches have helped revolutionize our understanding of chemical and biological mechanisms. Unfortunately, these methods are only suitable at low concentrations of fluorescent molecules so that single fluorescent species of interest can be successfully resolved beyond background signal. The application of these techniques has therefore been limited to high-affinity interactions despite most biological and chemical processes occurring at much higher reactant concentrations. Fortunately, recent methodological advances have demonstrated that this concentration barrier can indeed be broken, with techniques reaching concentrations as high as 1 mM. The goal of this Review is to discuss the challenges in performing single-molecule fluorescence techniques at high-concentration, offer applications in both biology and chemistry, and highlight the major milestones that shatter the concentration barrier. We also hope to inspire the widespread use of these techniques so we can begin exploring the new physical phenomena lying beyond this barrier.
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Affiliation(s)
- David
S. White
- Department
of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Mackinsey A. Smith
- Department
of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Baron Chanda
- Center
for
Investigation of Membrane Excitability Diseases, Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Randall H. Goldsmith
- Department
of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
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13
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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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14
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Schubert K, Karousis ED, Ban I, Lapointe CP, Leibundgut M, Bäumlin E, Kummerant E, Scaiola A, Schönhut T, Ziegelmüller J, Puglisi JD, Mühlemann O, Ban N. Universal features of Nsp1-mediated translational shutdown by coronaviruses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.31.543022. [PMID: 37398176 PMCID: PMC10312502 DOI: 10.1101/2023.05.31.543022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Nonstructural protein 1 (Nsp1) produced by coronaviruses shuts down host protein synthesis in infected cells. The C-terminal domain of SARS-CoV-2 Nsp1 was shown to bind to the small ribosomal subunit to inhibit translation, but it is not clear whether this mechanism is broadly used by coronaviruses, whether the N-terminal domain of Nsp1 binds the ribosome, or how Nsp1 specifically permits translation of viral mRNAs. Here, we investigated Nsp1 from three representative Betacoronaviruses - SARS-CoV-2, MERS-CoV, and Bat-Hp-CoV - using structural, biophysical, and biochemical assays. We revealed a conserved mechanism of host translational shutdown across the three coronaviruses. We further demonstrated that the N-terminal domain of Bat-Hp-CoV Nsp1 binds to the decoding center of the 40S subunit, where it would prevent mRNA and eIF1A binding. Structure-based biochemical experiments identified a conserved role of these inhibitory interactions in all three coronaviruses and showed that the same regions of Nsp1 are responsible for the preferential translation of viral mRNAs. Our results provide a mechanistic framework to understand how Betacoronaviruses overcome translational inhibition to produce viral proteins.
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Affiliation(s)
- Katharina Schubert
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Evangelos D Karousis
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Ivo Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Christopher P Lapointe
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Marc Leibundgut
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Emilie Bäumlin
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Eric Kummerant
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Alain Scaiola
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Tanja Schönhut
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Jana Ziegelmüller
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Oliver Mühlemann
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
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15
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Ghoneim M, Musselman CA. Single-Molecule Characterization of Cy3.5 -Cy5.5 Dye Pair for FRET Studies of Nucleic Acids and Nucleosomes. J Fluoresc 2023; 33:413-421. [PMID: 36435903 PMCID: PMC9957830 DOI: 10.1007/s10895-022-03093-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 11/17/2022] [Indexed: 11/27/2022]
Abstract
Single molecule FRET (Forster resonance energy transfer) is very powerful method for studying biomolecular binding dynamics and conformational transitions. Only a few donor - acceptor dye pairs have been characterized for use in single-molecule FRET (smFRET) studies. Hence, introducing and characterizing additional FRET dye pairs is important in order to widen the scope of applications of single-molecule FRET in biomolecular studies. Here we characterize the properties of the Cy3.5 and Cy5.5 dye pair under FRET at the single-molecule level using naked double-stranded DNA (dsDNA) and the nucleosome. We show that this pair of dyes is photostable for ~ 5 min under continuous illumination. We also report Cy3.5-Cy5.5 FRET proximity dependence and stability in the presence of several biochemical buffers and photoprotective reagents in the context of double-stranded DNA. Finally, we demonstrate compatibility of the Cy3.5-Cy5.5 pair for smFRET in vitro studies of nucleosomes.
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Affiliation(s)
- Mohamed Ghoneim
- Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, 80045, Aurora, CO, USA.
| | - Catherine A. Musselman
- grid.430503.10000 0001 0703 675XBiochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, 80045 Aurora, CO USA
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16
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Lin Y, Hu J, Zhang W, Jiang L, Yi D, Rujiralai T, Ma J. Broadband single-molecule fluorescence enhancement based on self-assembled Ag@Au dimer plasmonic nanoantennas. NANOSCALE 2022; 14:17550-17560. [PMID: 36318052 DOI: 10.1039/d2nr03466b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Dimer optical antennas (OAs) enable great fluorescence enhancement and excitation volume reduction and hence potentially can be a very useful tool for single-molecule detection. The realization of broadband fluorescence enhancement with a dimer OA remains an essential step for its usage in multi-color single-molecule fluorescence (SMF) detection. Although silver dimer OAs have been shown to be able to yield broadband fluorescence enhancement over the visible spectrum, they are amenable to oxidization, hard to functionalize, and could cause cytotoxicity. To overcome these limitations, in this work, we took advantage of nano-sized silver due to its optical properties and gold due to its chemical properties and developed an ameliorated Ag@Au dimer OA in terms of its overall performance. The Ag@Au nanoparticle in the dimer OA contains a 70 nm silver core and an ultra-thin (∼1-5 nm) gold shell which play a key role in its optical responses. Furthermore, we employed three typical dyes, i.e., FAM, TAMRA and Cy5, representing the blue, yellow and red ranges, respectively, and characterized their single-molecule fluorescence enhancements in the presence of Au or Ag@Au OAs. Our results indicate that, in contrast to its Au counterpart, the Ag@Au dimer OA prepared here can greatly improve its optical response in the blue range and eventually achieve broadband fluorescence enhancement throughout almost the whole visible spectral range. Meanwhile, it also maintains good chemical stability and accessibility to functionalization. Such Ag@Au dimer OAs are thus expected to have many important applications in the future, including single-molecule sequencing and multi-color biosensing.
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Affiliation(s)
- Yunpeng Lin
- School of Physics, Sun Yat-sen University, Guangzhou 510275, P.R. China.
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Jinyong Hu
- School of Physics and Optoelectronics, Xiangtan University, Xiangtan 411105, P.R. China
| | - Wenbo Zhang
- School of Physics, Sun Yat-sen University, Guangzhou 510275, P.R. China.
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Li Jiang
- College of Science, Guilin University of Technology, Guilin 541004, P.R. China
| | - Deqi Yi
- School of Physics, Sun Yat-sen University, Guangzhou 510275, P.R. China.
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Thitima Rujiralai
- Division of Physical Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90110, Thailand
| | - Jie Ma
- School of Physics, Sun Yat-sen University, Guangzhou 510275, P.R. China.
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, P.R. China
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17
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Wang J, Shin BS, Alvarado C, Kim JR, Bohlen J, Dever TE, Puglisi JD. Rapid 40S scanning and its regulation by mRNA structure during eukaryotic translation initiation. Cell 2022; 185:4474-4487.e17. [PMID: 36334590 PMCID: PMC9691599 DOI: 10.1016/j.cell.2022.10.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 08/22/2022] [Accepted: 10/05/2022] [Indexed: 11/06/2022]
Abstract
How the eukaryotic 43S preinitiation complex scans along the 5' untranslated region (5' UTR) of a capped mRNA to locate the correct start codon remains elusive. Here, we directly track yeast 43S-mRNA binding, scanning, and 60S subunit joining by real-time single-molecule fluorescence spectroscopy. 43S engagement with mRNA occurs through a slow, ATP-dependent process driven by multiple initiation factors including the helicase eIF4A. Once engaged, 43S scanning occurs rapidly and directionally at ∼100 nucleotides per second, independent of multiple cycles of ATP hydrolysis by RNA helicases post ribosomal loading. Scanning ribosomes can proceed through RNA secondary structures, but 5' UTR hairpin sequences near start codons drive scanning ribosomes at start codons backward in the 5' direction, requiring rescanning to arrive once more at a start codon. Direct observation of scanning ribosomes provides a mechanistic framework for translational regulation by 5' UTR structures and upstream near-cognate start codons.
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Affiliation(s)
- Jinfan Wang
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Byung-Sik Shin
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Carlos Alvarado
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Joo-Ran Kim
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Jonathan Bohlen
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, Institut National de la Santé et de la Recherche Médicale U1163, Paris, France; University of Paris, Imagine Institute, Paris, France
| | - Thomas E Dever
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.
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18
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Prabhakar A, Krahn N, Zhang J, Vargas-Rodriguez O, Krupkin M, Fu Z, Acosta-Reyes FJ, Ge X, Choi J, Crnković A, Ehrenberg M, Puglisi EV, Söll D, Puglisi J. Uncovering translation roadblocks during the development of a synthetic tRNA. Nucleic Acids Res 2022; 50:10201-10211. [PMID: 35882385 PMCID: PMC9561287 DOI: 10.1093/nar/gkac576] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/14/2022] [Accepted: 07/22/2022] [Indexed: 11/24/2022] Open
Abstract
Ribosomes are remarkable in their malleability to accept diverse aminoacyl-tRNA substrates from both the same organism and other organisms or domains of life. This is a critical feature of the ribosome that allows the use of orthogonal translation systems for genetic code expansion. Optimization of these orthogonal translation systems generally involves focusing on the compatibility of the tRNA, aminoacyl-tRNA synthetase, and a non-canonical amino acid with each other. As we expand the diversity of tRNAs used to include non-canonical structures, the question arises as to the tRNA suitability on the ribosome. Specifically, we investigated the ribosomal translation of allo-tRNAUTu1, a uniquely shaped (9/3) tRNA exploited for site-specific selenocysteine insertion, using single-molecule fluorescence. With this technique we identified ribosomal disassembly occurring from translocation of allo-tRNAUTu1 from the A to the P site. Using cryo-EM to capture the tRNA on the ribosome, we pinpointed a distinct tertiary interaction preventing fluid translocation. Through a single nucleotide mutation, we disrupted this tertiary interaction and relieved the translation roadblock. With the continued diversification of genetic code expansion, our work highlights a targeted approach to optimize translation by distinct tRNAs as they move through the ribosome.
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Affiliation(s)
| | | | | | - Oscar Vargas-Rodriguez
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Miri Krupkin
- Department of Structural Biology, Stanford University, Stanford, CA 94305-5126, USA
| | - Ziao Fu
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Francisco J Acosta-Reyes
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Xueliang Ge
- Department of Cell and Molecular Biology, Uppsala University, Uppsala 751 24, Sweden
| | - Junhong Choi
- Department of Structural Biology, Stanford University, Stanford, CA 94305-5126, USA
| | - Ana Crnković
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Måns Ehrenberg
- Department of Cell and Molecular Biology, Uppsala University, Uppsala 751 24, Sweden
| | | | - Dieter Söll
- Correspondence may also be addressed to Dieter Söll.
| | - Joseph Puglisi
- To whom correspondence should be addressed. Tel: +1 650 498 4397;
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19
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Çetin B, O’Leary SE. mRNA- and factor-driven dynamic variability controls eIF4F-cap recognition for translation initiation. Nucleic Acids Res 2022; 50:8240-8261. [PMID: 35871304 PMCID: PMC9371892 DOI: 10.1093/nar/gkac631] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/29/2022] [Accepted: 07/20/2022] [Indexed: 11/29/2022] Open
Abstract
mRNA 5′ cap recognition by eIF4F is a key element of eukaryotic translational control. Kinetic differences in eIF4F–mRNA interactions have long been proposed to mediate translation-efficiency differences between mRNAs, and recent transcriptome-wide studies have revealed significant heterogeneity in eIF4F engagement with differentially-translated mRNAs. However, detailed kinetic information exists only for eIF4F interactions with short model RNAs. We developed and applied single-molecule fluorescence approaches to directly observe real-time Saccharomyces cerevisiae eIF4F subunit interactions with full-length polyadenylated mRNAs. We found that eIF4E–mRNA association rates linearly anticorrelate with mRNA length. eIF4G–mRNA interaction accelerates eIF4E–mRNA association in proportion to mRNA length, as does an eIF4F-independent activity of eIF4A, though cap-proximal secondary structure still plays an important role in defining the final association rates. eIF4F–mRNA interactions remained dominated by effects of eIF4G, but were modulated to different extents for different mRNAs by the presence of eIF4A and ATP. We also found that eIF4A-catalyzed ATP hydrolysis ejects eIF4E, and likely eIF4E•eIF4G from the mRNA after initial eIF4F•mRNA complex formation, suggesting a mechanism to prepare the mRNA 5′ end for ribosome recruitment. Our results support a role for mRNA-specific, factor-driven eIF4F association rates in kinetically controlling translation.
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Affiliation(s)
- Burak Çetin
- Graduate Program in Cell, Molecular, and Developmental Biology, University of California Riverside , Riverside, CA 92521, USA
| | - Seán E O’Leary
- Graduate Program in Cell, Molecular, and Developmental Biology, University of California Riverside , Riverside, CA 92521, USA
- Department of Biochemistry, University of California Riverside , Riverside, CA 92521, USA
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20
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Lapointe CP, Grosely R, Sokabe M, Alvarado C, Wang J, Montabana E, Villa N, Shin BS, Dever TE, Fraser CS, Fernández IS, Puglisi JD. eIF5B and eIF1A reorient initiator tRNA to allow ribosomal subunit joining. Nature 2022; 607:185-190. [PMID: 35732735 PMCID: PMC9728550 DOI: 10.1038/s41586-022-04858-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 05/11/2022] [Indexed: 01/03/2023]
Abstract
Translation initiation defines the identity and quantity of a synthesized protein. The process is dysregulated in many human diseases1,2. A key commitment step is when the ribosomal subunits join at a translation start site on a messenger RNA to form a functional ribosome. Here, we combined single-molecule spectroscopy and structural methods using an in vitro reconstituted system to examine how the human ribosomal subunits join. Single-molecule fluorescence revealed when the universally conserved eukaryotic initiation factors eIF1A and eIF5B associate with and depart from initiation complexes. Guided by single-molecule dynamics, we visualized initiation complexes that contained both eIF1A and eIF5B using single-particle cryo-electron microscopy. The resulting structure revealed how eukaryote-specific contacts between the two proteins remodel the initiation complex to orient the initiator aminoacyl-tRNA in a conformation compatible with ribosomal subunit joining. Collectively, our findings provide a quantitative and architectural framework for the molecular choreography orchestrated by eIF1A and eIF5B during translation initiation in humans.
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Affiliation(s)
- Christopher P Lapointe
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Rosslyn Grosely
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Masaaki Sokabe
- Department of Molecular and Cellular Biology College of Biological Sciences, University of California, Davis, CA, USA
| | - Carlos Alvarado
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Jinfan Wang
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Elizabeth Montabana
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Nancy Villa
- Department of Molecular and Cellular Biology College of Biological Sciences, University of California, Davis, CA, USA
| | - Byung-Sik Shin
- Section on Protein Biosynthesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Thomas E Dever
- Section on Protein Biosynthesis, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Christopher S Fraser
- Department of Molecular and Cellular Biology College of Biological Sciences, University of California, Davis, CA, USA
| | - Israel S Fernández
- Department of Structural Biology, St Jude Children's Research Hospital, Memphis, TN, USA.
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.
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21
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Li H, Liu T, Yang H. Amplifying Intermolecular Events by Streptavidin-Induced Proximity. J Am Chem Soc 2022; 144:11377-11385. [PMID: 35715211 DOI: 10.1021/jacs.2c03666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Weak interactions between biomolecules play important roles in many cellular functions. Structural and kinetic analyses of these interactions, however, have been hindered by the transient nature of such events. Here, we pointed out a general approach to overcome this obstacle─anchoring the molecular partners to streptavidin hosts─and achieved constrained proximity and stoichiometry for the sought-after molecular coupling. We elaborated this idea through a series of DNA hybridization reactions and quantitatively characterized them using single-molecule experiments. Compared to a nominally 1 μM solution, for example, the streptavidin-induced proximity (SIP) amounted to an effective molarity of ∼10-30 μM for the binding partners. There was also a significantly increased proportion of molecular association, manifested in both ensemble population and single-molecule residence time. As an application example, we showed how SIP enabled the observation and quantitative characterization of an unstable complex between Cas9-RNA and noncognate DNA substrates, interactions that had been challenging to characterize previously. Conceptually simple and implementationally robust, SIP was shown to considerably enhance the efficacy in capturing weak interactions and, as demonstrated here, could empower scientists to see the otherwise unseeable.
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Affiliation(s)
- Hao Li
- Department of Chemistry, Princeton University,, Princeton, New Jersey 08544, United States
| | - Tao Liu
- Department of Chemistry, Princeton University,, Princeton, New Jersey 08544, United States
| | - Haw Yang
- Department of Chemistry, Princeton University,, Princeton, New Jersey 08544, United States
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22
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Nemashkalo A, Phipps ME, Hennelly SP, Goodwin PM. Real-time, single-molecule observation of biomolecular interactions inside nanophotonic zero mode waveguides. NANOTECHNOLOGY 2022; 33:165101. [PMID: 34959227 DOI: 10.1088/1361-6528/ac467c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/26/2021] [Indexed: 06/14/2023]
Abstract
Living cells rely on numerous protein-protein, RNA-protein and DNA-protein interactions for processes such as gene expression, biomolecular assembly, protein and RNA degradation. Single-molecule microscopy and spectroscopy are ideal tools for real-time observation and quantification of nucleic acids-protein and protein-protein interactions. One of the major drawbacks of conventional single-molecule imaging methods is low throughput. Methods such as sequencing by synthesis utilizing nanofabrication and single-molecule spectroscopy have brought high throughput into the realm of single-molecule biology. The Pacific Biosciences RS2 sequencer utilizes sequencing by synthesis within nanophotonic zero mode waveguides. A number of years ago this instrument was unlocked by Pacific Biosciences for custom use by researchers allowing them to monitor biological interactions at the single-molecule level with high throughput. In this capability letter we demonstrate the use of the RS2 sequencer for real-time observation of DNA-to-RNA transcription and RNA-protein interactions. We use a relatively complex model-transcription of structured ribosomal RNA fromE. coliand interactions of ribosomal RNA with ribosomal proteins. We also show evidence of observation of transcriptional pausing without the application of an external force (as is required for single-molecule pausing studies using optical traps). Overall, in the unlocked, custom mode, the RS2 sequencer can be used to address a wide variety of biological assembly and interaction questions at the single-molecule level with high throughput. This instrument is available for use at the Center for Integrated Nanotechnologies Gateway located at Los Alamos National Laboratory.
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Affiliation(s)
- A Nemashkalo
- MPA-CINT (Materials Physics and Applications, Center for Integrated Nanotechnologies, Los Alamos National Laboratory), United States of America
| | - M E Phipps
- MPA-CINT (Materials Physics and Applications, Center for Integrated Nanotechnologies, Los Alamos National Laboratory), United States of America
| | - S P Hennelly
- B-11 (Bioenergy and Biome Sciences, Los Alamos National Laboratory), United States of America
| | - P M Goodwin
- MPA-CINT (Materials Physics and Applications, Center for Integrated Nanotechnologies, Los Alamos National Laboratory), United States of America
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23
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Kawai K, Fujitsuka M. Single-molecule fluorescence kinetic sandwich assay using a DNA sequencer. CHEM LETT 2022. [DOI: 10.1246/cl.210726] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Kiyohiko Kawai
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Mamoru Fujitsuka
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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24
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Małecka EM, Hua B, Woodson SA. Single-Molecule FRET Studies of RNA Structural Rearrangements and RNA-RNA Interactions. Methods Mol Biol 2022; 2518:271-289. [PMID: 35666451 PMCID: PMC10052914 DOI: 10.1007/978-1-0716-2421-0_16] [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] [Indexed: 06/15/2023]
Abstract
RNA-guided regulation of gene expression is found in all cell types. In this mode of regulation, antisense interactions between the regulatory RNA and its target are typically facilitated by a protein partner. Single-molecule fluorescence microscopy is a powerful tool for dissecting the conformational states and intermediates that contribute to target recognition. This chapter describes protocols for studying target recognition by bacterial small RNAs and their chaperone Hfq on the single-molecule level, using a total internal reflection fluorescence microscope. The sections cover the design of suitable RNA substrates for sRNA-mRNA annealing reactions, preparation of internally labeled mRNA for detecting conformational changes in the target, and key steps of the data analysis. These protocols can be adapted to other RNA-binding proteins that chaperone RNA interactions.
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Affiliation(s)
- Ewelina M Małecka
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA
| | - Boyang Hua
- Department of Molecular Biology and Genetics, Johns Hopkins Medical School, Baltimore, MD, USA
| | - Sarah A Woodson
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA.
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25
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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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26
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Ordabayev YA, Friedman LJ, Gelles J, Theobald DL. Bayesian machine learning analysis of single-molecule fluorescence colocalization images. eLife 2022; 11:73860. [PMID: 35319463 PMCID: PMC9183235 DOI: 10.7554/elife.73860] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 03/19/2022] [Indexed: 01/07/2023] Open
Abstract
Multi-wavelength single-molecule fluorescence colocalization (CoSMoS) methods allow elucidation of complex biochemical reaction mechanisms. However, analysis of CoSMoS data is intrinsically challenging because of low image signal-to-noise ratios, non-specific surface binding of the fluorescent molecules, and analysis methods that require subjective inputs to achieve accurate results. Here, we use Bayesian probabilistic programming to implement Tapqir, an unsupervised machine learning method that incorporates a holistic, physics-based causal model of CoSMoS data. This method accounts for uncertainties in image analysis due to photon and camera noise, optical non-uniformities, non-specific binding, and spot detection. Rather than merely producing a binary 'spot/no spot' classification of unspecified reliability, Tapqir objectively assigns spot classification probabilities that allow accurate downstream analysis of molecular dynamics, thermodynamics, and kinetics. We both quantitatively validate Tapqir performance against simulated CoSMoS image data with known properties and also demonstrate that it implements fully objective, automated analysis of experiment-derived data sets with a wide range of signal, noise, and non-specific binding characteristics.
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Affiliation(s)
| | - Larry J Friedman
- Department of Biochemistry, Brandeis UniversityWalthamUnited States
| | - Jeff Gelles
- Department of Biochemistry, Brandeis UniversityWalthamUnited States
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27
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Patra S, Claude JB, Naubron JV, Wenger J. Fast interaction dynamics of G-quadruplex and RGG-rich peptides unveiled in zero-mode waveguides. Nucleic Acids Res 2021; 49:12348-12357. [PMID: 34791437 PMCID: PMC8643622 DOI: 10.1093/nar/gkab1002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 09/30/2021] [Accepted: 10/11/2021] [Indexed: 11/14/2022] Open
Abstract
G-quadruplexes (GQs), a non-canonical form of DNA, are receiving a huge interest as target sites for potential applications in antiviral and anticancer drug treatments. The biological functions of GQs can be controlled by specifically binding proteins known as GQs binding proteins. Some of the GQs binding proteins contain an arginine and glycine-rich sequence known as RGG peptide. Despite the important role of RGG, the GQs-RGG interaction remains poorly understood. By single molecule measurements, the interaction dynamics can be determined in principle. However, the RGG-GQs interaction occurs at micromolar concentrations, making conventional single-molecule experiments impossible with a diffraction-limited confocal microscope. Here, we use a 120 nm zero-mode waveguide (ZMW) nanoaperture to overcome the diffraction limit. The combination of dual-color fluorescence cross-correlation spectroscopy (FCCS) with FRET is used to unveil the interaction dynamics and measure the association and dissociation rates. Our data show that the RGG-GQs interaction is predominantly driven by electrostatics but that a specific affinity between the RGG sequence and the GQs structure is preserved. The single molecule approach at micromolar concentration is the key to improve our understanding of GQs function and develop its therapeutic applications by screening a large library of GQs-targeting peptides and proteins.
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Affiliation(s)
- Satyajit Patra
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, 13013 Marseille, France
| | - Jean-Benoît Claude
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, 13013 Marseille, France
| | - Jean-Valère Naubron
- Aix Marseille Univ, CNRS, Centrale Marseille, FSCM – Spectropole, 13013 Marseille, France
| | - Jérome Wenger
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, 13013 Marseille, France
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28
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Patel VR, Salinas AM, Qi D, Gupta S, Sidote DJ, Goldschen-Ohm MP. Single-molecule imaging with cell-derived nanovesicles reveals early binding dynamics at a cyclic nucleotide-gated ion channel. Nat Commun 2021; 12:6459. [PMID: 34753946 PMCID: PMC8578382 DOI: 10.1038/s41467-021-26816-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 10/21/2021] [Indexed: 12/05/2022] Open
Abstract
Ligand binding to membrane proteins is critical for many biological signaling processes. However, individual binding events are rarely directly observed, and their asynchronous dynamics are occluded in ensemble-averaged measures. For membrane proteins, single-molecule approaches that resolve these dynamics are challenged by dysfunction in non-native lipid environments, lack of access to intracellular sites, and costly sample preparation. Here, we introduce an approach combining cell-derived nanovesicles, microfluidics, and single-molecule fluorescence colocalization microscopy to track individual binding events at a cyclic nucleotide-gated TAX-4 ion channel critical for sensory transduction. Our observations reveal dynamics of both nucleotide binding and a subsequent conformational change likely preceding pore opening. Kinetic modeling suggests that binding of the second ligand is either independent of the first ligand or exhibits up to ~10-fold positive binding cooperativity. This approach is broadly applicable to studies of binding dynamics for proteins with extracellular or intracellular domains in native cell membrane.
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Affiliation(s)
- Vishal R Patel
- Department of Neuroscience, The University of Texas at Austin, Austin, TX, USA
- Dell Medical School, The University of Texas at Austin, Austin, TX, USA
| | - Arturo M Salinas
- Department of Physics, The University of Texas at Austin, Austin, TX, USA
| | - Darong Qi
- Department of Neuroscience, The University of Texas at Austin, Austin, TX, USA
| | - Shipra Gupta
- Department of Neuroscience, The University of Texas at Austin, Austin, TX, USA
| | - David J Sidote
- Department of Neuroscience, The University of Texas at Austin, Austin, TX, USA
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29
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Unsupervised selection of optimal single-molecule time series idealization criterion. Biophys J 2021; 120:4472-4483. [PMID: 34487708 PMCID: PMC8553667 DOI: 10.1016/j.bpj.2021.08.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/22/2021] [Accepted: 08/31/2021] [Indexed: 11/30/2022] Open
Abstract
Single-molecule (SM) approaches have provided valuable mechanistic information on many biophysical systems. As technological advances lead to ever-larger data sets, tools for rapid analysis and identification of molecules exhibiting the behavior of interest are increasingly important. In many cases the underlying mechanism is unknown, making unsupervised techniques desirable. The divisive segmentation and clustering (DISC) algorithm is one such unsupervised method that idealizes noisy SM time series much faster than computationally intensive approaches without sacrificing accuracy. However, DISC relies on a user-selected objective criterion (OC) to guide its estimation of the ideal time series. Here, we explore how different OCs affect DISC’s performance for data typical of SM fluorescence imaging experiments. We find that OCs differing in their penalty for model complexity each optimize DISC’s performance for time series with different properties such as signal/noise and number of sample points. Using a machine learning approach, we generate a decision boundary that allows unsupervised selection of OCs based on the input time series to maximize performance for different types of data. This is particularly relevant for SM fluorescence data sets, which often have signal/noise near the derived decision boundary and include time series of nonuniform length because of stochastic bleaching. Our approach, AutoDISC, allows unsupervised per-molecule optimization of DISC, which will substantially assist in the rapid analysis of high-throughput SM data sets with noisy samples and nonuniform time windows.
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30
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Lawson MR, Lessen LN, Wang J, Prabhakar A, Corsepius NC, Green R, Puglisi JD. Mechanisms that ensure speed and fidelity in eukaryotic translation termination. Science 2021; 373:876-882. [PMID: 34413231 PMCID: PMC9017434 DOI: 10.1126/science.abi7801] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 07/07/2021] [Indexed: 11/02/2022]
Abstract
Translation termination, which liberates a nascent polypeptide from the ribosome specifically at stop codons, must occur accurately and rapidly. We established single-molecule fluorescence assays to track the dynamics of ribosomes and two requisite release factors (eRF1 and eRF3) throughout termination using an in vitro-reconstituted yeast translation system. We found that the two eukaryotic release factors bound together to recognize stop codons rapidly and elicit termination through a tightly regulated, multistep process that resembles transfer RNA selection during translation elongation. Because the release factors are conserved from yeast to humans, the molecular events that underlie yeast translation termination are likely broadly fundamental to eukaryotic protein synthesis.
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Affiliation(s)
- Michael R Lawson
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Laura N Lessen
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
- Program in Molecular Biophysics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jinfan Wang
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Arjun Prabhakar
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Nicholas C Corsepius
- Program in Molecular Biophysics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Rachel Green
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- 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
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.
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31
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Tibbs J, Ghoneim M, Caldwell CC, Buzynski T, Bowie W, Boehm EM, Washington MT, Tabei SMA, Spies M. KERA: analysis tool for multi-process, multi-state single-molecule data. Nucleic Acids Res 2021; 49:e53. [PMID: 33660771 PMCID: PMC8136784 DOI: 10.1093/nar/gkab087] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/17/2021] [Accepted: 02/24/2021] [Indexed: 12/16/2022] Open
Abstract
Molecular machines within cells dynamically assemble, disassemble and reorganize. Molecular interactions between their components can be observed at the single-molecule level and quantified using colocalization single-molecule spectroscopy, in which individual labeled molecules are seen transiently associating with a surface-tethered partner, or other total internal reflection fluorescence microscopy approaches in which the interactions elicit changes in fluorescence in the labeled surface-tethered partner. When multiple interacting partners can form ternary, quaternary and higher order complexes, the types of spatial and temporal organization of these complexes can be deduced from the order of appearance and reorganization of the components. Time evolution of complex architectures can be followed by changes in the fluorescence behavior in multiple channels. Here, we describe the kinetic event resolving algorithm (KERA), a software tool for organizing and sorting the discretized fluorescent trajectories from a range of single-molecule experiments. KERA organizes the data in groups by transition patterns, and displays exhaustive dwell time data for each interaction sequence. Enumerating and quantifying sequences of molecular interactions provides important information regarding the underlying mechanism of the assembly, dynamics and architecture of the macromolecular complexes. We demonstrate KERA's utility by analyzing conformational dynamics of two DNA binding proteins: replication protein A and xeroderma pigmentosum complementation group D helicase.
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Affiliation(s)
- Joseph Tibbs
- Department of Physics, University of Northern Iowa, Cedar Falls, IA 50614, USA
| | - Mohamed Ghoneim
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Colleen C Caldwell
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Troy Buzynski
- Department of Physics, University of Northern Iowa, Cedar Falls, IA 50614, USA
| | - Wayne Bowie
- Department of Physics, University of Northern Iowa, Cedar Falls, IA 50614, USA
| | - Elizabeth M Boehm
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - M Todd Washington
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - S M Ali Tabei
- Department of Physics, University of Northern Iowa, Cedar Falls, IA 50614, USA
| | - Maria Spies
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
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32
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DNMT1 reads heterochromatic H4K20me3 to reinforce LINE-1 DNA methylation. Nat Commun 2021; 12:2490. [PMID: 33941775 PMCID: PMC8093215 DOI: 10.1038/s41467-021-22665-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 03/15/2021] [Indexed: 12/13/2022] Open
Abstract
DNA methylation and trimethylated histone H4 Lysine 20 (H4K20me3) constitute two important heterochromatin-enriched marks that frequently cooperate in silencing repetitive elements of the mammalian genome. However, it remains elusive how these two chromatin modifications crosstalk. Here, we report that DNA methyltransferase 1 (DNMT1) specifically ‘recognizes’ H4K20me3 via its first bromo-adjacent-homology domain (DNMT1BAH1). Engagement of DNMT1BAH1-H4K20me3 ensures heterochromatin targeting of DNMT1 and DNA methylation at LINE-1 retrotransposons, and cooperates with the previously reported readout of histone H3 tail modifications (i.e., H3K9me3 and H3 ubiquitylation) by the RFTS domain to allosterically regulate DNMT1’s activity. Interplay between RFTS and BAH1 domains of DNMT1 profoundly impacts DNA methylation at both global and focal levels and genomic resistance to radiation-induced damage. Together, our study establishes a direct link between H4K20me3 and DNA methylation, providing a mechanism in which multivalent recognition of repressive histone modifications by DNMT1 ensures appropriate DNA methylation patterning and genomic stability. How histone modifications crosstalk with DNA methylation to regulate epigenomic patterning and genome stability in mammals remains elusive. Here, the authors show that DNA methyltransferase DNMT1 is a reader for histone H4K20 trimethylation via its BAH1 domain, which leads to optimal maintenance of DNA methylation at repetitive LINE-1 elements.
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33
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Feng XA, Poyton MF, Ha T. Multicolor single-molecule FRET for DNA and RNA processes. Curr Opin Struct Biol 2021; 70:26-33. [PMID: 33894656 DOI: 10.1016/j.sbi.2021.03.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 03/10/2021] [Indexed: 12/31/2022]
Abstract
Single-molecule fluorescence resonance energy transfer (smFRET) is a useful tool for observing the dynamics of protein-nucleic acid interactions. Although most smFRET measurements have used two fluorophores, multicolor smFRET measurements using more than two fluorophores offer more information about how protein-nucleic acid complexes dynamically move, assemble, and disassemble. Multicolor smFRET experiments include three or more fluorophores and at least one donor-acceptor pair. This review highlights how multicolor smFRET is being used to probe the dynamics of three different classes of biochemical processes-protein-DNA interactions, chromatin remodeling, and protein translation.
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Affiliation(s)
- Xinyu A Feng
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA; Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA
| | - Matthew F Poyton
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Taekjip Ha
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA; Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA; Howard Hughes Medical Institute, Baltimore, MD, USA.
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34
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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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35
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Takahashi S, Oshige M, Katsura S. DNA Manipulation and Single-Molecule Imaging. Molecules 2021; 26:1050. [PMID: 33671359 PMCID: PMC7922115 DOI: 10.3390/molecules26041050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 02/12/2021] [Accepted: 02/14/2021] [Indexed: 11/22/2022] Open
Abstract
DNA replication, repair, and recombination in the cell play a significant role in the regulation of the inheritance, maintenance, and transfer of genetic information. To elucidate the biomolecular mechanism in the cell, some molecular models of DNA replication, repair, and recombination have been proposed. These biological studies have been conducted using bulk assays, such as gel electrophoresis. Because in bulk assays, several millions of biomolecules are subjected to analysis, the results of the biological analysis only reveal the average behavior of a large number of biomolecules. Therefore, revealing the elementary biological processes of a protein acting on DNA (e.g., the binding of protein to DNA, DNA synthesis, the pause of DNA synthesis, and the release of protein from DNA) is difficult. Single-molecule imaging allows the analysis of the dynamic behaviors of individual biomolecules that are hidden during bulk experiments. Thus, the methods for single-molecule imaging have provided new insights into almost all of the aspects of the elementary processes of DNA replication, repair, and recombination. However, in an aqueous solution, DNA molecules are in a randomly coiled state. Thus, the manipulation of the physical form of the single DNA molecules is important. In this review, we provide an overview of the unique studies on DNA manipulation and single-molecule imaging to analyze the dynamic interaction between DNA and protein.
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Affiliation(s)
- Shunsuke Takahashi
- Division of Life Science and Engineering, School of Science and Engineering, Tokyo Denki University, Hatoyama-cho, Hiki-gun, Saitama 350-0394, Japan;
| | - Masahiko Oshige
- Department of Environmental Engineering Science, Graduate School of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan;
- Gunma University Center for Food Science and Wellness (GUCFW), Maebashi, Gunma 371-8510, Japan
| | - Shinji Katsura
- Department of Environmental Engineering Science, Graduate School of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan;
- Gunma University Center for Food Science and Wellness (GUCFW), Maebashi, Gunma 371-8510, Japan
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36
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Lapointe CP, Grosely R, Johnson AG, Wang J, Fernández IS, Puglisi JD. Dynamic competition between SARS-CoV-2 NSP1 and mRNA on the human ribosome inhibits translation initiation. Proc Natl Acad Sci U S A 2021; 118:e2017715118. [PMID: 33479166 PMCID: PMC8017934 DOI: 10.1073/pnas.2017715118] [Citation(s) in RCA: 118] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a beta-CoV that recently emerged as a human pathogen and is the causative agent of the COVID-19 pandemic. A molecular framework of how the virus manipulates host cellular machinery to facilitate infection remains unclear. Here, we focus on SARS-CoV-2 NSP1, which is proposed to be a virulence factor that inhibits protein synthesis by directly binding the human ribosome. We demonstrate biochemically that NSP1 inhibits translation of model human and SARS-CoV-2 messenger RNAs (mRNAs). NSP1 specifically binds to the small (40S) ribosomal subunit, which is required for translation inhibition. Using single-molecule fluorescence assays to monitor NSP1-40S subunit binding in real time, we determine that eukaryotic translation initiation factors (eIFs) allosterically modulate the interaction of NSP1 with ribosomal preinitiation complexes in the absence of mRNA. We further elucidate that NSP1 competes with RNA segments downstream of the start codon to bind the 40S subunit and that the protein is unable to associate rapidly with 80S ribosomes assembled on an mRNA. Collectively, our findings support a model where NSP1 proteins from viruses in at least two subgenera of beta-CoVs associate with the open head conformation of the 40S subunit to inhibit an early step of translation, by preventing accommodation of mRNA within the entry channel.
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Affiliation(s)
- Christopher P Lapointe
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Rosslyn Grosely
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Alex G Johnson
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Jinfan Wang
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Israel S Fernández
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York City, NY 10032
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305;
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37
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Lapointe CP, Grosely R, Johnson AG, Wang J, Fernández IS, Puglisi JD. Dynamic competition between SARS-CoV-2 NSP1 and mRNA on the human ribosome inhibits translation initiation. Proc Natl Acad Sci U S A 2021. [PMID: 33479166 DOI: 10.1101/2020.08.20.259770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a beta-CoV that recently emerged as a human pathogen and is the causative agent of the COVID-19 pandemic. A molecular framework of how the virus manipulates host cellular machinery to facilitate infection remains unclear. Here, we focus on SARS-CoV-2 NSP1, which is proposed to be a virulence factor that inhibits protein synthesis by directly binding the human ribosome. We demonstrate biochemically that NSP1 inhibits translation of model human and SARS-CoV-2 messenger RNAs (mRNAs). NSP1 specifically binds to the small (40S) ribosomal subunit, which is required for translation inhibition. Using single-molecule fluorescence assays to monitor NSP1-40S subunit binding in real time, we determine that eukaryotic translation initiation factors (eIFs) allosterically modulate the interaction of NSP1 with ribosomal preinitiation complexes in the absence of mRNA. We further elucidate that NSP1 competes with RNA segments downstream of the start codon to bind the 40S subunit and that the protein is unable to associate rapidly with 80S ribosomes assembled on an mRNA. Collectively, our findings support a model where NSP1 proteins from viruses in at least two subgenera of beta-CoVs associate with the open head conformation of the 40S subunit to inhibit an early step of translation, by preventing accommodation of mRNA within the entry channel.
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Affiliation(s)
- Christopher P Lapointe
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Rosslyn Grosely
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Alex G Johnson
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Jinfan Wang
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Israel S Fernández
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York City, NY 10032
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305;
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38
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Çetin B, Song GJ, O'Leary SE. Heterogeneous Dynamics of Protein-RNA Interactions across Transcriptome-Derived Messenger RNA Populations. J Am Chem Soc 2020; 142:21249-21253. [PMID: 33315378 DOI: 10.1021/jacs.0c09841] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Dynamic RNA-protein interactions underpin numerous molecular control mechanisms in biology. However, relatively little is known about the kinetic landscape of protein interactions with full-length RNAs. The extent to which interaction kinetics vary for the same RNA element across the transcriptome and the molecular determinants of variability therefore remain poorly defined. Moreover, it is unclear how one protein-RNA interaction might be transduced by RNA to kinetically impact a second. We report a parallelized, real-time single-molecule fluorescence assay for protein interaction kinetics on eukaryotic mRNA populations obtained from cells. We observed ∼100-fold heterogeneity for interactions of the translation initiation factor eIF4E with the universal mRNA 5' cap structure, dominated by steric effects on barrier-height variability for association. We also found that an RNA helicase, eIF4A, independently accelerated eIF4E-cap association. These data support a kinetic mechanism for how mRNA can determine the sensitivity of its translation to reduction in cellular eIF4E concentrations. They also support the view that global RNA structure significantly modulates protein-RNA interaction dynamics and can facilitate real-time communication between protein interactions at distinct sites.
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Affiliation(s)
- Burak Çetin
- Graduate Program in Cell, Molecular, and Developmental Biology, University of California, Riverside, California 92521, United States
| | - Gary J Song
- Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Seán E O'Leary
- Department of Biochemistry, University of California, Riverside, California 92521, United States
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39
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Sobek J, Schlapbach R. Dependence of Fluorescence Quenching of CY3 Oligonucleotide Conjugates on the Oxidation Potential of the Stacking Base Pair. Molecules 2020; 25:molecules25225369. [PMID: 33212871 PMCID: PMC7698394 DOI: 10.3390/molecules25225369] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 11/15/2020] [Accepted: 11/16/2020] [Indexed: 01/02/2023] Open
Abstract
To understand the complex fluorescence properties of astraphloxin (CY3)-labelled oligonucleotides, it is necessary to take into account the redox properties of the nucleobases. In oligonucleotide hybrids, we observed a dependence of the fluorescence intensity on the oxidation potential of the neighbouring base pair. For the series I < A < G < 8-oxoG, the extent of fluorescence quenching follows the trend of decreasing oxidation potentials. In a series of 7 nt hybrids, stacking interactions of CY3 with perfect match and mismatch base pairs were found to stabilise the hybrid by 7–8 kJ/mol. The fluorescence measurements can be explained by complex formation resulting in fluorescence quenching that prevails over the steric effect of a reduced excited state trans-cis isomerisation, which was expected to increase the fluorescence efficiency of the dye when stacking to a base pair. This can be explained by the fact that, in a double strand, base pairing and stacking cause a dramatic change in the oxidation potential of the nucleobases. In single-molecule fluorescence measurements, the oxidation of G to 8-oxoG was observed as a result of photoinduced electron transfer and subsequent chemical reactions. Our results demonstrate that covalently linked CY3 is a potent oxidant towards dsDNA. Sulfonated derivatives should be used instead.
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40
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Baibakov M, Barulin A, Roy P, Claude JB, Patra S, Wenger J. Zero-mode waveguides can be made better: fluorescence enhancement with rectangular aluminum nanoapertures from the visible to the deep ultraviolet. NANOSCALE ADVANCES 2020; 2:4153-4160. [PMID: 36132755 PMCID: PMC9417158 DOI: 10.1039/d0na00366b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 07/20/2020] [Indexed: 05/25/2023]
Abstract
Nanoapertures milled in metallic films called zero-mode waveguides (ZMWs) overcome the limitations of classical confocal microscopes by enabling single molecule analysis at micromolar concentrations with improved fluorescence brightness. While the ZMWs have found many applications in single molecule fluorescence studies, their shape has been mainly limited to be circular. Owing to the large parameter space to explore and the lack of guidelines, earlier attempts using more elaborate shapes have led to unclear conclusions whether or not the performance was improved as compared to a circular ZMW. Here, we comparatively analyze the performance of rectangular-shaped nanoapertures milled in aluminum to enhance the fluorescence emission rate of single molecules from the near infrared to the deep ultraviolet. Our new design is based on rational principles taking maximum advantage of the laser linear polarization. While the long edge of the nanorectangle is set to meet the cut-off size for the propagation of light into the nanoaperture, the short edge is reduced to 30 nm to accelerate the photodynamics while maintaining bright fluorescence rates. Our results show that both in the red and in the ultraviolet, the nanorectangles provide 50% brighter photon count rates as compared to the best performing circular ZMWs and achieve fluorescence lifetimes shorter than 300 ps. These findings can be readily used to improve the performance of ZMWs, especially for fast biomolecular dynamics, bright single-photon sources, and ultraviolet plasmonics.
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Affiliation(s)
- Mikhail Baibakov
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel 13013 Marseille France
| | - Aleksandr Barulin
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel 13013 Marseille France
| | - Prithu Roy
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel 13013 Marseille France
| | - Jean-Benoît Claude
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel 13013 Marseille France
| | - Satyajit Patra
- 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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41
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Sobek J, Schmidt M, Grossmann J, Rehrauer H, Schmidt L, Schlapbach R. Single-molecule chemistry. Part I: monitoring oxidation of G in oligonucleotides using CY3 fluorescence. Methods Appl Fluoresc 2020; 8:035010. [PMID: 32428873 DOI: 10.1088/2050-6120/ab947d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Single-molecule hybridisation of CY3 dye labelled short oligonucleotides to surface immobilised probes was investigated in zero-mode waveguide nanostructures using a modified DNA sequencer. At longer measuring times, we observed changes of the initial hybridisation fluorescence pulse pattern which we attribute to products created by chemical reactions at the nucleobases. The origin is a charge separated state created by a photoinduced electron transfer from nucleobases to the dye followed by secondary reactions with oxygen and water, respectively. The positive charge can migrate through the hybrid resulting in base modifications at distant sites. Static fluorescence spectra were recorded in order to determine the properties of CY3 stacking to different base pairs, and compared to pulse intensities. A characteristic pulse pattern change was assigned to the oxidation of G to 8-oG besides the formation of a number of secondary products that are not yet identified. Further, we present a method to visualise the degree of chemical reactions to gain an overview of ongoing processes. Our study demonstrates that CY3 is able to oxidise nucleobases in ds DNA, and also in ss overhangs. An important finding is the correlation between nucleobase oxidation potential and fluorescence quenching which explains the intensity changes observed in single molecule measurements. The analysis of fluorescence traces provides the opportunity to track complete and coherent reaction sequences enabling to follow the fate of a single molecule over a long period of time, and to observe chemical reactions in real-time. This opens up the opportunity to analyse reaction pathways, to detect new products and short-lived intermediates, and to investigate rare events due to the large number of single molecules observed in parallel.
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Affiliation(s)
- Jens Sobek
- Functional Genomics Center Zurich, Eidgenössische Technische Hochschule (ETH) Zurich and University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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42
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White DS, Goldschen-Ohm MP, Goldsmith RH, Chanda B. Top-down machine learning approach for high-throughput single-molecule analysis. eLife 2020; 9:e53357. [PMID: 32267232 PMCID: PMC7205464 DOI: 10.7554/elife.53357] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 04/08/2020] [Indexed: 12/16/2022] Open
Abstract
Single-molecule approaches provide enormous insight into the dynamics of biomolecules, but adequately sampling distributions of states and events often requires extensive sampling. Although emerging experimental techniques can generate such large datasets, existing analysis tools are not suitable to process the large volume of data obtained in high-throughput paradigms. Here, we present a new analysis platform (DISC) that accelerates unsupervised analysis of single-molecule trajectories. By merging model-free statistical learning with the Viterbi algorithm, DISC idealizes single-molecule trajectories up to three orders of magnitude faster with improved accuracy compared to other commonly used algorithms. Further, we demonstrate the utility of DISC algorithm to probe cooperativity between multiple binding events in the cyclic nucleotide binding domains of HCN pacemaker channel. Given the flexible and efficient nature of DISC, we anticipate it will be a powerful tool for unsupervised processing of high-throughput data across a range of single-molecule experiments.
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Affiliation(s)
- David S White
- Department of Neuroscience, University of Wisconsin-MadisonMadisonUnited States
- Department of Chemistry, University of Wisconsin-MadisonMadisonUnited States
| | | | - Randall H Goldsmith
- Department of Chemistry, University of Wisconsin-MadisonMadisonUnited States
| | - Baron Chanda
- Department of Neuroscience, University of Wisconsin-MadisonMadisonUnited States
- Department of Biomolecular Chemistry University of Wisconsin-MadisonMadisonUnited States
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43
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Schendel LC, Bauer MS, Sedlak SM, Gaub HE. Single-Molecule Manipulation in Zero-Mode Waveguides. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1906740. [PMID: 32141169 DOI: 10.1002/smll.201906740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 02/08/2020] [Indexed: 06/10/2023]
Abstract
The mechanobiology of receptor-ligand interactions and force-induced enzymatic turnover can be revealed by simultaneous measurements of force response and fluorescence. Investigations at physiologically relevant high labeled substrate concentrations require total internal reflection fluorescence microscopy or zero mode waveguides (ZMWs), which are difficult to combine with atomic force microscopy (AFM). A fully automatized workflow is established to manipulate single molecules inside ZMWs autonomously with noninvasive cantilever tip localization. A protein model system comprising a receptor-ligand pair of streptavidin blocked with a biotin-tagged ligand is introduced. The ligand is pulled out of streptavidin by an AFM cantilever leaving the receptor vacant for reoccupation by freely diffusing fluorescently labeled biotin, which can be detected in single-molecule fluorescence concurrently to study rebinding rates. This work illustrates the potential of the seamless fusion of these two powerful single-molecule techniques.
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Affiliation(s)
- Leonard C Schendel
- Lehrstuhl für Angewandte Physik and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Amalienstrasse 54, Munich, 80799, Germany
| | - Magnus S Bauer
- Lehrstuhl für Angewandte Physik and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Amalienstrasse 54, Munich, 80799, Germany
| | - Steffen M Sedlak
- Lehrstuhl für Angewandte Physik and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Amalienstrasse 54, Munich, 80799, Germany
| | - Hermann E Gaub
- Lehrstuhl für Angewandte Physik and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Amalienstrasse 54, Munich, 80799, Germany
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44
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Baibakov M, Patra S, Claude JB, Wenger J. Long-Range Single-Molecule Förster Resonance Energy Transfer between Alexa Dyes in Zero-Mode Waveguides. ACS OMEGA 2020; 5:6947-6955. [PMID: 32258931 PMCID: PMC7114734 DOI: 10.1021/acsomega.0c00322] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 03/05/2020] [Indexed: 06/11/2023]
Abstract
Zero-mode waveguide (ZMW) nano-apertures milled in metal films were proposed to improve the Förster resonance energy transfer (FRET) efficiency and enable single-molecule FRET detection beyond the 10 nm barrier, overcoming the restrictions of diffraction-limited detection in a homogeneous medium. However, the earlier ZMW demonstrations were limited to the Atto 550-Atto 647N fluorophore pair, asking the question whether the FRET enhancement observation was an artifact related to this specific set of fluorescent dyes. Here, we use Alexa Fluor 546 and Alexa Fluor 647 to investigate single-molecule FRET at large donor-acceptor separations exceeding 10 nm inside ZMWs. These Alexa fluorescent dyes feature a markedly different chemical structure, surface charge, and hydrophobicity as compared to their Atto counterparts. Our single molecule data on Alexa 546-Alexa 647 demonstrate enhanced FRET efficiencies at large separations exceeding 10 nm, extending the spatial range available for FRET and confirming the earlier conclusions. By showing that the FRET enhancement inside a ZMW does not depend on the set of fluorescent dyes, this report is an important step to establish the relevance of ZMWs to extend the sensitivity and detection range of FRET, while preserving its ability to work on regular fluorescent dye pairs.
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Affiliation(s)
- Mikhail Baibakov
- Aix Marseille Univ, CNRS, Centrale
Marseille, Institut Fresnel, 13013 Marseille, France
| | - Satyajit Patra
- Aix Marseille Univ, CNRS, Centrale
Marseille, Institut Fresnel, 13013 Marseille, France
| | - Jean-Benoît Claude
- 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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45
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Patra S, Baibakov M, Claude JB, Wenger J. Surface passivation of zero-mode waveguide nanostructures: benchmarking protocols and fluorescent labels. Sci Rep 2020; 10:5235. [PMID: 32251328 PMCID: PMC7089978 DOI: 10.1038/s41598-020-61856-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 12/19/2019] [Indexed: 11/10/2022] Open
Abstract
Zero mode waveguide (ZMW) nanoapertures efficiently confine the light down to the nanometer scale and overcome the diffraction limit in single molecule fluorescence analysis. However, unwanted adhesion of the fluorescent molecules on the ZMW surface can severely hamper the experiments. Therefore a proper surface passivation is required for ZMWs, but information is currently lacking on both the nature of the adhesion phenomenon and the optimization of the different passivation protocols. Here we monitor the influence of the fluorescent dye (Alexa Fluor 546 and 647, Atto 550 and 647N) on the non-specific adhesion of double stranded DNA molecule. We show that the nonspecific adhesion of DNA double strands onto the ZMW surface is directly mediated by the organic fluorescent dye being used, as Atto 550 and Atto 647N show a pronounced tendency to adhere to the ZMW while the Alexa Fluor 546 and 647 are remarkably free of this effect. Despite the small size of the fluorescent label, the surface charge and hydrophobicity of the dye appear to play a key role in promoting the DNA affinity for the ZMW surface. Next, different surface passivation methods (bovine serum albumin BSA, polyethylene glycol PEG, polyvinylphosphonic acid PVPA) are quantitatively benchmarked by fluorescence correlation spectroscopy to determine the most efficient approaches to prevent the adsorption of Atto 647N labeled DNA. Protocols using PVPA and PEG-silane of 1000 Da molar mass are found to drastically avoid the non-specific adsorption into ZMWs. Optimizing both the choice of the fluorescent dye and the surface passivation protocol are highly significant to expand the use of ZMWs for single molecule fluorescence applications.
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Affiliation(s)
- Satyajit Patra
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, 13013, Marseille, France
| | - Mikhail Baibakov
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, 13013, Marseille, France
| | - Jean-Benoît Claude
- 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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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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Verma M, Choi J, Cottrell KA, Lavagnino Z, Thomas EN, Pavlovic-Djuranovic S, Szczesny P, Piston DW, Zaher HS, Puglisi JD, Djuranovic S. A short translational ramp determines the efficiency of protein synthesis. Nat Commun 2019; 10:5774. [PMID: 31852903 PMCID: PMC6920384 DOI: 10.1038/s41467-019-13810-1] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 11/25/2019] [Indexed: 01/26/2023] Open
Abstract
Translation initiation is a major rate-limiting step for protein synthesis. However, recent studies strongly suggest that the efficiency of protein synthesis is additionally regulated by multiple factors that impact the elongation phase. To assess the influence of early elongation on protein synthesis, we employed a library of more than 250,000 reporters combined with in vitro and in vivo protein expression assays. Here we report that the identity of the amino acids encoded by codons 3 to 5 impact protein yield. This effect is independent of tRNA abundance, translation initiation efficiency, or overall mRNA structure. Single-molecule measurements of translation kinetics revealed pausing of the ribosome and aborted protein synthesis on codons 4 and 5 of distinct amino acid and nucleotide compositions. Finally, introduction of preferred sequence motifs only at specific codon positions improves protein synthesis efficiency for recombinant proteins. Collectively, our data underscore the critical role of early elongation events in translational control of gene expression. Several factors contribute to the efficiency of protein expression. Here the authors show that the identity of amino acids encoded by codons at position 3–5 significantly impact translation efficiency and protein expression levels.
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Affiliation(s)
- Manasvi Verma
- Department of Cell Biology and Physiology, Washington University School of Medicine, 600 South Euclid Avenue, Campus Box 8228, St. Louis, MO, 63110, USA
| | - Junhong Choi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, 94305-5126, USA.,Department of Applied Physics, Stanford University, Stanford, CA, 94305-5126, USA.,Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Kyle A Cottrell
- Department of Cell Biology and Physiology, Washington University School of Medicine, 600 South Euclid Avenue, Campus Box 8228, St. Louis, MO, 63110, USA
| | - Zeno Lavagnino
- Department of Cell Biology and Physiology, Washington University School of Medicine, 600 South Euclid Avenue, Campus Box 8228, St. Louis, MO, 63110, USA.,Experimental Imaging Center, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Erica N Thomas
- Department of Biology, Washington University, St Louis, MO, 63105, USA
| | - Slavica Pavlovic-Djuranovic
- Department of Cell Biology and Physiology, Washington University School of Medicine, 600 South Euclid Avenue, Campus Box 8228, St. Louis, MO, 63110, USA
| | - Pawel Szczesny
- Department of Bioinformatics, Institute of Biochemistry and Biophysics Polish Academy of Sciences, Warsaw, Poland
| | - David W Piston
- Department of Cell Biology and Physiology, Washington University School of Medicine, 600 South Euclid Avenue, Campus Box 8228, St. Louis, MO, 63110, USA
| | - Hani S Zaher
- Department of Biology, Washington University, St Louis, MO, 63105, USA
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, 94305-5126, USA
| | - Sergej Djuranovic
- Department of Cell Biology and Physiology, Washington University School of Medicine, 600 South Euclid Avenue, Campus Box 8228, St. Louis, MO, 63110, USA.
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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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Duss O, Stepanyuk GA, Puglisi JD, Williamson JR. Transient Protein-RNA Interactions Guide Nascent Ribosomal RNA Folding. Cell 2019; 179:1357-1369.e16. [PMID: 31761533 DOI: 10.1016/j.cell.2019.10.035] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/18/2019] [Accepted: 10/28/2019] [Indexed: 11/28/2022]
Abstract
Ribosome assembly is an efficient but complex and heterogeneous process during which ribosomal proteins assemble on the nascent rRNA during transcription. Understanding how the interplay between nascent RNA folding and protein binding determines the fate of transcripts remains a major challenge. Here, using single-molecule fluorescence microscopy, we follow assembly of the entire 3' domain of the bacterial small ribosomal subunit in real time. We find that co-transcriptional rRNA folding is complicated by the formation of long-range RNA interactions and that r-proteins self-chaperone the rRNA folding process prior to stable incorporation into a ribonucleoprotein (RNP) complex. Assembly is initiated by transient rather than stable protein binding, and the protein-RNA binding dynamics gradually decrease during assembly. This work questions the paradigm of strictly sequential and cooperative ribosome assembly and suggests that transient binding of RNA binding proteins to cellular RNAs could provide a general mechanism to shape nascent RNA folding during RNP assembly.
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Affiliation(s)
- Olivier Duss
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Galina A Stepanyuk
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - James R Williamson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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50
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Choi J, Grosely R, Puglisi EV, Puglisi JD. Expanding single-molecule fluorescence spectroscopy to capture complexity in biology. Curr Opin Struct Biol 2019; 58:233-240. [PMID: 31213390 PMCID: PMC6778503 DOI: 10.1016/j.sbi.2019.05.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 05/03/2019] [Accepted: 05/08/2019] [Indexed: 11/16/2022]
Abstract
Fundamental biological processes are driven by diverse molecular machineries. In recent years, single-molecule fluorescence spectroscopy has matured as a unique tool in biology to study how structural dynamics of molecular complexes drive various biochemical reactions. In this review, we highlight underlying developments in single-molecule fluorescence methods that enable deep biological investigations. Recent progress in these methods points toward increasing complexity of measurements to capture biological processes in a living cell, where multiple processes often occur simultaneously and are mechanistically coupled.
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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
| | - Rosslyn Grosely
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA
| | - Elisabetta V Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA.
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA.
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