101
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RNase III Domain of KREPB9 and KREPB10 Association with Editosomes in Trypanosoma brucei. mSphere 2018; 3:mSphere00585-17. [PMID: 29359194 PMCID: PMC5770545 DOI: 10.1128/mspheredirect.00585-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 12/20/2017] [Indexed: 01/10/2023] Open
Abstract
Editosomes are the multiprotein complexes that catalyze the insertion and deletion of uridines to create translatable mRNAs in the mitochondria of kinetoplastids. Recognition and cleavage of a broad diversity of RNA substrates in vivo require three functionally distinct RNase III-type endonucleases, as well as five additional editosome proteins that contain noncatalytic RNase III domains. RNase III domains have recently been identified in the editosome accessory proteins KREPB9 and KREPB10, suggesting a role related to editing endonuclease function. In this report, we definitively show that KREPB9 and KREPB10 are not essential in either bloodstream-form parasites (BF) or procyclic-form parasites (PF) by creating null or conditional null cell lines. While preedited and edited transcripts are largely unaffected by the loss of KREPB9 in both PF and BF, loss of KREPB10 produces distinct responses in BF and PF. BF cells lacking KREPB10 also lack edited CYb, while PF cells have increased edited A6, RPS12, ND3, and COII after loss of KREPB10. We also demonstrate that mutation of the RNase III domain of either KREPB9 or KREPB10 results in decreased association with ~20S editosomes. Editosome interactions with KREPB9 and KREPB10 are therefore mediated by the noncatalytic RNase III domain, consistent with a role in endonuclease specialization in Trypanosoma brucei. IMPORTANCETrypanosoma brucei is a protozoan parasite that causes African sleeping sickness. U insertion/deletion RNA editing in T. brucei generates mature mitochondrial mRNAs. Editing is essential for survival in mammalian hosts and tsetse fly vectors and is differentially regulated during the parasite life cycle. Three multiprotein "editosomes," typified by exclusive RNase III endonucleases that act at distinct sites, catalyze editing. Here, we show that editosome accessory proteins KREPB9 and KREPB10 are not essential for mammalian blood- or insect-form parasite survival but have specific and differential effects on edited RNA abundance in different stages. We also characterize KREPB9 and KREPB10 noncatalytic RNase III domains and show they are essential for editosome association, potentially via dimerization with RNase III domains in other editosome proteins. This work enhances the understanding of distinct editosome and accessory protein functions, and thus differential editing, during the parasite life cycle and highlights the importance of RNase III domain interactions to editosome architecture.
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102
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Structural basis of STAT2 recognition by IRF9 reveals molecular insights into ISGF3 function. Proc Natl Acad Sci U S A 2018; 115:E601-E609. [PMID: 29317535 PMCID: PMC5789952 DOI: 10.1073/pnas.1718426115] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Cytokines interact with their receptors and activate JAK–STAT signaling pathways that lead to changes in gene expression. In mammals, there are seven STATs that have arisen due to gene duplication and genetic drift. STATs have similar DNA binding specificity, and how individual STATs have subfunctionalized to regulate very specific cytokine responses in cells is poorly understood. Here we describe X-ray structures that show how one STAT family member, STAT2, specifically pairs with a member of the IRF family of transcription factors, IRF9. Despite overall structural similarity among STAT and IRF family members, surface features in the interacting domains of IRF9 and STAT2 have diverged to enable specific interaction between these family members and to enable the antiviral response. Cytokine signaling through the JAK/STAT pathway controls multiple cellular responses including growth, survival, differentiation, and pathogen resistance. An expansion in the gene regulatory repertoire controlled by JAK/STAT signaling occurs through the interaction of STATs with IRF transcription factors to form ISGF3, a complex that contains STAT1, STAT2, and IRF9 and regulates expression of IFN-stimulated genes. ISGF3 function depends on selective interaction between IRF9, through its IRF-association domain (IAD), with the coiled-coil domain (CCD) of STAT2. Here, we report the crystal structures of the IRF9–IAD alone and in a complex with STAT2–CCD. Despite similarity in the overall structure among respective paralogs, the surface features of the IRF9–IAD and STAT2–CCD have diverged to enable specific interaction between these family members. We derive a model for the ISGF3 complex bound to an ISRE DNA element and demonstrate that the observed interface between STAT2 and IRF9 is required for ISGF3 function in cells.
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103
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Yu C, Huang L. Cross-Linking Mass Spectrometry: An Emerging Technology for Interactomics and Structural Biology. Anal Chem 2018; 90:144-165. [PMID: 29160693 PMCID: PMC6022837 DOI: 10.1021/acs.analchem.7b04431] [Citation(s) in RCA: 218] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Clinton Yu
- Department of Physiology & Biophysics, University of California, Irvine, Irvine, CA 92697
| | - Lan Huang
- Department of Physiology & Biophysics, University of California, Irvine, Irvine, CA 92697
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104
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Piotrowski C, Sinz A. Structural Investigation of Proteins and Protein Complexes by Chemical Cross-Linking/Mass Spectrometry. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1105:101-121. [PMID: 30617826 DOI: 10.1007/978-981-13-2200-6_8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
During the last two decades, cross-linking combined with mass spectrometry (MS) has evolved as a valuable tool to gain structural insights into proteins and protein assemblies. Structural information is obtained by introducing covalent connections between amino acids that are in spatial proximity in proteins and protein complexes. The distance constraints imposed by the cross-linking reagent provide information on the three-dimensional arrangement of the covalently connected amino acid residues and serve as basis for de-novo or homology modeling approaches. As cross-linking/MS allows investigating protein 3D-structures and protein-protein interactions not only in-vitro, but also in-vivo, it is especially appealing for studying protein systems in their native environment. In this chapter, we describe the principles of cross-linking/MS and illustrate its value for investigating protein 3D-structures and for unraveling protein interaction networks.
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Affiliation(s)
- Christine Piotrowski
- Department of Pharmaceutical Chemistry & Bioanalytics, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Andrea Sinz
- Department of Pharmaceutical Chemistry & Bioanalytics, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
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105
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Schilbach S, Hantsche M, Tegunov D, Dienemann C, Wigge C, Urlaub H, Cramer P. Structures of transcription pre-initiation complex with TFIIH and Mediator. Nature 2017; 551:204-209. [PMID: 29088706 PMCID: PMC6078178 DOI: 10.1038/nature24282] [Citation(s) in RCA: 183] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Accepted: 09/14/2017] [Indexed: 12/18/2022]
Abstract
For the initiation of transcription, RNA polymerase II (Pol II) assembles with general transcription factors on promoter DNA to form the pre-initiation complex (PIC). Here we report cryo-electron microscopy structures of the Saccharomyces cerevisiae PIC and PIC-core Mediator complex at nominal resolutions of 4.7 Å and 5.8 Å, respectively. The structures reveal transcription factor IIH (TFIIH), and suggest how the core and kinase TFIIH modules function in the opening of promoter DNA and the phosphorylation of Pol II, respectively. The TFIIH core subunit Ssl2 (a homologue of human XPB) is positioned on downstream DNA by the 'E-bridge' helix in TFIIE, consistent with TFIIE-stimulated DNA opening. The TFIIH kinase module subunit Tfb3 (MAT1 in human) anchors the kinase Kin28 (CDK7), which is mobile in the PIC but preferentially located between the Mediator hook and shoulder in the PIC-core Mediator complex. Open spaces between the Mediator head and middle modules may allow access of the kinase to its substrate, the C-terminal domain of Pol II.
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Affiliation(s)
- S Schilbach
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - M Hantsche
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - D Tegunov
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - C Dienemann
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - C Wigge
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - H Urlaub
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
- University Medical Center Göttingen, Institute of Clinical Chemistry, Bioanalytics Group, Robert-Koch-Straße 40, 37075 Göttingen, Germany
| | - P Cramer
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
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106
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Teimer R, Kosinski J, von Appen A, Beck M, Hurt E. A short linear motif in scaffold Nup145C connects Y-complex with pre-assembled outer ring Nup82 complex. Nat Commun 2017; 8:1107. [PMID: 29062044 PMCID: PMC5653651 DOI: 10.1038/s41467-017-01160-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 08/22/2017] [Indexed: 02/05/2023] Open
Abstract
Nucleocytoplasmic transport occurs through nuclear pore complexes (NPCs), which are formed from multiple copies of ~30 different nucleoporins (Nups) and inserted into the double nuclear membrane. Many of these Nups are organized into subcomplexes, of which the Y-shaped Nup84 complex is the major constituent of the nuclear and cytoplasmic rings. The Nup82–Nup159–Nsp1 complex is another module that, however, is only assembled into the cytoplasmic ring. By means of crosslinking mass spectrometry, biochemical reconstitution, and molecular modeling, we identified a short linear motif in the unstructured N-terminal region of Chaetomium thermophilum Nup145C, a subunit of the Y-complex, that is sufficient to recruit the Nup82 complex, but only in its assembled state. This finding points to a more general mechanism that short linear motifs in structural Nups can act as sensors to cooperatively connect pre-assembled NPC modules, thereby facilitating the formation and regulation of the higher-order NPC assembly. The Nup82–Nup159–Nsp1 complex, which plays a key role in mRNA export, is recruited late during the process of nuclear pore complex (NPC) assembly. Here the authors combine crosslinking mass spectrometry, biochemical reconstitution and molecular modeling to gain insights into the mechanism of Nup82 recruitment to the NPC.
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Affiliation(s)
- Roman Teimer
- Biochemistry Center of Heidelberg University (BZH), Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Jan Kosinski
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, 69117, Heidelberg, Germany
| | - Alexander von Appen
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, 69117, Heidelberg, Germany
| | - Martin Beck
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, 69117, Heidelberg, Germany.
| | - Ed Hurt
- Biochemistry Center of Heidelberg University (BZH), Im Neuenheimer Feld 328, 69120, Heidelberg, Germany.
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107
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Schmidt C, Urlaub H. Combining cryo-electron microscopy (cryo-EM) and cross-linking mass spectrometry (CX-MS) for structural elucidation of large protein assemblies. Curr Opin Struct Biol 2017; 46:157-168. [DOI: 10.1016/j.sbi.2017.10.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 09/21/2017] [Accepted: 10/05/2017] [Indexed: 01/11/2023]
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108
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Eek P, Põldemaa K, Kasvandik S, Järving I, Samel N. A PDZ-like domain mediates the dimerization of 11 R -lipoxygenase. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1121-1128. [DOI: 10.1016/j.bbalip.2017.07.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 07/04/2017] [Accepted: 07/26/2017] [Indexed: 01/18/2023]
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109
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Maes E, Dyer JM, McKerchar HJ, Deb-Choudhury S, Clerens S. Protein-protein cross-linking and human health: the challenge of elucidating with mass spectrometry. Expert Rev Proteomics 2017; 14:917-929. [PMID: 28759730 DOI: 10.1080/14789450.2017.1362336] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
INTRODUCTION In several biomedical research fields, the cross-linking of peptides and proteins has an important impact on health and wellbeing. It is therefore of crucial importance to study this class of post-translational modifications in detail. The huge potential of mass spectrometric technologies in the mapping of these protein-protein cross-links is however overshadowed by the challenges that the field has to overcome. Areas covered: In this review, we summarize the different pitfalls and challenges that the protein-protein cross-linking field is confronted with when using mass spectrometry approaches. We additionally focus on native disulfide bridges as an example and provide some examples of cross-links that are important in the biomedical field. Expert commentary: The current flow of methodological improvements, mainly from the chemical cross-linking field, has delivered a significant contribution to deciphering native and insult-induced cross-links. Although an automated data analysis of proteome-wide peptide cross-linking is currently only possible in chemical cross-linking experiments, the field is well on the way towards a more automated analysis of native and insult-induced cross-links in raw mass spectrometry data that will boost its potential in biomedical applications.
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Affiliation(s)
- Evelyne Maes
- a Food & Bio-Based Products, AgResearch Ltd ., Lincoln , New Zealand
| | - Jolon M Dyer
- a Food & Bio-Based Products, AgResearch Ltd ., Lincoln , New Zealand.,b Biomolecular Interaction Centre , University of Canterbury , Christchurch , New Zealand.,c Riddet Institute, Massey University , Palmerston North , New Zealand.,d Wine, Food & Molecular Biosciences , Lincoln University , Lincoln , New Zealand
| | - Hannah J McKerchar
- a Food & Bio-Based Products, AgResearch Ltd ., Lincoln , New Zealand.,b Biomolecular Interaction Centre , University of Canterbury , Christchurch , New Zealand
| | | | - Stefan Clerens
- a Food & Bio-Based Products, AgResearch Ltd ., Lincoln , New Zealand.,b Biomolecular Interaction Centre , University of Canterbury , Christchurch , New Zealand
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110
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Courcelles M, Coulombe-Huntington J, Cossette É, Gingras AC, Thibault P, Tyers M. CLMSVault: A Software Suite for Protein Cross-Linking Mass-Spectrometry Data Analysis and Visualization. J Proteome Res 2017; 16:2645-2652. [PMID: 28537071 DOI: 10.1021/acs.jproteome.7b00205] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Protein cross-linking mass spectrometry (CL-MS) enables the sensitive detection of protein interactions and the inference of protein complex topology. The detection of chemical cross-links between protein residues can identify intra- and interprotein contact sites or provide physical constraints for molecular modeling of protein structure. Recent innovations in cross-linker design, sample preparation, mass spectrometry, and software tools have significantly improved CL-MS approaches. Although a number of algorithms now exist for the identification of cross-linked peptides from mass spectral data, a dearth of user-friendly analysis tools represent a practical bottleneck to the broad adoption of the approach. To facilitate the analysis of CL-MS data, we developed CLMSVault, a software suite designed to leverage existing CL-MS algorithms and provide intuitive and flexible tools for cross-platform data interpretation. CLMSVault stores and combines complementary information obtained from different cross-linkers and search algorithms. CLMSVault provides filtering, comparison, and visualization tools to support CL-MS analyses and includes a workflow for label-free quantification of cross-linked peptides. An embedded 3D viewer enables the visualization of quantitative data and the mapping of cross-linked sites onto PDB structural models. We demonstrate the application of CLMSVault for the analysis of a noncovalent Cdc34-ubiquitin protein complex cross-linked under different conditions. CLMSVault is open-source software (available at https://gitlab.com/courcelm/clmsvault.git ), and a live demo is available at http://democlmsvault.tyerslab.com/ .
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Affiliation(s)
- Mathieu Courcelles
- Institute for Research in Immunology and Cancer, Université de Montréal , Montréal, Québec H3C 3J7, Canada
| | - Jasmin Coulombe-Huntington
- Institute for Research in Immunology and Cancer, Université de Montréal , Montréal, Québec H3C 3J7, Canada
| | - Émilie Cossette
- Institute for Research in Immunology and Cancer, Université de Montréal , Montréal, Québec H3C 3J7, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute at Sinai Health Service , Toronto, Ontario M5G 1X5, Canada.,Department of Molecular Genetics, University of Toronto , Toronto, Ontario M5S 1A8, Canada
| | - Pierre Thibault
- Institute for Research in Immunology and Cancer, Université de Montréal , Montréal, Québec H3C 3J7, Canada.,Department of Chemistry, Université de Montréal , Montréal, Québec H3C 3J7, Canada
| | - Mike Tyers
- Institute for Research in Immunology and Cancer, Université de Montréal , Montréal, Québec H3C 3J7, Canada.,Department of Medicine, Université de Montréal , Montréal, Québec H3C 3J7, Canada
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111
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Lössl P, van de Waterbeemd M, Heck AJ. The diverse and expanding role of mass spectrometry in structural and molecular biology. EMBO J 2016; 35:2634-2657. [PMID: 27797822 PMCID: PMC5167345 DOI: 10.15252/embj.201694818] [Citation(s) in RCA: 171] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 07/25/2016] [Accepted: 10/07/2016] [Indexed: 12/20/2022] Open
Abstract
The emergence of proteomics has led to major technological advances in mass spectrometry (MS). These advancements not only benefitted MS-based high-throughput proteomics but also increased the impact of mass spectrometry on the field of structural and molecular biology. Here, we review how state-of-the-art MS methods, including native MS, top-down protein sequencing, cross-linking-MS, and hydrogen-deuterium exchange-MS, nowadays enable the characterization of biomolecular structures, functions, and interactions. In particular, we focus on the role of mass spectrometry in integrated structural and molecular biology investigations of biological macromolecular complexes and cellular machineries, highlighting work on CRISPR-Cas systems and eukaryotic transcription complexes.
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Affiliation(s)
- Philip Lössl
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, The Netherlands
- Netherlands Proteomics Center, Utrecht, The Netherlands
| | - Michiel van de Waterbeemd
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, The Netherlands
- Netherlands Proteomics Center, Utrecht, The Netherlands
| | - Albert Jr Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Utrecht, The Netherlands
- Netherlands Proteomics Center, Utrecht, The Netherlands
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112
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Dauden MI, Kosinski J, Kolaj-Robin O, Desfosses A, Ori A, Faux C, Hoffmann NA, Onuma OF, Breunig KD, Beck M, Sachse C, Séraphin B, Glatt S, Müller CW. Architecture of the yeast Elongator complex. EMBO Rep 2016; 18:264-279. [PMID: 27974378 PMCID: PMC5286394 DOI: 10.15252/embr.201643353] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 10/20/2016] [Accepted: 11/08/2016] [Indexed: 11/09/2022] Open
Abstract
The highly conserved eukaryotic Elongator complex performs specific chemical modifications on wobble base uridines of tRNAs, which are essential for proteome stability and homeostasis. The complex is formed by six individual subunits (Elp1-6) that are all equally important for its tRNA modification activity. However, its overall architecture and the detailed reaction mechanism remain elusive. Here, we report the structures of the fully assembled yeast Elongator and the Elp123 sub-complex solved by an integrative structure determination approach showing that two copies of the Elp1, Elp2, and Elp3 subunits form a two-lobed scaffold, which binds Elp456 asymmetrically. Our topological models are consistent with previous studies on individual subunits and further validated by complementary biochemical analyses. Our study provides a structural framework on how the tRNA modification activity is carried out by Elongator.
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Affiliation(s)
- Maria I Dauden
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany
| | - Jan Kosinski
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany
| | - Olga Kolaj-Robin
- Université de Strasbourg, IGBMC, Illkirch, France.,CNRS, IGBMC UMR 7104, Illkirch, France.,Inserm, IGBMC U964, Illkirch, France
| | - Ambroise Desfosses
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany
| | - Alessandro Ori
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany
| | - Celine Faux
- Université de Strasbourg, IGBMC, Illkirch, France.,CNRS, IGBMC UMR 7104, Illkirch, France.,Inserm, IGBMC U964, Illkirch, France
| | - Niklas A Hoffmann
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany
| | - Osita F Onuma
- Institute of Biology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Karin D Breunig
- Institute of Biology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Martin Beck
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany
| | - Carsten Sachse
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany
| | - Bertrand Séraphin
- Université de Strasbourg, IGBMC, Illkirch, France.,CNRS, IGBMC UMR 7104, Illkirch, France.,Inserm, IGBMC U964, Illkirch, France
| | - Sebastian Glatt
- Max Planck Research Group at the Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Christoph W Müller
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany
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113
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Kiosze-Becker K, Ori A, Gerovac M, Heuer A, Nürenberg-Goloub E, Rashid UJ, Becker T, Beckmann R, Beck M, Tampé R. Structure of the ribosome post-recycling complex probed by chemical cross-linking and mass spectrometry. Nat Commun 2016; 7:13248. [PMID: 27824037 PMCID: PMC5105147 DOI: 10.1038/ncomms13248] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 09/15/2016] [Indexed: 02/03/2023] Open
Abstract
Ribosome recycling orchestrated by the ATP binding cassette (ABC) protein ABCE1 can be considered as the final—or the first—step within the cyclic process of protein synthesis, connecting translation termination and mRNA surveillance with re-initiation. An ATP-dependent tweezer-like motion of the nucleotide-binding domains in ABCE1 transfers mechanical energy to the ribosome and tears the ribosome subunits apart. The post-recycling complex (PRC) then re-initiates mRNA translation. Here, we probed the so far unknown architecture of the 1-MDa PRC (40S/30S·ABCE1) by chemical cross-linking and mass spectrometry (XL-MS). Our study reveals ABCE1 bound to the translational factor-binding (GTPase) site with multiple cross-link contacts of the helix–loop–helix motif to the S24e ribosomal protein. Cross-linking of the FeS cluster domain to the ribosomal protein S12 substantiates an extreme lever-arm movement of the FeS cluster domain during ribosome recycling. We were thus able to reconstitute and structurally analyse a key complex in the translational cycle, resembling the link between translation initiation and ribosome recycling. Ribosome recycling orchestrated by ABCE1 connects translation termination and mRNA surveillance mechanisms with re-initiation. Using a cross-linking and mass spectrometry approach, Kiosze-Becker et al. provide new information on the large conformational rearrangements that occur during ribosome recycling.
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Affiliation(s)
- Kristin Kiosze-Becker
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt a.M., Germany
| | - Alessandro Ori
- Structural and Computational Biology Unit, EMBL Heidelberg, Meyerhofstr. 1, 69117 Heidelberg, Germany
| | - Milan Gerovac
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt a.M., Germany
| | - André Heuer
- Gene Center and Center for Integrated Protein Science Munich (CiPSM), Department of Biochemistry, University of Munich, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Elina Nürenberg-Goloub
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt a.M., Germany
| | - Umar Jan Rashid
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt a.M., Germany
| | - Thomas Becker
- Gene Center and Center for Integrated Protein Science Munich (CiPSM), Department of Biochemistry, University of Munich, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Roland Beckmann
- Gene Center and Center for Integrated Protein Science Munich (CiPSM), Department of Biochemistry, University of Munich, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Martin Beck
- Structural and Computational Biology Unit, EMBL Heidelberg, Meyerhofstr. 1, 69117 Heidelberg, Germany
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt a.M., Germany
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114
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Riffle M, Jaschob D, Zelter A, Davis TN. ProXL (Protein Cross-Linking Database): A Platform for Analysis, Visualization, and Sharing of Protein Cross-Linking Mass Spectrometry Data. J Proteome Res 2016; 15:2863-70. [PMID: 27302480 PMCID: PMC4977572 DOI: 10.1021/acs.jproteome.6b00274] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
![]()
ProXL
is a Web application and accompanying database designed for
sharing, visualizing, and analyzing bottom-up protein cross-linking
mass spectrometry data with an emphasis on structural analysis and
quality control. ProXL is designed to be independent of any particular
software pipeline. The import process is simplified by the use of
the ProXL XML data format, which shields developers of data importers
from the relative complexity of the relational database schema. The
database and Web interfaces function equally well for any software
pipeline and allow data from disparate pipelines to be merged and
contrasted. ProXL includes robust public and private data sharing
capabilities, including a project-based interface designed to ensure
security and facilitate collaboration among multiple researchers.
ProXL provides multiple interactive and highly dynamic data visualizations
that facilitate structural-based analysis of the observed cross-links
as well as quality control. ProXL is open-source, well-documented,
and freely available at https://github.com/yeastrc/proxl-web-app.
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Affiliation(s)
- Michael Riffle
- Department of Biochemistry, University of Washington , Seattle, Washington 98195, United States.,Department of Genome Sciences, University of Washington , Seattle, Washington 98195, United States
| | - Daniel Jaschob
- Department of Biochemistry, University of Washington , Seattle, Washington 98195, United States
| | - Alex Zelter
- Department of Biochemistry, University of Washington , Seattle, Washington 98195, United States
| | - Trisha N Davis
- Department of Biochemistry, University of Washington , Seattle, Washington 98195, United States
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115
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Automated structure modeling of large protein assemblies using crosslinks as distance restraints. Nat Methods 2016; 13:515-20. [PMID: 27111507 DOI: 10.1038/nmeth.3838] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 03/19/2016] [Indexed: 11/08/2022]
Abstract
Crosslinking mass spectrometry is increasingly used for structural characterization of multisubunit protein complexes. Chemical crosslinking captures conformational heterogeneity, which typically results in conflicting crosslinks that cannot be satisfied in a single model, making detailed modeling a challenging task. Here we introduce an automated modeling method dedicated to large protein assemblies ('XL-MOD' software is available at http://aria.pasteur.fr/supplementary-data/x-links) that (i) uses a form of spatial restraints that realistically reflects the distribution of experimentally observed crosslinked distances; (ii) automatically deals with ambiguous and/or conflicting crosslinks and identifies alternative conformations within a Bayesian framework; and (iii) allows subunit structures to be flexible during conformational sampling. We demonstrate our method by testing it on known structures and available crosslinking data. We also crosslinked and modeled the 17-subunit yeast RNA polymerase III at atomic resolution; the resulting model agrees remarkably well with recently published cryoelectron microscopy structures and provides additional insights into the polymerase structure.
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116
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Makowski MM, Willems E, Jansen PWTC, Vermeulen M. Cross-linking immunoprecipitation-MS (xIP-MS): Topological Analysis of Chromatin-associated Protein Complexes Using Single Affinity Purification. Mol Cell Proteomics 2016; 15:854-65. [PMID: 26560067 PMCID: PMC4813705 DOI: 10.1074/mcp.m115.053082] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 11/04/2015] [Indexed: 12/31/2022] Open
Abstract
In recent years, cross-linking mass spectrometry has proven to be a robust and effective method of interrogating macromolecular protein complex topologies at peptide resolution. Traditionally, cross-linking mass spectrometry workflows have utilized homogenous complexes obtained through time-limiting reconstitution, tandem affinity purification, and conventional chromatography workflows. Here, we present cross-linking immunoprecipitation-MS (xIP-MS), a simple, rapid, and efficient method for structurally probing chromatin-associated protein complexes using small volumes of mammalian whole cell lysates, single affinity purification, and on-bead cross-linking followed by LC-MS/MS analysis. We first benchmarked xIP-MS using the structurally well-characterized phosphoribosyl pyrophosphate synthetase complex. We then applied xIP-MS to the chromatin-associated cohesin (SMC1A/3), XRCC5/6 (Ku70/86), and MCM complexes, and we provide novel structural and biological insights into their architectures and molecular function. Of note, we use xIP-MS to perform topological studies under cell cycle perturbations, showing that the xIP-MS protocol is sufficiently straightforward and efficient to allow comparative cross-linking experiments. This work, therefore, demonstrates that xIP-MS is a robust, flexible, and widely applicable methodology for interrogating chromatin-associated protein complex architectures.
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Affiliation(s)
- Matthew M Makowski
- From the ‡Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Geert Grooteplein 28, 6525 GA Nijmegen, the Netherlands
| | - Esther Willems
- From the ‡Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Geert Grooteplein 28, 6525 GA Nijmegen, the Netherlands
| | - Pascal W T C Jansen
- From the ‡Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Geert Grooteplein 28, 6525 GA Nijmegen, the Netherlands
| | - Michiel Vermeulen
- From the ‡Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Geert Grooteplein 28, 6525 GA Nijmegen, the Netherlands; §Cancer Genomics Netherlands, University Medical Center Utrecht, 3584 CG Utrecht, the Netherlands
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117
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Thierry E, Guilligay D, Kosinski J, Bock T, Gaudon S, Round A, Pflug A, Hengrung N, El Omari K, Baudin F, Hart DJ, Beck M, Cusack S. Influenza Polymerase Can Adopt an Alternative Configuration Involving a Radical Repacking of PB2 Domains. Mol Cell 2016; 61:125-37. [PMID: 26711008 PMCID: PMC4712189 DOI: 10.1016/j.molcel.2015.11.016] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 10/13/2015] [Accepted: 11/05/2015] [Indexed: 01/26/2023]
Abstract
Influenza virus polymerase transcribes or replicates the segmented RNA genome (vRNA) into respectively viral mRNA or full-length copies and initiates RNA synthesis by binding the conserved 3' and 5' vRNA ends (the promoter). In recent structures of promoter-bound polymerase, the cap-binding and endonuclease domains are configured for cap snatching, which generates capped transcription primers. Here, we present a FluB polymerase structure with a bound complementary cRNA 5' end that exhibits a major rearrangement of the subdomains within the C-terminal two-thirds of PB2 (PB2-C). Notably, the PB2 nuclear localization signal (NLS)-containing domain translocates ∼90 Å to bind to the endonuclease domain. FluA PB2-C alone and RNA-free FluC polymerase are similarly arranged. Biophysical and cap-dependent endonuclease assays show that in solution the polymerase explores different conformational distributions depending on which RNA is bound. The inherent flexibility of the polymerase allows it to adopt alternative conformations that are likely important during polymerase maturation into active progeny RNPs.
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Affiliation(s)
- Eric Thierry
- European Molecular Biology Laboratory Grenoble Outstation and Unit of Virus Host-Cell Interactions, University Grenoble Alpes-CNRS-EMBL, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Delphine Guilligay
- European Molecular Biology Laboratory Grenoble Outstation and Unit of Virus Host-Cell Interactions, University Grenoble Alpes-CNRS-EMBL, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Jan Kosinski
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Thomas Bock
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Stephanie Gaudon
- European Molecular Biology Laboratory Grenoble Outstation and Unit of Virus Host-Cell Interactions, University Grenoble Alpes-CNRS-EMBL, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Adam Round
- European Molecular Biology Laboratory Grenoble Outstation and Unit of Virus Host-Cell Interactions, University Grenoble Alpes-CNRS-EMBL, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Alexander Pflug
- European Molecular Biology Laboratory Grenoble Outstation and Unit of Virus Host-Cell Interactions, University Grenoble Alpes-CNRS-EMBL, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Narin Hengrung
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK; Division of Structural Biology, Henry Wellcome Building for Genomic Medicine, University of Oxford, Oxford OX3 7BN, UK
| | - Kamel El Omari
- Division of Structural Biology, Henry Wellcome Building for Genomic Medicine, University of Oxford, Oxford OX3 7BN, UK
| | - Florence Baudin
- European Molecular Biology Laboratory Grenoble Outstation and Unit of Virus Host-Cell Interactions, University Grenoble Alpes-CNRS-EMBL, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France; Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Darren J Hart
- European Molecular Biology Laboratory Grenoble Outstation and Unit of Virus Host-Cell Interactions, University Grenoble Alpes-CNRS-EMBL, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Martin Beck
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Stephen Cusack
- European Molecular Biology Laboratory Grenoble Outstation and Unit of Virus Host-Cell Interactions, University Grenoble Alpes-CNRS-EMBL, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France.
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118
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Leitner A, Faini M, Stengel F, Aebersold R. Crosslinking and Mass Spectrometry: An Integrated Technology to Understand the Structure and Function of Molecular Machines. Trends Biochem Sci 2016; 41:20-32. [DOI: 10.1016/j.tibs.2015.10.008] [Citation(s) in RCA: 226] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 10/18/2015] [Accepted: 10/29/2015] [Indexed: 01/30/2023]
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119
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Hoffmann NA, Jakobi AJ, Moreno-Morcillo M, Glatt S, Kosinski J, Hagen WJH, Sachse C, Müller CW. Molecular structures of unbound and transcribing RNA polymerase III. Nature 2015; 528:231-6. [PMID: 26605533 PMCID: PMC4681132 DOI: 10.1038/nature16143] [Citation(s) in RCA: 139] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 10/13/2015] [Indexed: 12/11/2022]
Abstract
Transcription of genes encoding small structured RNAs such as transfer RNAs, spliceosomal U6 small nuclear RNA and ribosomal 5S RNA is carried out by RNA polymerase III (Pol III), the largest yet structurally least characterized eukaryotic RNA polymerase. Here we present the cryo-electron microscopy structures of the Saccharomyces cerevisiae Pol III elongating complex at 3.9 Å resolution and the apo Pol III enzyme in two different conformations at 4.6 and 4.7 Å resolution, respectively, which allow the building of a 17-subunit atomic model of Pol III. The reconstructions reveal the precise orientation of the C82-C34-C31 heterotrimer in close proximity to the stalk. The C53-C37 heterodimer positions residues involved in transcription termination close to the non-template DNA strand. In the apo Pol III structures, the stalk adopts different orientations coupled with closed and open conformations of the clamp. Our results provide novel insights into Pol III-specific transcription and the adaptation of Pol III towards its small transcriptional targets.
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Affiliation(s)
- Niklas A. Hoffmann
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Arjen J. Jakobi
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
- European Molecular Biology Laboratory (EMBL), Hamburg Unit, Notkestr. 85, 22607 Hamburg, Germany
| | - Maria Moreno-Morcillo
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Sebastian Glatt
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Jan Kosinski
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Wim J. H. Hagen
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Carsten Sachse
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Correspondence and requests for materials should be addressed to C.S. () or C.W.M. ()
| | - Christoph W. Müller
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Correspondence and requests for materials should be addressed to C.S. () or C.W.M. ()
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120
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Bricker TM, Mummadisetti MP, Frankel LK. Recent advances in the use of mass spectrometry to examine structure/function relationships in photosystem II. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2015; 152:227-46. [PMID: 26390944 DOI: 10.1016/j.jphotobiol.2015.08.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 08/27/2015] [Accepted: 08/31/2015] [Indexed: 01/24/2023]
Abstract
Tandem mass spectrometry often coupled with chemical modification techniques, is developing into increasingly important tool in structural biology. These methods can provide important supplementary information concerning the structural organization and subunit make-up of membrane protein complexes, identification of conformational changes occurring during enzymatic reactions, identification of the location of posttranslational modifications, and elucidation of the structure of assembly and repair complexes. In this review, we will present a brief introduction to Photosystem II, tandem mass spectrometry and protein modification techniques that have been used to examine the photosystem. We will then discuss a number of recent case studies that have used these techniques to address open questions concerning PS II. These include the nature of subunit-subunit interactions within the phycobilisome, the interaction of phycobilisomes with Photosystem I and the Orange Carotenoid Protein, the location of CyanoQ, PsbQ and PsbP within Photosystem II, and the identification of phosphorylation and oxidative modification sites within the photosystem. Finally, we will discuss some of the future prospects for the use of these methods in examining other open questions in PS II structural biochemistry.
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Affiliation(s)
- Terry M Bricker
- Department of Biological Sciences, Division of Biochemistry and Molecular Biology, Louisiana State University, Baton Rouge, LA 70803, United States.
| | - Manjula P Mummadisetti
- Department of Biological Sciences, Division of Biochemistry and Molecular Biology, Louisiana State University, Baton Rouge, LA 70803, United States
| | - Laurie K Frankel
- Department of Biological Sciences, Division of Biochemistry and Molecular Biology, Louisiana State University, Baton Rouge, LA 70803, United States
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121
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Dodonova SO, Diestelkoetter-Bachert P, von Appen A, Hagen WJH, Beck R, Beck M, Wieland F, Briggs JAG. VESICULAR TRANSPORT. A structure of the COPI coat and the role of coat proteins in membrane vesicle assembly. Science 2015; 349:195-8. [PMID: 26160949 DOI: 10.1126/science.aab1121] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Transport of material within cells is mediated by trafficking vesicles that bud from one cellular compartment and fuse with another. Formation of a trafficking vesicle is driven by membrane coats that localize cargo and polymerize into cages to bend the membrane. Although extensive structural information is available for components of these coats, the heterogeneity of trafficking vesicles has prevented an understanding of how complete membrane coats assemble on the membrane. We combined cryo-electron tomography, subtomogram averaging, and cross-linking mass spectrometry to derive a complete model of the assembled coat protein complex I (COPI) coat involved in traffic between the Golgi and the endoplasmic reticulum. The highly interconnected COPI coat structure contradicted the current "adaptor-and-cage" understanding of coated vesicle formation.
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Affiliation(s)
- S O Dodonova
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - P Diestelkoetter-Bachert
- Heidelberg University Biochemistry Center, Heidelberg University, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - A von Appen
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - W J H Hagen
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - R Beck
- Heidelberg University Biochemistry Center, Heidelberg University, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - M Beck
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - F Wieland
- Heidelberg University Biochemistry Center, Heidelberg University, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - J A G Briggs
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany. Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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122
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Architecture of TFIIIC and its role in RNA polymerase III pre-initiation complex assembly. Nat Commun 2015; 6:7387. [PMID: 26060179 PMCID: PMC4490372 DOI: 10.1038/ncomms8387] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 05/04/2015] [Indexed: 02/05/2023] Open
Abstract
In eukaryotes, RNA Polymerase III (Pol III) is specifically responsible for transcribing genes encoding tRNAs and other short non-coding RNAs. The recruitment of Pol III to tRNA-encoding genes requires the transcription factors (TF) IIIB and IIIC. TFIIIC has been described as a conserved, multi-subunit protein complex composed of two subcomplexes, called τA and τB. How these two subcomplexes are linked and how their interaction affects the formation of the Pol III pre-initiation complex (PIC) is poorly understood. Here we use chemical crosslinking mass spectrometry and determine the molecular architecture of TFIIIC. We further report the crystal structure of the essential TPR array from τA subunit τ131 and characterize its interaction with a central region of τB subunit τ138. The identified τ131–τ138 interacting region is essential in vivo and overlaps with TFIIIB-binding sites, revealing a crucial interaction platform for the regulation of tRNA transcription initiation. TFIIIC is a RNA polymerase III-specific general transcription factor complex essential for tRNA synthesis. Here the authors combine chemical crosslinking/mass spectrometry and X-ray crystallography to define the architecture of TFIIIC and suggest a model for the assembly of pre-initiation complexes at tRNA genes.
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123
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Grimm M, Zimniak T, Kahraman A, Herzog F. xVis: a web server for the schematic visualization and interpretation of crosslink-derived spatial restraints. Nucleic Acids Res 2015; 43:W362-9. [PMID: 25956653 PMCID: PMC4489277 DOI: 10.1093/nar/gkv463] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 04/27/2015] [Indexed: 01/31/2023] Open
Abstract
The identification of crosslinks by mass spectrometry has recently been established as an integral part of the hybrid structural analysis of protein complexes and networks. The crosslinking analysis determines distance restraints between two covalently linked amino acids which are typically summarized in a table format that precludes the immediate and comprehensive interpretation of the topological data. xVis displays crosslinks in clear schematic representations in form of a circular, bar or network diagram. The interactive graphs indicate the linkage sites and identification scores, depict the spatial proximity of structurally and functionally annotated protein regions and the evolutionary conservation of amino acids and facilitate clustering of proteins into subcomplexes according to the crosslink density. Furthermore, xVis offers two options for the qualitative assessment of the crosslink identifications by filtering crosslinks according to identification scores or false discovery rates and by displaying the corresponding fragment ion spectrum of each crosslink for the manual validation of the mass spectrometric data. Our web server provides an easy-to-use tool for the fast topological and functional interpretation of distance information on protein complex architectures and for the evaluation of crosslink fragment ion spectra. xVis is available under a Creative Commons Attribution-ShareAlike 4.0 International license at http://xvis.genzentrum.lmu.de/.
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Affiliation(s)
- Maximilian Grimm
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich 81377, Germany
| | - Tomasz Zimniak
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich 81377, Germany
| | - Abdullah Kahraman
- Institute of Molecular Life Sciences, University of Zurich, Zurich 8057, Switzerland
| | - Franz Herzog
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich 81377, Germany
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