1
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Fersht AR. From covalent transition states in chemistry to noncovalent in biology: from β- to Φ-value analysis of protein folding. Q Rev Biophys 2024; 57:e4. [PMID: 38597675 DOI: 10.1017/s0033583523000045] [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: 04/11/2024]
Abstract
Solving the mechanism of a chemical reaction requires determining the structures of all the ground states on the pathway and the elusive transition states linking them. 2024 is the centenary of Brønsted's landmark paper that introduced the β-value and structure-activity studies as the only experimental means to infer the structures of transition states. It involves making systematic small changes in the covalent structure of the reactants and analysing changes in activation and equilibrium-free energies. Protein engineering was introduced for an analogous procedure, Φ-value analysis, to analyse the noncovalent interactions in proteins central to biological chemistry. The methodology was developed first by analysing noncovalent interactions in transition states in enzyme catalysis. The mature procedure was then applied to study transition states in the pathway of protein folding - 'part (b) of the protein folding problem'. This review describes the development of Φ-value analysis of transition states and compares and contrasts the interpretation of β- and Φ-values and their limitations. Φ-analysis afforded the first description of transition states in protein folding at the level of individual residues. It revealed the nucleation-condensation folding mechanism of protein domains with the transition state as an expanded, distorted native structure, containing little fully formed secondary structure but many weak tertiary interactions. A spectrum of transition states with various degrees of structural polarisation was then uncovered that spanned from nucleation-condensation to the framework mechanism of fully formed secondary structure. Φ-analysis revealed how movement of the expanded transition state on an energy landscape accommodates the transition from framework to nucleation-condensation mechanisms with a malleability of structure as a unifying feature of folding mechanisms. Such movement follows the rubric of analysis of classical covalent chemical mechanisms that began with Brønsted. Φ-values are used to benchmark computer simulation, and Φ and simulation combine to describe folding pathways at atomic resolution.
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Affiliation(s)
- Alan R Fersht
- MRC Laboratory of Molecular Biology, Cambridge, UK
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- Gonville and Caius College, University of Cambridge, Cambridge, UK
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2
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Sahtoe DD, Andrzejewska EA, Han HL, Rennella E, Schneider MM, Meisl G, Ahlrichs M, Decarreau J, Nguyen H, Kang A, Levine P, Lamb M, Li X, Bera AK, Kay LE, Knowles TPJ, Baker D. Design of amyloidogenic peptide traps. Nat Chem Biol 2024:10.1038/s41589-024-01578-5. [PMID: 38503834 DOI: 10.1038/s41589-024-01578-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 02/09/2024] [Indexed: 03/21/2024]
Abstract
Segments of proteins with high β-strand propensity can self-associate to form amyloid fibrils implicated in many diseases. We describe a general approach to bind such segments in β-strand and β-hairpin conformations using de novo designed scaffolds that contain deep peptide-binding clefts. The designs bind their cognate peptides in vitro with nanomolar affinities. The crystal structure of a designed protein-peptide complex is close to the design model, and NMR characterization reveals how the peptide-binding cleft is protected in the apo state. We use the approach to design binders to the amyloid-forming proteins transthyretin, tau, serum amyloid A1 and amyloid β1-42 (Aβ42). The Aβ binders block the assembly of Aβ fibrils as effectively as the most potent of the clinically tested antibodies to date and protect cells from toxic Aβ42 species.
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Affiliation(s)
- Danny D Sahtoe
- Department of Biochemistry, University of Washington, Seattle, WA, USA.
- Institute for Protein Design, University of Washington, Seattle, WA, USA.
- HHMI, University of Washington, Seattle, WA, USA.
- Hubrecht Institute, Utrecht, the Netherlands.
| | - Ewa A Andrzejewska
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Hannah L Han
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Enrico Rennella
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | | | - Georg Meisl
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Maggie Ahlrichs
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Justin Decarreau
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Hannah Nguyen
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Alex Kang
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Paul Levine
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Mila Lamb
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Xinting Li
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Asim K Bera
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Lewis E Kay
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Tuomas P J Knowles
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, WA, USA.
- Institute for Protein Design, University of Washington, Seattle, WA, USA.
- HHMI, University of Washington, Seattle, WA, USA.
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3
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Dávalos AL, Rivera Echeverri JD, Favaro DC, Junio de Oliveira R, Penteado Battesini Carretero G, Lacerda C, Midea Cuccovia I, Cangussu Cardoso MV, Farah CS, Kopke Salinas R. Uncovering the Association Mechanism between Two Intrinsically Flexible Proteins. ACS Chem Biol 2024; 19:669-686. [PMID: 38486495 DOI: 10.1021/acschembio.3c00649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
The understanding of protein-protein interaction mechanisms is key to the atomistic description of cell signaling pathways and for the development of new drugs. In this context, the mechanism of intrinsically disordered proteins folding upon binding has attracted attention. The VirB9 C-terminal domain (VirB9Ct) and the VirB7 N-terminal motif (VirB7Nt) associate with VirB10 to form the outer membrane core complex of the Type IV Secretion System injectisome. Despite forming a stable and rigid complex, VirB7Nt behaves as a random coil, while VirB9Ct is intrinsically dynamic in the free state. Here we combined NMR, stopped-flow fluorescence, and computer simulations using structure-based models to characterize the VirB9Ct-VirB7Nt coupled folding and binding mechanism. Qualitative data analysis suggested that VirB9Ct preferentially binds to VirB7Nt by way of a conformational selection mechanism at lower temperatures. However, at higher temperatures, energy barriers between different VirB9Ct conformations are more easily surpassed. Under these conditions the formation of non-native initial encounter complexes may provide alternative pathways toward the native complex conformation. These observations highlight the intimate relationship between folding and binding, calling attention to the fact that the two molecular partners must search for the most favored intramolecular and intermolecular interactions on a rugged and funnelled conformational energy landscape, along which multiple intermediates may lead to the final native state.
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Affiliation(s)
- Angy Liseth Dávalos
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, 05508-000, Brazil
| | | | - Denize C Favaro
- Department of Organic Chemistry, State University of Campinas, Campinas, 13083-862, Brazil
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, New York 10031, United States
| | - Ronaldo Junio de Oliveira
- Department of Physics, Institute of Exact, Natural and Educational Sciences, Federal University of Triângulo Mineiro, Uberaba, 38064-200, Brazil
| | | | - Caroline Lacerda
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Iolanda Midea Cuccovia
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, 05508-000, Brazil
| | | | - Chuck S Farah
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Roberto Kopke Salinas
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, 05508-000, Brazil
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4
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Holehouse AS, Kragelund BB. The molecular basis for cellular function of intrinsically disordered protein regions. Nat Rev Mol Cell Biol 2024; 25:187-211. [PMID: 37957331 DOI: 10.1038/s41580-023-00673-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2023] [Indexed: 11/15/2023]
Abstract
Intrinsically disordered protein regions exist in a collection of dynamic interconverting conformations that lack a stable 3D structure. These regions are structurally heterogeneous, ubiquitous and found across all kingdoms of life. Despite the absence of a defined 3D structure, disordered regions are essential for cellular processes ranging from transcriptional control and cell signalling to subcellular organization. Through their conformational malleability and adaptability, disordered regions extend the repertoire of macromolecular interactions and are readily tunable by their structural and chemical context, making them ideal responders to regulatory cues. Recent work has led to major advances in understanding the link between protein sequence and conformational behaviour in disordered regions, yet the link between sequence and molecular function is less well defined. Here we consider the biochemical and biophysical foundations that underlie how and why disordered regions can engage in productive cellular functions, provide examples of emerging concepts and discuss how protein disorder contributes to intracellular information processing and regulation of cellular function.
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Affiliation(s)
- Alex S Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St Louis, MO, USA.
- Center for Biomolecular Condensates, Washington University in St Louis, St Louis, MO, USA.
| | - Birthe B Kragelund
- REPIN, Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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5
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Sisk TR, Robustelli P. Folding-upon-binding pathways of an intrinsically disordered protein from a deep Markov state model. Proc Natl Acad Sci U S A 2024; 121:e2313360121. [PMID: 38294935 PMCID: PMC10861926 DOI: 10.1073/pnas.2313360121] [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: 08/10/2023] [Accepted: 11/22/2023] [Indexed: 02/02/2024] Open
Abstract
A central challenge in the study of intrinsically disordered proteins is the characterization of the mechanisms by which they bind their physiological interaction partners. Here, we utilize a deep learning-based Markov state modeling approach to characterize the folding-upon-binding pathways observed in a long timescale molecular dynamics simulation of a disordered region of the measles virus nucleoprotein NTAIL reversibly binding the X domain of the measles virus phosphoprotein complex. We find that folding-upon-binding predominantly occurs via two distinct encounter complexes that are differentiated by the binding orientation, helical content, and conformational heterogeneity of NTAIL. We observe that folding-upon-binding predominantly proceeds through a multi-step induced fit mechanism with several intermediates and do not find evidence for the existence of canonical conformational selection pathways. We observe four kinetically separated native-like bound states that interconvert on timescales of eighty to five hundred nanoseconds. These bound states share a core set of native intermolecular contacts and stable NTAIL helices and are differentiated by a sequential formation of native and non-native contacts and additional helical turns. Our analyses provide an atomic resolution structural description of intermediate states in a folding-upon-binding pathway and elucidate the nature of the kinetic barriers between metastable states in a dynamic and heterogenous, or "fuzzy", protein complex.
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Affiliation(s)
- Thomas R. Sisk
- Department of Chemistry, Dartmouth College, Hanover, NH03755
| | - Paul Robustelli
- Department of Chemistry, Dartmouth College, Hanover, NH03755
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6
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Brown KA, Gellman SH. Effects of Replacing a Central Glycine Residue in GLP-1 on Receptor Affinity and Signaling Profile. Chembiochem 2023; 24:e202300504. [PMID: 37624685 PMCID: PMC10666649 DOI: 10.1002/cbic.202300504] [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: 07/10/2023] [Revised: 08/23/2023] [Accepted: 08/23/2023] [Indexed: 08/27/2023]
Abstract
Agonists of the glucagon-like peptide-1 receptor (GLP-1R) are used to treat diabetes and obesity. Cryo-EM structures indicate that GLP-1 is completely α-helical when bound to the GLP-1R. The mature form of this hormone, GLP-1(7-36), contains a glycine residue near the center (Gly22). Since glycine has the second-lowest α-helix propensity among the proteinogenic α-amino acid residues, and Gly22 does not appear to make direct contact with the receptor, we were motivated to explore the impact on agonist activity of altering the α-helix propensity at this position. We examined GLP-1 analogues in which Gly22 was replaced with L-Ala, D-Ala, or β-amino acid residues with varying helix propensities. The results suggest that the receptor is reasonably tolerant of variations in helix propensity, and that the functional receptor-agonist complex may comprise a conformational spectrum rather than a single fixed structure.
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Affiliation(s)
- Kyle A. Brown
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Samuel H. Gellman
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
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7
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Liang P, Lister K, Yates L, Argunhan B, Zhang X. Phosphoregulation of DNA repair via the Rad51 auxiliary factor Swi5-Sfr1. J Biol Chem 2023; 299:104929. [PMID: 37330173 PMCID: PMC10366545 DOI: 10.1016/j.jbc.2023.104929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 06/19/2023] Open
Abstract
Homologous recombination (HR) is a major pathway for the repair of DNA double-strand breaks, the most severe form of DNA damage. The Rad51 protein is central to HR, but multiple auxiliary factors regulate its activity. The heterodimeric Swi5-Sfr1 complex is one such factor. It was previously shown that two sites within the intrinsically disordered domain of Sfr1 are critical for the interaction with Rad51. Here, we show that phosphorylation of five residues within this domain regulates the interaction of Swi5-Sfr1 with Rad51. Biochemical reconstitutions demonstrated that a phosphomimetic mutant version of Swi5-Sfr1 is defective in both the physical and functional interaction with Rad51. This translated to a defect in DNA repair, with the phosphomimetic mutant yeast strain phenocopying a previously established interaction mutant. Interestingly, a strain in which Sfr1 phosphorylation was blocked also displayed sensitivity to DNA damage. Taken together, we propose that controlled phosphorylation of Sfr1 is important for the role of Swi5-Sfr1 in promoting Rad51-dependent DNA repair.
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Affiliation(s)
- Pengtao Liang
- Section of Structural and Synthetic Biology, Faculty of Medicine, Imperial College London, London, UK
| | - Katie Lister
- Section of Structural and Synthetic Biology, Faculty of Medicine, Imperial College London, London, UK
| | - Luke Yates
- Section of Structural and Synthetic Biology, Faculty of Medicine, Imperial College London, London, UK
| | - Bilge Argunhan
- Section of Structural and Synthetic Biology, Faculty of Medicine, Imperial College London, London, UK.
| | - Xiaodong Zhang
- Section of Structural and Synthetic Biology, Faculty of Medicine, Imperial College London, London, UK.
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8
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Sisk T, Robustelli P. Folding-upon-binding pathways of an intrinsically disordered protein from a deep Markov state model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.21.550103. [PMID: 37546728 PMCID: PMC10401938 DOI: 10.1101/2023.07.21.550103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
A central challenge in the study of intrinsically disordered proteins is the characterization of the mechanisms by which they bind their physiological interaction partners. Here, we utilize a deep learning based Markov state modeling approach to characterize the folding-upon-binding pathways observed in a long-time scale molecular dynamics simulation of a disordered region of the measles virus nucleoprotein NTAIL reversibly binding the X domain of the measles virus phosphoprotein complex. We find that folding-upon-binding predominantly occurs via two distinct encounter complexes that are differentiated by the binding orientation, helical content, and conformational heterogeneity of NTAIL. We do not, however, find evidence for the existence of canonical conformational selection or induced fit binding pathways. We observe four kinetically separated native-like bound states that interconvert on time scales of eighty to five hundred nanoseconds. These bound states share a core set of native intermolecular contacts and stable NTAIL helices and are differentiated by a sequential formation of native and non-native contacts and additional helical turns. Our analyses provide an atomic resolution structural description of intermediate states in a folding-upon-binding pathway and elucidate the nature of the kinetic barriers between metastable states in a dynamic and heterogenous, or "fuzzy", protein complex.
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Affiliation(s)
- Thomas Sisk
- Dartmouth College, Department of Chemistry, Hanover, NH, 03755
| | - Paul Robustelli
- Dartmouth College, Department of Chemistry, Hanover, NH, 03755
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9
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Madhurima K, Nandi B, Munshi S, Naganathan AN, Sekhar A. Functional regulation of an intrinsically disordered protein via a conformationally excited state. SCIENCE ADVANCES 2023; 9:eadh4591. [PMID: 37379390 PMCID: PMC10306299 DOI: 10.1126/sciadv.adh4591] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 05/23/2023] [Indexed: 06/30/2023]
Abstract
A longstanding goal in the field of intrinsically disordered proteins (IDPs) is to characterize their structural heterogeneity and pinpoint the role of this heterogeneity in IDP function. Here, we use multinuclear chemical exchange saturation (CEST) nuclear magnetic resonance to determine the structure of a thermally accessible globally folded excited state in equilibrium with the intrinsically disordered native ensemble of a bacterial transcriptional regulator CytR. We further provide evidence from double resonance CEST experiments that the excited state, which structurally resembles the DNA-bound form of cytidine repressor (CytR), recognizes DNA by means of a "folding-before-binding" conformational selection pathway. The disorder-to-order regulatory switch in DNA recognition by natively disordered CytR therefore operates through a dynamical variant of the lock-and-key mechanism where the structurally complementary conformation is transiently accessed via thermal fluctuations.
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Affiliation(s)
- Kulkarni Madhurima
- Molecular Biophysics Unit, Indian Institute of Science Bangalore, Bengaluru 560 012, India
| | - Bodhisatwa Nandi
- Molecular Biophysics Unit, Indian Institute of Science Bangalore, Bengaluru 560 012, India
| | - Sneha Munshi
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Athi N. Naganathan
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Ashok Sekhar
- Molecular Biophysics Unit, Indian Institute of Science Bangalore, Bengaluru 560 012, India
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10
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Padmanabhan S, Manjithaya R. Leaderless secretory proteins of the neurodegenerative diseases via TNTs: a structure-function perspective. Front Mol Neurosci 2023; 16:983108. [PMID: 37396786 PMCID: PMC10308029 DOI: 10.3389/fnmol.2023.983108] [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: 06/30/2022] [Accepted: 05/26/2023] [Indexed: 07/04/2023] Open
Abstract
Neurodegenerative disease-causing proteins such as alpha-synuclein, tau, and huntingtin are known to traverse across cells via exosomes, extracellular vesicles and tunneling nanotubes (TNTs). There seems to be good synergy between exosomes and TNTs in intercellular communication. Interestingly, many of the known major neurodegenerative proteins/proteolytic products are leaderless and are also reported to be secreted out of the cell via unconventional protein secretion. Such classes contain intrinsically disordered proteins and regions (IDRs) within them. The dynamic behavior of these proteins is due to their heterogenic conformations that is exhibited owing to various factors that occur inside the cells. The amino acid sequence along with the chemical modifications has implications on the functional roles of IDRs inside the cells. Proteins that form aggregates resulting in neurodegeneration become resistant to degradation by the processes of autophagy and proteasome system thus leading to Tunneling nanotubes, TNT formation. The proteins that traverse across TNTs may or may not be dependent on the autophagy machinery. It is not yet clear whether the conformation of the protein plays a crucial role in its transport from one cell to another without getting degraded. Although there is some experimental data, there are many grey areas which need to be revisited. This review provides a different perspective on the structural and functional aspects of these leaderless proteins that get secreted outside the cell. In this review, attention has been focused on the characteristic features that lead to aggregation of leaderless secretory proteins (from structural-functional aspect) with special emphasis on TNTs.
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11
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Mori Y, Mizukami T, Segawa S, Roder H, Maki K. Folding of Staphylococcal Nuclease Induced by Binding of Chemically Modified Substrate Analogues Sheds Light on Mechanisms of Coupled Folding/Binding Reactions. Biochemistry 2023; 62:1670-1678. [PMID: 37227385 PMCID: PMC10583223 DOI: 10.1021/acs.biochem.3c00094] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Several proteins have been shown to undergo a shift in the mechanism of ligand binding-induced folding from conformational selection (CS; folding precedes binding) to induced fit (IF; binding precedes folding) with increasing ligand concentration. In previous studies of the coupled folding/binding reaction of staphylococcal nuclease (SNase) in the presence of a substrate analogue, adenosine-3',5'-diphosphate (prAp), we found that the two phosphate groups make important energetic contributions toward stabilizing its complex with the native protein as well as transient conformational states encountered at high ligand concentrations favoring IF. However, the structural contributions of each phosphate group during the reaction remain unclear. To address this question, we relied on fluorescence, nuclear magnetic resonance (NMR), absorption, and isothermal titration calorimetry to study the effects of deletion of the phosphate groups of prAp on the kinetics of ligand-induced folding, using a strategy analogous to mutational ϕ-value analysis to interpret the results. Kinetic measurements over a wide range of ligand concentrations, together with structural characterization of a transient protein-ligand encounter complex using 2D NMR, indicated that, at high ligand concentrations favoring IF, (i) the 5'-phosphate group interacts weakly with denatured SNase during early stages of the reaction, resulting in loose docking of the two domains of SNase, and (ii) the 3'-phosphate group engages in some specific contacts with the polypeptide in the transition state prior to formation of the native SNase-prAp complex.
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Affiliation(s)
- Yujiro Mori
- Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Takuya Mizukami
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111
| | - Saho Segawa
- School of Science, Nagoya University, Nagoya, Aichi, 464-8602 Japan
| | - Heinrich Roder
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111
| | - Kosuke Maki
- Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
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12
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Flapan E, Mashaghi A, Wong H. A tile model of circuit topology for self-entangled biopolymers. Sci Rep 2023; 13:8889. [PMID: 37264056 DOI: 10.1038/s41598-023-35771-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 05/23/2023] [Indexed: 06/03/2023] Open
Abstract
Building on the theory of circuit topology for intra-chain contacts in entangled proteins, we introduce tiles as a way to rigorously model local entanglements which are held in place by molecular forces. We develop operations that combine tiles so that entangled chains can be represented by algebraic expressions. Then we use our model to show that the only knot types that such entangled chains can have are [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and connected sums of these knots. This includes all proteins knots that have thus far been identified.
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Affiliation(s)
- Erica Flapan
- Mathematics and Statistics Department, Pomona College, Claremont, CA, 91711, USA.
| | - Alireza Mashaghi
- Faculty of Science, Leiden University, 2333CC, Leiden, The Netherlands
| | - Helen Wong
- Mathematical Sciences Department, Claremont McKenna College, Claremont, CA, 91711, USA
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13
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Priyadarshi A, Devi HM, Swaminathan R. Disruption of Spatial Proximities among Charged Groups in Equilibrium-Denatured States of Proteins Tracked Using Protein Charge Transfer Spectra. Biochemistry 2023. [PMID: 37162303 DOI: 10.1021/acs.biochem.3c00006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The absorption and luminescence originating from protein charge transfer spectra (ProCharTS) depend on the proximity between multiple charged groups in a protein. This makes ProCharTS absorbance/luminescence intensity a sensitive probe for detecting changes in the protein structure, which alter the proximity among charged groups in the protein. In this work, ProCharTS absorbance of charge-rich proteins like human serum albumin (HSA), α3C, and α3W was used to monitor structural changes upon chemical denaturant-induced protein unfolding under equilibrium conditions. The denaturation midpoints were estimated using nonlinear regression analysis. For HSA, absorbance at 325 and 340 nm estimated the GdnHCl-induced denaturation midpoints to be 0.80 and 0.61 M, respectively. A similar analysis of α3C and α3W ProCharTS absorbance yielded denaturation midpoints of 0.88 and 0.86 M at 325 nm and 0.96 and 0.66 M at 340 nm, respectively. A previously reported molten globule-like state in the GdnHCl-induced HSA unfolding pathway was detected by the increase in HSA ProCharTS absorbance at 0.5 M GdnHCl. To validate the above results, protein unfolding was additionally monitored using conventional methods like circular dichroism (CD), Trp, and dansyl fluorescence. Our results suggest that disruption of charged amino acid sidechain contacts as revealed by ProCharTS occurs at lower denaturant concentrations compared to the loss of secondary/folded structure monitored by CD and fluorescence. Further, HSA ProCharTS absorbance at 315-340 nm revealed that tertiary contacts among charged residues were disrupted at lower GdnHCl concentrations compared to sequence adjacent contacts. Our data underscore the utility of ProCharTS as a novel label-free tool to track unfolding in charge-rich proteins.
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Affiliation(s)
- Anurag Priyadarshi
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781 039, Assam, India
| | - Himanshi Maniram Devi
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781 039, Assam, India
| | - Rajaram Swaminathan
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781 039, Assam, India
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14
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Zhang Y, Liu X, Chen J. Coupled binding and folding of disordered SPIN N-terminal region in myeloperoxidase inhibition. Front Mol Biosci 2023; 10:1130189. [PMID: 36845554 PMCID: PMC9948029 DOI: 10.3389/fmolb.2023.1130189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 01/27/2023] [Indexed: 02/11/2023] Open
Abstract
Gram-positive pathogenic bacteria Staphylococcus express and secret staphylococcal peroxidase inhibitor (SPIN) proteins to help evade neutrophil-mediated immunity by inhibiting the activity of the main oxidative-defense player myeloperoxidase (MPO) enzyme. SPIN contains a structured 3-helix bundle C-terminal domain, which can specifically bind to MPO with high affinity, and an intrinsically disordered N-terminal domain (NTD), which folds into a structured β-hairpin and inserts itself into the active site of MPO for inhibition. Mechanistic insights of the coupled folding and binding process are needed in order to better understand how residual structures and/or conformational flexibility of NTD contribute to the different strengths of inhibition of SPIN homologs. In this work, we applied atomistic molecular dynamics simulations on two SPIN homologs, from S. aureus and S. delphini, respectively, which share high sequence identity and similarity, to explore the possible mechanistic basis for their different inhibition efficacies on human MPO. Direct simulations of the unfolding and unbinding processes at 450 K reveal that these two SPIN/MPO complexes systems follow surprisingly different mechanisms of coupled binding and folding. While coupled binding and folding of SPIN-aureus NTD is highly cooperative, SPIN-delphini NTD appears to mainly utilize a conformational selection-like mechanism. These observations are in contrast to an overwhelming prevalence of induced folding-like mechanisms for intrinsically disordered proteins that fold into helical structures upon binding. Further simulations of unbound SPIN NTDs at room temperature reveal that SPIN-delphini NTD has a much stronger propensity of forming β-hairpin like structures, consistent with its preference to fold and then bind. These may help explain why the inhibition strength is not well correlated with binding affinity for different SPIN homologs. Altogether, our work establishes the relationship between the residual conformational stability of SPIN-NTD and their inhibitory function, which can help us develop new strategies towards treating Staphylococcal infections.
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Affiliation(s)
| | | | - Jianhan Chen
- Department of Chemistry, University of Massachusetts, Amherst, MA, United States
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15
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Evolutionary fine-tuning of residual helix structure in disordered proteins manifests in complex structure and lifetime. Commun Biol 2023; 6:63. [PMID: 36653471 PMCID: PMC9849366 DOI: 10.1038/s42003-023-04445-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 01/09/2023] [Indexed: 01/19/2023] Open
Abstract
Transcription depends on complex networks, where folded hub proteins interact with intrinsically disordered transcription factors undergoing coupled folding and binding. For this, local residual structure, a prototypical feature of intrinsic disorder, is key. Here, we dissect the unexplored functional potential of residual structure by comparing structure, kinetics, and thermodynamics within the model system constituted of the DREB2A transcription factor interacting with the αα-hub RCD1-RST. To maintain biological relevance, we developed an orthogonal evolutionary approach for the design of variants with varying amounts of structure. Biophysical analysis revealed a correlation between the amount of residual helical structure and binding affinity, manifested in altered complex lifetime due to changed dissociation rate constants. It also showed a correlation between helical structure in free and bound DREB2A variants. Overall, this study demonstrated how evolution can balance and fine-tune residual structure to regulate complexes in coupled folding and binding, potentially affecting transcription factor competition.
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16
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Portability of a Small-Molecule Binding Site between Disordered Proteins. Biomolecules 2022; 12:biom12121887. [PMID: 36551315 PMCID: PMC9775153 DOI: 10.3390/biom12121887] [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: 10/04/2022] [Revised: 12/07/2022] [Accepted: 12/09/2022] [Indexed: 12/23/2022] Open
Abstract
Intrinsically disordered proteins (IDPs) are important in both normal and disease states. Small molecules can be targeted to disordered regions, but we currently have only a limited understanding of the nature of small-molecule binding sites in IDPs. Here, we show that a minimal small-molecule binding sequence of eight contiguous residues derived from the Myc protein can be ported into a different disordered protein and recapitulate small-molecule binding activity in the new context. We also find that the residue immediately flanking the binding site can have opposing effects on small-molecule binding in the different disordered protein contexts. The results demonstrate that small-molecule binding sites can act modularly and are portable between disordered protein contexts but that residues outside of the minimal binding site can modulate binding affinity.
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17
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A modular approach to map out the conformational landscapes of unbound intrinsically disordered proteins. Proc Natl Acad Sci U S A 2022; 119:e2113572119. [PMID: 35658083 PMCID: PMC9191344 DOI: 10.1073/pnas.2113572119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
SignificanceIntrinsically disordered proteins have the unique ability to morph in response to multiple partners and thereby process sophisticated inputs and outputs. It is, however, a mystery whether their response is passive, that is, entirely determined by the partner, or controlled via an internal, yet unknown, folding mechanism. Here we introduce an approach to examine this key question and demonstrate its potential by dissecting the conformational properties of the partially disordered protein NCBD and obtaining important clues about how it performs its biological function.
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18
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Seim I, Posey AE, Snead WT, Stormo BM, Klotsa D, Pappu RV, Gladfelter AS. Dilute phase oligomerization can oppose phase separation and modulate material properties of a ribonucleoprotein condensate. Proc Natl Acad Sci U S A 2022; 119:e2120799119. [PMID: 35333653 PMCID: PMC9060498 DOI: 10.1073/pnas.2120799119] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 02/16/2022] [Indexed: 01/02/2023] Open
Abstract
SignificanceA large subclass of biomolecular condensates are linked to RNA regulation and are known as ribonucleoprotein (RNP) bodies. While extensive work has identified driving forces for biomolecular condensate formation, relatively little is known about forces that oppose assembly. Here, using a fungal RNP protein, Whi3, we show that a portion of its intrinsically disordered, glutamine-rich region modulates phase separation by forming transient alpha helical structures that promote the assembly of dilute phase oligomers. These oligomers detour Whi3 proteins from condensates, thereby impacting the driving forces for phase separation, the protein-to-RNA ratio in condensates, and the material properties of condensates. Our findings show how nanoscale conformational and oligomerization equilibria can influence mesoscale phase equilibria.
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Affiliation(s)
- Ian Seim
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Ammon E. Posey
- Department of Biomedical Engineering, Center for Science & Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130
| | - Wilton T. Snead
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Benjamin M. Stormo
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Daphne Klotsa
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Rohit V. Pappu
- Department of Biomedical Engineering, Center for Science & Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130
| | - Amy S. Gladfelter
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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19
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Improved prediction of protein-protein interactions using AlphaFold2. Nat Commun 2022; 13:1265. [PMID: 35273146 PMCID: PMC8913741 DOI: 10.1038/s41467-022-28865-w] [Citation(s) in RCA: 289] [Impact Index Per Article: 144.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 02/11/2022] [Indexed: 01/02/2023] Open
Abstract
Predicting the structure of interacting protein chains is a fundamental step towards understanding protein function. Unfortunately, no computational method can produce accurate structures of protein complexes. AlphaFold2, has shown unprecedented levels of accuracy in modelling single chain protein structures. Here, we apply AlphaFold2 for the prediction of heterodimeric protein complexes. We find that the AlphaFold2 protocol together with optimised multiple sequence alignments, generate models with acceptable quality (DockQ ≥ 0.23) for 63% of the dimers. From the predicted interfaces we create a simple function to predict the DockQ score which distinguishes acceptable from incorrect models as well as interacting from non-interacting proteins with state-of-art accuracy. We find that, using the predicted DockQ scores, we can identify 51% of all interacting pairs at 1% FPR. Predicting the structure of protein complexes is extremely difficult. Here, authors apply AlphaFold2 with optimized multiple sequence alignments to model complexes of interacting proteins, enabling prediction of both if and how proteins interact with state-of-art accuracy.
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20
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Reid KM, Singh AK, Bikash CR, Wei J, Tal-Gan Y, Vinh NQ, Leitner DM. The origin and impact of bound water around intrinsically disordered proteins. Biophys J 2022; 121:540-551. [PMID: 35074392 PMCID: PMC8874019 DOI: 10.1016/j.bpj.2022.01.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 12/14/2021] [Accepted: 01/13/2022] [Indexed: 12/29/2022] Open
Abstract
Proteins and water couple dynamically over a wide range of time scales. Motivated by their central role in protein function, protein-water dynamics and thermodynamics have been extensively studied for structured proteins, where correspondence to structural features has been made. However, properties controlling intrinsically disordered protein (IDP)-water dynamics are not yet known. We report results of megahertz-to-terahertz dielectric spectroscopy and molecular dynamics simulations of a group of IDPs with varying charge content along with structured proteins of similar size. Hydration water around IDPs is found to exhibit more heterogeneous rotational and translational dynamics compared with water around structured proteins of similar size, yielding on average more restricted dynamics around individual residues of IDPs, charged or neutral, compared with structured proteins. The on-average slower water dynamics is found to arise from excess tightly bound water in the first hydration layer, which is related to greater exposure to charged groups. The more tightly bound water to IDPs correlates with the smaller hydration shell found experimentally, and affects entropy associated with protein-water interactions, the contribution of which we estimate based on the dielectric measurements and simulations. Water-IDP dynamic coupling at terahertz frequencies is characterized by the dielectric measurements and simulations.
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Affiliation(s)
- Korey M. Reid
- Department of Chemistry, University of Nevada, Reno, Nevada
| | - Abhishek K. Singh
- Department of Physics and Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, Virginia
| | | | - Jessica Wei
- Department of Chemistry, University of Nevada, Reno, Nevada
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, Nevada
| | - Nguyen Q. Vinh
- Department of Physics and Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, Virginia,Corresponding author
| | - David M. Leitner
- Department of Chemistry, University of Nevada, Reno, Nevada,Corresponding author
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21
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Heckmeier PJ, Ruf J, Buhrke D, Janković BG, Hamm P. Signal propagation within the MCL-1/BIM protein complex. J Mol Biol 2022; 434:167499. [DOI: 10.1016/j.jmb.2022.167499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/24/2022] [Accepted: 02/07/2022] [Indexed: 11/26/2022]
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22
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Ning S, Chao HJ, Li S, Zhou R, Zou L, Zhang X, Liu J, Yan D, Duan M. The auto-inhibition mechanism of transcription factor Ets-1 induced by phosphorylation on the intrinsically disordered region. Comput Struct Biotechnol J 2022; 20:1132-1141. [PMID: 35317227 PMCID: PMC8902471 DOI: 10.1016/j.csbj.2022.02.025] [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: 11/02/2021] [Revised: 02/20/2022] [Accepted: 02/26/2022] [Indexed: 12/01/2022] Open
Abstract
As the most abundant post-translation modifications (PTMs), the phosphorylation usually occurred on the intrinsically disordered regions (IDRs). The regulation on the structures and interactions of IDRs induced by phosphorylation is critical to the function performing. The eukaryotic transcription factor 1 (Ets-1) is a member of transcription factor family, which participates in many important biological processes. The DNA-binding ability of Ets-1 is auto-inhibited by a disordered serine-rich region (SRR) on the Ets-1. The inhibition ability of SRR is greatly enhanced by the phosphorylation of the serine on the SRR. Nevertheless, the molecular mechanisms of the phosphorylation regulation on the structure and activity of Ets-1 are still unclear and under debates. By using both of the molecular simulations and biochemical experiments, we studied the molecule mechanism of phosphorylation regulation on the auto-inhibition of the Ets-1. The reasons of stabilization of Ets-1 core by phosphorylation on SRR region were elucidated. More important, the free energy landscapes (FEL) show that both of the steric hindrance and allosteric regulation are responsible for the DNA-binding inhibitory induced by phosphorylation, but the steric effects contribute greater than the allosteric regulation. The phosphorylation not only enhances the electrostatic interactions to facilitate the steric impedance, but also promotes the formation of hydrophobic residue clusters, which provide major driven force for the allosteric regulation. The structural basis of auto-inhibition of Ets-1 induced by the phosphorylation revealed in this study would great help the developing of inhibitor for the cancer therapy.
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Affiliation(s)
- Shangbo Ning
- National Centre for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, Hubei, People’s Republic of China
- School of Life Science and Technology, Wuhan Polytechnic University, Wuhan 430023, People’s Republic of China
| | - Hong-Jun Chao
- School of Life Science and Technology, Wuhan Polytechnic University, Wuhan 430023, People’s Republic of China
| | - Shuangli Li
- National Centre for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, Hubei, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Rui Zhou
- National Centre for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, Hubei, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Lei Zou
- School of Life Science and Technology, Wuhan Polytechnic University, Wuhan 430023, People’s Republic of China
| | - Xu Zhang
- National Centre for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, Hubei, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Jun Liu
- School of Life Science and Technology, Wuhan Polytechnic University, Wuhan 430023, People’s Republic of China
| | - Dazhong Yan
- School of Life Science and Technology, Wuhan Polytechnic University, Wuhan 430023, People’s Republic of China
- Corresponding authors at: National Centre for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, Hubei, People’s Republic of China (M. Duan).
| | - Mojie Duan
- National Centre for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, Hubei, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
- Corresponding authors at: National Centre for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, Hubei, People’s Republic of China (M. Duan).
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23
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Baudin A, Moreno-Romero AK, Xu X, Selig EE, Penalva LOF, Libich DS. Structural Characterization of the RNA-Binding Protein SERBP1 Reveals Intrinsic Disorder and Atypical RNA Binding Modes. Front Mol Biosci 2021; 8:744707. [PMID: 34631798 PMCID: PMC8497785 DOI: 10.3389/fmolb.2021.744707] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 09/07/2021] [Indexed: 11/18/2022] Open
Abstract
RNA binding proteins (RBPs) are essential for critical biological processes such as translation regulation and mRNA processing, and misfunctions of these proteins are associated with diseases such as cancer and neurodegeneration. SERBP1 (SERPINE1 mRNA Binding Protein 1) is an RBP that comprises two RG/RGG repeat regions yet lacks other recognizable RNA-binding motifs. It is involved in mRNA maturation, and translational regulation. It was initially identified as a hyaluronic acid binding protein, but recent studies have identified central roles for SERBP1 in brain function and development, especially neurogenesis and synaptogenesis. SERBP1 regulates One-carbon metabolism and epigenetic modification of histones, and increased SERBP1 expression in cancers such as leukemia, ovarian, prostate, liver and glioblastoma is correlated with poor patient outcomes. Despite these important regulatory roles for SERBP1, little is known about its structural and dynamic properties, nor about the molecular mechanisms governing its interaction with mRNA. Here, we define SERBP1 as an intrinsically disordered protein, containing highly conserved elements that were shown to be functionally important. The RNA binding activity of SERBP1 was explored using solution NMR and other biophysical techniques. The outcome of these experiments revealed that SERBP1 preferentially samples compact conformations including a central, stable α-helix and show that SERBP1 recognizes G-rich RNA sequences at the C-terminus involving the RGG box and neighboring residues. Despite the role in RNA recognition, the RGG boxes do not seem to stabilize the central helix and the central helix does not participate in RNA binding. Further, SERBP1 undergoes liquid-liquid phase separation, mediated by salt and RNA, and both RGG boxes are necessary for the efficient formation of condensed phases. Together, these results provide a foundation for understanding the molecular mechanisms of SERBP1 functions in physiological and pathological processes.
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Affiliation(s)
- Antoine Baudin
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States.,Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Alma K Moreno-Romero
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States.,Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Xiaoping Xu
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States.,Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Emily E Selig
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States.,Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Luiz O F Penalva
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States.,Department of Cell Systems and Anatomy, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - David S Libich
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States.,Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
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24
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Fuzzy protein theory for disordered proteins. Biochem Soc Trans 2021; 48:2557-2564. [PMID: 33170209 PMCID: PMC7752076 DOI: 10.1042/bst20200239] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/08/2020] [Accepted: 10/12/2020] [Indexed: 01/02/2023]
Abstract
Why proteins are fuzzy? Constant adaptation to the cellular environment requires a wide range of changes in protein structure and interactions. Conformational ensembles of disordered proteins in particular exhibit large shifts to activate or inhibit alternative pathways. Fuzziness is critical for liquid–liquid phase separation and conversion of biomolecular condensates into fibrils. Interpretation of these phenomena presents a challenge for the classical structure-function paradigm. Here I discuss a multi-valued formalism, based on fuzzy logic, which can be applied to describe complex cellular behavior of proteins.
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25
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Emenecker RJ, Holehouse AS, Strader LC. Sequence determinants of in cell condensate morphology, dynamics, and oligomerization as measured by number and brightness analysis. Cell Commun Signal 2021; 19:65. [PMID: 34090478 PMCID: PMC8178893 DOI: 10.1186/s12964-021-00744-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 04/20/2021] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Biomolecular condensates are non-stoichiometric assemblies that are characterized by their capacity to spatially concentrate biomolecules and play a key role in cellular organization. Proteins that drive the formation of biomolecular condensates frequently contain oligomerization domains and intrinsically disordered regions (IDRs), both of which can contribute multivalent interactions that drive higher-order assembly. Our understanding of the relative and temporal contribution of oligomerization domains and IDRs to the material properties of in vivo biomolecular condensates is limited. Similarly, the spatial and temporal dependence of protein oligomeric state inside condensates has been largely unexplored in vivo. METHODS In this study, we combined quantitative microscopy with number and brightness analysis to investigate the aging, material properties, and protein oligomeric state of biomolecular condensates in vivo. Our work is focused on condensates formed by AUXIN RESPONSE FACTOR 19 (ARF19), a transcription factor integral to the auxin signaling pathway in plants. ARF19 contains a large central glutamine-rich IDR and a C-terminal Phox Bem1 (PB1) oligomerization domain and forms cytoplasmic condensates. RESULTS Our results reveal that the IDR amino acid composition can influence the morphology and material properties of ARF19 condensates. In contrast the distribution of oligomeric species within condensates appears insensitive to the IDR composition. In addition, we identified a relationship between the abundance of higher- and lower-order oligomers within individual condensates and their apparent fluidity. CONCLUSIONS IDR amino acid composition affects condensate morphology and material properties. In ARF condensates, altering the amino acid composition of the IDR did not greatly affect the oligomeric state of proteins within the condensate. Video Abstract.
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Affiliation(s)
- Ryan J. Emenecker
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110 USA
- Center for Science and Engineering Living Systems (CSELS), Washington University, St. Louis, MO 63130 USA
- Center for Engineering Mechanobiology, Washington University, St. Louis, MO 63130 USA
| | - Alex S. Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110 USA
- Center for Science and Engineering Living Systems (CSELS), Washington University, St. Louis, MO 63130 USA
| | - Lucia C. Strader
- Center for Science and Engineering Living Systems (CSELS), Washington University, St. Louis, MO 63130 USA
- Center for Engineering Mechanobiology, Washington University, St. Louis, MO 63130 USA
- Department of Biology, Duke University, Durham, NC 27708 USA
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26
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Matthees ESF, Haider RS, Hoffmann C, Drube J. Differential Regulation of GPCRs-Are GRK Expression Levels the Key? Front Cell Dev Biol 2021; 9:687489. [PMID: 34109182 PMCID: PMC8182058 DOI: 10.3389/fcell.2021.687489] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 04/29/2021] [Indexed: 01/14/2023] Open
Abstract
G protein-coupled receptors (GPCRs) comprise the largest family of transmembrane receptors and their signal transduction is tightly regulated by GPCR kinases (GRKs) and β-arrestins. In this review, we discuss novel aspects of the regulatory GRK/β-arrestin system. Therefore, we briefly revise the origin of the "barcode" hypothesis for GPCR/β-arrestin interactions, which states that β-arrestins recognize different receptor phosphorylation states to induce specific functions. We emphasize two important parameters which may influence resulting GPCR phosphorylation patterns: (A) direct GPCR-GRK interactions and (B) tissue-specific expression and availability of GRKs and β-arrestins. In most studies that focus on the molecular mechanisms of GPCR regulation, these expression profiles are underappreciated. Hence we analyzed expression data for GRKs and β-arrestins in 61 tissues annotated in the Human Protein Atlas. We present our analysis in the context of pathophysiological dysregulation of the GPCR/GRK/β-arrestin system. This tissue-specific point of view might be the key to unraveling the individual impact of different GRK isoforms on GPCR regulation.
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Affiliation(s)
| | | | - Carsten Hoffmann
- Institut für Molekulare Zellbiologie, CMB – Center for Molecular Biomedicine, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, Jena, Germany
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27
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Jankovic B, Bozovic O, Hamm P. Intrinsic Dynamics of Protein-Peptide Unbinding. Biochemistry 2021; 60:1755-1763. [PMID: 33999611 DOI: 10.1021/acs.biochem.1c00262] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The dynamics of peptide-protein binding and unbinding of a variant of the RNase S system has been investigated. To initiate the process, a photoswitchable azobenzene moiety has been covalently linked to the S-peptide, thereby switching its binding affinity to the S-protein. Transient fluorescence quenching was measured with the help of a time-resolved fluorometer, which has been specifically designed for these experiments and is based on inexpensive light-emitting diodes and laser diodes only. One mutant shows on-off behavior with no specific binding detectable in one of the states of the photoswitch. Unbinding is faster by at least 2 orders of magnitude, compared to that of other variants of the RNase S system. We conclude that unbinding is essentially barrier-less in that case, revealing the intrinsic dynamics of the unbinding event, which occurs on a time scale of a few hundred microseconds in a strongly stretched-exponential manner.
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Affiliation(s)
- Brankica Jankovic
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Olga Bozovic
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Peter Hamm
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
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28
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Covaceuszach S, Peche L, Konarev P, Lamba D. A combined evolutionary and structural approach to disclose the primary structural determinants essential for proneurotrophins biological functions. Comput Struct Biotechnol J 2021; 19:2891-2904. [PMID: 34094000 PMCID: PMC8144349 DOI: 10.1016/j.csbj.2021.05.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/03/2021] [Accepted: 05/03/2021] [Indexed: 12/24/2022] Open
Abstract
The neurotrophins, i.e., Nerve Growth Factor (NGF), Brain-Derived Neurotrophic Factor (BDNF), Neurotrophin 3 (NT3) and Neurotrophin 4 (NT4), are known to play a range of crucial functions in the developing and adult peripheral and central nervous systems. Initially synthesized as precursors, i.e., proneurotrophins (proNTs), that are cleaved to release C-terminal mature forms, they act through two types of receptors, the specific Trk receptors (Tropomyosin-related kinases) and the pan-neurotrophin receptor p75NTR, to initiate survival and differentiative responses. Recently, all the proNTs but proNT4 have been demonstrated to be not just inactive precursors, but signaling ligands that mediate opposing actions in fundamental aspects of the nervous system with respect to the mature counterparts through dual-receptor complexes formation with a member of the VPS10 family and p75NTR. Despite the functional relevance, the molecular determinants underpinning the interactions between the pro-domains and their receptors are still elusive probably due to their intrinsically disordered nature. Here we present an evolutionary approach coupled to an experimental study aiming to uncover the structural and dynamical basis of the biological function displayed by proNGF, proBDNF and proNT3 but missing in proNT4. A bioinformatic analysis allowed to elucidate the functional adaptability of the proNTs family in vertebrates, identifying conserved key structural features. The combined biochemical and SAXS experiments shed lights on the structure and dynamic behavior of the human proNTs in solution, giving insights on the evolutionary conserved structural motifs, essential for the multifaceted roles of proNTs in physiological as well as in pathological contexts.
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Affiliation(s)
- S. Covaceuszach
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, Trieste, Italy
| | - L.Y. Peche
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, Trieste, Italy
| | - P.V. Konarev
- A.V. Shubnikov Institute of Crystallography of Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Moscow, Russia
| | - D. Lamba
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, Trieste, Italy
- Interuniversity Consortium “Biostructures and Biosystems National Institute”, Roma, Italy
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Deciphering the Role of Residues Involved in Disorder-To-Order Transition Regions in Archaeal tRNA Methyltransferase 5. Genes (Basel) 2021; 12:genes12030399. [PMID: 33799704 PMCID: PMC8000304 DOI: 10.3390/genes12030399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/01/2021] [Accepted: 03/08/2021] [Indexed: 11/16/2022] Open
Abstract
tRNA methyltransferase 5 (Trm5) enzyme is an S-adenosyl methionine (AdoMet)-dependent methyltransferase which methylates the G37 nucleotide at the N1 atom of the tRNA. The free form of Trm5 enzyme has three intrinsically disordered regions, which are highly flexible and lack stable three-dimensional structures. These regions gain ordered structures upon the complex formation with tRNA, also called disorder-to-order transition (DOT) regions. In this study, we performed molecular dynamics (MD) simulations of archaeal Trm5 in free and complex forms and observed that the DOT residues are highly flexible in free proteins and become stable in complex structures. The energetic contributions show that DOT residues are important for stabilising the complex. The DOT1 and DOT2 are mainly observed to be important for stabilising the complex, while DOT3 is present near the active site to coordinate the interactions between methyl-donating ligands and G37 nucleotides. In addition, mutational studies on the Trm5 complex showed that the wild type is more stable than the G37A tRNA mutant complex. The loss of productive interactions upon G37A mutation drives the AdoMet ligand away from the 37th nucleotide, and Arg145 in DOT3 plays a crucial role in stabilising the ligand, as well as the G37 nucleotide, in the wild-type complex. Further, the overall energetic contribution calculated using MMPBSA corroborates that the wild-type complex has a better affinity between Trm5 and tRNA. Overall, our study reveals that targeting DOT regions for binding could improve the inhibition of Trm5.
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30
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Freiberger MI, Wolynes PG, Ferreiro DU, Fuxreiter M. Frustration in Fuzzy Protein Complexes Leads to Interaction Versatility. J Phys Chem B 2021; 125:2513-2520. [PMID: 33667107 PMCID: PMC8041309 DOI: 10.1021/acs.jpcb.0c11068] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
![]()
Disordered
proteins frequently serve as interaction hubs involving
a constrained variety of partners. Complexes with different partners
frequently exhibit distinct binding modes, involving regions that
remain disordered in the bound state. While the conformational properties
of disordered proteins are well-characterized in their free states,
less is known about the molecular mechanisms by which specificity
can be achieved not with one but with multiple partners. Using the
energy landscape theory concept of protein frustration, we demonstrate
that complexes of disordered proteins exhibit a high degree of local
frustration, especically at the binding interface. These suboptimal
interactions lead to the possibility of multiple bound substates,
each displaying distinct frustration patterns, which are differently
populated in complexes with different partners. These results explain
how specificity of disordered proteins can be achieved without a single
common bound conformation and how the confliict between different
interactions can be used to control the binding to multiple partners.
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Affiliation(s)
- Maria I Freiberger
- Protein Physiology Lab, Departamento de Quimica Biologica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires-CONICET-IQUIBICEN, Buenos Aires, 1428, Argentina
| | - Peter G Wolynes
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
| | - Diego U Ferreiro
- Protein Physiology Lab, Departamento de Quimica Biologica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires-CONICET-IQUIBICEN, Buenos Aires, 1428, Argentina
| | - Monika Fuxreiter
- Department of Biomedical Sciences, University of Padova, Padova, 35131, Italy.,Laboratory of Protein Dynamics, University of Debrecen, Debrecen, 4032, Hungary
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31
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Bugge K, Staby L, Salladini E, Falbe-Hansen RG, Kragelund BB, Skriver K. αα-Hub domains and intrinsically disordered proteins: A decisive combo. J Biol Chem 2021; 296:100226. [PMID: 33361159 PMCID: PMC7948954 DOI: 10.1074/jbc.rev120.012928] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/22/2020] [Accepted: 12/22/2020] [Indexed: 01/02/2023] Open
Abstract
Hub proteins are central nodes in protein-protein interaction networks with critical importance to all living organisms. Recently, a new group of folded hub domains, the αα-hubs, was defined based on a shared αα-hairpin supersecondary structural foundation. The members PAH, RST, TAFH, NCBD, and HHD are found in large proteins such as Sin3, RCD1, TAF4, CBP, and harmonin, which organize disordered transcriptional regulators and membrane scaffolds in interactomes of importance to human diseases and plant quality. In this review, studies of structures, functions, and complexes across the αα-hubs are described and compared to provide a unified description of the group. This analysis expands the associated molecular concepts of "one domain-one binding site", motif-based ligand binding, and coupled folding and binding of intrinsically disordered ligands to additional concepts of importance to signal fidelity. These include context, motif reversibility, multivalency, complex heterogeneity, synergistic αα-hub:ligand folding, accessory binding sites, and supramodules. We propose that these multifaceted protein-protein interaction properties are made possible by the characteristics of the αα-hub fold, including supersite properties, dynamics, variable topologies, accessory helices, and malleability and abetted by adaptability of the disordered ligands. Critically, these features provide additional filters for specificity. With the presentations of new concepts, this review opens for new research questions addressing properties across the group, which are driven from concepts discovered in studies of the individual members. Combined, the members of the αα-hubs are ideal models for deconvoluting signal fidelity maintained by folded hubs and their interactions with intrinsically disordered ligands.
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Affiliation(s)
- Katrine Bugge
- REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark; Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Lasse Staby
- REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark; Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Edoardo Salladini
- REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Rasmus G Falbe-Hansen
- REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Birthe B Kragelund
- REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark; Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
| | - Karen Skriver
- REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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32
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Salladini E, Jørgensen MLM, Theisen FF, Skriver K. Intrinsic Disorder in Plant Transcription Factor Systems: Functional Implications. Int J Mol Sci 2020; 21:E9755. [PMID: 33371315 PMCID: PMC7767404 DOI: 10.3390/ijms21249755] [Citation(s) in RCA: 8] [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: 11/30/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 01/07/2023] Open
Abstract
Eukaryotic cells are complex biological systems that depend on highly connected molecular interaction networks with intrinsically disordered proteins as essential components. Through specific examples, we relate the conformational ensemble nature of intrinsic disorder (ID) in transcription factors to functions in plants. Transcription factors contain large regulatory ID-regions with numerous orphan sequence motifs, representing potential important interaction sites. ID-regions may affect DNA-binding through electrostatic interactions or allosterically as for the bZIP transcription factors, in which the DNA-binding domains also populate ensembles of dynamic transient structures. The flexibility of ID is well-suited for interaction networks requiring efficient molecular adjustments. For example, Radical Induced Cell Death1 depends on ID in transcription factors for its numerous, structurally heterogeneous interactions, and the JAZ:MYC:MED15 regulatory unit depends on protein dynamics, including binding-associated unfolding, for regulation of jasmonate-signaling. Flexibility makes ID-regions excellent targets of posttranslational modifications. For example, the extent of phosphorylation of the NAC transcription factor SOG1 regulates target gene expression and the DNA-damage response, and phosphorylation of the AP2/ERF transcription factor DREB2A acts as a switch enabling heat-regulated degradation. ID-related phase separation is emerging as being important to transcriptional regulation with condensates functioning in storage and inactivation of transcription factors. The applicative potential of ID-regions is apparent, as removal of an ID-region of the AP2/ERF transcription factor WRI1 affects its stability and consequently oil biosynthesis. The highlighted examples show that ID plays essential functional roles in plant biology and has a promising potential in engineering.
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Affiliation(s)
| | | | | | - Karen Skriver
- REPIN and the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, DK-2200 Copenhagen, Denmark; (E.S.); (M.L.M.J.); (F.F.T.)
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33
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The Role of Protein Disorder in Nuclear Transport and in Its Subversion by Viruses. Cells 2020; 9:cells9122654. [PMID: 33321790 PMCID: PMC7764567 DOI: 10.3390/cells9122654] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 12/08/2020] [Accepted: 12/08/2020] [Indexed: 12/12/2022] Open
Abstract
The transport of host proteins into and out of the nucleus is key to host function. However, nuclear transport is restricted by nuclear pores that perforate the nuclear envelope. Protein intrinsic disorder is an inherent feature of this selective transport barrier and is also a feature of the nuclear transport receptors that facilitate the active nuclear transport of cargo, and the nuclear transport signals on the cargo itself. Furthermore, intrinsic disorder is an inherent feature of viral proteins and viral strategies to disrupt host nucleocytoplasmic transport to benefit their replication. In this review, we highlight the role that intrinsic disorder plays in the nuclear transport of host and viral proteins. We also describe viral subversion mechanisms of the host nuclear transport machinery in which intrinsic disorder is a feature. Finally, we discuss nuclear import and export as therapeutic targets for viral infectious disease.
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34
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Binding and folding in transcriptional complexes. Curr Opin Struct Biol 2020; 66:156-162. [PMID: 33248428 DOI: 10.1016/j.sbi.2020.10.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 10/16/2020] [Accepted: 10/27/2020] [Indexed: 01/13/2023]
Abstract
Transcription factors are among the classes of proteins with the highest levels of disorder. Investigation of these regulatory proteins is uncovering not just the mechanisms that underlie gene regulation, but relationships that apply to all intrinsically disordered proteins. Recent studies confirm that binding does not necessarily induce folding but that when it does, it tends to follow induced fit mechanisms. Other work emphasises the importance of electrostatics to interactions involving intrinsically disordered proteins, and roles of intrinsic disorder in phase transitions. All these features help direct transcription factors to target sites in the genome to upregulate or downregulate transcription.
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35
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Sottini A, Borgia A, Borgia MB, Bugge K, Nettels D, Chowdhury A, Heidarsson PO, Zosel F, Best RB, Kragelund BB, Schuler B. Polyelectrolyte interactions enable rapid association and dissociation in high-affinity disordered protein complexes. Nat Commun 2020; 11:5736. [PMID: 33184256 PMCID: PMC7661507 DOI: 10.1038/s41467-020-18859-x] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/14/2020] [Indexed: 02/07/2023] Open
Abstract
Highly charged intrinsically disordered proteins can form complexes with very high affinity in which both binding partners fully retain their disorder and dynamics, exemplified by the positively charged linker histone H1.0 and its chaperone, the negatively charged prothymosin α. Their interaction exhibits another surprising feature: The association/dissociation kinetics switch from slow two-state-like exchange at low protein concentrations to fast exchange at higher, physiologically relevant concentrations. Here we show that this change in mechanism can be explained by the formation of transient ternary complexes favored at high protein concentrations that accelerate the exchange between bound and unbound populations by orders of magnitude. Molecular simulations show how the extreme disorder in such polyelectrolyte complexes facilitates (i) diffusion-limited binding, (ii) transient ternary complex formation, and (iii) fast exchange of monomers by competitive substitution, which together enable rapid kinetics. Biological polyelectrolytes thus have the potential to keep regulatory networks highly responsive even for interactions with extremely high affinities.
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Affiliation(s)
- Andrea Sottini
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Alessandro Borgia
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Madeleine B Borgia
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Katrine Bugge
- Structural Biology and NMR Laboratory (SBiNLab) and REPIN, Department of Biology, Ole Maaloes Vej 5, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Daniel Nettels
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Aritra Chowdhury
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Pétur O Heidarsson
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
- Department of Biochemistry, Science Institute, University of Iceland, Dunhagi 3, 107, Reykjavík, Iceland
| | - Franziska Zosel
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
- Novo Nordisk A/S, Novo Nordisk Park, 2760, Måløv, Denmark
| | - Robert B Best
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA.
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory (SBiNLab) and REPIN, Department of Biology, Ole Maaloes Vej 5, University of Copenhagen, 2200, Copenhagen, Denmark.
| | - Benjamin Schuler
- Department of Biochemistry, University of Zurich, Zurich, Switzerland.
- Department of Physics, University of Zurich, Zurich, Switzerland.
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36
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Sonar P, Bellucci L, Mossa A, Heidarsson PO, Kragelund BB, Cecconi C. Effects of Ligand Binding on the Energy Landscape of Acyl-CoA-Binding Protein. Biophys J 2020; 119:1821-1832. [PMID: 33080224 PMCID: PMC7677128 DOI: 10.1016/j.bpj.2020.09.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 08/14/2020] [Accepted: 09/08/2020] [Indexed: 12/19/2022] Open
Abstract
Binding of ligands is often crucial for function yet the effects of ligand binding on the mechanical stability and energy landscape of proteins are incompletely understood. Here, we use a combination of single-molecule optical tweezers and MD simulations to investigate the effect of ligand binding on the energy landscape of acyl-coenzyme A (CoA)-binding protein (ACBP). ACBP is a topologically simple and highly conserved four-α-helix bundle protein that acts as an intracellular transporter and buffer for fatty-acyl-CoA and is active in membrane assembly. We have previously described the behavior of ACBP under tension, revealing a highly extended transition state (TS) located almost halfway between the unfolded and native states. Here, we performed force-ramp and force-jump experiments, in combination with advanced statistical analysis, to show that octanoyl-CoA binding increases the activation free energy for the unfolding reaction of ACBP without affecting the position of the transition state along the reaction coordinate. It follows that ligand binding enhances the mechanical resistance and thermodynamic stability of the protein, without changing its mechanical compliance. Steered molecular dynamics simulations allowed us to rationalize the results in terms of key interactions that octanoyl-CoA establishes with the four α-helices of ACBP and showed that the unfolding pathway is marginally affected by the ligand. The results show that ligand-induced mechanical stabilization effects can be complex and may prove useful for the rational design of stabilizing ligands.
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Affiliation(s)
- Punam Sonar
- Physik-Department E22, Technische Universität München, Garching Germany
| | - Luca Bellucci
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa, Italy
| | - Alessandro Mossa
- INFN Firenze, Sesto Fiorentino, Italy; Istituto Statale di Istruzione Superiore "Leonardo da Vinci", Firenze, Italy.
| | - Pétur O Heidarsson
- Department of Biochemistry, Science Institute, University of Iceland, Reykjavík, Iceland.
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen N, Denmark.
| | - Ciro Cecconi
- Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, Modena, Italy; Center S3, CNR Institute Nanoscience, Modena, Italy.
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37
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Risser F, Collin S, Dos Santos-Morais R, Gruez A, Chagot B, Weissman KJ. Towards improved understanding of intersubunit interactions in modular polyketide biosynthesis: Docking in the enacyloxin IIa polyketide synthase. J Struct Biol 2020; 212:107581. [DOI: 10.1016/j.jsb.2020.107581] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 07/14/2020] [Accepted: 07/16/2020] [Indexed: 12/26/2022]
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38
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Liu N, Guo Y, Ning S, Duan M. Phosphorylation regulates the binding of intrinsically disordered proteins via a flexible conformation selection mechanism. Commun Chem 2020; 3:123. [PMID: 36703366 PMCID: PMC9814494 DOI: 10.1038/s42004-020-00370-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 08/11/2020] [Indexed: 01/29/2023] Open
Abstract
Phosphorylation is one of the most common post-translational modifications. The phosphorylation of the kinase-inducible domain (KID), which is an intrinsically disordered protein (IDP), promotes the folding of KID and binding with the KID-interacting domain (KIX). However, the regulation mechanism of the phosphorylation on KID is still elusive. In this study, the structural ensembles and binding process of pKID and KIX are studied by all-atom enhanced sampling technologies. The results show that more hydrophobic interactions are formed in pKID, which promote the formation of the special hydrophobic residue cluster (HRC). The pre-formed HRC promotes binding to the correct sites of KIX and further lead the folding of pKID. Consequently, a flexible conformational selection model is proposed to describe the binding and folding process of intrinsically disordered proteins. The binding mechanism revealed in this work provides new insights into the dynamic interactions and phosphorylation regulation of proteins.
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Affiliation(s)
- Na Liu
- grid.458518.50000 0004 1803 4970Key Laboratory of magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071 People’s Republic of China ,grid.412969.10000 0004 1798 1968School of biological and pharmaceutical engineering, Wuhan Polytechnic University, Wuhan, 430023 People’s Republic of China
| | - Yue Guo
- grid.458518.50000 0004 1803 4970Key Laboratory of magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071 People’s Republic of China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
| | - Shangbo Ning
- grid.458518.50000 0004 1803 4970Key Laboratory of magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071 People’s Republic of China ,grid.412969.10000 0004 1798 1968School of biological and pharmaceutical engineering, Wuhan Polytechnic University, Wuhan, 430023 People’s Republic of China
| | - Mojie Duan
- grid.458518.50000 0004 1803 4970Key Laboratory of magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071 People’s Republic of China
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Gerlach GJ, Carrock R, Stix R, Stollar EJ, Ball KA. A disordered encounter complex is central to the yeast Abp1p SH3 domain binding pathway. PLoS Comput Biol 2020; 16:e1007815. [PMID: 32925900 PMCID: PMC7514057 DOI: 10.1371/journal.pcbi.1007815] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 09/24/2020] [Accepted: 08/15/2020] [Indexed: 12/20/2022] Open
Abstract
Protein-protein interactions are involved in a wide range of cellular processes. These interactions often involve intrinsically disordered proteins (IDPs) and protein binding domains. However, the details of IDP binding pathways are hard to characterize using experimental approaches, which can rarely capture intermediate states present at low populations. SH3 domains are common protein interaction domains that typically bind proline-rich disordered segments and are involved in cell signaling, regulation, and assembly. We hypothesized, given the flexibility of SH3 binding peptides, that their binding pathways include multiple steps important for function. Molecular dynamics simulations were used to characterize the steps of binding between the yeast Abp1p SH3 domain (AbpSH3) and a proline-rich IDP, ArkA. Before binding, the N-terminal segment 1 of ArkA is pre-structured and adopts a polyproline II helix, while segment 2 of ArkA (C-terminal) adopts a 310 helix, but is far less structured than segment 1. As segment 2 interacts with AbpSH3, it becomes more structured, but retains flexibility even in the fully engaged state. Binding simulations reveal that ArkA enters a flexible encounter complex before forming the fully engaged bound complex. In the encounter complex, transient nonspecific hydrophobic and long-range electrostatic contacts form between ArkA and the binding surface of SH3. The encounter complex ensemble includes conformations with segment 1 in both the forward and reverse orientation, suggesting that segment 2 may play a role in stabilizing the correct binding orientation. While the encounter complex forms quickly, the slow step of binding is the transition from the disordered encounter ensemble to the fully engaged state. In this transition, ArkA makes specific contacts with AbpSH3 and buries more hydrophobic surface. Simulating the binding between ApbSH3 and ArkA provides insight into the role of encounter complex intermediates and nonnative hydrophobic interactions for other SH3 domains and IDPs in general.
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Affiliation(s)
- Gabriella J. Gerlach
- Department of Chemistry, Skidmore College, Saratoga Springs, New York, United States
| | - Rachel Carrock
- Department of Chemistry, Skidmore College, Saratoga Springs, New York, United States
| | - Robyn Stix
- Department of Chemistry, Skidmore College, Saratoga Springs, New York, United States
| | - Elliott J. Stollar
- School of Life Sciences, University of Liverpool, Liverpool, United Kingdom
| | - K. Aurelia Ball
- Department of Chemistry, Skidmore College, Saratoga Springs, New York, United States
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40
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Seiffert P, Bugge K, Nygaard M, Haxholm GW, Martinsen JH, Pedersen MN, Arleth L, Boomsma W, Kragelund BB. Orchestration of signaling by structural disorder in class 1 cytokine receptors. Cell Commun Signal 2020; 18:132. [PMID: 32831102 PMCID: PMC7444064 DOI: 10.1186/s12964-020-00626-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/08/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Class 1 cytokine receptors (C1CRs) are single-pass transmembrane proteins responsible for transmitting signals between the outside and the inside of cells. Remarkably, they orchestrate key biological processes such as proliferation, differentiation, immunity and growth through long disordered intracellular domains (ICDs), but without having intrinsic kinase activity. Despite these key roles, their characteristics remain rudimentarily understood. METHODS The current paper asks the question of why disorder has evolved to govern signaling of C1CRs by reviewing the literature in combination with new sequence and biophysical analyses of chain properties across the family. RESULTS We uncover that the C1CR-ICDs are fully disordered and brimming with SLiMs. Many of these short linear motifs (SLiMs) are overlapping, jointly signifying a complex regulation of interactions, including network rewiring by isoforms. The C1CR-ICDs have unique properties that distinguish them from most IDPs and we forward the perception that the C1CR-ICDs are far from simple strings with constitutively bound kinases. Rather, they carry both organizational and operational features left uncovered within their disorder, including mechanisms and complexities of regulatory functions. CONCLUSIONS Critically, the understanding of the fascinating ability of these long, completely disordered chains to orchestrate complex cellular signaling pathways is still in its infancy, and we urge a perceptional shift away from the current simplistic view towards uncovering their full functionalities and potential. Video abstract.
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Affiliation(s)
- Pernille Seiffert
- REPIN, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Katrine Bugge
- REPIN, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Mads Nygaard
- REPIN, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Gitte W. Haxholm
- REPIN, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Jacob H. Martinsen
- REPIN, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Martin N. Pedersen
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen Ø, Denmark
| | - Lise Arleth
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen Ø, Denmark
| | - Wouter Boomsma
- Department of Computer Science, University of Copenhagen, Universitetsparken 1, 2100 Copenhagen Ø, Denmark
| | - Birthe B. Kragelund
- REPIN, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
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41
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Cook EC, Creamer TP. Influence of electrostatic forces on the association kinetics and conformational ensemble of an intrinsically disordered protein. Proteins 2020; 88:1607-1619. [PMID: 32654182 DOI: 10.1002/prot.25979] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/15/2020] [Accepted: 07/05/2020] [Indexed: 01/26/2023]
Abstract
Recent work has revealed that the association of a disordered region of a protein with a folded binding partner can occur as rapidly as association between two folded proteins. This is the case for the phosphatase calcineurin (CaN) and its association with its activator calmodulin. Calmodulin binds to the intrinsically disordered regulatory domain of CaN. Previous studies have shown that electrostatic steering can accelerate the binding of folded proteins with disordered ligands. Given that electrostatic forces are strong determinants of disordered protein ensembles, the relationship between electrostatics, conformational ensembles, and quaternary interactions is unclear. Here, we employ experimental approaches to explore the impact of electrostatic interactions on the association of calmodulin with the disordered regulatory region of CaN. We find that estimated association rate constants of calmodulin with our chosen calmodulin-substrates are within the diffusion-limited regime. The association rates are dependent on the ionic strength, indicating that favorable electrostatic forces increase the rate of association. Further, we show that charged amino acids outside the calmodulin-binding site modulate the binding rate. Conformational ensembles obtained from computer simulations suggest that electrostatic interactions within the regulatory domain might bias the conformational ensemble such that the calmodulin binding region is readily accessible. Given the prevalence of charged residues in disordered protein chains, our findings are likely relevant to many protein-protein interactions.
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Affiliation(s)
- Erik C Cook
- Center for Structural Biology and Department of Molecular & Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Trevor P Creamer
- Center for Structural Biology and Department of Molecular & Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
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42
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Kumar D, Mishra PM, Gadhave K, Giri R. Conformational dynamics of p53 N-terminal TAD2 region under different solvent conditions. Arch Biochem Biophys 2020; 689:108459. [DOI: 10.1016/j.abb.2020.108459] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 05/28/2020] [Accepted: 06/03/2020] [Indexed: 01/31/2023]
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43
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Rogers JM. Peptide Folding and Binding Probed by Systematic Non-canonical Mutagenesis. Front Mol Biosci 2020; 7:100. [PMID: 32671094 PMCID: PMC7326784 DOI: 10.3389/fmolb.2020.00100] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 05/04/2020] [Indexed: 12/20/2022] Open
Abstract
Many proteins and peptides fold upon binding another protein. Mutagenesis has proved an essential tool in the study of these multi-step molecular recognition processes. By comparing the biophysical behavior of carefully selected mutants, the concert of interactions and conformational changes that occur during folding and binding can be separated and assessed. Recently, this mutagenesis approach has been radically expanded by deep mutational scanning methods, which allow for many thousands of mutations to be examined in parallel. Furthermore, these high-throughput mutagenesis methods have been expanded to include mutations to non-canonical amino acids, returning peptide structure-activity relationships with unprecedented depth and detail. These developments are timely, as the insights they provide can guide the optimization of de novo cyclic peptides, a promising new modality for chemical probes and therapeutic agents.
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Affiliation(s)
- Joseph M Rogers
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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44
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Zhang XX, Tokmakoff A. Revealing the Dynamical Role of Co-solvents in the Coupled Folding and Dimerization of Insulin. J Phys Chem Lett 2020; 11:4353-4358. [PMID: 32401513 PMCID: PMC7850624 DOI: 10.1021/acs.jpclett.0c00982] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Solvent-protein interactions are important for protein biological functions, especially for a coupled folding and binding system such as insulin. By monitoring the change in the conformation of insulin dimers during dissociation with temperature-jump infrared spectroscopy, we show that co-solvents can significantly destabilize the dimers by perturbing their hydrophobic center. The transition from the native to intermediate dimer state is observed as the buried residues are exposed to solvents in the presence of 10% dimethyl sulfoxide and with α-helices unfolding when ethanol is present, which reduces the dissociation time dramatically to 50% and 20% of the value in a D2O solution, respectively. We propose a self-consistent analysis using complementary methods to resolve this coupled folding and binding process and obtain a much higher rate of monomer association than of intermediate folding. Our results demonstrate that the conformational changes are critical in dimer formation and strongly affected by co-solvents.
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Affiliation(s)
- Xin-Xing Zhang
- Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
| | - Andrei Tokmakoff
- Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
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45
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Yruela I, Neira JL. Intrinsically disordered proteins in biology: One for all, all for one. Arch Biochem Biophys 2020; 684:108328. [PMID: 32145248 DOI: 10.1016/j.abb.2020.108328] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Inmaculada Yruela
- Group of Computational and Structural Biology, Estación Experimental de Aula Dei (EEAD-CSIC), Avda. Montañana 1005, 50059, Zaragoza, Spain; Group of Biochemistry, Biophysics and Computational Biology (BIFI-Unizar) Joint Unit to CSIC, Spain.
| | - José L Neira
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, 03202, Elche, Alicante, Spain; Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, 50018, Zaragoza, Spain.
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46
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Malagrinò F, Visconti L, Pagano L, Toto A, Troilo F, Gianni S. Understanding the Binding Induced Folding of Intrinsically Disordered Proteins by Protein Engineering: Caveats and Pitfalls. Int J Mol Sci 2020; 21:ijms21103484. [PMID: 32429036 PMCID: PMC7279032 DOI: 10.3390/ijms21103484] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 12/20/2022] Open
Abstract
Many proteins lack a well-defined three-dimensional structure in isolation. These proteins, typically denoted as intrinsically disordered proteins (IDPs), may display a characteristic disorder-to-order transition when binding their physiological partner(s). From an experimental perspective, it is of great importance to establish the general grounds to understand how such folding processes may be explored. Here we discuss the caveats and the pitfalls arising when applying to IDPs one of the key techniques to characterize the folding of globular proteins, the Φ value analysis. This method is based on measurements of the free energy changes of transition and native states upon conservative, non-disrupting, mutations. On the basis of available data, we reinforce the validity of Φ value analysis in the study of IDPs and suggest future experiments to further validate this powerful experimental method.
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47
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Feng M, Bell DR, Wang Z, Zhang W. Length-Dependent Structural Transformations of Huntingtin PolyQ Domain Upon Binding to 2D-Nanomaterials. Front Chem 2020; 8:299. [PMID: 32391325 PMCID: PMC7189795 DOI: 10.3389/fchem.2020.00299] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 03/26/2020] [Indexed: 11/13/2022] Open
Abstract
There is a strong negative correlation between the polyglutamine (polyQ) domain length (Q-length) in the intrinsically disordered Huntingtin protein (Htt) exon-1 and the age of onset of Huntington's disease (HD). PolyQ of Q-length longer than 40 has the propensity of forming very compact aggregate structures, leading to HD at full penetrance. Recent advances in nanobiotechnology provided a new platform for the development of novel diagnosis and therapeutics. Here, we explore the possibility of utilizing 2D-nanomaterials to inhibit the formation of supercompact polyQ structures through the so-called “folding-upon-binding” where the protein structure is dependent on the binding substrate. Using molecular dynamics simulations, we characterize two polyQ peptides with Q-length of 22 (Q22, normal length) and 46 (Q46, typical length causing HD) binding to both graphene and molybdenum disulfide (MoS2) nanosheets, which have been applied as antibacterial or anticancer agents. Upon binding, Q22 unfolds and elongates on both grapheme and MoS2 surfaces, regardless of its initial conformation, with graphene showing slightly stronger effect. In contrast, initially collapsed Q46 remains mostly collapsed within our simulation time on both nanosheets even though they do provide some “stretching” to Q46 as well. Further analyses indicate that the hydrophobic nature of graphene/MoS2 promotes the stretching of polyQ on nanosheets. However, there is strong competition with the intra-polyQ interactions (mainly internal hydrogen bonds) leading to the disparate folding/binding behaviors of Q22 and Q46. Our results present distinct Q-length specific behavior of the polyQ domain upon binding to two types of 2D-nanomaterials which holds clinical relevance for Huntington's disease.
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Affiliation(s)
- Mei Feng
- Department of Physics, Institute of Quantitative Biology, Zhejiang University, Hangzhou, China
| | - David R Bell
- Computational Biological Center, IBM Thomas J. Watson Research Center, Yorktown Heights, NY, United States
| | - Zhenhua Wang
- Department of Physics, Institute of Quantitative Biology, Zhejiang University, Hangzhou, China
| | - Wei Zhang
- School of Materials and Physics, China University of Mining and Technology, Xuzhou, China
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48
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Bokhovchuk F, Mesrouze Y, Meyerhofer M, Zimmermann C, Fontana P, Erdmann D, Jemth P, Chène P. An Early Association between the α-Helix of the TEAD Binding Domain of YAP and TEAD Drives the Formation of the YAP:TEAD Complex. Biochemistry 2020; 59:1804-1812. [PMID: 32329346 DOI: 10.1021/acs.biochem.0c00217] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The Hippo pathway is an evolutionarily conserved signaling pathway that is involved in the control of organ size and development. The TEAD transcription factors are the most downstream elements of the Hippo pathway, and their transcriptional activity is regulated via the interaction with different co-regulators such as YAP. The structure of the YAP:TEAD complex shows that YAP binds to TEAD via two distinct secondary structure elements, an α-helix and an Ω-loop, and site-directed mutagenesis experiments revealed that the Ω-loop is the "hot spot" of this interaction. While much is known about how YAP and TEAD interact with each other, little is known about the mechanism leading to the formation of a complex between these two proteins. Here we combine site-directed mutagenesis with pre-steady-state kinetic measurements to show that the association between these proteins follows an apparent one-step binding mechanism. Furthermore, linear free energy relationships and a Φ analysis suggest that binding-induced folding of the YAP α-helix to TEAD occurs independently of and before formation of the Ω-loop interface. Thus, the binding-induced folding of YAP appears not to conform to the concomitant formation of tertiary structure (nucleation-condensation) usually observed for coupled binding and folding reactions. Our findings demonstrate how a mechanism reminiscent of the classical framework (diffusion-collision) mechanism of protein folding may operate in disorder-to-order transitions involving intrinsically disordered proteins.
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Affiliation(s)
- Fedir Bokhovchuk
- Disease Area Oncology, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland
| | - Yannick Mesrouze
- Disease Area Oncology, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland
| | - Marco Meyerhofer
- Disease Area Oncology, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland
| | - Catherine Zimmermann
- Disease Area Oncology, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland
| | - Patrizia Fontana
- Disease Area Oncology, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland
| | - Dirk Erdmann
- Disease Area Oncology, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland
| | - Per Jemth
- Department of Medical Biochemistry and Microbiology, Uppsala University, 751 23 Uppsala, Sweden
| | - Patrick Chène
- Disease Area Oncology, Novartis Institutes for Biomedical Research, CH-4002 Basel, Switzerland
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49
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Robustelli P, Piana S, Shaw DE. Mechanism of Coupled Folding-upon-Binding of an Intrinsically Disordered Protein. J Am Chem Soc 2020; 142:11092-11101. [DOI: 10.1021/jacs.0c03217] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Paul Robustelli
- D. E. Shaw Research, New York, New York 10036, United States
| | - Stefano Piana
- D. E. Shaw Research, New York, New York 10036, United States
| | - David E. Shaw
- D. E. Shaw Research, New York, New York 10036, United States
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032, United States
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50
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Shi J, Shen Q, Cho JH, Hwang W. Entropy Hotspots for the Binding of Intrinsically Disordered Ligands to a Receptor Domain. Biophys J 2020; 118:2502-2512. [PMID: 32311315 DOI: 10.1016/j.bpj.2020.03.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 02/28/2020] [Accepted: 03/23/2020] [Indexed: 11/18/2022] Open
Abstract
Proline-rich motifs (PRMs) are widely used for mediating protein-protein interactions with weak binding affinities. Because they are intrinsically disordered when unbound, conformational entropy plays a significant role for the binding. However, residue-level differences of the entropic contribution in the binding of different ligands remain not well understood. We use all-atom molecular dynamics simulation and the maximal information spanning tree formalism to analyze conformational entropy associated with the binding of two PRMs, one from the Abl kinase and the other from the nonstructural protein 1 of the 1918 Spanish influenza A virus, to the N-terminal SH3 (nSH3) domain of the CrkII protein. Side chains of the stably folded nSH3 experience more entropy change upon ligand binding than the backbone, whereas PRMs involve comparable but heterogeneous entropy changes among the backbone and side chains. In nSH3, two conserved nonpolar residues forming contacts with the PRM experience the largest side-chain entropy loss. In contrast, the C-terminal charged residues of PRMs that form polar contacts with nSH3 experience the greatest side-chain entropy loss, although their "fuzzy" nature is attributable to the backbone that remains relatively flexible. Thus, residues that form high-occupancy contacts between nSH3 and PRM do not reciprocally contribute to entropy loss. Furthermore, certain surface residues of nSH3 distal to the interface with PRMs gain entropy, indicating a nonlocal effect of ligand binding. Comparing between the PRMs from cAbl and nonstructural protein 1, the latter involves a larger side-chain entropy loss and forms more contacts with nSH3. Consistent with experiments, this indicates stronger binding of the viral ligand at the expense of losing the flexibility of side chains, whereas the backbone experiences less entropy loss. The entropy "hotspots" as identified in this study will be important for tuning the binding affinity of various ligands to a receptor.
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Affiliation(s)
- Jie Shi
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas
| | - Qingliang Shen
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Jae-Hyun Cho
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas.
| | - Wonmuk Hwang
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas; Department of Materials Science and Engineering, Texas A&M University, College Station, Texas; Department of Physics and Astronomy, Texas A&M University, College Station, Texas; School of Computational Sciences, Korea Institute for Advanced Study, Seoul, South Korea.
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