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Sesterhenn F, Yang C, Bonet J, Cramer JT, Wen X, Wang Y, Chiang CI, Abriata LA, Kucharska I, Castoro G, Vollers SS, Galloux M, Dheilly E, Rosset S, Corthésy P, Georgeon S, Villard M, Richard CA, Descamps D, Delgado T, Oricchio E, Rameix-Welti MA, Más V, Ervin S, Eléouët JF, Riffault S, Bates JT, Julien JP, Li Y, Jardetzky T, Krey T, Correia BE. De novo protein design enables the precise induction of RSV-neutralizing antibodies. Science 2020; 368:eaay5051. [PMID: 32409444 PMCID: PMC7391827 DOI: 10.1126/science.aay5051] [Citation(s) in RCA: 109] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 01/30/2020] [Accepted: 04/08/2020] [Indexed: 12/27/2022]
Abstract
De novo protein design has been successful in expanding the natural protein repertoire. However, most de novo proteins lack biological function, presenting a major methodological challenge. In vaccinology, the induction of precise antibody responses remains a cornerstone for next-generation vaccines. Here, we present a protein design algorithm called TopoBuilder, with which we engineered epitope-focused immunogens displaying complex structural motifs. In both mice and nonhuman primates, cocktails of three de novo-designed immunogens induced robust neutralizing responses against the respiratory syncytial virus. Furthermore, the immunogens refocused preexisting antibody responses toward defined neutralization epitopes. Overall, our design approach opens the possibility of targeting specific epitopes for the development of vaccines and therapeutic antibodies and, more generally, will be applicable to the design of de novo proteins displaying complex functional motifs.
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Affiliation(s)
- Fabian Sesterhenn
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne CH-1015, Switzerland
| | - Che Yang
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne CH-1015, Switzerland
| | - Jaume Bonet
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne CH-1015, Switzerland
| | - Johannes T Cramer
- Institute of Virology, Hannover Medical School, Hannover 30625, Germany
| | - Xiaolin Wen
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yimeng Wang
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Chi-I Chiang
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Luciano A Abriata
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne CH-1015, Switzerland
| | - Iga Kucharska
- Program in Molecular Medicine, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada
- Departments of Biochemistry and Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Giacomo Castoro
- Institute of Virology, Hannover Medical School, Hannover 30625, Germany
| | - Sabrina S Vollers
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne CH-1015, Switzerland
| | - Marie Galloux
- Université Paris-Saclay, INRAE, UVSQ, VIM, 78350 Jouy-en-Josas, France
| | - Elie Dheilly
- Swiss Institute for Experimental Cancer Research, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | - Stéphane Rosset
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne CH-1015, Switzerland
| | - Patricia Corthésy
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne CH-1015, Switzerland
| | - Sandrine Georgeon
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne CH-1015, Switzerland
| | - Mélanie Villard
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne CH-1015, Switzerland
| | | | - Delphyne Descamps
- Université Paris-Saclay, INRAE, UVSQ, VIM, 78350 Jouy-en-Josas, France
| | - Teresa Delgado
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Madrid, Spain
| | - Elisa Oricchio
- Swiss Institute for Experimental Cancer Research, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | | | - Vicente Más
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Madrid, Spain
| | - Sean Ervin
- Wake Forest Baptist Medical Center, Winston Salem, NC 27157, USA
| | | | - Sabine Riffault
- Université Paris-Saclay, INRAE, UVSQ, VIM, 78350 Jouy-en-Josas, France
| | - John T Bates
- University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Jean-Philippe Julien
- Program in Molecular Medicine, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 0A4, Canada
- Departments of Biochemistry and Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Yuxing Li
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
- Department of Microbiology and Immunology & Center of Biomolecular Therapeutics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Theodore Jardetzky
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Thomas Krey
- Institute of Virology, Hannover Medical School, Hannover 30625, Germany
- German Center for Infection Research (DZIF), 38124 Braunschweig, Germany
- Institute of Biochemistry, Center of Structural and Cell Biology in Medicine, University of Luebeck, D-23538 Luebeck, Germany
- Excellence Cluster 2155 RESIST, Hannover Medical School, 30625 Hannover, Germany
- Centre for Structural Systems Biology (CSSB), 22607 Hamburg, Germany
| | - Bruno E Correia
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland.
- Swiss Institute of Bioinformatics (SIB), Lausanne CH-1015, Switzerland
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2
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Sesterhenn F, Galloux M, Vollers SS, Csepregi L, Yang C, Descamps D, Bonet J, Friedensohn S, Gainza P, Corthésy P, Chen M, Rosset S, Rameix-Welti MA, Éléouët JF, Reddy ST, Graham BS, Riffault S, Correia BE. Boosting subdominant neutralizing antibody responses with a computationally designed epitope-focused immunogen. PLoS Biol 2019; 17:e3000164. [PMID: 30789898 PMCID: PMC6400402 DOI: 10.1371/journal.pbio.3000164] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 03/05/2019] [Accepted: 02/08/2019] [Indexed: 12/20/2022] Open
Abstract
Throughout the last several decades, vaccination has been key to prevent and eradicate infectious diseases. However, many pathogens (e.g., respiratory syncytial virus [RSV], influenza, dengue, and others) have resisted vaccine development efforts, largely because of the failure to induce potent antibody responses targeting conserved epitopes. Deep profiling of human B cells often reveals potent neutralizing antibodies that emerge from natural infection, but these specificities are generally subdominant (i.e., are present in low titers). A major challenge for next-generation vaccines is to overcome established immunodominance hierarchies and focus antibody responses on crucial neutralization epitopes. Here, we show that a computationally designed epitope-focused immunogen presenting a single RSV neutralization epitope elicits superior epitope-specific responses compared to the viral fusion protein. In addition, the epitope-focused immunogen efficiently boosts antibodies targeting the palivizumab epitope, resulting in enhanced neutralization. Overall, we show that epitope-focused immunogens can boost subdominant neutralizing antibody responses in vivo and reshape established antibody hierarchies. A computationally designed epitope-focused immunogen presenting a single neutralization epitope from Respiratory Syncytial Virus elicits superior epitope-specific responses compared to the viral fusion protein. Furthermore, epitope-focused immunogens can reshape established antibody hierarchies. Vaccines are one of the most valuable instruments to prevent and control infectious diseases. Their primary correlate of protection is the level of induction of neutralizing antibodies that target critical antigenic sites and thereby block infection. Natural infections with pathogens such as the respiratory syncytial virus (RSV) or influenza induce a broad repertoire of antibodies that target multiple epitopes. Among those, functional antibodies with key specificities are often subdominant (present in low titers). Thus, a central goal for vaccine development is to focus antibody responses on such neutralization epitopes. Here, we show that a computationally designed, epitope-focused immunogen mimicking an important RSV neutralization epitope (site II) can focus antibodies onto this well-defined epitope. In a scenario of preexisting immunity, in which site II–specific antibodies were subdominant, the epitope-focused immunogen selectively boosted site II–specific antibodies, resulting in an increased viral neutralization through this epitope. We propose that rationally designed immunogens spotlighting defined epitopes have a unique potential to focus antibody responses on functionally conserved sites in cases of preexisting immunity. Our results have broad implications for vaccine design as a strategy to steer preexisting antibody responses away from immunodominant, variable epitopes and toward subdominant epitopes that confer broad and potent neutralization.
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MESH Headings
- Animals
- Antibodies, Monoclonal, Humanized/chemistry
- Antibodies, Monoclonal, Humanized/immunology
- Antibodies, Neutralizing/biosynthesis
- Antibodies, Neutralizing/genetics
- Antibodies, Viral/biosynthesis
- Antibodies, Viral/genetics
- Cloning, Molecular
- Computer-Aided Design
- Epitopes/chemistry
- Epitopes/immunology
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Female
- Gene Expression
- Genetic Vectors/chemistry
- Genetic Vectors/metabolism
- Immunization/methods
- Immunogenicity, Vaccine
- Mice
- Mice, Inbred BALB C
- Nanoparticles/administration & dosage
- Nanoparticles/chemistry
- Palivizumab/chemistry
- Palivizumab/immunology
- Receptors, Antigen, B-Cell/chemistry
- Receptors, Antigen, B-Cell/genetics
- Receptors, Antigen, B-Cell/immunology
- Recombinant Fusion Proteins/administration & dosage
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/immunology
- Respiratory Syncytial Virus Vaccines/administration & dosage
- Respiratory Syncytial Virus Vaccines/biosynthesis
- Respiratory Syncytial Virus Vaccines/genetics
- Respiratory Syncytial Viruses/immunology
- Structural Homology, Protein
- Viral Fusion Proteins/administration & dosage
- Viral Fusion Proteins/chemistry
- Viral Fusion Proteins/genetics
- Viral Fusion Proteins/immunology
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Affiliation(s)
- Fabian Sesterhenn
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
| | - Marie Galloux
- Unité de Virologie et Immunologie Moléculaires (UR892), INRA, Université Paris-Saclay, Jouy-en-Josas, France
| | - Sabrina S. Vollers
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Lucia Csepregi
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
| | - Che Yang
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
| | - Delphyne Descamps
- Unité de Virologie et Immunologie Moléculaires (UR892), INRA, Université Paris-Saclay, Jouy-en-Josas, France
| | - Jaume Bonet
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
| | - Simon Friedensohn
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
| | - Pablo Gainza
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
| | - Patricia Corthésy
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Man Chen
- Viral Pathogenesis Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Stéphane Rosset
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Marie-Anne Rameix-Welti
- UMR1173, INSERM, Université de Versailles St. Quentin, Montigny le Bretonneux, France
- AP-HP, Laboratoire de Microbiologie, Hôpital Ambroise Paré, Boulogne-Billancourt, France
| | - Jean-François Éléouët
- Unité de Virologie et Immunologie Moléculaires (UR892), INRA, Université Paris-Saclay, Jouy-en-Josas, France
| | - Sai T. Reddy
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
| | - Barney S. Graham
- Viral Pathogenesis Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sabine Riffault
- Unité de Virologie et Immunologie Moléculaires (UR892), INRA, Université Paris-Saclay, Jouy-en-Josas, France
| | - Bruno E. Correia
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
- * E-mail:
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3
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Vollers SS, Carruthers A. Sequence determinants of GLUT1-mediated accelerated-exchange transport: analysis by homology-scanning mutagenesis. J Biol Chem 2012; 287:42533-44. [PMID: 23093404 DOI: 10.1074/jbc.m112.369587] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The class 1 equilibrative glucose transporters GLUT1 and GLUT4 are structurally similar but catalyze distinct modes of transport. GLUT1 exhibits trans-acceleration, in which the presence of intracellular sugar stimulates the rate of unidirectional sugar uptake. GLUT4-mediated uptake is unaffected by intracellular sugar. Using homology-scanning mutagenesis in which domains of GLUT1 are substituted with equivalent domains from GLUT4 and vice versa, we show that GLUT1 transmembrane domain 6 is both necessary and sufficient for trans-acceleration. This region is not directly involved in GLUT1 binding of substrate or inhibitors. Rather, transmembrane domain 6 is part of two putative scaffold domains, which coordinate membrane-spanning amphipathic helices that form the sugar translocation pore. We propose that GLUT1 transmembrane domain 6 restrains import when intracellular sugar is absent by slowing transport-associated conformational changes.
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Affiliation(s)
- Sabrina S Vollers
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
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4
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Maji SK, Ogorzalek Loo RR, Inayathullah M, Spring SM, Vollers SS, Condron MM, Bitan G, Loo JA, Teplow DB. Amino acid position-specific contributions to amyloid beta-protein oligomerization. J Biol Chem 2009; 284:23580-91. [PMID: 19567875 PMCID: PMC2749133 DOI: 10.1074/jbc.m109.038133] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Indexed: 12/21/2022] Open
Abstract
Understanding the structural and assembly dynamics of the amyloid beta-protein (Abeta) has direct relevance to the development of therapeutic agents for Alzheimer disease. To elucidate these dynamics, we combined scanning amino acid substitution with a method for quantitative determination of the Abeta oligomer frequency distribution, photo-induced cross-linking of unmodified proteins (PICUP), to perform "scanning PICUP." Tyr, a reactive group in PICUP, was substituted at position 1, 10, 20, 30, or 40 (for Abeta40) or 42 (for Abeta42). The effects of these substitutions were probed using circular dichroism spectroscopy, thioflavin T binding, electron microscopy, PICUP, and mass spectrometry. All peptides displayed a random coil --> alpha/beta --> beta transition, but substitution-dependent alterations in assembly kinetics and conformer complexity were observed. Tyr(1)-substituted homologues of Abeta40 and Abeta42 assembled the slowest and yielded unusual patterns of oligomer bands in gel electrophoresis experiments, suggesting oligomer compaction had occurred. Consistent with this suggestion was the observation of relatively narrow [Tyr(1)]Abeta40 fibrils. Substitution of Abeta40 at the C terminus decreased the population conformational complexity and substantially extended the highest order of oligomers observed. This latter effect was observed in both Abeta40 and Abeta42 as the Tyr substitution position number increased. The ability of a single substitution (Tyr(1)) to alter Abeta assembly kinetics and the oligomer frequency distribution suggests that the N terminus is not a benign peptide segment, but rather that Abeta conformational dynamics and assembly are affected significantly by the competition between the N and C termini to form a stable complex with the central hydrophobic cluster.
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Affiliation(s)
| | - Rachel R. Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine
- Molecular Biology Institute
| | | | | | | | | | - Gal Bitan
- From the Department of Neurology and
- Molecular Biology Institute
- Brain Research Institute, and
| | - Joseph A. Loo
- Department of Biological Chemistry, David Geffen School of Medicine
- Molecular Biology Institute
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095
| | - David B. Teplow
- From the Department of Neurology and
- Molecular Biology Institute
- Brain Research Institute, and
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5
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Abstract
The use of major histocompatibility complex (MHC) tetramers in the detection and analysis of antigen-specific T cells has become more widespread since its introduction 11 years ago. Early challenges in the application of tetramer staining to CD4+ T cells centred around difficulties in the expression of various class II MHC allelic variants and the detection of low-frequency T cells in mixed populations. As many of the technical obstacles to class II MHC tetramer staining have been overcome, the focus has returned to uncertainties concerning how oligomer valency and T-cell receptor/MHC affinity affect tetramer binding. Such issues have become more important with an increase in the number of studies relying on direct ex vivo analysis of antigen-specific CD4+ T cells. In this review we discuss which problems in class II MHC tetramer staining have been solved to date, and which matters remain to be considered.
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Affiliation(s)
- Sabrina S Vollers
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, USA
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6
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Abstract
The assembly of the amyloid beta-protein (Abeta) into neurotoxic oligomers and fibrils is a seminal pathogenic process in Alzheimer's disease (AD). Understanding the mechanisms of Abeta assembly could prove useful in the identification of therapeutic targets. Owing to the metastable nature of Abeta oligomers, it is difficult to obtain interpretable data through application of classical methods, such as electrophoresis, chromatography, fluorescence, and light scattering. Here, we apply the method Photo-Induced Crosslinking of Unmodified Proteins (PICUP) to the study of Abeta oligomerization. This method directly produces covalent bonds among unmodified polypeptide chains through in situ generation of peptide free radicals. PICUP provides a snapshot of the native oligomerization state of proteins and can be used for assembly state analysis of a wide variety of peptides and proteins.
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Affiliation(s)
- Sabrina S Vollers
- Center for Neurologic Diseases, Brigham and Women's Hospital and Department of Neurology, Harvard Medical School, Boston, MA, USA
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7
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Maji S, Bitan G, Vollers SS, Spring S, Condron MM, Teplow DB. P1-236 Site-specific analysis of Abeta oligomerization using photochemical cross-linking. Neurobiol Aging 2004. [DOI: 10.1016/s0197-4580(04)80549-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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8
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Bitan G, Tarus B, Vollers SS, Lashuel HA, Condron MM, Straub JE, Teplow DB. A molecular switch in amyloid assembly: Met35 and amyloid beta-protein oligomerization. J Am Chem Soc 2004; 125:15359-65. [PMID: 14664580 DOI: 10.1021/ja0349296] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aberrant protein oligomerization is an important pathogenetic process in vivo. In Alzheimer's disease (AD), the amyloid beta-protein (Abeta) forms neurotoxic oligomers. The predominant in vivo Abeta alloforms, Abeta40 and Abeta42, have distinct oligomerization pathways. Abeta42 monomers oligomerize into pentamer/hexamer units (paranuclei) which self-associate to form larger oligomers. Abeta40 does not form these paranuclei, a fact which may explain the particularly strong linkage of Abeta42 with AD. Here, we sought to determine the structural elements controlling paranucleus formation as a first step toward the development of strategies for treating AD. Because oxidation of Met(35) is associated with altered Abeta assembly, we examined the role of Met(35) in controlling Abeta oligomerization. Oxidation of Met(35) in Abeta42 blocked paranucleus formation and produced oligomers indistinguishable in size and morphology from those produced by Abeta40. Systematic structural alterations of the C(gamma)(35)-substituent group revealed that its electronic nature, rather than its size (van der Waals volume), was the factor controlling oligomerization pathway choice. Preventing assembly of toxic Abeta42 paranuclei through selective oxidation of Met(35) thus represents a potential therapeutic approach for AD.
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Affiliation(s)
- Gal Bitan
- Center for Neurologic Diseases, Brigham and Women's Hospital, Boston, MA 02115, USA
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9
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Abstract
Assembly of monomeric amyloid beta-protein (A beta) into oligomeric structures is an important pathogenetic feature of Alzheimer's disease. The oligomer size distributions of aggregate-free, low molecular weight A beta 40 and A beta 42 can be assessed quantitatively using the technique of photo-induced cross-linking of unmodified proteins. This approach revealed that low molecular weight A beta 40 is a mixture of monomer, dimer, trimer, and tetramer, in rapid equilibrium, whereas low molecular weight A beta 42 preferentially exists as pentamer/hexamer units (paranuclei), which self-associate to form larger oligomers. Here, photo-induced cross-linking of unmodified proteins was used to evaluate systematically the oligomerization of 34 physiologically relevant A beta alloforms, including those containing familial Alzheimer's disease-linked amino acid substitutions, naturally occurring N-terminal truncations, and modifications altering the charge, the hydrophobicity, or the conformation of the peptide. The most important structural feature controlling early oligomerization was the length of the C terminus. Specifically, the side-chain of residue 41 in A beta 42 was important both for effective formation of paranuclei and for self-association of paranuclei into larger oligomers. The side-chain of residue 42, and the C-terminal carboxyl group, affected paranucleus self-association. A beta 40 oligomerization was particularly sensitive to substitutions of Glu22 or Asp23 and to truncation of the N terminus, but not to substitutions of Phe19 or Ala21. A beta 42 oligomerization, in contrast, was largely unaffected by substitutions at positions 22 or 23 or by N-terminal truncations, but was affected significantly by substitutions of Phe19 or Ala21. These results reveal how specific regions and residues control A beta oligomerization and show that these controlling elements differ between A beta 40 and A beta 42.
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Affiliation(s)
- Gal Bitan
- Center for Neurologic Diseases, Brigham and Women's Hospital, and Department of Neurology, Harvard Medical School, Boston, Massachusetts 02115, USA
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10
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Bitan G, Kirkitadze MD, Lomakin A, Vollers SS, Benedek GB, Teplow DB. Amyloid beta -protein (Abeta) assembly: Abeta 40 and Abeta 42 oligomerize through distinct pathways. Proc Natl Acad Sci U S A 2003; 100:330-5. [PMID: 12506200 PMCID: PMC140968 DOI: 10.1073/pnas.222681699] [Citation(s) in RCA: 1010] [Impact Index Per Article: 48.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2002] [Indexed: 01/20/2023] Open
Abstract
Amyloid beta-protein (Abeta) is linked to neuronal injury and death in Alzheimer's disease (AD). Of particular relevance for elucidating the role of Abeta in AD is new evidence that oligomeric forms of Abeta are potent neurotoxins that play a major role in neurodegeneration and the strong association of the 42-residue form of Abeta, Abeta42, with the disease. Detailed knowledge of the structure and assembly dynamics of Abeta thus is important for the development of properly targeted AD therapeutics. Recently, we have shown that Abeta oligomers can be cross-linked efficiently, and their relative abundances quantified, by using the technique of photo-induced cross-linking of unmodified proteins (PICUP). Here, PICUP, size-exclusion chromatography, dynamic light scattering, circular dichroism spectroscopy, and electron microscopy have been combined to elucidate fundamental features of the early assembly of Abeta40 and Abeta42. Carefully prepared aggregate-free Abeta40 existed as monomers, dimers, trimers, and tetramers, in rapid equilibrium. In contrast, Abeta42 preferentially formed pentamerhexamer units (paranuclei) that assembled further to form beaded superstructures similar to early protofibrils. Addition of Ile-41 to Abeta40 was sufficient to induce formation of paranuclei, but the presence of Ala-42 was required for their further association. These data demonstrate that Abeta42 assembly involves formation of several distinct transient structures that gradually rearrange into protofibrils. The strong etiologic association of Abeta42 with AD may thus be a result of assemblies formed at the earliest stages of peptide oligomerization.
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Affiliation(s)
- Gal Bitan
- Center for Neurologic Diseases, Brigham and Women's Hospital, Boston, MA 02115, USA
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