1
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Prosswimmer T, Daggett V. The role of α-sheet structure in amyloidogenesis: characterization and implications. Open Biol 2022; 12:220261. [PMID: 36416010 PMCID: PMC9682440 DOI: 10.1098/rsob.220261] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/01/2022] [Indexed: 11/25/2022] Open
Abstract
Amyloid diseases are linked to protein misfolding whereby the amyloidogenic protein undergoes a conformational change, aggregates and eventually forms amyloid fibrils. While the amyloid fibrils and plaques are hallmarks of these diseases, they typically form late in the disease process and do not correlate with disease. Instead, there is growing evidence that smaller, soluble toxic oligomers form prior and appear to be early triggers of the molecular pathology underlying these diseases. Nearly 20 years ago, we proposed the α-sheet hypothesis after discovering that the early conformational changes observed during atomistic molecular dynamics simulations involve the formation of a non-standard protein structure, α-sheet. Furthermore, we proposed that toxic oligomers contain α-sheet structure and that preferentially targeting this structure could neutralize the toxicity, prevent further aggregation and serve as the basis for early detection of disease. Here, we present the origin of the α-sheet hypothesis and describe α-sheet structure and the corresponding mechanisms of conversion. We discuss experimental studies demonstrating that both mammalian and bacterial amyloid systems form α-sheet oligomers before converting to conventional β-sheet fibrils. Furthermore, we show that the process can be inhibited with de novo designed α-sheet peptides complementary to the structure in the toxic oligomers.
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Affiliation(s)
- Tatum Prosswimmer
- Molecular Engineering Program, University of Washington, Seattle, WA 98195-5013, USA
| | - Valerie Daggett
- Molecular Engineering Program, University of Washington, Seattle, WA 98195-5013, USA
- Department of Bioengineering, University of Washington, Seattle, WA 98195-5013, USA
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2
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Serwer P, Wright ET, Hunter B. Additions to Alpha-Sheet Based Hypotheses for the Cause of Alzheimer's Disease. J Alzheimers Dis 2022; 88:429-438. [PMID: 35662126 DOI: 10.3233/jad-220311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Protein amyloid-β (Aβ) oligomers with β-sheet-like backbone (β-structured) form extracellular amyloid plaques associated with Alzheimer's disease (AD). However, the relationship to AD is not known. Some investigations suggest that the toxic Aβ component has α-sheet-like backbone (α-structured) subsequently detoxified by intracellular α-to-β conversion before plaque formation. Our objective is to compare this latter hypothesis with observations made by electron microscopy of thin sections of AD-cerebral cortex. We observe irregular, 200-2,000 nm, intracellular, lipofuscin-like inclusions. Some are light-staining and smooth. Others are dark-staining and made granular by fibers that are usually overlapping and are sometimes individually seen. Aspects unusual for lipofuscin include 1) dark and light inclusions interlocking as though previously one inclusion, 2) dark inclusion-contained 2.6 nm thick sub-fibers that are bent as though α-structured, and 3) presence of inclusions in lysosomes and apparent transfer of dark inclusion material to damaged, nearby lysosomal membranes. These data suggest the following additions to α-structure-based hypotheses: 1) Lipofuscin-associated, α-structured protein toxicity to lysosomal membranes is in the chain of AD causation; 2) α-to-β detoxification of α-structured protein occurs in lipofuscin and causes dark-to-light transition that, when incomplete, is the origin of cell-to-cell transmission essential for development of AD.
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Affiliation(s)
- Philip Serwer
- The University of Texas Health Center, San Antonio, TX, USA
| | - Elena T Wright
- The University of Texas Health Center, San Antonio, TX, USA
| | - Barbara Hunter
- The University of Texas Health Center, San Antonio, TX, USA
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3
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Hayward S, Milner-White EJ. Determination of amino acids that favour the α L region using Ramachandran propensity plots. Implications for α-sheet as the possible amyloid intermediate. J Struct Biol 2021; 213:107738. [PMID: 33838226 DOI: 10.1016/j.jsb.2021.107738] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 04/01/2021] [Accepted: 04/04/2021] [Indexed: 11/28/2022]
Abstract
In amyloid diseases an insoluble amyloid fibril forms via a soluble oligomeric intermediate. It is this intermediate that mediates toxicity and it has been suggested, somewhat controversially, that it has the α-sheet structure. Nests and α-strands are similar peptide motifs in that alternate residues lie in the αR and γL regions of the Ramachandran plot for nests, or αR and αL regions for α-strands. In nests a concavity is formed by the main chain NH atoms whereas in α-strands the main chain is almost straight. Using "Ramachandran propensity plots" to focus on the αL/γL region, it is shown that glycine favours γL (82% of amino acids are glycine), but disfavours αL (3% are glycine). Most charged and polar amino acids favour αL with asparagine having by far the highest propensity. Thus, glycine favours nests but, contrary to common expectation, should not favour α-sheet. By contrast most charged or polar amino acids should favour α-sheet by their propensity for the αL conformation, which is more discriminating amongst amino acids than the αR conformation. Thus, these results suggest the composition of sequences that favour α-sheet formation and point towards effective prediction of α-sheet from sequence.
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Affiliation(s)
- Steven Hayward
- Computational Biology Laboratory, School of Computing Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
| | - E James Milner-White
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
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4
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Bromley D, Daggett V. Tumorigenic p53 mutants undergo common structural disruptions including conversion to α-sheet structure. Protein Sci 2020; 29:1983-1999. [PMID: 32715544 DOI: 10.1002/pro.3921] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 05/15/2020] [Accepted: 07/17/2020] [Indexed: 12/28/2022]
Abstract
The p53 protein is a commonly studied cancer target because of its role in tumor suppression. Unfortunately, it is susceptible to mutation-associated loss of function; approximately 50% of cancers are associated with mutations to p53, the majority of which are located in the central DNA-binding domain. Here, we report molecular dynamics simulations of wild-type (WT) p53 and 20 different mutants, including a stabilized pseudo-WT mutant. Our findings indicate that p53 mutants tend to exacerbate latent structural-disruption tendencies, or vulnerabilities, already present in the WT protein, suggesting that it may be possible to develop cancer therapies by targeting a relatively small set of structural-disruption motifs rather than a multitude of effects specific to each mutant. In addition, α-sheet secondary structure formed in almost all of the proteins. α-Sheet has been hypothesized and recently demonstrated to play a role in amyloidogenesis, and its presence in the reported p53 simulations coincides with the recent re-consideration of cancer as an amyloid disease.
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Affiliation(s)
- Dennis Bromley
- Division of Biomedical and Health Informatics, Department of Biomedical Informatics and Medical Education, University of Washington, Seattle, Washington, USA
| | - Valerie Daggett
- Division of Biomedical and Health Informatics, Department of Biomedical Informatics and Medical Education, University of Washington, Seattle, Washington, USA.,Department of Bioengineering, University of Washington, Seattle, Washington, USA
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5
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Huin C, Cronier S, Guégan P, Béringue V, Rezaei H, Noinville S. Conformation-dependent membrane permeabilization by neurotoxic PrP oligomers: The role of the H2H3 oligomerization domain. Arch Biochem Biophys 2020; 692:108517. [PMID: 32738196 DOI: 10.1016/j.abb.2020.108517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/08/2020] [Accepted: 07/26/2020] [Indexed: 12/11/2022]
Abstract
The relationship between prion propagation and the generation of neurotoxic species and clinical onset remains unclear. Several converging lines of evidence suggest that interactions with lipids promote various precursors to form aggregation-prone states that are involved in amyloid fibrils. Here, we compared the cytotoxicities of different soluble isolated oligomeric constructs from murine full-length PrP and from the restricted helical H2H3 domain with their effects on lipid vesicles. The helical H2H3 domain is suggested to be the minimal region of PrP involved in the oligomerization process. The discrete PrP oligomers of both the full-length sequence and the H2H3 domain have de novo β-sheeted structure when interacting with the membrane. They were shown to permeabilize synthetic negatively charged vesicles in a dose-dependent manner. Restricting the polymerization domain of the full-length PrP to the H2H3 helices strongly diminished the ability of the corresponding oligomers to associate with the lipid vesicles. Furthermore, the membrane impairment mechanism occurs differently for the full-length PrP oligomers and the H2H3 helices, as shown by dye-release and black lipid membrane experiments. The membrane damage caused by the full-length PrP oligomers is correlated to their neuronal toxicity at submicromolar concentrations, as shown by cell culture assays. Although oligomers of synthetic H2H3 could compromise in vitro cell homeostasis, they followed a membrane-disruptive pattern that was different from the full-length oligomers, as revealed by the role of PrPC in cell viability assays.
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Affiliation(s)
- Cécile Huin
- Sorbonne Universités, CNRS, Institut Parisien de Chimie Moléculaire, Equipe Chimie des Polymères, 4 Place Jussieu, F-75005, Paris, France; University of Evry, F-91025, Evry, France
| | - Sabrina Cronier
- UR892, Virologie et Immunologie Moléculaires, Institut National de la Recherche Agronomique (INRA), Jouy-en-Josas, France
| | - Philippe Guégan
- Sorbonne Universités, CNRS, Institut Parisien de Chimie Moléculaire, Equipe Chimie des Polymères, 4 Place Jussieu, F-75005, Paris, France
| | - Vincent Béringue
- UR892, Virologie et Immunologie Moléculaires, Institut National de la Recherche Agronomique (INRA), Jouy-en-Josas, France
| | - Human Rezaei
- UR892, Virologie et Immunologie Moléculaires, Institut National de la Recherche Agronomique (INRA), Jouy-en-Josas, France
| | - Sylvie Noinville
- UR892, Virologie et Immunologie Moléculaires, Institut National de la Recherche Agronomique (INRA), Jouy-en-Josas, France; Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR8233, MONARIS, Université Pierre et Marie Curie, Paris, France.
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6
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Meng F, Lu T, Li F. Stabilization of Solvent to α-Sheet Structure and Conversion between α-Sheet and β-Sheet in the Fibrillation Process of Amyloid Peptide. J Phys Chem B 2019; 123:9576-9583. [DOI: 10.1021/acs.jpcb.9b07903] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Feihong Meng
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Qianjin Avenue 2699, Changchun 130012, P. R. China
| | - Tong Lu
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Qianjin Avenue 2699, Changchun 130012, P. R. China
| | - Fei Li
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Qianjin Avenue 2699, Changchun 130012, P. R. China
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7
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Milner-White EJ. Protein three-dimensional structures at the origin of life. Interface Focus 2019; 9:20190057. [PMID: 31641431 DOI: 10.1098/rsfs.2019.0057] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/10/2019] [Indexed: 12/22/2022] Open
Abstract
Proteins are relatively easy to synthesize, compared to nucleic acids and it is likely that there existed a stage prior to the RNA world which can be called the protein world. Some of the three-dimensional (3D) peptide structures in these proteins have, we argue, been conserved since then and may constitute the oldest biological relics in existence. We focus on 3D peptide motifs consisting of up to eight or so amino acid residues. The best known of these is the 'nest', a three- to seven-residue protein motif, which has the function of binding anionic atoms or groups of atoms. Ten per cent of amino acids in typical proteins belong to a nest, so it is a common motif. A five-residue nest is found as part of the well-known P-loop that is a recurring feature of many ATP or GTP-binding proteins and it has the function of binding the phosphate part of these ligands. A synthetic hexapeptide, ser-gly-ala-gly-lys-thr, designed to resemble the P-loop, has been shown to bind inorganic phosphate. Another type of nest binds iron-sulfur centres. A range of other simple motifs occur with various intriguing 3D structures; others bind cations or form channels that transport potassium ions; other peptides form catalytically active haem-like or sheet structures with certain transition metals. Amyloid peptides are also discussed. It now seems that the earliest polypeptides were far from being functionless stretches, and had many of the properties, both binding and catalytic, that might be expected to encourage and stabilize simple life forms in the hydrothermal vents of ocean depths.
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Affiliation(s)
- E James Milner-White
- Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G128QQ, UK
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8
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Hayward S, Kitao A. Multi-strand β-sheet of Alzheimer Aβ(1–40) folds to β-strip helix: implication for protofilament formation. J Biomol Struct Dyn 2019; 37:2143-2153. [DOI: 10.1080/07391102.2018.1477626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Steven Hayward
- D’Arcy Thompson Centre for Computational Biology, School of Computing Sciences, University of East Anglia, Norwich, UK
| | - Akio Kitao
- School of Life Science and Technology, Tokyo Institute of Technology, Ookayama, Meguro, Tokyo, Japan
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9
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Balasco N, Smaldone G, Ruggiero A, De Simone A, Vitagliano L. Local structural motifs in proteins: Detection and characterization of fragments inserted in helices. Int J Biol Macromol 2018; 118:1924-1930. [PMID: 30017977 DOI: 10.1016/j.ijbiomac.2018.07.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/06/2018] [Accepted: 07/11/2018] [Indexed: 11/26/2022]
Abstract
The global/local fold of protein structures is stabilized by a variety of specific interactions. A primary role in this context is played by hydrogen bonds. In order to identify novel motifs in proteins, we searched Protein Data Bank structures looking for backbone H-bonds formed by NH groups of two (or more) consecutive residues with consecutive CO groups of distant residues in the sequence. The present analysis unravels the occurrence of recurrent structural motifs that, to the best of our knowledge, had not been characterized in literature. Indeed, these H-bonding patterns are found (i) in a specific parallel β-sheet capping, (ii) in linking of β-hairpins to α-helices, and (iii) in α-helix insertions. Interestingly, structural analyses of these motifs indicate that Gly residues frequently occupy prominent positions. The formation of these motifs is likely favored by the limited propensity of Gly to be embodied in helices/sheets. Of particular interest is the motif corresponding to insertions in helices that was detected in 1% of analyzed structures. Inserted fragments may assume different structures and aminoacid compositions and usually display diversified evolutionary conservation. Since inserted regions are physically separated from the rest of the protein structure, they represent hot spots for ad-hoc protein functionalization.
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Affiliation(s)
- Nicole Balasco
- Institute of Biostructures and Bioimaging, C.N.R., Naples, Italy.
| | | | - Alessia Ruggiero
- Institute of Biostructures and Bioimaging, C.N.R., Naples, Italy
| | - Alfonso De Simone
- Division of Molecular Biosciences, Imperial College South Kensington Campus, London SW7 2AZ, UK
| | - Luigi Vitagliano
- Institute of Biostructures and Bioimaging, C.N.R., Naples, Italy.
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10
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Hilaire MR, Ding B, Mukherjee D, Chen J, Gai F. Possible Existence of α-Sheets in the Amyloid Fibrils Formed by a TTR 105-115 Mutant. J Am Chem Soc 2018; 140:629-635. [PMID: 29241000 PMCID: PMC5796419 DOI: 10.1021/jacs.7b09262] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herein, we combine several methods to characterize the fibrils formed by a TTR105-115 mutant in which Leu111 is replaced by the unnatural amino acid aspartic acid 4-methyl ester. We find that this mutant peptide exhibits significantly different aggregation behavior than the wild-type peptide: (1) it forms fibrils with a much faster rate, (2) its fibrils lack the long-range helical twists observed in TTR105-115 fibrils, (3) its fibrils exhibit a giant far-UV circular dichroism signal, and (4) its fibrils give rise to an unusual amide I' band consisting of four distinct and sharp peaks. On the basis of these results and also several previous computational studies, we hypothesize that the fibrils formed by this TTR mutant peptide contain both β- and α-sheets.
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Affiliation(s)
- Mary Rose Hilaire
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
| | - Bei Ding
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
- The Ultrafast Optical Processes Laboratory, University of Pennsylvania, Philadelphia, PA 19104
| | | | - Jianxin Chen
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
- The Ultrafast Optical Processes Laboratory, University of Pennsylvania, Philadelphia, PA 19104
| | - Feng Gai
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
- The Ultrafast Optical Processes Laboratory, University of Pennsylvania, Philadelphia, PA 19104
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11
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Hayward S, Milner-White EJ. Geometrical principles of homomeric β-barrels and β-helices: Application to modeling amyloid protofilaments. Proteins 2017. [PMID: 28646497 DOI: 10.1002/prot.25341] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Examples of homomeric β-helices and β-barrels have recently emerged. Here we generalize the theory for the shear number in β-barrels to encompass β-helices and homomeric structures. We introduce the concept of the "β-strip," the set of parallel or antiparallel neighboring strands, from which the whole helix can be generated giving it n-fold rotational symmetry. In this context, the shear number is interpreted as the sum around the helix of the fixed register shift between neighboring identical β-strips. Using this approach, we have derived relationships between helical width, pitch, angle between strand direction and helical axis, mass per length, register shift, and number of strands. The validity and unifying power of the method is demonstrated with known structures including α-hemolysin, T4 phage spike, cylindrin, and the HET-s(218-289) prion. From reported dimensions measured by X-ray fiber diffraction on amyloid fibrils, the relationships can be used to predict the register shift and the number of strands within amyloid protofilaments. This was used to construct models of transthyretin and Alzheimer β(40) amyloid protofilaments that comprise a single strip of in-register β-strands folded into a "β-strip helix." Results suggest both stabilization of an individual β-strip helix and growth by addition of further β-strip helices can involve the same pair of sequence segments associating with β-sheet hydrogen bonding at the same register shift. This process would be aided by a repeat sequence. Hence, understanding how the register shift (as the distance between repeat sequences) relates to helical dimensions will be useful for nanotube design.
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Affiliation(s)
- Steven Hayward
- D'Arcy Thompson Centre for Computational Biology, School of Computing Sciences, University of East Anglia, Norwich, NR4 7TJ, United Kingdom
| | - E James Milner-White
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
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12
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Huntingtin exon 1 fibrils feature an interdigitated β-hairpin-based polyglutamine core. Proc Natl Acad Sci U S A 2016; 113:1546-51. [PMID: 26831073 DOI: 10.1073/pnas.1521933113] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Polyglutamine expansion within the exon1 of huntingtin leads to protein misfolding, aggregation, and cytotoxicity in Huntington's disease. This incurable neurodegenerative disease is the most prevalent member of a family of CAG repeat expansion disorders. Although mature exon1 fibrils are viable candidates for the toxic species, their molecular structure and how they form have remained poorly understood. Using advanced magic angle spinning solid-state NMR, we directly probe the structure of the rigid core that is at the heart of huntingtin exon1 fibrils and other polyglutamine aggregates, via measurements of long-range intramolecular and intermolecular contacts, backbone and side-chain torsion angles, relaxation measurements, and calculations of chemical shifts. These experiments reveal the presence of β-hairpin-containing β-sheets that are connected through interdigitating extended side chains. Despite dramatic differences in aggregation behavior, huntingtin exon1 fibrils and other polyglutamine-based aggregates contain identical β-strand-based cores. Prior structural models, derived from X-ray fiber diffraction and computational analyses, are shown to be inconsistent with the solid-state NMR results. Internally, the polyglutamine amyloid fibrils are coassembled from differently structured monomers, which we describe as a type of "intrinsic" polymorphism. A stochastic polyglutamine-specific aggregation mechanism is introduced to explain this phenomenon. We show that the aggregation of mutant huntingtin exon1 proceeds via an intramolecular collapse of the expanded polyglutamine domain and discuss the implications of this observation for our understanding of its misfolding and aggregation mechanisms.
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13
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Hayward S, Kitao A. Monte Carlo Sampling with Linear Inverse Kinematics for Simulation of Protein Flexible Regions. J Chem Theory Comput 2015; 11:3895-905. [DOI: 10.1021/acs.jctc.5b00215] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Steven Hayward
- D’Arcy
Thompson Centre for Computational Biology, School of Computing Sciences, University of East Anglia, Norwich NR4 7TJ, U.K
| | - Akio Kitao
- Institute
of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-0032, Japan
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14
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Hayward S, Leader DP, Al-Shubailly F, Milner-White EJ. Rings and ribbons in protein structures: Characterization using helical parameters and Ramachandran plots for repeating dipeptides. Proteins 2013; 82:230-9. [DOI: 10.1002/prot.24357] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 06/10/2013] [Accepted: 06/10/2013] [Indexed: 12/30/2022]
Affiliation(s)
- Steven Hayward
- School of Computing Sciences; University of East Anglia; Norwich NR4 7TJ United Kingdom
| | - David P. Leader
- College of Medical, Veterinary and Life Sciences; University of Glasgow; Glasgow G12 8QQ United Kingdom
| | - Fawzia Al-Shubailly
- College of Medical, Veterinary and Life Sciences; University of Glasgow; Glasgow G12 8QQ United Kingdom
| | - E. James Milner-White
- College of Medical, Veterinary and Life Sciences; University of Glasgow; Glasgow G12 8QQ United Kingdom
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15
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Milner-White EJ, Russell MJ. Functional capabilities of the earliest peptides and the emergence of life. Genes (Basel) 2011; 2:671-88. [PMID: 24710286 PMCID: PMC3927598 DOI: 10.3390/genes2040671] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 09/14/2011] [Accepted: 09/14/2011] [Indexed: 02/01/2023] Open
Abstract
Considering how biological macromolecules first evolved, probably within a marine environment, it seems likely the very earliest peptides were not encoded by nucleic acids, or at least not via the genetic code as we know it. An objective of the present work is to demonstrate that sequence-independent peptides, or peptides with variable and unreliable lengths and sequences, have the potential to perform a variety of chemically useful functions such as anion and cation binding and membrane and channel formation as well as simple types of catalysis. These functions tend to be performed with the assistance of the main chain CONH atoms rather than the more variable or limited side chain atoms of the peptides presumed to exist then.
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Affiliation(s)
- E James Milner-White
- College of Medical, Veterinary and Life Sciences, Glasgow University, Glasgow G128QQ, UK.
| | - Michael J Russell
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA.
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