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  1. Article ; Online: Structure of Amyloid Peptide Ribbons Characterized by Electron Microscopy, Atomic Force Microscopy, and Solid-State Nuclear Magnetic Resonance.

    Thurber, Kent R / Yau, Wai-Ming / Tycko, Robert

    The journal of physical chemistry. B

    2024  Volume 128, Issue 7, Page(s) 1711–1723

    Abstract: Polypeptides often self-assemble to form amyloid fibrils, which contain cross-β structural motifs and are typically 5-15 nm in width and micrometers in length. In many cases, short segments of longer amyloid-forming protein or peptide sequences also form ...

    Abstract Polypeptides often self-assemble to form amyloid fibrils, which contain cross-β structural motifs and are typically 5-15 nm in width and micrometers in length. In many cases, short segments of longer amyloid-forming protein or peptide sequences also form cross-β assemblies but with distinctive ribbon-like morphologies that are characterized by a well-defined thickness (on the order of 5 nm) in one lateral dimension and a variable width (typically 10-100 nm) in the other. Here, we use a novel combination of data from solid-state nuclear magnetic resonance (ssNMR), dark-field transmission electron microscopy (TEM), atomic force microscopy (AFM), and cryogenic electron microscopy (cryoEM) to investigate the structures within amyloid ribbons formed by residues 14-23 and residues 11-25 of the Alzheimer's disease-associated amyloid-β peptide (Aβ
    MeSH term(s) Microscopy, Atomic Force ; Electrons ; Protein Structure, Secondary ; Nuclear Magnetic Resonance, Biomolecular/methods ; Amyloid/chemistry ; Amyloidogenic Proteins ; Amyloid beta-Peptides/chemistry
    Chemical Substances Amyloid ; Amyloidogenic Proteins ; Amyloid beta-Peptides
    Language English
    Publishing date 2024-02-13
    Publishing country United States
    Document type Journal Article
    ISSN 1520-5207
    ISSN (online) 1520-5207
    DOI 10.1021/acs.jpcb.3c07867
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Experimental Evidence for Millisecond-Timescale Structural Evolution Following the Microsecond-Timescale Folding of a Small Protein.

    Wilson, C Blake / Yau, Wai-Ming / Tycko, Robert

    Physical review letters

    2024  Volume 132, Issue 4, Page(s) 48402

    Abstract: Prior work has shown that small proteins can fold (i.e., convert from unstructured to structured states) within 10  μs. Here we use time-resolved solid state nuclear magnetic resonance (ssNMR) methods to show that full folding of the 35-residue villin ... ...

    Abstract Prior work has shown that small proteins can fold (i.e., convert from unstructured to structured states) within 10  μs. Here we use time-resolved solid state nuclear magnetic resonance (ssNMR) methods to show that full folding of the 35-residue villin headpiece subdomain (HP35) requires a slow annealing process that has not been previously detected. ^{13}C ssNMR spectra of frozen HP35 solutions, acquired with a variable time τ_{e} at 30 °C after rapid cooling from 95 °C and before rapid freezing, show changes on the 3-10 ms timescale, attributable to slow rearrangements of protein sidechains during τ_{e}.
    MeSH term(s) Protein Folding ; Magnetic Resonance Spectroscopy
    Language English
    Publishing date 2024-02-09
    Publishing country United States
    Document type Journal Article
    ZDB-ID 208853-8
    ISSN 1079-7114 ; 0031-9007
    ISSN (online) 1079-7114
    ISSN 0031-9007
    DOI 10.1103/PhysRevLett.132.048402
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  3. Article ; Online: From Milliseconds to Minutes: Melittin Self-Assembly from Concerted Non-Equilibrium Pressure-Jump and Equilibrium Relaxation Nuclear Magnetic Resonance.

    Gelenter, Martin D / Yau, Wai-Ming / Anfinrud, Philip A / Bax, Ad

    The journal of physical chemistry letters

    2024  Volume 15, Issue 7, Page(s) 1930–1935

    Abstract: Non-equilibrium kinetics techniques like pressure-jump nuclear magnetic resonance (NMR) are powerful in tracking changes in oligomeric populations and are not limited by relaxation rates for the time scales of exchange that can be probed. However, these ... ...

    Abstract Non-equilibrium kinetics techniques like pressure-jump nuclear magnetic resonance (NMR) are powerful in tracking changes in oligomeric populations and are not limited by relaxation rates for the time scales of exchange that can be probed. However, these techniques are less sensitive to minor, transient populations than are Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion experiments. We integrated non-equilibrium pressure-jump and equilibrium CPMG relaxation dispersion data to fully map the kinetic landscape of melittin tetramerization. While monomeric peptides weakly form dimers (
    MeSH term(s) Melitten ; Nuclear Magnetic Resonance, Biomolecular/methods ; Models, Molecular ; Magnetic Resonance Spectroscopy ; Magnetic Resonance Imaging
    Chemical Substances Melitten (20449-79-0)
    Language English
    Publishing date 2024-02-12
    Publishing country United States
    Document type Journal Article
    ISSN 1948-7185
    ISSN (online) 1948-7185
    DOI 10.1021/acs.jpclett.3c03563
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  4. Article ; Online: Early events in amyloid-β self-assembly probed by time-resolved solid state NMR and light scattering.

    Jeon, Jaekyun / Yau, Wai-Ming / Tycko, Robert

    Nature communications

    2023  Volume 14, Issue 1, Page(s) 2964

    Abstract: Self-assembly of amyloid-β peptides leads to oligomers, protofibrils, and fibrils that are likely instigators of neurodegeneration in Alzheimer's disease. We report results of time-resolved solid state nuclear magnetic resonance (ssNMR) and light ... ...

    Abstract Self-assembly of amyloid-β peptides leads to oligomers, protofibrils, and fibrils that are likely instigators of neurodegeneration in Alzheimer's disease. We report results of time-resolved solid state nuclear magnetic resonance (ssNMR) and light scattering experiments on 40-residue amyloid-β (Aβ40) that provide structural information for oligomers that form on time scales from 0.7 ms to 1.0 h after initiation of self-assembly by a rapid pH drop. Low-temperature ssNMR spectra of freeze-trapped intermediates indicate that β-strand conformations within and contacts between the two main hydrophobic segments of Aβ40 develop within 1 ms, while light scattering data imply a primarily monomeric state up to 5 ms. Intermolecular contacts involving residues 18 and 33 develop within 0.5 s, at which time Aβ40 is approximately octameric. These contacts argue against β-sheet organizations resembling those found previously in protofibrils and fibrils. Only minor changes in the Aβ40 conformational distribution are detected as larger assemblies develop.
    MeSH term(s) Humans ; Magnetic Resonance Imaging ; Amyloid beta-Peptides ; Alzheimer Disease ; Amyloidogenic Proteins ; Magnetic Resonance Spectroscopy
    Chemical Substances Amyloid beta-Peptides ; Amyloidogenic Proteins
    Language English
    Publishing date 2023-05-23
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Intramural
    ZDB-ID 2553671-0
    ISSN 2041-1723 ; 2041-1723
    ISSN (online) 2041-1723
    ISSN 2041-1723
    DOI 10.1038/s41467-023-38494-6
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  5. Article ; Online: Structures of brain-derived 42-residue amyloid-β fibril polymorphs with unusual molecular conformations and intermolecular interactions.

    Lee, Myungwoon / Yau, Wai-Ming / Louis, John M / Tycko, Robert

    Proceedings of the National Academy of Sciences of the United States of America

    2023  Volume 120, Issue 11, Page(s) e2218831120

    Abstract: Fibrils formed by the 42-residue amyloid-β peptide (Aβ42), a main component of amyloid deposits in Alzheimer's disease (AD), are known to be polymorphic, i.e., to contain multiple possible molecular structures. Previous studies of Aβ42 fibrils, including ...

    Abstract Fibrils formed by the 42-residue amyloid-β peptide (Aβ42), a main component of amyloid deposits in Alzheimer's disease (AD), are known to be polymorphic, i.e., to contain multiple possible molecular structures. Previous studies of Aβ42 fibrils, including fibrils prepared entirely in vitro or extracted from brain tissue and using solid-state NMR (ssNMR) or cryogenic electron microscopy (cryo-EM) methods, have found polymorphs with differences in amino acid sidechain orientations, lengths of structurally ordered segments, and contacts between cross-β subunit pairs within a single filament. Despite these differences, Aβ42 molecules adopt a common S-shaped conformation in all previously described high-resolution Aβ42 fibril structures. Here we report two cryo-EM-based structures of Aβ42 fibrils that are qualitatively different, in samples derived from AD brain tissue by seeded growth. In type A fibrils, residues 12 to 42 adopt a ν-shaped conformation, with both intra-subunit and intersubunit hydrophobic contacts to form a compact core. In type B fibrils, residues 2 to 42 adopt an υ-shaped conformation, with only intersubunit contacts and internal pores. Type A and type B fibrils have opposite helical handedness. Cryo-EM density maps and molecular dynamics simulations indicate intersubunit K16-A42 salt bridges in type B fibrils and partially occupied K28-A42 salt bridges in type A fibrils. The coexistence of two predominant polymorphs, with differences in N-terminal dynamics, is supported by ssNMR data, as is faithful propagation of structures from first-generation to second-generation brain-seeded Aβ42 fibril samples. These results demonstrate that Aβ42 fibrils can exhibit a greater range of structural variations than seen in previous studies.
    MeSH term(s) Humans ; Amyloid beta-Peptides/metabolism ; Alzheimer Disease/metabolism ; Magnetic Resonance Spectroscopy ; Brain/metabolism ; Molecular Conformation ; Amyloid/chemistry ; Peptide Fragments/metabolism
    Chemical Substances Amyloid beta-Peptides ; Amyloid ; Peptide Fragments
    Language English
    Publishing date 2023-03-09
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Intramural
    ZDB-ID 209104-5
    ISSN 1091-6490 ; 0027-8424
    ISSN (online) 1091-6490
    ISSN 0027-8424
    DOI 10.1073/pnas.2218831120
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  6. Article ; Online: Nitroxide-based triradical dopants for efficient low-temperature dynamic nuclear polarization in aqueous solutions over a broad pH range.

    Yau, Wai-Ming / Blake Wilson, C / Jeon, Jaekyun / Tycko, Robert

    Journal of magnetic resonance (San Diego, Calif. : 1997)

    2022  Volume 342, Page(s) 107284

    Abstract: Dynamic nuclear polarization (DNP) can provide substantial sensitivity enhancements in solid state nuclear magnetic resonance (ssNMR) measurements on frozen solutions, thereby enabling experiments that would otherwise be impractical. Previous work has ... ...

    Abstract Dynamic nuclear polarization (DNP) can provide substantial sensitivity enhancements in solid state nuclear magnetic resonance (ssNMR) measurements on frozen solutions, thereby enabling experiments that would otherwise be impractical. Previous work has shown that nitroxide-based triradical compounds are particularly effective as dopants in DNP-enhanced measurements at moderate magic-angle spinning frequencies and moderate magnetic field strengths, generally leading to a more rapid build-up of nuclear spin polarizations under microwave irradiation than the more common biradical dopants at the same electron spin concentrations. Here we report the synthesis and DNP performance at 25 K and 9.41 T for two new triradical compounds, sulfoacetyl-DOTOPA and PEG12-DOTOPA. Under our experimental conditions, these compounds exhibit ssNMR signal enhancements and DNP build-up times that are nearly identical to those of previously described triradical dopants. Moreover, these compounds have high solubility in aqueous buffers and water/glycerol mixtures at both acidic and basic pH values, making them useful in a wide variety of experiments on biomolecular systems.
    MeSH term(s) Hydrogen-Ion Concentration ; Nitrogen Oxides/chemistry ; Temperature ; Water
    Chemical Substances Nitrogen Oxides ; Water (059QF0KO0R) ; nitroxyl (GFQ4MMS07W)
    Language English
    Publishing date 2022-08-12
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Intramural
    ZDB-ID 1469665-4
    ISSN 1096-0856 ; 1557-8968 ; 1090-7807 ; 0022-2364
    ISSN (online) 1096-0856 ; 1557-8968
    ISSN 1090-7807 ; 0022-2364
    DOI 10.1016/j.jmr.2022.107284
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  7. Article ; Online: Depletion of amyloid-β peptides from solution by sequestration within fibril-seeded hydrogels.

    Yau, Wai-Ming / Tycko, Robert

    Protein science : a publication of the Protein Society

    2018  Volume 27, Issue 7, Page(s) 1218–1230

    Abstract: Aggregation of amyloid-β (Aβ) peptides in brain tissue leads to neurodegeneration in Alzheimer's disease (AD). Regardless of the kinetics or detailed mechanisms of Aβ aggregation, aggregation can only occur if Aβ concentrations exceed their local ... ...

    Abstract Aggregation of amyloid-β (Aβ) peptides in brain tissue leads to neurodegeneration in Alzheimer's disease (AD). Regardless of the kinetics or detailed mechanisms of Aβ aggregation, aggregation can only occur if Aβ concentrations exceed their local equilibrium solubility values. We propose that excess Aβ peptides can be removed from supersaturated solutions, including solutions in biological fluids, by the addition of hydrogels that are seeded with Aβ fibril fragments. Fibril growth within the hydrogels then sequesters excess peptides until equilibrium concentrations are reached. Experiments with 40- and 42-residue Aβ peptides (Aβ40 and Aβ42) in phosphate buffer at 24°C and in filtered fetal bovine serum at 37°C, using crosslinked polyacrylamide hydrogels, demonstrate the validity of this concept. Aβ sequestration in fibril-seeded hydrogels (or other porous media) may prove to be a useful technique in experiments with animal models of AD and may represent a possible approach to preventing or slowing the progression of AD in humans.
    MeSH term(s) Amyloid/chemistry ; Amyloid beta-Peptides/chemistry ; Humans ; Hydrogels/chemistry ; Peptide Fragments/chemistry ; Protein Aggregates ; Solutions ; Temperature
    Chemical Substances Amyloid ; Amyloid beta-Peptides ; Hydrogels ; Peptide Fragments ; Protein Aggregates ; Solutions ; amyloid beta-protein (1-40) ; amyloid beta-protein (1-42)
    Language English
    Publishing date 2018-03-08
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 1106283-6
    ISSN 1469-896X ; 0961-8368
    ISSN (online) 1469-896X
    ISSN 0961-8368
    DOI 10.1002/pro.3387
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  8. Article ; Online: Millisecond Time-Resolved Solid-State NMR Reveals a Two-Stage Molecular Mechanism for Formation of Complexes between Calmodulin and a Target Peptide from Myosin Light Chain Kinase.

    Jeon, Jaekyun / Yau, Wai-Ming / Tycko, Robert

    Journal of the American Chemical Society

    2020  Volume 142, Issue 50, Page(s) 21220–21232

    Abstract: Calmodulin (CaM) mediates a wide range of biological responses to changes in intracellular ... ...

    Abstract Calmodulin (CaM) mediates a wide range of biological responses to changes in intracellular Ca
    MeSH term(s) Calmodulin/chemistry ; Calmodulin/metabolism ; Kinetics ; Molecular Docking Simulation ; Myosin-Light-Chain Kinase/chemistry ; Nuclear Magnetic Resonance, Biomolecular ; Peptide Fragments/chemistry ; Peptide Fragments/metabolism ; Protein Domains
    Chemical Substances Calmodulin ; Peptide Fragments ; Myosin-Light-Chain Kinase (EC 2.7.11.18)
    Language English
    Publishing date 2020-12-07
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Intramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 3155-0
    ISSN 1520-5126 ; 0002-7863
    ISSN (online) 1520-5126
    ISSN 0002-7863
    DOI 10.1021/jacs.0c11156
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  9. Article ; Online: Structural differences in amyloid-β fibrils from brains of nondemented elderly individuals and Alzheimer's disease patients.

    Ghosh, Ujjayini / Yau, Wai-Ming / Collinge, John / Tycko, Robert

    Proceedings of the National Academy of Sciences of the United States of America

    2021  Volume 118, Issue 45

    Abstract: Although amyloid plaques composed of fibrillar amyloid-β (Aβ) assemblies are a diagnostic hallmark of Alzheimer's disease (AD), quantities of amyloid similar to those in AD patients are observed in brain tissue of some nondemented elderly individuals. ... ...

    Abstract Although amyloid plaques composed of fibrillar amyloid-β (Aβ) assemblies are a diagnostic hallmark of Alzheimer's disease (AD), quantities of amyloid similar to those in AD patients are observed in brain tissue of some nondemented elderly individuals. The relationship between amyloid deposition and neurodegeneration in AD has, therefore, been unclear. Here, we use solid-state NMR to investigate whether molecular structures of Aβ fibrils from brain tissue of nondemented elderly individuals with high amyloid loads differ from structures of Aβ fibrils from AD tissue. Two-dimensional solid-state NMR spectra of isotopically labeled Aβ fibrils, prepared by seeded growth from frontal lobe tissue extracts, are similar in the two cases but with statistically significant differences in intensity distributions of cross-peak signals. Differences in solid-state NMR data are greater for 42-residue amyloid-β (Aβ42) fibrils than for 40-residue amyloid-β (Aβ40) fibrils. These data suggest that similar sets of fibril polymorphs develop in nondemented elderly individuals and AD patients but with different relative populations on average.
    MeSH term(s) Aged, 80 and over ; Alzheimer Disease/pathology ; Amyloid beta-Peptides/chemistry ; Case-Control Studies ; Female ; Frontal Lobe/pathology ; Humans ; Magnetic Resonance Spectroscopy ; Male ; Plaque, Amyloid/chemistry ; Plaque, Amyloid/pathology
    Chemical Substances Amyloid beta-Peptides
    Language English
    Publishing date 2021-11-01
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, N.I.H., Intramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 209104-5
    ISSN 1091-6490 ; 0027-8424
    ISSN (online) 1091-6490
    ISSN 0027-8424
    DOI 10.1073/pnas.2111863118
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  10. Article ; Online: Molecular structure of a prevalent amyloid-β fibril polymorph from Alzheimer's disease brain tissue.

    Ghosh, Ujjayini / Thurber, Kent R / Yau, Wai-Ming / Tycko, Robert

    Proceedings of the National Academy of Sciences of the United States of America

    2021  Volume 118, Issue 4

    Abstract: Amyloid-β (Aβ) fibrils exhibit self-propagating, molecular-level polymorphisms that may contribute to variations in clinical and pathological characteristics of Alzheimer's disease (AD). We report the molecular structure of a specific fibril polymorph, ... ...

    Abstract Amyloid-β (Aβ) fibrils exhibit self-propagating, molecular-level polymorphisms that may contribute to variations in clinical and pathological characteristics of Alzheimer's disease (AD). We report the molecular structure of a specific fibril polymorph, formed by 40-residue Aβ peptides (Aβ40), that is derived from cortical tissue of an AD patient by seeded fibril growth. The structure is determined from cryogenic electron microscopy (cryoEM) images, supplemented by mass-per-length (MPL) measurements and solid-state NMR (ssNMR) data. Previous ssNMR studies with multiple AD patients had identified this polymorph as the most prevalent brain-derived Aβ40 fibril polymorph from typical AD patients. The structure, which has 2.8-Å resolution according to standard criteria, differs qualitatively from all previously described Aβ fibril structures, both in its molecular conformations and its organization of cross-β subunits. Unique features include twofold screw symmetry about the fibril growth axis, despite an MPL value that indicates three Aβ40 molecules per 4.8-Å β-sheet spacing, a four-layered architecture, and fully extended conformations for molecules in the central two cross-β layers. The cryoEM density, ssNMR data, and MPL data are consistent with β-hairpin conformations for molecules in the outer cross-β layers. Knowledge of this brain-derived fibril structure may contribute to the development of structure-specific amyloid imaging agents and aggregation inhibitors with greater diagnostic and therapeutic utility.
    MeSH term(s) Alzheimer Disease/metabolism ; Alzheimer Disease/pathology ; Amyloid/metabolism ; Amyloid/ultrastructure ; Amyloid beta-Peptides/metabolism ; Amyloid beta-Peptides/ultrastructure ; Binding Sites ; Cerebral Cortex/chemistry ; Cerebral Cortex/pathology ; Cryoelectron Microscopy ; Humans ; Models, Molecular ; Nuclear Magnetic Resonance, Biomolecular ; Peptide Fragments/metabolism ; Peptide Fragments/ultrastructure ; Protein Binding ; Protein Conformation, beta-Strand ; Protein Interaction Domains and Motifs ; Thermodynamics
    Chemical Substances Amyloid ; Amyloid beta-Peptides ; Peptide Fragments ; amyloid beta-protein (1-40)
    Language English
    Publishing date 2021-01-11
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Intramural
    ZDB-ID 209104-5
    ISSN 1091-6490 ; 0027-8424
    ISSN (online) 1091-6490
    ISSN 0027-8424
    DOI 10.1073/pnas.2023089118
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