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Yugay D, Goronzy DP, Kawakami LM, Claridge SA, Song TB, Yan Z, Xie YH, Gilles J, Yang Y, Weiss PS. Copper Ion Binding Site in β-Amyloid Peptide. NANO LETTERS 2016; 16:6282-6289. [PMID: 27616333 DOI: 10.1021/acs.nanolett.6b02590] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
β-Amyloid aggregates in the brain play critical roles in Alzheimer's disease, a chronic neurodegenerative condition. Amyloid-associated metal ions, particularly zinc and copper ions, have been implicated in disease pathogenesis. Despite the importance of such ions, the binding sites on the β-amyloid peptide remain poorly understood. In this study, we use scanning tunneling microscopy, circular dichroism, and surface-enhanced Raman spectroscopy to probe the interactions between Cu2+ ions and a key β-amyloid peptide fragment, consisting of the first 16 amino acids, and define the copper-peptide binding site. We observe that in the presence of Cu2+, this peptide fragment forms β-sheets, not seen without the metal ion. By imaging with scanning tunneling microscopy, we are able to identify the binding site, which involves two histidine residues, His13 and His14. We conclude that the binding of copper to these residues creates an interstrand histidine brace, which enables the formation of β-sheets.
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Affiliation(s)
- Diana Yugay
- California NanoSystems Institute, University of California, Los Angeles , Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, University of California, Los Angeles , Los Angeles, California 90095, United States
| | - Dominic P Goronzy
- California NanoSystems Institute, University of California, Los Angeles , Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, University of California, Los Angeles , Los Angeles, California 90095, United States
| | - Lisa M Kawakami
- Department of Chemistry and Biochemistry, University of California, Los Angeles , Los Angeles, California 90095, United States
| | - Shelley A Claridge
- Department of Chemistry and Biochemistry, University of California, Los Angeles , Los Angeles, California 90095, United States
| | - Tze-Bin Song
- Department of Materials Science and Engineering, University of California, Los Angeles , Los Angeles, California 90095, United States
| | - Zhongbo Yan
- Department of Materials Science and Engineering, University of California, Los Angeles , Los Angeles, California 90095, United States
| | - Ya-Hong Xie
- California NanoSystems Institute, University of California, Los Angeles , Los Angeles, California 90095, United States
- Department of Materials Science and Engineering, University of California, Los Angeles , Los Angeles, California 90095, United States
| | - Jérôme Gilles
- Department of Mathematics and Statistics, San Diego State University , San Diego, California 92182, United States
| | - Yang Yang
- California NanoSystems Institute, University of California, Los Angeles , Los Angeles, California 90095, United States
- Department of Materials Science and Engineering, University of California, Los Angeles , Los Angeles, California 90095, United States
| | - Paul S Weiss
- California NanoSystems Institute, University of California, Los Angeles , Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, University of California, Los Angeles , Los Angeles, California 90095, United States
- Department of Materials Science and Engineering, University of California, Los Angeles , Los Angeles, California 90095, United States
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Abstract
The great progress made in defining the structure of protein and peptide amyloid assemblies, particularly the arrangement of peptides in beta-sheets, is counterbalanced by the still poor understanding of the higher organization of beta-sheets within the fibril and overall fibril/fibril associations. The assembly pathway and basis of amyloid toxicity may well depend on these higher-order structural features. For example, significant evidence points to association between sheets as the rate limiting step in fibril assembly, and a critical metal binding site has now been identified that involves residues from different individual sheets. Here we review experiments that are identifying some of the issues associated with sheet-sheet association by investigating simple model peptides derived from the central core of the Abeta peptide implicated in Alzheimer's disease. These peptides transit between fibril/ribbon/nanotube morphologies in response to assembly conditions, laying the foundation for understanding the folding landscape for these higher order assemblies, revealing potential targets for therapeutic intervention, and opening strategies for the design of highly ordered peptide self-assembled microscale morphologies.
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Affiliation(s)
- Jijun Dong
- Center for the Analysis of Supramolecular Self-assemblies, Departments of Chemistry and Biology, Emory University, Atlanta, GA 30322, USA
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Dong J, Apkarian RP, Lynn DG. Imaging amyloid β peptide oligomeric particles in solution. Bioorg Med Chem 2005; 13:5213-7. [PMID: 15993093 DOI: 10.1016/j.bmc.2005.05.052] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2005] [Revised: 05/22/2005] [Accepted: 05/23/2005] [Indexed: 11/28/2022]
Abstract
While all protein misfolding diseases are characterized by fibrous amyloid deposits, the favorable free energy and strongly cooperative nature of the self-assembly have complicated the development of therapeutic strategies aimed at preventing their formation. As structural models for the amyloid fibrils approach atomic resolution, increasing evidence suggests that early folding intermediates, rather than the final structure, are more strongly associated with the loss of neuronal function. For that reason we now demonstrate the use of cryo-etch high-resolution scanning electron microscopy (cryo-HRSEM) for the direct observation of pathway intermediates in amyloid assembly. A congener of the Abeta peptide of Alzheimer's disease, Abeta(13-21), samples a variety of time-dependent self-assembles in a manner similar to those seen for larger proteins. A morphological description of these intermediates is the first step towards their structural characterization and the definition of their role in both amyloid assembly and neurotoxicity.
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Affiliation(s)
- Jijun Dong
- Center for the Analysis of SupraMolecular Self-assemblies, Integrated Microscopy and Microanalytical Facility, Department of Chemistry, Emory University, 1521 Dickey Drive, Atlanta, GA 30322, USA
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Lu K, Jacob J, Thiyagarajan P, Conticello VP, Lynn DG. Exploiting amyloid fibril lamination for nanotube self-assembly. J Am Chem Soc 2003; 125:6391-3. [PMID: 12785778 DOI: 10.1021/ja0341642] [Citation(s) in RCA: 275] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fundamental questions about the relative arrangement of the beta-sheet arrays within amyloid fibrils remain central to both its structure and the mechanism of self-assembly. Recent computational analyses suggested that sheet-to-sheet lamination was limited by the length of the strand. On the basis of this hypothesis, a short seven-residue segment of the Alzheimer's disease-related Abeta peptide, Abeta(16-22), was allowed to self-assemble under conditions that maintained the basic amphiphilic character of Abeta. Indeed, the number increased over 20-fold to 130 laminates, giving homogeneous bilayer structures that supercoil into long robust nanotubes. Small-angle neutron scattering and X-ray scattering defined the outer and inner radii of the nanotubes in solution to contain a 44-nm inner cavity with 4-nm-thick walls. Atomic force microscopy and transmission electron microscopy images further confirmed these homogeneous arrays of solvent-filled nanotubes arising from a flat rectangular bilayer, 130 nm wide x 4 nm thick, with each bilayer leaflet composed of laminated beta-sheets. The corresponding backbone H-bonds are along the long axis, and beta-sheet lamination defines the 130-nm bilayer width. This bilayer coils to give the final nanotube. Such robust and persistent self-assembling nanotubes with positively charged surfaces of very different inner and outer curvature now offer a unique, robust, and easily accessible scaffold for nanotechnology.
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Affiliation(s)
- Kun Lu
- Center for the Analysis of Supramolecular Self-assemblies, Departments of Chemistry and Biology, Emory University, Atlanta, Georgia 30322, USA
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Lakdawala AS, Morgan DM, Liotta DC, Lynn DG, Snyder JP. Dynamics and fluidity of amyloid fibrils: a model of fibrous protein aggregates. J Am Chem Soc 2002; 124:15150-1. [PMID: 12487571 DOI: 10.1021/ja0273290] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A previous experimentally defined model for the fibril formed from the core residues of the beta-amyloid (Abeta) peptides of Alzheimer's disease, 10YEVHHQKLVFFAEDVGSNKGAIIGLM, Abeta(10-35) using spectroscopic and scattering analyses reports on the average structure, benefiting immensely from the homogeneous assembly of Abeta(10-35). However, the energetic constraints that contribute to fibril dynamics and stability remain poorly understood. Here we perform molecular dynamics simulations to extend the structural assignment by providing evidence for a dynamic average ensemble with transient backbone H-bonds and internal solvation contributing to the inherent stability of amyloid fibrils.
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Affiliation(s)
- Ami S Lakdawala
- Center for the Analysis of Supramolecular Self-assemblies, Department of Chemistry, Department of Chemistry, Emory University, 1521 Pierce Drive, Atlanta, Georgia 30322, USA
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