1
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Azargoonjahromi A. The duality of amyloid-β: its role in normal and Alzheimer's disease states. Mol Brain 2024; 17:44. [PMID: 39020435 PMCID: PMC11256416 DOI: 10.1186/s13041-024-01118-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 07/14/2024] [Indexed: 07/19/2024] Open
Abstract
Alzheimer's disease (AD) is a degenerative neurological condition that gradually impairs cognitive abilities, disrupts memory retention, and impedes daily functioning by impacting the cells of the brain. A key characteristic of AD is the accumulation of amyloid-beta (Aβ) plaques, which play pivotal roles in disease progression. These plaques initiate a cascade of events including neuroinflammation, synaptic dysfunction, tau pathology, oxidative stress, impaired protein clearance, mitochondrial dysfunction, and disrupted calcium homeostasis. Aβ accumulation is also closely associated with other hallmark features of AD, underscoring its significance. Aβ is generated through cleavage of the amyloid precursor protein (APP) and plays a dual role depending on its processing pathway. The non-amyloidogenic pathway reduces Aβ production and has neuroprotective and anti-inflammatory effects, whereas the amyloidogenic pathway leads to the production of Aβ peptides, including Aβ40 and Aβ42, which contribute to neurodegeneration and toxic effects in AD. Understanding the multifaceted role of Aβ, particularly in AD, is crucial for developing effective therapeutic strategies that target Aβ metabolism, aggregation, and clearance with the aim of mitigating the detrimental consequences of the disease. This review aims to explore the mechanisms and functions of Aβ under normal and abnormal conditions, particularly in AD, by examining both its beneficial and detrimental effects.
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2
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Dean TT, Jelú-Reyes J, Allen AC, Moore TW. Peptide-Drug Conjugates: An Emerging Direction for the Next Generation of Peptide Therapeutics. J Med Chem 2024; 67:1641-1661. [PMID: 38277480 PMCID: PMC10922862 DOI: 10.1021/acs.jmedchem.3c01835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2024]
Abstract
Building on recent advances in peptide science, medicinal chemists have developed a hybrid class of bioconjugates, called peptide-drug conjugates, that demonstrate improved efficacy compared to peptides and small molecules independently. In this Perspective, we discuss how the conjugation of synergistic peptides and small molecules can be used to overcome complex disease states and resistance mechanisms that have eluded contemporary therapies because of their multi-component activity. We highlight how peptide-drug conjugates display a multi-factor therapeutic mechanism similar to that of antibody-drug conjugates but also demonstrate improved therapeutic properties such as less-severe off-target effects and conjugation strategies with greater site-specificity. The many considerations that go into peptide-drug conjugate design and optimization, such as peptide/small-molecule pairing and chemo-selective chemistries, are discussed. We also examine several peptide-drug conjugate series that demonstrate notable activity toward complex disease states such as neurodegenerative disorders and inflammation, as well as viral and bacterial targets with established resistance mechanisms.
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3
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Jiang B, Umezaki U, Augustine A, Jayasinghe-Arachchige VM, Serafim LF, He ZMS, Wyss KM, Prabhakar R, Martí AA. Deconvoluting binding sites in amyloid nanofibrils using time-resolved spectroscopy. Chem Sci 2023; 14:1072-1081. [PMID: 36756322 PMCID: PMC9891369 DOI: 10.1039/d2sc05418c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 12/19/2022] [Indexed: 01/20/2023] Open
Abstract
Steady-state fluorescence spectroscopy has a central role not only for sensing applications, but also in biophysics and imaging. Light switching probes, such as ruthenium dipyridophenazine complexes, have been used to study complex systems such as DNA, RNA, and amyloid fibrils. Nonetheless, steady-state spectroscopy is limited in the kind of information it can provide. In this paper, we use time-resolved spectroscopy for studying binding interactions between amyloid-β fibrillar structures and photoluminescent ligands. Using time-resolved spectroscopy, we demonstrate that ruthenium complexes with a pyrazino phenanthroline derivative can bind to two distinct binding sites on the surface of fibrillar amyloid-β, in contrast with previous studies using steady-state photoluminescence spectroscopy, which only identified one binding site for similar compounds. The second elusive binding site is revealed when deconvoluting the signals from the time-resolved decay traces, allowing the determination of dissociation constants of 3 and 2.2 μM. Molecular dynamic simulations agree with two binding sites on the surface of amyloid-β fibrils. Time-resolved spectroscopy was also used to monitor the aggregation of amyloid-β in real-time. In addition, we show that common polypyridine complexes can bind to amyloid-β also at two different binding sites. Information on how molecules bind to amyloid proteins is important to understand their toxicity and to design potential drugs that bind and quench their deleterious effects. The additional information contained in time-resolved spectroscopy provides a powerful tool not only for studying excited state dynamics but also for sensing and revealing important information about the system including hidden binding sites.
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Affiliation(s)
- Bo Jiang
- Department of Chemistry, Rice University Houston TX USA
| | - Utana Umezaki
- Department of Chemistry, Rice University Houston TX USA
| | | | | | | | | | - Kevin M. Wyss
- Department of Chemistry, Rice UniversityHoustonTXUSA
| | - Rajeev Prabhakar
- Department of Chemistry, University of Miami Coral Gables FL USA
| | - Angel A. Martí
- Department of Chemistry, Rice UniversityHoustonTXUSA,Department of Bioengineering, Rice UniversityHoustonTXUSA,Department of Materials Science & Nanoengineering, Rice UniversityHoustonTXUSA
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4
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Saha D, Jana B. Identifying the Template for Oligomer to Fibril Conversion for Amyloid-β (1-42) Oligomers using Hamiltonian Replica Exchange Molecular Dynamics. Chemphyschem 2022; 23:e202200393. [PMID: 36052514 DOI: 10.1002/cphc.202200393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 08/26/2022] [Indexed: 01/04/2023]
Abstract
The toxicity of amyloid-β (Aβ) oligomers has been known to be higher compared to mature fibrils. Yet the presence of plaques in Alzheimer's disease patients indicates the significance of oligomer to fibril conversion for Aβ aggregates. In this study, we investigate Aβ13-42 oligomers having two to five peptide chains using extensive all-atom molecular dynamics simulations to identify the on- or off-pathway intermediates in fibril formation pathway. Hamiltonian replica exchange method through solute tempering (REST2) has been employed to explore the different structures attained by these aggregates. Using intra-chain and inter-chain contacts as reaction coordinates, we obtain the free energy surface for the Aβ13-42 oligomers. Consequently, their stable conformations and structural features have been identified. The found conformations belonging to most probable structures possess both parallel and anti-parallel β-sheets, characteristic of on- and off-pathway intermediates, respectively. Further, we have measured the tendency to form fibril like interactions among the β-sheet forming residues. Our analysis finds that residues 30-36 possess higher tendency to form fibril like contacts among all the residues. While we find stronger interaction among residues 30-36, these amino acids are also found to be more shielded from water compared to others. With previous experimental studies finding these residues to be more crucial for the stability of Aβ42 oligomers, we propose that interactions within this patch could trigger seed formation that leads to conversion of on-pathway oligomers into disease relevant fibrils.
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Affiliation(s)
- Debasis Saha
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Kolkata, Jadavpur, Kolkata, 700032, West Bengal, India
| | - Biman Jana
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Kolkata, Jadavpur, Kolkata, 700032, West Bengal, India
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5
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Schaefer A, Naser D, Siebeneichler B, Tarasca MV, Meiering EM. Methodological advances and strategies for high resolution structure determination of cellular protein aggregates. J Biol Chem 2022; 298:102197. [PMID: 35760099 PMCID: PMC9396402 DOI: 10.1016/j.jbc.2022.102197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 06/20/2022] [Accepted: 06/21/2022] [Indexed: 01/14/2023] Open
Abstract
Aggregation of proteins is at the nexus of molecular processes crucial to aging, disease, and employing proteins for biotechnology and medical applications. There has been much recent progress in determining the structural features of protein aggregates that form in cells; yet, owing to prevalent heterogeneity in aggregation, many aspects remain obscure and often experimentally intractable to define. Here we review recent results of structural studies for cell-derived aggregates of normally globular proteins, with a focus on high resolution methods for their analysis and prediction. Complementary results obtained by solid-state NMR spectroscopy, Fourier transform infrared (FTIR) spectroscopy and microspectroscopy, cryo-electron microscopy, and amide hydrogen/deuterium exchange measured by NMR and mass spectrometry (MS), applied to bacterial inclusion bodies and disease inclusions, are uncovering novel information on in-cell aggregation patterns as well as great diversity in the structural features of useful and aberrant protein aggregates. Using these advances as a guide, this review aims to advise the reader on which combination of approaches may be the most appropriate to apply to their unique system.
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Affiliation(s)
- Anna Schaefer
- Department of Chemistry, University of Waterloo Waterloo ON Canada
| | - Dalia Naser
- Department of Chemistry, University of Waterloo Waterloo ON Canada
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6
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Jeong H, Shin H, Hong S, Kim Y. Physiological Roles of Monomeric Amyloid-β and Implications for Alzheimer's Disease Therapeutics. Exp Neurobiol 2022; 31:65-88. [PMID: 35673997 PMCID: PMC9194638 DOI: 10.5607/en22004] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/26/2022] [Accepted: 03/30/2022] [Indexed: 12/23/2022] Open
Abstract
Alzheimer's disease (AD) progressively inflicts impairment of synaptic functions with notable deposition of amyloid-β (Aβ) as senile plaques within the extracellular space of the brain. Accordingly, therapeutic directions for AD have focused on clearing Aβ plaques or preventing amyloidogenesis based on the amyloid cascade hypothesis. However, the emerging evidence suggests that Aβ serves biological roles, which include suppressing microbial infections, regulating synaptic plasticity, promoting recovery after brain injury, sealing leaks in the blood-brain barrier, and possibly inhibiting the proliferation of cancer cells. More importantly, these functions were found in in vitro and in vivo investigations in a hormetic manner, that is to be neuroprotective at low concentrations and pathological at high concentrations. We herein summarize the physiological roles of monomeric Aβ and current Aβ-directed therapies in clinical trials. Based on the evidence, we propose that novel therapeutics targeting Aβ should selectively target Aβ in neurotoxic forms such as oligomers while retaining monomeric Aβ in order to preserve the physiological functions of Aβ monomers.
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Affiliation(s)
- Hyomin Jeong
- Division of Integrated Science and Engineering, Underwood International College, Yonsei University, Incheon 21983, Korea
- Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon 21983, Korea
- Yonsei Institute of Pharmaceutical Sciences, College of Pharmacy, Yonsei University, Incheon 21983, Korea
| | - Heewon Shin
- Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon 21983, Korea
- Yonsei Institute of Pharmaceutical Sciences, College of Pharmacy, Yonsei University, Incheon 21983, Korea
| | - Seungpyo Hong
- Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon 21983, Korea
- Yonsei Frontier Lab, Yonsei University, Seoul 03722, Korea
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA
- Wisconsin Center for NanoBioSystems, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - YoungSoo Kim
- Division of Integrated Science and Engineering, Underwood International College, Yonsei University, Incheon 21983, Korea
- Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon 21983, Korea
- Yonsei Institute of Pharmaceutical Sciences, College of Pharmacy, Yonsei University, Incheon 21983, Korea
- Yonsei Frontier Lab, Yonsei University, Seoul 03722, Korea
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7
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Vugmeyster L, Ostrovsky D, Greenwood A, Fu R. Deuteron rotating frame relaxation for the detection of slow motions in rotating solids. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 337:107171. [PMID: 35219160 PMCID: PMC8994516 DOI: 10.1016/j.jmr.2022.107171] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 02/15/2022] [Accepted: 02/16/2022] [Indexed: 06/06/2023]
Abstract
We demonstrate experimental and computational approaches for measuring 2H rotating frame NMR relaxation for solid samples under magic angle spinning (MAS) conditions. The relaxation properties of the deuterium spin-1 system are dominated by the reorientation of the anisotropic quadrupolar tensors, with the effective quadrupolar coupling constant around 55 kHz for methyl groups. The technique is demonstrated using the model compound dimethyl-sulfone at MAS rates of 10 and 60 kHz as well as for an amyloid fibril sample comprising an amyloid-β (1-40) protein with a selective methyl group labeled in the disordered domain of the fibrils, at an MAS rate of 8 kHz. For both systems, the motional parameters fall well within the ranges determined by other techniques, thus validating its feasibility. Experimental and computational factors such as i) the probe's radio frequency inhomogeneity profiles, ii) rotary resonances at conditions for which the spin-lock field strength matches the half- or full-integer of the MAS rate, iii) the choice of MAS rates and spin-lock field strengths, and iv) simulations that account for the interconversion of multiple coherences for the spin-1 system under MAS and deviations from the analytical Redfield treatment are thoroughly considered.
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Affiliation(s)
- Liliya Vugmeyster
- Department of Chemistry, University of Colorado Denver, Denver, CO 80204, USA.
| | - Dmitry Ostrovsky
- Department of Mathematics, University of Colorado Denver, Denver, CO 80204, USA
| | - Alexander Greenwood
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221-0172, USA
| | - Riqiang Fu
- National High Field Magnetic Laboratory, Tallahassee, FL 32310, USA
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8
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Pyroglutamate Aβ cascade as drug target in Alzheimer's disease. Mol Psychiatry 2022; 27:1880-1885. [PMID: 34880449 PMCID: PMC9126800 DOI: 10.1038/s41380-021-01409-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/19/2021] [Accepted: 11/25/2021] [Indexed: 02/07/2023]
Abstract
One of the central aims in Alzheimer's disease (AD) research is the identification of clinically relevant drug targets. A plethora of potential molecular targets work very well in preclinical model systems both in vitro and in vivo in AD mouse models. However, the lack of translation into clinical settings in the AD field is a challenging endeavor. Although it is long known that N-terminally truncated and pyroglutamate-modified Abeta (AβpE3) peptides are abundantly present in the brain of AD patients, form stable and soluble low-molecular weight oligomers, and induce neurodegeneration in AD mouse models, their potential as drug target has not been generally accepted in the past. This situation has dramatically changed with the report that passive immunization with donanemab, an AβpE3-specific antibody, cleared aymloid plaques and stabilized cognitive deficits in a group of patients with mild AD in a phase II trial. This review summarizes the current knowledge on the molecular mechanisms of generation of AβpE, its biochemical properties, and the intervention points as a drug target in AD.
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9
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Vugmeyster L, Ostrovsky D. Deuterium solid-state NMR quadrupolar order rotating frame relaxation with applications to amyloid-β fibrils. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:853-863. [PMID: 33161607 PMCID: PMC8105426 DOI: 10.1002/mrc.5114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/06/2020] [Accepted: 11/03/2020] [Indexed: 05/27/2023]
Abstract
We describe a new method for measuring molecular dynamics based on the deuterium solid-state nuclear magnetic resonance (NMR) quadrupolar order rotating frame relaxation rate R1ρ,Q under static conditions. The observed quadrupolar order coherence is created using the broad-band Jeener-Broekaert excitation and is locked with a weak radio frequency (RF) field. We describe the experimental and theoretical approaches and show applications to a selectively deuterated valine side chain of the phosphorylated amyloid-β (1-40) fibrils phosphorylated at the serine-8 position. The R1ρ,Q rate is sensitive to the rotameric exchange mode. For biological samples, the low spin-lock field in the 5- to 10-kHz range has the advantage of avoiding sample heating and dehydration. Thus, it provides an alternative to approaches based on single-quantum coherence, which require larger spin-lock fields.
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Affiliation(s)
- Liliya Vugmeyster
- Department of Chemistry, University of Colorado Denver, Denver CO USA 80204
| | - Dmitry Ostrovsky
- Department of Mathematics, University of Colorado Denver, Denver CO USA 80204
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10
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Zhao M, Guo C. Multipronged Regulatory Functions of Serum Albumin in Early Stages of Amyloid-β Aggregation. ACS Chem Neurosci 2021; 12:2409-2420. [PMID: 34160192 DOI: 10.1021/acschemneuro.1c00150] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Human serum albumin (HSA) is a major interacting-partner of Alzheimer's amyloid-β (Aβ) peptide in the plasma and has emerged as a promising therapeutic target. HSA inhibits Aβ fibrillization, but the underlying molecular mechanism is not well elucidated. In this work, we investigated the role of HSA in the early stages of Aβ aggregation by simulating the binding process of multiple Aβ monomers and protofibrils to HSA with extensive molecular dynamics simulations. HSA could simultaneously trap multiple Aβ monomers and accommodate the formation of nonfibrillar Aβ oligomers after binding. In particular, domains I and III show stronger binding capacities and hold preferable interaction sites for oligomers. Consequently, HSA prevents the formation of fibrillar oligomers in water, thus interfering with the nucleation process. On the other aspect, when protofibrils are preformed, HSA tends to block the β-strand spanning the central hydrophobic core located at the protofibril end, preventing the addition of monomers to protofibrils. Furthermore, Aβ protofibril structures are severely disrupted both globally and locally. Thus, further growth of protofibrils to fibrils is impeded by HSA. Our results collectively indicate that HSA performs multipronged regulatory functions in the early stages of Aβ aggregation. Our work advances the understanding of the amyloid inhibition of Aβ by HSA and provides theoretical guidance for developing rational therapies of Alzheimer's disease.
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Affiliation(s)
- Mengjuan Zhao
- Department of Physics and International Centre for Quantum and Molecular Structures, College of Sciences, Shanghai University, 99 Shangda Road, Shanghai 200444, China
| | - Cong Guo
- Department of Physics and International Centre for Quantum and Molecular Structures, College of Sciences, Shanghai University, 99 Shangda Road, Shanghai 200444, China
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11
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Yoon A, Zhen J, Guo Z. Segmental structural dynamics in Aβ42 globulomers. Biochem Biophys Res Commun 2021; 545:119-124. [PMID: 33548624 PMCID: PMC7904658 DOI: 10.1016/j.bbrc.2021.01.081] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 01/23/2021] [Indexed: 02/06/2023]
Abstract
Aβ42 aggregation plays a central role in the pathogenesis of Alzheimer's disease. In addition to the insoluble fibrils that comprise the amyloid plaques, Aβ42 also forms soluble aggregates collectively called oligomers, which are more toxic and pathogenic than fibrils. Understanding the structure and dynamics of Aβ42 oligomers is critical for developing effective therapeutic interventions against these oligomers. Here we studied the structural dynamics of Aβ42 globulomers, a type of Aβ42 oligomers prepared in the presence of sodium dodecyl sulfate, using site-directed spin labeling. Spin labels were introduced, one at a time, at all 42 residue positions of Aβ42 sequence. Electron paramagnetic resonance spectra of spin-labeled samples reveal four structural segments based on site-dependent spin label mobility pattern. Segment-1 consists of residues 1-6, which have the highest mobility that is consistent with complete disorder. Segment-3 is the most immobilized region, including residues 31-34. Segment-2 and -4 have intermediate mobility and are composed of residues 7-30 and 35-42, respectively. Considering the inverse relationship between protein dynamics and stability, our results suggest that residues 31-34 are the most stable segment in Aβ42 oligomers. At the same time, the EPR spectral lineshape suggests that Aβ42 globulomers lack a well-packed structural core akin to that of globular proteins.
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Affiliation(s)
- Allison Yoon
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA, 90095, USA
| | - James Zhen
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA, 90095, USA
| | - Zhefeng Guo
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA, 90095, USA.
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12
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Vugmeyster L. Recent developments in deuterium solid-state NMR for the detection of slow motions in proteins. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2021; 111:101710. [PMID: 33450712 PMCID: PMC7903970 DOI: 10.1016/j.ssnmr.2020.101710] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/19/2020] [Accepted: 12/05/2020] [Indexed: 05/14/2023]
Abstract
Slow timescale dynamics in proteins are essential for a variety of biological functions spanning ligand binding, enzymatic catalysis, protein folding and misfolding regulations, as well as protein-protein and protein-nucleic acid interactions. In this review, we focus on the experimental and theoretical developments of 2H static NMR methods applicable for studies of microsecond to millisecond motional modes in proteins, particularly rotating frame relaxation dispersion (R1ρ), quadrupolar Carr-Purcell-Meiboom-Gill (QCPMG) relaxation dispersion, and quadrupolar chemical exchange saturation transfer NMR experiments (Q-CEST). With applications chosen from amyloid-β fibrils, we show the complementarity of these approaches for elucidating the complexities of conformational ensembles in disordered domains in the non-crystalline solid state, with the employment of selective deuterium labels. Combined with recent advances in relaxation dispersion backbone measurements for 15N/13C/1H nuclei, these techniques provide powerful tools for studies of biologically relevant timescale dynamics in disordered domains in the solid state.
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Affiliation(s)
- Liliya Vugmeyster
- Department of Chemistry, University of Colorado Denver, Denver, CO, 80204, USA.
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13
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Masuda Y. Bioactive 3D structures of naturally occurring peptides and their application in drug design. Biosci Biotechnol Biochem 2021; 85:24-32. [PMID: 33577656 DOI: 10.1093/bbb/zbaa008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 09/10/2020] [Indexed: 11/14/2022]
Abstract
Naturally occurring peptides form unique 3D structures, which are critical for their bioactivities. To gain useful insights into drug design, the relationship between the 3D structure and bioactivity of the peptides has been studied. Solid-state nuclear magnetic resonance (NMR) analysis of the 42-residue amyloid β-protein (Aβ42) suggested the presence of toxic conformers with a turn structure at positions 22 and 23 in the aggregates. Antibodies specific to this turn structure could be utilized for immunotherapy and early diagnosis of Alzheimer's disease. Solution NMR analysis of apratoxin A, a cyclic depsipeptide with potent cytotoxicity, proposed an accurate structural model with an important bend structure, which led to the development of highly active mimetics. X-ray crystal analysis of PF1171F, a cyclic hexapeptide with insecticidal activity, indicated the formation of 4 intramolecular hydrogen bonds, which play an important role in cell membrane permeability of PF1171F.
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Affiliation(s)
- Yuichi Masuda
- Graduate School of Bioresources, Mie University, Tsu, Japan
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14
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Khorvash M, Blinov N, Ladner-Keay C, Lu J, Silverman JM, Gibbs E, Wang YT, Kovalenko A, Wishart D, Cashman NR. Molecular interactions between monoclonal oligomer-specific antibody 5E3 and its amyloid beta cognates. PLoS One 2020; 15:e0232266. [PMID: 32469918 PMCID: PMC7259632 DOI: 10.1371/journal.pone.0232266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 04/12/2020] [Indexed: 11/30/2022] Open
Abstract
Oligomeric amyloid β (Aβ) is currently considered the most neurotoxic form of the Aβ peptide implicated in Alzheimer’s disease (AD). The molecular structures of the oligomers have remained mostly unknown due to their transient nature. As a result, the molecular mechanisms of interactions between conformation-specific antibodies and their Aβ oligomer (AβO) cognates are not well understood. A monoclonal conformation-specific antibody, m5E3, was raised against a structural epitope of Aβ oligomers. m5E3 binds to AβOs with high affinity, but not to Aβ monomers or fibrils. In this study, a computational model of the variable fragment (Fv) of the m5E3 antibody (Fv5E3) is introduced. We further employ docking and molecular dynamics simulations to determine the molecular details of the antibody-oligomer interactions, and to classify the AβOs as Fv5E3-positives and negatives, and to provide a rationale for the low affinity of Fv5E3 for fibrils. This information will help us to perform site-directed mutagenesis on the m5E3 antibody to improve its specificity and affinity toward oligomeric Aβ species. We also provide evidence for the possible capability of the m5E3 antibody to disaggregate AβOs and to fragment protofilaments.
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Affiliation(s)
- Massih Khorvash
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- University of British Columbia, Djavad Mowafaghian Centre for Brain Health, Vancouver, British Columbia, Canada
| | - Nick Blinov
- Department of Mechanical Engineering, Edmonton, Alberta, Canada
- National Research Council of Canada, Edmonton, Alberta, Canada
| | - Carol Ladner-Keay
- National Research Council of Canada, Edmonton, Alberta, Canada
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Jie Lu
- University of British Columbia, Djavad Mowafaghian Centre for Brain Health, Vancouver, British Columbia, Canada
| | - Judith M. Silverman
- University of British Columbia, Djavad Mowafaghian Centre for Brain Health, Vancouver, British Columbia, Canada
| | - Ebrima Gibbs
- University of British Columbia, Djavad Mowafaghian Centre for Brain Health, Vancouver, British Columbia, Canada
| | - Yu Tian Wang
- University of British Columbia, Djavad Mowafaghian Centre for Brain Health, Vancouver, British Columbia, Canada
| | - Andriy Kovalenko
- Department of Mechanical Engineering, Edmonton, Alberta, Canada
- National Research Council of Canada, Edmonton, Alberta, Canada
| | - David Wishart
- National Research Council of Canada, Edmonton, Alberta, Canada
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- Department of Computing Science, University of Alberta, Edmonton, Alberta, Canada
| | - Neil R. Cashman
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- University of British Columbia, Djavad Mowafaghian Centre for Brain Health, Vancouver, British Columbia, Canada
- * E-mail:
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15
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Vugmeyster L, Au DF, Ostrovsky D, Kierl B, Fu R, Hu ZW, Qiang W. Effect of Post-Translational Modifications and Mutations on Amyloid-β Fibrils Dynamics at N Terminus. Biophys J 2019; 117:1524-1535. [PMID: 31570231 PMCID: PMC6817547 DOI: 10.1016/j.bpj.2019.09.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 09/01/2019] [Accepted: 09/09/2019] [Indexed: 02/04/2023] Open
Abstract
We investigate the variability in the dynamics of the disordered N-terminal domain of amyloid-β fibrils (Aβ), comprising residues 1-16 of Aβ1-40, due to post-translational modifications and mutations in the β-bend regions known to modulate aggregation properties. Using 2H static solid-state NMR approaches, we compare the dynamics in the wild-type Aβ fibrils in the threefold symmetric polymorph with the fibrils from three post-translational modification sequences: isoaspartate-D7, the phosphorylation of S8, and an N-terminal truncation ΔE3. Additional comparisons are made with the mutants in the β-bend region (residues 21-23) corresponding to the familial Osaka E22Δ deletion and D23N Iowa mutation. We also include the aggregates induced by Zn2+ ions. The dynamics are probed at the F4 and G9 positions. The main motional model involves two free states undergoing diffusion and conformational exchanges with the bound state in which the diffusion is quenched because of transient interactions involving fibril core and other intrastrand contacts. The fraction of the bound state increases in a sigmoidal fashion with a decrease in temperature. There is clear variability in the dynamics: the phosphorylation of S8 variant is the most rigid at the G9 site in line with structural studies, the ΔE3 fibrils are more flexible at the G9 site in line with the morphological fragmentation pattern, the Zn-induced aggregates are the most mobile, and the two β-bend mutants have the strongest changes at the F4 site toward higher rigidity. Overall, the changes underlie the potential role of conformational ensembles in setting the stage for aggregation-prone states.
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Affiliation(s)
- Liliya Vugmeyster
- Department of Chemistry, University of Colorado Denver, Denver, Colorado.
| | - Dan F Au
- Department of Chemistry, University of Colorado Denver, Denver, Colorado
| | - Dmitry Ostrovsky
- Department of Mathematics, University of Colorado Denver, Denver, Colorado
| | - Brian Kierl
- Department of Chemistry, University of Colorado Denver, Denver, Colorado
| | - Riqiang Fu
- National High Field Magnetic Laboratory, Tallahassee, Florida
| | - Zhi-Wen Hu
- Department of Chemistry, Binghamton University, Binghamton, New York
| | - Wei Qiang
- Department of Chemistry, Binghamton University, Binghamton, New York
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16
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Vugmeyster L, Au DF, Ostrovsky D, Fu R. Deuteron Solid-State NMR Relaxation Measurements Reveal Two Distinct Conformational Exchange Processes in the Disordered N-Terminal Domain of Amyloid-β Fibrils. Chemphyschem 2019; 20:1680-1689. [PMID: 31087613 PMCID: PMC6663588 DOI: 10.1002/cphc.201900363] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 05/12/2019] [Indexed: 12/26/2022]
Abstract
We employed deuterium solid-state NMR techniques under static conditions to discern the details of the μs-ms timescale motions in the flexible N-terminal subdomain of Aβ1-40 amyloid fibrils, which spans residues 1-16. In particular, we utilized a rotating frame (R1ρ ) and the newly developed time domain quadrupolar Carr-Purcell-Meiboom-Gill (QCPMG) relaxation measurements at the selectively deuterated side chains of A2, H6, and G9. The two experiments are complementary in terms of probing somewhat different timescales of motions, governed by the tensor parameters and the sampling window of the magnetization decay curves. The results indicated two mobile "free" states of the N-terminal domain undergoing global diffusive motions, with isotropic diffusion coefficients of 0.7-1 ⋅ 108 and 0.3-3 ⋅ 106 ad2 s-1 . The free states are also involved in the conformational exchange with a single bound state, in which the diffusive motions are quenched, likely due to transient interactions with the structured hydrophobic core. The conformational exchange rate constants are 2-3 ⋅ 105 s-1 and 2-3 ⋅ 104 s-1 for the fast and slow diffusion free states, respectively.
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Affiliation(s)
- Liliya Vugmeyster
- Department of Chemistry, University of Colorado Denver, Denver CO, USA, 80204
| | - Dan Fai Au
- Department of Chemistry, University of Colorado Denver, Denver CO, USA, 80204
| | - Dmitry Ostrovsky
- Department of Mathematics, University of Colorado Denver, Denver CO, USA, 80204
| | - Riqiang Fu
- National High Field Magnetic Laboratory, Tallahassee, FL, 32310
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17
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Au DF, Ostrovsky D, Fu R, Vugmeyster L. Solid-state NMR reveals a comprehensive view of the dynamics of the flexible, disordered N-terminal domain of amyloid-β fibrils. J Biol Chem 2019; 294:5840-5853. [PMID: 30737281 DOI: 10.1074/jbc.ra118.006559] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 02/08/2019] [Indexed: 11/06/2022] Open
Abstract
Amyloid fibril deposits observed in Alzheimer's disease comprise amyloid-β (Aβ) protein possessing a structured hydrophobic core and a disordered N-terminal domain (residues 1-16). The internal flexibility of the disordered domain is likely essential for Aβ aggregation. Here, we used 2H static solid-state NMR methods to probe the dynamics of selected side chains of the N-terminal domain of Aβ1-40 fibrils. Line shape and relaxation data suggested a two-state model in which the domain's free state undergoes a diffusive motion that is quenched in the bound state, likely because of transient interactions with the structured C-terminal domain. At 37 °C, we observed freezing of the dynamics progressively along the Aβ sequence, with the fraction of the bound state increasing and the rate of diffusion decreasing. We also found that without solvation, the diffusive motion is quenched. The solvent acted as a plasticizer reminiscent of its role in the onset of global dynamics in globular proteins. As the temperature was lowered, the fraction of the bound state exhibited sigmoidal behavior. The midpoint of the freezing curve coincided with the bulk solvent freezing for the N-terminal residues and increased further along the sequence. Using 2H R 1ρ measurements, we determined the conformational exchange rate constant between the free and bound states under physiological conditions. Zinc-induced aggregation leads to the enhancement of the dynamics, manifested by the faster conformational exchange, faster diffusion, and lower freezing-curve midpoints.
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Affiliation(s)
- Dan Fai Au
- From the Department of Chemistry, University of Colorado, Denver, Colorado 80204
| | - Dmitry Ostrovsky
- Department of Mathematics, University of Colorado, Denver, Colorado 80204
| | - Riqiang Fu
- National High Field Magnetic Laboratory, Tallahassee, Florida 32310
| | - Liliya Vugmeyster
- From the Department of Chemistry, University of Colorado, Denver, Colorado 80204.
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18
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Lee CT, Terentjev EM. Mechanisms and rates of nucleation of amyloid fibrils. J Chem Phys 2018; 147:105103. [PMID: 28915747 DOI: 10.1063/1.4995255] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The classical nucleation theory finds the rate of nucleation proportional to the monomer concentration raised to the power, which is the "critical nucleus size," nc. The implicit assumption, that amyloids nucleate in the same way, has been recently challenged by an alternative two-step mechanism, when the soluble monomers first form a metastable aggregate (micelle) and then undergo conversion into the conformation rich in β-strands that are able to form a stable growing nucleus for the protofilament. Here we put together the elements of extensive knowledge about aggregation and nucleation kinetics, using a specific case of Aβ1-42 amyloidogenic peptide for illustration, to find theoretical expressions for the effective rate of amyloid nucleation. We find that at low monomer concentrations in solution and also at low interaction energy between two peptide conformations in the micelle, the nucleation occurs via the classical route. At higher monomer concentrations, and a range of other interaction parameters between peptides, the two-step "aggregation-conversion" mechanism of nucleation takes over. In this regime, the effective rate of the process can be interpreted as a power of monomer concentration in a certain range of parameters; however, the exponent is determined by a complicated interplay of interaction parameters and is not related to the minimum size of the growing nucleus (which we find to be ∼7-8 for Aβ1-42).
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Affiliation(s)
- Cheng-Tai Lee
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Eugene M Terentjev
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
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19
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Xiao Y, McElheny D, Hoshi M, Ishii Y. Solid-State NMR Studies of Amyloid Materials: A Protocol to Define an Atomic Model of Aβ(1-42) in Amyloid Fibrils. Methods Mol Biol 2018; 1777:407-428. [PMID: 29744851 DOI: 10.1007/978-1-4939-7811-3_26] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Intense efforts have been made to understand the molecular structures of misfolded amyloid β (Aβ) in order to gain insight into the pathological mechanism of Alzheimer's disease. Solid-state NMR spectroscopy (SSNMR) is considered a primary tool for elucidating the structures of insoluble and noncrystalline amyloid fibrils and other amyloid assemblies. In this chapter, we describe a detailed protocol to obtain the first atomic model of the 42-residue human Aβ peptide Aβ(1-42) in structurally homogeneous amyloid fibrils from our recent SSNMR study (Nat Struct Mol Biol 22:499-505, 2015). Despite great biological and clinical interest in Aβ(1-42) fibrils, their structural details have been long-elusive until this study. The protocol is divided into four sections. First, the solid-phase peptide synthesis (SPPS) and purification of monomeric Aβ(1-42) is described. We illustrate a controlled incubation method to prompt misfolding of Aβ(1-42) into homogeneous amyloid fibrils in an aqueous solution with fragmented Aβ(1-42) fibrils as seeds. Next, we detail analysis of Aβ(1-42) fibrils by SSNMR to obtain structural restraints. Finally, we describe methods to construct atomic models of Aβ(1-42) fibrils based on SSNMR results through two-stage molecular dynamics calculations.
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Affiliation(s)
- Yiling Xiao
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, USA
| | - Dan McElheny
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, USA
| | - Minako Hoshi
- Institute of Biomedical Research and Innovation, FBRI, Kobe, Japan
- Department of Anatomy and Developmental Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yoshitaka Ishii
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, USA.
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan.
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20
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Roberts VA, Pique ME, Hsu S, Li S. Combining H/D Exchange Mass Spectrometry and Computational Docking To Derive the Structure of Protein-Protein Complexes. Biochemistry 2017; 56:6329-6342. [PMID: 29099587 DOI: 10.1021/acs.biochem.7b00643] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Protein-protein interactions are essential for biological function, but structures of protein-protein complexes are difficult to obtain experimentally. To derive the protein complex of the DNA-repair enzyme human uracil-DNA-glycosylase (hUNG) with its protein inhibitor (UGI), we combined rigid-body computational docking with hydrogen/deuterium exchange mass spectrometry (DXMS). Computational docking of the unbound protein structures provides a list of possible three-dimensional models of the complex; DXMS identifies solvent-protected protein residues. DXMS showed that unbound hUNG is compactly folded, but unbound UGI is loosely packed. An increased level of solvent protection of hUNG in the complex was localized to four regions on the same face. The decrease in the number of incorporated deuterons was quantitatively interpreted as the minimum number of main-chain hUNG amides buried in the protein-protein interface. The level of deuteration of complexed UGI decreased throughout the protein chain, indicating both tighter packing and direct solvent protection by hUNG. Three UGI regions showing the greatest decreases were best interpreted leniently, requiring just one main-chain amide from each in the interface. Applying the DXMS constraints as filters to a list of docked complexes gave the correct complex as the largest favorable energy cluster. Thus, identification of approximate protein interfaces was sufficient to distinguish the protein complex. Surprisingly, incorporating the DXMS data as added favorable potentials in the docking calculation was less effective in finding the correct complex. The filtering method has greater flexibility, with the capability to test each constraint and enforce simultaneous contact by multiple regions, but with the caveat that the list from the unbiased docking must include correct complexes.
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Affiliation(s)
- Victoria A Roberts
- San Diego Supercomputer Center, University of California, San Diego , La Jolla, California 92093, United States
| | - Michael E Pique
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Simon Hsu
- School of Medicine, University of California, San Diego , La Jolla, California 92093, United States
| | - Sheng Li
- School of Medicine, University of California, San Diego , La Jolla, California 92093, United States
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21
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Shi JM, Zhang L, Liu EQ. Dissecting the behaviour of β-amyloid peptide variants during oligomerization and fibrillation. J Pept Sci 2017; 23:810-817. [PMID: 28795459 DOI: 10.1002/psc.3028] [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] [Received: 02/22/2017] [Revised: 07/06/2017] [Accepted: 07/10/2017] [Indexed: 12/20/2022]
Abstract
The oligomerization and fibrillation of β-amyloid (Aβ) peptides are important events in the pathogenesis of Alzheimer's disease. However, the motifs within the Aβ sequence that contribute to oligomerization and fibrillation and the complex interplay among these short motifs are unclear. In this study, the oligomerization and fibrillation abilities of the Aβ variants Aβ1-28, Aβ1-36, Aβ11-42, Aβ17-42, Aβ1-40 and Aβ1-42 were examined by thioflavin T fluorescence, western blotting and transmission electron microscopy. Compared with two C-terminal-truncated peptides (i.e. Aβ1-28 and Aβ1-36), Aβ11-42, Aβ17-42 and Aβ1-42 had stronger abilities to form oligomers. This indicated that amino acids 37-42 strengthen the β-hairpin structure of Aβ. Both Aβ1-42 and Aβ1-40 could form fibres, but Aβ17-42 formed irregular fibres, suggesting that amino acids 1-17 were essential for Aβ fibre formation. Aβ1-28 and Aβ1-36 exhibited weak oligomerization and fibrillation, implying that they formed an unstable β-hairpin structure owing to the incomplete C-terminal region. Intermediate peptides were likely to form a stable structure, consistent with previous results. This work explains the roles and interplay among motifs within Aβ during oligomerization and fibrillation. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.
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Affiliation(s)
- Jing-Ming Shi
- Research Institute of Atherosclerotic Disease, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an, 710061, China.,School of Medicine, Xizang Minzu University, Xianyang, 712082, China
| | - Lin Zhang
- Department of Biochemistry and Molecular Biology, Xi'an Jiaotong University, Xi'an, 710061, China
| | - En-Qi Liu
- Research Institute of Atherosclerotic Disease, Xi'an Jiaotong University Cardiovascular Research Center, Xi'an, 710061, China
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22
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Grohe K, Movellan KT, Vasa SK, Giller K, Becker S, Linser R. Non-equilibrium hydrogen exchange for determination of H-bond strength and water accessibility in solid proteins. JOURNAL OF BIOMOLECULAR NMR 2017; 68:7-17. [PMID: 28393279 DOI: 10.1007/s10858-017-0110-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 04/02/2017] [Indexed: 06/07/2023]
Abstract
We demonstrate measurement of non-equilibrium backbone amide hydrogen-deuterium exchange rates (HDX) for solid proteins. The target of this study are the slowly exchanging residues in solid samples, which are associated with stable secondary-structural elements of proteins. These hydrogen exchange processes escape methods measuring equilibrium exchange rates of faster processes. The method was applied to a micro-crystalline preparation of the SH3 domain of chicken α-spectrin. Therefore, from a 100% back-exchanged micro-crystalline protein preparation, the supernatant buffer was exchanged by a partially deuterated buffer to reach a final protonation level of approximately 20% before packing the sample in a 1.3 mm rotor. Tracking of the HN peak intensities for 2 weeks reports on site-specific hydrogen bond strength and also likely reflects water accessibility in a qualitative manner. H/D exchange can be directly determined for hydrogen-bonded amides using 1H detection under fast magic angle spinning. This approach complements existing methods and provides the means to elucidate interesting site-specific characteristics for protein functionality in the solid state.
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Affiliation(s)
- Kristof Grohe
- Department Chemie und Pharmazie, Ludwig-Maximilians-Universität München, 81377, Munich, Germany
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Kumar Tekwani Movellan
- Department Chemie und Pharmazie, Ludwig-Maximilians-Universität München, 81377, Munich, Germany
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Suresh Kumar Vasa
- Department Chemie und Pharmazie, Ludwig-Maximilians-Universität München, 81377, Munich, Germany
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Karin Giller
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Stefan Becker
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Rasmus Linser
- Department Chemie und Pharmazie, Ludwig-Maximilians-Universität München, 81377, Munich, Germany.
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany.
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23
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Tran J, Chang D, Hsu F, Wang H, Guo Z. Cross-seeding between Aβ40 and Aβ42 in Alzheimer's disease. FEBS Lett 2016; 591:177-185. [PMID: 27981583 DOI: 10.1002/1873-3468.12526] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 11/29/2016] [Accepted: 12/05/2016] [Indexed: 12/23/2022]
Abstract
Aβ42 is the major component of parenchymal plaques in the brain of Alzheimer's patients, while Aβ40 is the major component of cerebrovascular plaques. Since Aβ40 and Aβ42 coexist in the brain, understanding the interaction between Aβ40 and Aβ42 during their aggregation is important to delineate the molecular mechanism underlying Alzheimer's disease. Here, we present a rigorous and systematic study of the cross-seeding effects between Aβ40 and Aβ42. We show that Aβ40 fibril seeds can promote Aβ42 aggregation in a concentration-dependent manner, and vice versa. Our results also suggest that seeded aggregation and spontaneous aggregation may be two separate pathways. These findings may partly resolve conflicting observations in the literature regarding the cross-seeding effects between Aβ40 and Aβ42.
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Affiliation(s)
- Joyce Tran
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA, USA
| | - Dennis Chang
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA, USA
| | - Frederick Hsu
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA, USA
| | - Hongsu Wang
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA, USA
| | - Zhefeng Guo
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA, USA
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24
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Hiew SH, Guerette PA, Zvarec OJ, Phillips M, Zhou F, Su H, Pervushin K, Orner BP, Miserez A. Modular peptides from the thermoplastic squid sucker ring teeth form amyloid-like cross-β supramolecular networks. Acta Biomater 2016; 46:41-54. [PMID: 27693688 DOI: 10.1016/j.actbio.2016.09.040] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 09/23/2016] [Accepted: 09/28/2016] [Indexed: 12/22/2022]
Abstract
The hard sucker ring teeth (SRT) from decapodiforme cephalopods, which are located inside the sucker cups lining the arms and tentacles of these species, have recently emerged as a unique model structure for biomimetic structural biopolymers. SRT are entirely composed of modular, block co-polymer-like proteins that self-assemble into a large supramolecular network. In order to unveil the molecular principles behind SRT's self-assembly and robustness, we describe a combinatorial screening assay that maps the molecular-scale interactions between the most abundant modular peptide blocks of suckerin proteins. By selecting prominent interaction hotspots from this assay, we identified four peptides that exhibited the strongest homo-peptidic interactions, and conducted further in-depth biophysical characterizations complemented by molecular dynamic (MD) simulations to investigate the nature of these interactions. Circular Dichroism (CD) revealed conformations that transitioned from semi-extended poly-proline II (PII) towards β-sheet structure. The peptides spontaneously self-assembled into microfibers enriched with cross β-structures, as evidenced by Fourier-Transform Infrared Spectroscopy (FTIR) and Congo red staining. Nuclear Magnetic Resonance (NMR) experiments identified the residues involved in the hydrogen-bonded network and demonstrated that these self-assembled β-sheet-based fibers exhibit high protection factors that bear resemblance to amyloids. The high stability of the β-sheet network and an amyloid-like model of fibril assembly were supported by MD simulations. The work sheds light on how Nature has evolved modular sequence design for the self-assembly of mechanically robust functional materials, and expands our biomolecular toolkit to prepare load-bearing biomaterials from protein-based block co-polymers and self-assembled peptides. STATEMENT OF SIGNIFICANCE The sucker ring teeth (SRT) located on the arms and tentacles of cephalopods represent as a very promising protein-based biopolymer with the potential to rival silk in biomedical and engineering applications. SRT are made of modular, block co-polymer like proteins (suckerins), which assemble into a semicrystalline polymer reinforced by nano-confined β-sheets, resulting in a supramolecular network with mechanical properties that match those of the strongest engineering polymers. In this study, we aimed to understand the molecular mechanisms behind SRT's self-assembly and robustness. The most abundant modular peptidic blocks of suckerin proteins were studied by various spectroscopic methods, which demonstrate that SRT peptides form amyloid-like cross-β structures.
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25
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Bastidas OH, Green B, Sprague M, Peters MH. Few Ramachandran Angle Changes Provide Interaction Strength Increase in Aβ42 versus Aβ40 Amyloid Fibrils. Sci Rep 2016; 6:36499. [PMID: 27808259 PMCID: PMC5093553 DOI: 10.1038/srep36499] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 10/17/2016] [Indexed: 12/30/2022] Open
Abstract
The pathology of Alzheimer's disease can ultimately be traced to the increased aggregation stability of Aβ42 peptides which possess two extra residues (Ile 41 &Ala 42) that the non-pathological strain (Aβ40) lacks. We have found Aβ42 fibrils to exhibit stronger energies in inter-chain interactions and we have also identified the cause for this increase to be the result of different Ramachandran angle values in certain residues of the Aβ42 strain compared to Aβ40. These unique angle configurations result in the peptide planes in the fibril structures to be more vertical along the fibril axis for Aβ42 which thus reduces the inter-atomic distance between interacting atoms on vicinal peptide chains thereby increasing the electrostatic interaction energies. We lastly postulate that these different Ramachandran angle values could possibly be traced to the unique conformational folding avenues sampled by the Aβ42 peptide owing to the presence of its two extra residues.
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Affiliation(s)
- Oscar H Bastidas
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Benjamin Green
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Mary Sprague
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Michael H Peters
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, Virginia, United States of America
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26
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Zhao J, Ma B, Nussinov R. Compilation and Analysis of Enzymes, Engineered Antibodies, and Nanoparticles Designed to Interfere with Amyloid-β Aggregation. Isr J Chem 2016. [DOI: 10.1002/ijch.201600093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jun Zhao
- Cancer and Inflammation Program; National Cancer Institute; Frederick Maryland 21702 USA
| | - Buyong Ma
- Basic Science Program; Leidos Biomedical Research, Inc.; Cancer and Inflammation Program; National Cancer Institute; Frederick Maryland 21702 USA
| | - Ruth Nussinov
- Basic Science Program; Leidos Biomedical Research, Inc.; Cancer and Inflammation Program; National Cancer Institute; Frederick Maryland 21702 USA
- Sackler Institute of Molecular Medicine; Department of Human Genetics and Molecular Medicine; Sackler School of Medicine; Tel Aviv University; Tel Aviv 69978 Israel
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27
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Hoshino M. Fibril formation from the amyloid-β peptide is governed by a dynamic equilibrium involving association and dissociation of the monomer. Biophys Rev 2016; 9:9-16. [PMID: 28510040 DOI: 10.1007/s12551-016-0217-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 08/09/2016] [Indexed: 11/28/2022] Open
Abstract
Here I review the molecular mechanisms by which water-soluble monomeric amyloid-β (Aβ) peptides are transformed into well-organized supramolecular complexes called amyloid fibrils. The mechanism of amyloid formation is considered theoretically on the basis of experimental results, and the structural and mechanistic similarities of amyloid fibrils to three-dimensional crystals are highlighted. A number of important results from the literature are described. These include the observation that a correct ratio of monomer association and dissociation rate constants is key for formation of well-organized amyloid fibrils. The dynamic nature of the amyloid-β structure is discussed, along with the possibly obligate requirement of the transient formation of a hairpin-like fold prior to its incorporation into amyloid fibrils. Many rounds of monomer association and dissociation events may be present during an apparently silent lag-period. Amongst these association/dissociation events, interaction between the C-terminal regions of the Aβ peptide seems to be more favored. Such association and dissociation events occurring in a "trial-and-error" fashion may be an important requirement for the formation of well-organized amyloid fibrils.
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Affiliation(s)
- Masaru Hoshino
- Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida-Shimoadachi, Sakyo-ku, Kyoto, 606-8501, Japan.
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28
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Vugmeyster L, Clark MA, Falconer IB, Ostrovsky D, Gantz D, Qiang W, Hoatson GL. Flexibility and Solvation of Amyloid-β Hydrophobic Core. J Biol Chem 2016; 291:18484-95. [PMID: 27402826 DOI: 10.1074/jbc.m116.740530] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Indexed: 11/06/2022] Open
Abstract
Amyloid fibril deposits found in Alzheimer disease patients are composed of amyloid-β (Aβ) protein forming a number of hydrophobic interfaces that are believed to be mostly rigid. We have investigated the μs-ms time-scale dynamics of the intra-strand hydrophobic core and interfaces of the fibrils composed of Aβ1-40 protein. Using solid-state (2)H NMR line shape experiments performed on selectively deuterated methyl groups, we probed the 3-fold symmetric and 2-fold symmetric polymorphs of native Aβ as well as the protofibrils of D23N Iowa mutant, associated with an early onset of Alzheimer disease. The dynamics of the hydrophobic regions probed at Leu-17, Leu-34, Val-36, and Met-35 side chains were found to be very pronounced at all sites and in all polymorphs of Aβ, with methyl axis motions persisting down to 230-200 K for most of the sites. The dominant mode of motions is the rotameric side chain jumps, with the Met-35 displaying the most complex multi-modal behavior. There are distinct differences in the dynamics among the three protein variants, with the Val-36 site displaying the most variability. Solvation of the fibrils does not affect methyl group motions within the hydrophobic core of individual cross-β subunits but has a clear effect on the motions at the hydrophobic interface between the cross-β subunits, which is defined by Met-35 contacts. In particular, hydration activates transitions between additional rotameric states that are not sampled in the dry protein. Thus, these results support the existence of water-accessible cavity recently predicted by molecular dynamics simulations and suggested by cryo-EM studies.
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Affiliation(s)
| | | | | | | | - Donald Gantz
- Boston University School of Medicine, Boston, Massachusetts 02118
| | - Wei Qiang
- Binghamton University, Binghamton, New York 13902, and
| | - Gina L Hoatson
- College of William and Mary, Williamsburg, Virginia 23187
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Biochemical and structural analysis of the interaction between β-amyloid and fibrinogen. Blood 2016; 128:1144-51. [PMID: 27389717 DOI: 10.1182/blood-2016-03-705228] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/29/2016] [Indexed: 11/20/2022] Open
Abstract
The majority of patients with Alzheimer disease (AD) suffer from impaired cerebral circulation. Accumulating evidence suggests that fibrinogen, the main protein component of blood clots, plays an important role in this circulatory dysfunction in AD. Fibrinogen interacts with β-amyloid (Aβ), forming plasmin-resistant abnormal blood clots, and increased fibrin deposition is found in the brains of AD patients and mouse models. In this study, we investigated the biochemical and structural details of the Aβ-fibrinogen interaction. We identified the central region of Aβ42 as the most critical region for the interaction, which can be inhibited by specific antibodies against the central region of Aβ and by naturally occurring p3 peptides, Aβ17-40 and Aβ17-42. X-ray crystallographic analysis revealed that Aβ42 binding to fragment D of fibrinogen induced a structural change in the C-terminal region of the fibrinogen β-chain (β384-393). Furthermore, we identified an additional Aβ-binding site within the αC region of fibrinogen. Aβ binding to this αC region blocked plasmin-mediated fibrin cleavage at this site, resulting in the generation of increased levels of a plasmin-resistant fibrin degradation fragment. Overall, our study elucidates the Aβ-fibrinogen interaction and clarifies the mechanism by which Aβ-fibrinogen binding delays fibrinolysis by plasmin. These results may facilitate the development of effective therapeutics against the Aβ-fibrinogen interaction to treat cerebrovascular abnormalities in AD.
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Arai T, Ohno A, Kazunori M, Kakizawa T, Kuwata H, Ozawa T, Shibanuma M, Hara S, Ishida S, Kurihara M, Miyata N, Nakagawa H, Fukuhara K. Design, synthesis, and evaluation of Trolox-conjugated amyloid-β C-terminal peptides for therapeutic intervention in an in vitro model of Alzheimer's disease. Bioorg Med Chem 2016; 24:4138-4143. [PMID: 27407032 DOI: 10.1016/j.bmc.2016.06.057] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 06/28/2016] [Accepted: 06/29/2016] [Indexed: 12/19/2022]
Abstract
Two hallmarks of Alzheimer's disease (AD) observed in the brains of patients with the disease include oxidative injury and deposition of protein aggregates comprised of amyloid-β (Aβ) variants. To inhibit these toxic processes, we synthesized antioxidant-conjugated peptides comprised of Trolox and various C-terminal motifs of Aβ variants, TxAβx-n (x=34, 36, 38, 40; n=40, 42, 43). Most of these compounds were found to exhibit anti-aggregation activities. Among them, TxAβ36-42 significantly inhibited Aβ1-42 aggregation, showed potent antioxidant activity, and protected SH-SY5Y cells from Aβ1-42-induced cytotoxicity. Thus, this method represents a promising strategy for developing multifunctional AD therapeutic agents.
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Affiliation(s)
- Takuya Arai
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Aichi 467-8603, Japan; School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Akiko Ohno
- Division of Organic Chemistry, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Mori Kazunori
- School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Taeko Kakizawa
- Division of Organic Chemistry, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Hiroshi Kuwata
- School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Toshihiko Ozawa
- Division of Oxidative Stress Research, Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida-shi, Tokyo 194-8543, Japan
| | - Motoko Shibanuma
- School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Shuntaro Hara
- School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Seiichi Ishida
- Division of Pharmacology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Masaaki Kurihara
- Division of Organic Chemistry, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Naoki Miyata
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Aichi 467-8603, Japan
| | - Hidehiko Nakagawa
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Aichi 467-8603, Japan
| | - Kiyoshi Fukuhara
- School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
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31
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Garvey M, Baumann M, Wulff M, Kumar ST, Markx D, Morgado I, Knüpfer U, Horn U, Mawrin C, Fändrich M, Balbach J. Molecular architecture of Aβ fibrils grown in cerebrospinal fluid solution and in a cell culture model of Aβ plaque formation. Amyloid 2016; 23:76-85. [PMID: 26972581 DOI: 10.3109/13506129.2016.1146989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES The detailed structure of brain-derived Aβ amyloid fibrils is unknown. To approach this issue, we investigate the molecular architecture of Aβ(1-40) fibrils grown in either human cerebrospinal fluid solution, in chemically simple phosphate buffer in vitro or extracted from a cell culture model of Aβ amyloid plaque formation. METHODS We have used hydrogen-deuterium exchange (HX) combined with nuclear magnetic resonance, transmission electron microscopy, seeding experiments both in vitro and in cell culture as well as several other spectroscopic measurements to compare the morphology and residue-specific conformation of these different Aβ fibrils. RESULTS AND CONCLUSIONS Our data reveal that, despite considerable variations in morphology, the spectroscopic properties and the pattern of slowly exchanging backbone amides are closely similar in the fibrils investigated. This finding implies that a fundamentally conserved molecular architecture of Aβ peptide fold is common to Aβ fibrils.
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Affiliation(s)
- Megan Garvey
- a School of Medicine, Deakin University , East Geelong , VIC , Australia
| | - Monika Baumann
- b Institute for Physics, Biophysics, Martin-Luther-University Halle-Wittenberg , Halle (Saale) , Germany
| | - Melanie Wulff
- c Institute for Pharmaceutical Biotechnology, Ulm University , Ulm , Germany
| | - Senthil T Kumar
- c Institute for Pharmaceutical Biotechnology, Ulm University , Ulm , Germany
| | - Daniel Markx
- c Institute for Pharmaceutical Biotechnology, Ulm University , Ulm , Germany
| | - Isabel Morgado
- d Boston University School of Medicine , Boston , MA , USA
| | - Uwe Knüpfer
- e Leibniz-Institute for Infection Biology and Natural Product Research, Hans-Knöll-Institut (HKI) , Jena , Germany , and
| | - Uwe Horn
- e Leibniz-Institute for Infection Biology and Natural Product Research, Hans-Knöll-Institut (HKI) , Jena , Germany , and
| | - Christian Mawrin
- f Institute for Neuropathology, Otto-von-Guericke University , Magdeburg , Germany
| | - Marcus Fändrich
- c Institute for Pharmaceutical Biotechnology, Ulm University , Ulm , Germany
| | - Jochen Balbach
- b Institute for Physics, Biophysics, Martin-Luther-University Halle-Wittenberg , Halle (Saale) , Germany
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32
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Eftekharzadeh B, Hyman BT, Wegmann S. Structural studies on the mechanism of protein aggregation in age related neurodegenerative diseases. Mech Ageing Dev 2016; 156:1-13. [PMID: 27005270 DOI: 10.1016/j.mad.2016.03.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 02/12/2016] [Accepted: 03/03/2016] [Indexed: 01/09/2023]
Abstract
The progression of many neurodegenerative diseases is assumed to be caused by misfolding of specific characteristic diseases related proteins, resulting in aggregation and fibril formation of these proteins. Protein misfolding associated age related diseases, although different in disease manifestations, share striking similarities. In all cases, one disease protein aggregates and loses its function or additionally shows a toxic gain of function. However, the clear link between these individual amyloid-like protein aggregates and cellular toxicity is often still uncertain. The similar features of protein misfolding and aggregation in this group of proteins, all involved in age related neurodegenerative diseases, results in high interest in characterization of their structural properties. We review here recent findings on structural properties of some age related disease proteins, in the context of their biological importance in disease.
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Affiliation(s)
- Bahareh Eftekharzadeh
- Department of Neurology, Massachusetts General Hospital and Mass General Institute for Neurodegenerative Disease, Charlestown, MA 02129, USA.
| | - Bradley T Hyman
- Department of Neurology, Massachusetts General Hospital and Mass General Institute for Neurodegenerative Disease, Charlestown, MA 02129, USA
| | - Susanne Wegmann
- Department of Neurology, Massachusetts General Hospital and Mass General Institute for Neurodegenerative Disease, Charlestown, MA 02129, USA
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33
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Gu L, Tran J, Jiang L, Guo Z. A new structural model of Alzheimer's Aβ42 fibrils based on electron paramagnetic resonance data and Rosetta modeling. J Struct Biol 2016; 194:61-7. [PMID: 26827680 DOI: 10.1016/j.jsb.2016.01.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/24/2016] [Accepted: 01/27/2016] [Indexed: 10/22/2022]
Abstract
Brain deposition of Aβ in the form of amyloid plaques is a pathological hallmark of Alzheimer's disease. There are two major species of Aβ in the brain: Aβ42 and Aβ40. Although Aβ40 is several-fold more abundant than Aβ42 in soluble form, Aβ42 is the major component of amyloid plaques. Structural knowledge of Aβ42 fibrils is important both for understanding the process of Aβ aggregation and for designing fibril-targeting drugs. Here we report site-specific structural information of Aβ42 fibrils at 22 residue positions based on electron paramagnetic resonance data. In combination with structure prediction program Rosetta, we modeled Aβ42 fibril structure at atomic resolution. Our Aβ42 fibril model consists of four parallel in-register β-sheets: βN (residues ∼7-13), β1 (residues ∼17-20), β2 (residues ∼32-36), and βC (residues 39-41). The region of β1-loop-β2 in Aβ42 fibrils adopts similar structure as that in Aβ40 fibrils. This is consistent with our cross seeding data that Aβ42 fibril seeds shortened the lag phase of Aβ40 fibrillization. On the other hand, Aβ42 fibrils contain a C-terminal β-arc-β motif with a special turn, termed "arc", at residues 37-38, which is absent in Aβ40 fibrils. Our results can explain both the higher aggregation propensity of Aβ42 and the importance of Aβ42 to Aβ40 ratio in the pathogenesis of Alzheimer's disease.
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Affiliation(s)
- Lei Gu
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
| | - Joyce Tran
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
| | - Lin Jiang
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
| | - Zhefeng Guo
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA.
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34
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Aran Terol P, Kumita JR, Hook SC, Dobson CM, Esbjörner EK. Solvent exposure of Tyr10 as a probe of structural differences between monomeric and aggregated forms of the amyloid-β peptide. Biochem Biophys Res Commun 2015; 468:696-701. [PMID: 26551456 PMCID: PMC4692451 DOI: 10.1016/j.bbrc.2015.11.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 11/03/2015] [Indexed: 12/25/2022]
Abstract
Aggregation of amyloid-β (Aβ) peptides is a characteristic pathological feature of Alzheimer's disease. We have exploited the relationship between solvent exposure and intrinsic fluorescence of a single tyrosine residue, Tyr10, in the Aβ sequence to probe structural features of the monomeric, oligomeric and fibrillar forms of the 42-residue Aβ1-42. By monitoring the quenching of Tyr10 fluorescence upon addition of water-soluble acrylamide, we show that in Aβ1-42 oligomers this residue is solvent-exposed to a similar extent to that found in the unfolded monomer. By contrast, Tyr10 is significantly shielded from acrylamide quenching in Aβ1-42 fibrils, consistent with its proximity to the fibrillar cross-β core. Furthermore, circular dichroism measurements reveal that Aβ1-42 oligomers have a considerably lower β-sheet content than the Aβ1-42 fibrils, indicative of a less ordered molecular arrangement in the former. Taken together these findings suggest significant differences in the structural assembly of oligomers and fibrils that are consistent with differences in their biological effects.
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Affiliation(s)
- Pablo Aran Terol
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Janet R Kumita
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Sharon C Hook
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Christopher M Dobson
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Elin K Esbjörner
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK; Department of Biology and Biological Engineering, Division of Chemical Biology, Chalmers University of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden.
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35
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Karamanos TK, Kalverda AP, Thompson GS, Radford SE. Mechanisms of amyloid formation revealed by solution NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2015; 88-89:86-104. [PMID: 26282197 PMCID: PMC4568309 DOI: 10.1016/j.pnmrs.2015.05.002] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 05/18/2015] [Accepted: 05/18/2015] [Indexed: 05/29/2023]
Abstract
Amyloid fibrils are proteinaceous elongated aggregates involved in more than fifty human diseases. Recent advances in electron microscopy and solid state NMR have allowed the characterization of fibril structures to different extents of refinement. However, structural details about the mechanism of fibril formation remain relatively poorly defined. This is mainly due to the complex, heterogeneous and transient nature of the species responsible for assembly; properties that make them difficult to detect and characterize in structural detail using biophysical techniques. The ability of solution NMR spectroscopy to investigate exchange between multiple protein states, to characterize transient and low-population species, and to study high molecular weight assemblies, render NMR an invaluable technique for studies of amyloid assembly. In this article we review state-of-the-art solution NMR methods for investigations of: (a) protein dynamics that lead to the formation of aggregation-prone species; (b) amyloidogenic intrinsically disordered proteins; and (c) protein-protein interactions on pathway to fibril formation. Together, these topics highlight the power and potential of NMR to provide atomic level information about the molecular mechanisms of one of the most fascinating problems in structural biology.
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Affiliation(s)
- Theodoros K Karamanos
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.
| | - Arnout P Kalverda
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Gary S Thompson
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.
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36
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Systematic Aβ Analysis in Drosophila Reveals High Toxicity for the 1-42, 3-42 and 11-42 Peptides, and Emphasizes N- and C-Terminal Residues. PLoS One 2015. [PMID: 26208119 PMCID: PMC4514787 DOI: 10.1371/journal.pone.0133272] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Brain amyloid plaques are a hallmark of Alzheimer's disease (AD), and primarily consist of aggregated Aβ peptides. While Aβ 1-40 and Aβ 1-42 are the most abundant, a number of other Aβ peptides have also been identified. Studies have indicated differential toxicity for these various Aβ peptides, but in vivo toxicity has not been systematically tested. To address this issue, we generated improved transgenic Drosophila UAS strains expressing 11 pertinent Aβ peptides. UAS transgenic flies were generated by identical chromosomal insertion, hence removing any transgenic position effects, and crossed to a novel and robust Gal4 driver line. Using this improved Gal4/UAS set-up, survival and activity assays revealed that Aβ 1-42 severely shortens lifespan and reduces activity. N-terminal truncated peptides were quite toxic, with 3-42 similar to 1-42, while 11-42 showed a pronounced but less severe phenotype. N-terminal mutations in 3-42 (E3A) or 11-42 (E11A) resulted in reduced toxicity for 11-42, and reduced aggregation for both variants. Strikingly, C-terminal truncation of Aβ (1-41, -40, -39, -38, -37) were non-toxic. In contrast, C-terminal extension to 1-43 resulted in reduced lifespan and activity, but not to the same extent as 1-42. Mutating residue 42 in 1-42 (A42D, A42R and A42W) greatly reduced Aβ accumulation and toxicity. Histological and biochemical analysis revealed strong correlation between in vivo toxicity and brain Aβ aggregate load, as well as amount of insoluble Aβ. This systematic Drosophila in vivo and in vitro analysis reveals crucial N- and C-terminal specificity for Aβ neurotoxicity and aggregation, and underscores the importance of residues 1-10 and E11, as well as a pivotal role of A42.
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37
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Hubin E, Deroo S, Schierle GK, Kaminski C, Serpell L, Subramaniam V, van Nuland N, Broersen K, Raussens V, Sarroukh R. Two distinct β-sheet structures in Italian-mutant amyloid-beta fibrils: a potential link to different clinical phenotypes. Cell Mol Life Sci 2015; 72:4899-913. [PMID: 26190022 PMCID: PMC4648968 DOI: 10.1007/s00018-015-1983-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 06/06/2015] [Accepted: 07/02/2015] [Indexed: 12/22/2022]
Abstract
Most Alzheimer’s disease (AD) cases are late-onset and characterized by the aggregation and deposition of the amyloid-beta (Aβ) peptide in extracellular plaques in the brain. However, a few rare and hereditary Aβ mutations, such as the Italian Glu22-to-Lys (E22K) mutation, guarantee the development of early-onset familial AD. This type of AD is associated with a younger age at disease onset, increased β-amyloid accumulation, and Aβ deposition in cerebral blood vessel walls, giving rise to cerebral amyloid angiopathy (CAA). It remains largely unknown how the Italian mutation results in the clinical phenotype that is characteristic of CAA. We therefore investigated how this single point mutation may affect the aggregation of Aβ1–42 in vitro and structurally characterized the resulting fibrils using a biophysical approach. This paper reports that wild-type and Italian-mutant Aβ both form fibrils characterized by the cross-β architecture, but with distinct β-sheet organizations, resulting in differences in thioflavin T fluorescence and solvent accessibility. E22K Aβ1–42 oligomers and fibrils both display an antiparallel β-sheet structure, in comparison with the parallel β-sheet structure of wild-type fibrils, characteristic of most amyloid fibrils described in the literature. Moreover, we demonstrate structural plasticity for Italian-mutant Aβ fibrils in a pH-dependent manner, in terms of their underlying β-sheet arrangement. These findings are of interest in the ongoing debate that (1) antiparallel β-sheet structure might represent a signature for toxicity, which could explain the higher toxicity reported for the Italian mutant, and that (2) fibril polymorphism might underlie differences in disease pathology and clinical manifestation.
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Affiliation(s)
- Ellen Hubin
- Nanobiophysics Group, Faculty of Science and Technology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, 7500 AE, Enschede, The Netherlands.,Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050, Brussels, Belgium.,Structural Biology Research Center, VIB, Pleinlaan 2, 1050, Brussels, Belgium
| | - Stéphanie Deroo
- Laboratory of Structure and Function of Biological Membrane, Faculté des Sciences, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles (ULB), Campus de la Plaine CP 206/02, Boulevard du Triomphe, 1050, Brussels, Belgium
| | - Gabriele Kaminksi Schierle
- Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street, Cambridge, CB2 3RA, UK
| | - Clemens Kaminski
- Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street, Cambridge, CB2 3RA, UK
| | - Louise Serpell
- School of Life Sciences, University of Sussex, Falmer, East Sussex, BN1 9QG, UK
| | - Vinod Subramaniam
- Nanobiophysics Group, Faculty of Science and Technology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, 7500 AE, Enschede, The Netherlands.,FOM Institute AMOLF, Science Park 104, 1098 XG, Amsterdam, The Netherlands
| | - Nico van Nuland
- Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050, Brussels, Belgium.,Structural Biology Research Center, VIB, Pleinlaan 2, 1050, Brussels, Belgium
| | - Kerensa Broersen
- Nanobiophysics Group, Faculty of Science and Technology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, 7500 AE, Enschede, The Netherlands.
| | - Vincent Raussens
- Laboratory of Structure and Function of Biological Membrane, Faculté des Sciences, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles (ULB), Campus de la Plaine CP 206/02, Boulevard du Triomphe, 1050, Brussels, Belgium
| | - Rabia Sarroukh
- Laboratory of Structure and Function of Biological Membrane, Faculté des Sciences, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles (ULB), Campus de la Plaine CP 206/02, Boulevard du Triomphe, 1050, Brussels, Belgium.
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38
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Xiao Y, Ma B, McElheny D, Parthasarathy S, Long F, Hoshi M, Nussinov R, Ishii Y. Aβ(1-42) fibril structure illuminates self-recognition and replication of amyloid in Alzheimer's disease. Nat Struct Mol Biol 2015; 22:499-505. [PMID: 25938662 PMCID: PMC4476499 DOI: 10.1038/nsmb.2991] [Citation(s) in RCA: 633] [Impact Index Per Article: 70.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 04/15/2015] [Indexed: 12/19/2022]
Abstract
Increasing evidence has suggested that formation and propagation of misfolded aggregates of 42-residue human amyloid β (Aβ(1-42)), rather than of the more abundant Aβ(1-40), provokes the Alzheimer's disease cascade. However, structural details of misfolded Aβ(1-42) have remained elusive. Here we present the atomic model of an Aβ(1-42) amyloid fibril, from solid-state NMR (ssNMR) data. It displays triple parallel-β-sheet segments that differ from reported structures of Aβ(1-40) fibrils. Remarkably, Aβ(1-40) is incompatible with the triple-β-motif, because seeding with Aβ(1-42) fibrils does not promote conversion of monomeric Aβ(1-40) into fibrils via cross-replication. ssNMR experiments suggest that C-terminal Ala42, absent in Aβ(1-40), forms a salt bridge with Lys28 to create a self-recognition molecular switch that excludes Aβ(1-40). The results provide insight into the Aβ(1-42)-selective self-replicating amyloid-propagation machinery in early-stage Alzheimer's disease.
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Affiliation(s)
- Yiling Xiao
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Buyong Ma
- Cancer and Inflammation Program, Leidos Biomedical Research, National Cancer Institute at Frederick, Frederick, Maryland, USA
| | - Dan McElheny
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois, USA
| | | | - Fei Long
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Minako Hoshi
- 1] Institute of Biomedical Research and Innovation, Kobe, Japan. [2] Department of Anatomy and Developmental Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Ruth Nussinov
- 1] Cancer and Inflammation Program, Leidos Biomedical Research, National Cancer Institute at Frederick, Frederick, Maryland, USA. [2] Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yoshitaka Ishii
- 1] Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois, USA. [2] Center for Structural Biology, University of Illinois at Chicago, Chicago, Illinois, USA
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Steady-state and time-resolved Thioflavin-T fluorescence can report on morphological differences in amyloid fibrils formed by Aβ(1-40) and Aβ(1-42). Biochem Biophys Res Commun 2015; 458:418-23. [DOI: 10.1016/j.bbrc.2015.01.132] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 01/26/2015] [Indexed: 11/23/2022]
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40
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Yu Y, Yang Y, Wang C. Site-specific Analysis of Amyloid Assemblies by Using Scanning Tunneling Microscopy. CHINESE J CHEM 2014. [DOI: 10.1002/cjoc.201400631] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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41
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Gu L, Liu C, Stroud JC, Ngo S, Jiang L, Guo Z. Antiparallel triple-strand architecture for prefibrillar Aβ42 oligomers. J Biol Chem 2014; 289:27300-27313. [PMID: 25118290 PMCID: PMC4175361 DOI: 10.1074/jbc.m114.569004] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 08/05/2014] [Indexed: 12/21/2022] Open
Abstract
Aβ42 oligomers play key roles in the pathogenesis of Alzheimer disease, but their structures remain elusive partly due to their transient nature. Here, we show that Aβ42 in a fusion construct can be trapped in a stable oligomer state, which recapitulates characteristics of prefibrillar Aβ42 oligomers and enables us to establish their detailed structures. Site-directed spin labeling and electron paramagnetic resonance studies provide structural restraints in terms of side chain mobility and intermolecular distances at all 42 residue positions. Using these restraints and other biophysical data, we present a novel atomic-level oligomer model. In our model, each Aβ42 protein forms a single β-sheet with three β-strands in an antiparallel arrangement. Each β-sheet consists of four Aβ42 molecules in a head-to-tail arrangement. Four β-sheets are packed together in a face-to-back fashion. The stacking of identical segments between different β-sheets within an oligomer suggests that prefibrillar oligomers may interconvert with fibrils via strand rotation, wherein β-strands undergo an ∼90° rotation along the strand direction. This work provides insights into rational design of therapeutics targeting the process of interconversion between toxic oligomers and non-toxic fibrils.
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Affiliation(s)
- Lei Gu
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California 90095
| | - Cong Liu
- Departments of Chemistry and Biochemistry and Biological Chemistry, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California 90095,; Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China, and
| | - James C Stroud
- Department of Chemistry and Chemical Biology, Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131
| | - Sam Ngo
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California 90095
| | - Lin Jiang
- Departments of Chemistry and Biochemistry and Biological Chemistry, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California 90095
| | - Zhefeng Guo
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California 90095.
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42
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López Deber MP, Hickman DT, Nand D, Baldus M, Pfeifer A, Muhs A. Engineering amyloid-like assemblies from unstructured peptides via site-specific lipid conjugation. PLoS One 2014; 9:e105641. [PMID: 25207975 PMCID: PMC4160191 DOI: 10.1371/journal.pone.0105641] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 07/22/2014] [Indexed: 11/21/2022] Open
Abstract
Aggregation of amyloid beta (Aβ) into oligomers and fibrils is believed to play an important role in the development of Alzheimer’s disease (AD). To gain further insight into the principles of aggregation, we have investigated the induction of β-sheet secondary conformation from disordered native peptide sequences through lipidation, in 1–2% hexafluoroisopropanol (HFIP) in phosphate buffered saline (PBS). Several parameters, such as type and number of lipid chains, peptide sequence, peptide length and net charge, were explored keeping the ratio peptide/HFIP constant. The resulting lipoconjugates were characterized by several physico-chemical techniques: Circular Dichroism (CD), Attenuated Total Reflection InfraRed (ATR-IR), Thioflavin T (ThT) fluorescence, Dynamic Light Scattering (DLS), solid-state Nuclear Magnetic Resonance (ssNMR) spectroscopy and Electron Microscopy (EM). Our data demonstrate the generation of β-sheet aggregates from numerous unstructured peptides under physiological pH, independent of the amino acid sequence. The amphiphilicity pattern and hydrophobicity of the scaffold were found to be key factors for their assembly into amyloid-like structures.
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Affiliation(s)
| | | | - Deepak Nand
- Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Marc Baldus
- Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
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43
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Hubin E, van Nuland NAJ, Broersen K, Pauwels K. Transient dynamics of Aβ contribute to toxicity in Alzheimer's disease. Cell Mol Life Sci 2014; 71:3507-21. [PMID: 24803005 PMCID: PMC4143600 DOI: 10.1007/s00018-014-1634-z] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 04/15/2014] [Accepted: 04/22/2014] [Indexed: 12/20/2022]
Abstract
The aggregation and deposition of the amyloid-β peptide (Aβ) in the brain has been linked with neuronal death, which progresses in the diagnostic and pathological signs of Alzheimer’s disease (AD). The transition of an unstructured monomeric peptide into self-assembled and more structured aggregates is the crucial conversion from what appears to be a harmless polypeptide into a malignant form that causes synaptotoxicity and neuronal cell death. Despite efforts to identify the toxic form of Aβ, the development of effective treatments for AD is still limited by the highly transient and dynamic nature of interconverting forms of Aβ. The variability within the in vivo “pool” of different Aβ peptides is another complicating factor. Here we review the dynamical interplay between various components that influence the heterogeneous Aβ system, from intramolecular Aβ flexibility to intermolecular dynamics between various Aβ alloforms and external factors. The complex dynamics of Aβ contributes to the causative role of Aβ in the pathogenesis of AD.
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Affiliation(s)
- E Hubin
- Nanobiophysics Group, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, University of Twente, 7500 AE, Enschede, The Netherlands
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44
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Brännström K, Lindhagen-Persson M, Gharibyan AL, Iakovleva I, Vestling M, Sellin ME, Brännström T, Morozova-Roche L, Forsgren L, Olofsson A. A generic method for design of oligomer-specific antibodies. PLoS One 2014; 9:e90857. [PMID: 24618582 PMCID: PMC3949727 DOI: 10.1371/journal.pone.0090857] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 02/06/2014] [Indexed: 01/07/2023] Open
Abstract
Antibodies that preferentially and specifically target pathological oligomeric protein and peptide assemblies, as opposed to their monomeric and amyloid counterparts, provide therapeutic and diagnostic opportunities for protein misfolding diseases. Unfortunately, the molecular properties associated with oligomer-specific antibodies are not well understood, and this limits targeted design and development. We present here a generic method that enables the design and optimisation of oligomer-specific antibodies. The method takes a two-step approach where discrimination between oligomers and fibrils is first accomplished through identification of cryptic epitopes exclusively buried within the structure of the fibrillar form. The second step discriminates between monomers and oligomers based on differences in avidity. We show here that a simple divalent mode of interaction, as within e.g. the IgG isotype, can increase the binding strength of the antibody up to 1500 times compared to its monovalent counterpart. We expose how the ability to bind oligomers is affected by the monovalent affinity and the turnover rate of the binding and, importantly, also how oligomer specificity is only valid within a specific concentration range. We provide an example of the method by creating and characterising a spectrum of different monoclonal antibodies against both the Aβ peptide and α-synuclein that are associated with Alzheimer's and Parkinson's diseases, respectively. The approach is however generic, does not require identification of oligomer-specific architectures, and is, in essence, applicable to all polypeptides that form oligomeric and fibrillar assemblies.
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Affiliation(s)
| | | | - Anna L. Gharibyan
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Irina Iakovleva
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Monika Vestling
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | | | | | | | - Lars Forsgren
- Department of Clinical Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden
| | - Anders Olofsson
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
- * E-mail:
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45
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Bolognesi B, Cohen SIA, Aran Terol P, Esbjörner EK, Giorgetti S, Mossuto MF, Natalello A, Brorsson AC, Knowles TPJ, Dobson CM, Luheshi LM. Single point mutations induce a switch in the molecular mechanism of the aggregation of the Alzheimer's disease associated Aβ42 peptide. ACS Chem Biol 2014; 9:378-82. [PMID: 24199868 DOI: 10.1021/cb400616y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Single point mutations in the Alzheimer's disease associated Aβ42 peptide are found to alter significantly its neurotoxic properties in vivo and have been associated with early onset forms of this devastating condition. We show that such mutations can induce structural changes in Aβ42 fibrils and are associated with a dramatic switch in the fibril-dependent mechanism by which Aβ42 aggregates. These observations reveal how subtle perturbations to the physicochemical properties of the Aβ peptide, and the structural properties of fibrils that it forms, can have profound effects on the mechanism of its aggregation and pathogenicity.
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Affiliation(s)
- Benedetta Bolognesi
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Samuel I. A. Cohen
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Pablo Aran Terol
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Elin K. Esbjörner
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Sofia Giorgetti
- Department
of Biochemistry, University of Pavia, via Taramelli, 27100, Pavia, Italy
| | | | - Antonino Natalello
- Department
of Biotechnology and Biosciences, University of Milano-Bicocca, Pizza
della Scienza 2, 20126 Milan, Italy
| | - Ann-Christin Brorsson
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Tuomas P. J. Knowles
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Christopher M. Dobson
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Leila M. Luheshi
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom
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46
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Zhao JH, Liu HL, Liu YF, Lin HY, Fang HW, Ho Y, Tsai WB. Molecular dynamics simulations to investigate the aggregation behaviors of the Abeta(17-42) oligomers. J Biomol Struct Dyn 2013; 26:481-90. [PMID: 19108587 DOI: 10.1080/07391102.2009.10507263] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The amyloid beta-peptides (Abetas) are the main protein components of amyloid deposits in Alzheimer's disease (AD). Detailed knowledge of the structure and assembly dynamics of Abeta is important for the development of properly targeted AD therapeutics. So far, the process of the monomeric Abeta assembling into oligomeric fibrils and the mechanism underlying the aggregation process remain unclear. In this study, several molecular dynamics simulations were conducted to investigate the aggregation behaviors of the Abeta(17-42) oligomers associated with various numbers of monomers (dimer, trimer, tetramer, and pentamer). Our results showed that the structural stability of the Abeta(17-42) oligomers increases with increasing the number of monomer. We further demonstrated that the native hydrophobic contacts are positive correlated with the beta-sheet contents, indicating that hydrophobic interaction plays an important role in maintaining the structural stability of the Abeta(17-42) oligomers, particularly for those associated with more monomers. Our results also showed that the stability of the C-terminal hydrophobic segment 2 (residues 30-42) is higher than that of the N-terminal hydrophobic segment 1 (residues 17-21), suggesting that hydrophobic segment 2 may act as the nucleation site for aggregation. We further identified that Met35 residue initiates the hydrophobic interactions and that the intermolecular contact pairs, Gly33-Gly33 and Gly37-Gly37, form a stable "molecular notch", which may mediate the packing of the beta-sheet involving many other hydrophobic residues during the early stage of amyloid-like fibril formation.
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Affiliation(s)
- Jian-Hua Zhao
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, 1 Sec. 3 ZhongXiao E. Rd., Taipei, Taiwan 10608
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47
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Gu L, Guo Z. Alzheimer's Aβ42 and Aβ40 peptides form interlaced amyloid fibrils. J Neurochem 2013; 126:305-11. [PMID: 23406382 DOI: 10.1111/jnc.12202] [Citation(s) in RCA: 163] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 02/08/2013] [Accepted: 02/12/2013] [Indexed: 11/28/2022]
Abstract
Deposition of amyloid β (Aβ) in the brain is a pathological hallmark of Alzheimer's disease. There are two major isoforms of Aβ: the 42-residue Aβ42 and the 40-residue Aβ40. The only difference between Aβ42 and Aβ40 is that Aβ42 has two extra residues at the C-terminus. The amyloid plaques in Alzheimer's brains consist of mostly Aβ42 and some plaques contain only Aβ42, even though Aβ40 concentration is several-fold more than Aβ42. Using electron paramagnetic resonance, we studied the formation of amyloid fibrils using a mixture of Aβ42 and Aβ40 in vitro. We show that Aβ42 and Aβ40 form mixed fibrils in an interlaced manner, although Aβ40 is not as efficient as Aβ42 in terms of being incorporated into Aβ42 fibrils. Our results suggest that both Aβ42 and Aβ40 would be present in amyloid plaques if in vivo aggregation of Aβ were similar to the in vitro process. Therefore, there must be some mechanisms that lead to the preferential deposition of Aβ42 at the extracellular space. Identifying such mechanisms may open new avenues for therapeutic interventions to treat Alzheimer's disease.
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Affiliation(s)
- Lei Gu
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, California 90095, USA
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48
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Abstract
Identifying factors that affect the self-assembly of Aβ (amyloid-β peptide) is of utmost importance in the quest to understand the molecular mechanisms causing AD (Alzheimer's disease). Ca2+ has previously been shown to accelerate both Aβ fibril nucleation and maturation, and dysregulated Ca2+ homoeostasis frequently correlates with development of AD. The mechanisms regarding Ca2+ binding, as well as its effect on fibril kinetics, are not fully understood. Using a polymerization assay we show that Ca2+ in a dynamic and reversible manner enhances both the elongation rate and fibrillar stability, where specifically the ‘dock and lock’ phase mechanism is enhanced. Through NMR analysis we found that Ca2+ affects the fibrillar architecture. In addition, and unexpectedly, we found that Ca2+ does not bind the free Aβ monomer. This implies that Ca2+ binding requires an architecture adopted by assembled peptides, and consequently is mediated through intermolecular interactions between adjacent peptides. This gives a mechanistic explanation to the enhancing effect on fibril maturation and indicates structural similarities between prefibrillar structures and mature amyloid. Taken together we show how Ca2+ levels affect the delicate equilibrium between the monomeric and assembled Aβ and how fluctuations in vivo may contribute to development and progression of the disease.
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49
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Lee YH, Goto Y. Kinetic intermediates of amyloid fibrillation studied by hydrogen exchange methods with nuclear magnetic resonance. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:1307-23. [DOI: 10.1016/j.bbapap.2012.07.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 07/24/2012] [Accepted: 07/26/2012] [Indexed: 01/28/2023]
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50
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Roberts VA, Pique ME, Hsu S, Li S, Slupphaug G, Rambo RP, Jamison JW, Liu T, Lee JH, Tainer JA, Ten Eyck LF, Woods VL. Combining H/D exchange mass spectroscopy and computational docking reveals extended DNA-binding surface on uracil-DNA glycosylase. Nucleic Acids Res 2012; 40:6070-81. [PMID: 22492624 PMCID: PMC3401472 DOI: 10.1093/nar/gks291] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 02/21/2012] [Accepted: 03/15/2012] [Indexed: 12/21/2022] Open
Abstract
X-ray crystallography provides excellent structural data on protein-DNA interfaces, but crystallographic complexes typically contain only small fragments of large DNA molecules. We present a new approach that can use longer DNA substrates and reveal new protein-DNA interactions even in extensively studied systems. Our approach combines rigid-body computational docking with hydrogen/deuterium exchange mass spectrometry (DXMS). DXMS identifies solvent-exposed protein surfaces; docking is used to create a 3-dimensional model of the protein-DNA interaction. We investigated the enzyme uracil-DNA glycosylase (UNG), which detects and cleaves uracil from DNA. UNG was incubated with a 30 bp DNA fragment containing a single uracil, giving the complex with the abasic DNA product. Compared with free UNG, the UNG-DNA complex showed increased solvent protection at the UNG active site and at two regions outside the active site: residues 210-220 and 251-264. Computational docking also identified these two DNA-binding surfaces, but neither shows DNA contact in UNG-DNA crystallographic structures. Our results can be explained by separation of the two DNA strands on one side of the active site. These non-sequence-specific DNA-binding surfaces may aid local uracil search, contribute to binding the abasic DNA product and help present the DNA product to APE-1, the next enzyme on the DNA-repair pathway.
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Affiliation(s)
- Victoria A Roberts
- San Diego Supercomputer Center, University of California, San Diego, 9500 Gilman Drive, MC 0505, La Jolla, CA 92093, USA.
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