Structural Insights into Amyloid Oligomers of the Parkinson Disease-related Protein α-Synuclein

Gallea, José Ignacio; Celej, M. Soledad

doi:10.1074/jbc.m114.566695

Cited by 52 publications

(62 citation statements)

References 50 publications

(70 reference statements)

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“…The average thickness of the walls of the cylindrical structures (30 and 40 Å on average for the 10S and the 15S oligomer subgroups, respectively) is too large for a folding core composed of a single β-sheet folded into a barrel structure of the type found for a crystalline hexameric species formed by a short segment of αB crystallin (12). The dimensions of the oligomeric species described here are, instead, much closer to those reported for fibrillar structures of αS from cryo-negative EM studies, which are 80-120 Å in diameter, with a central cavity of approximately 20-30 Å in diameter running through the structure (49) and, indeed, long cylindrical structures with water-filled interfaces have been proposed for a variety of amyloid fibrils (4, 5, 7-10) and similar protein regions as those found in the fibrillar core have been suggested to be involved in intermolecular contacts within αS oligomers prepared by using a similar approach to that we have used here (27).…”

Section: Discussionmentioning

confidence: 99%

“…For this reason, we have generated and purified samples of stable αS oligomers at micromolar concentrations and used a range of biophysical methods to characterize the nature and distributions of their sizes, morphologies, and structural characteristics. All of the information accumulated from these studies indicates that the purified αS oligomers characterized here have a remarkably high degree of similarity, in terms of physico-chemical, structural, and toxic properties, with oligomeric species formed by αS under different conditions and other amyloidogenic peptides and proteins (16,17,21,22,(24)(25)(26)(27)(28)47), and are representative of the most highly compact and stable oligomeric αS species identified to accumulate during fibril formation by means of single-molecule fluorescence techniques (23).…”

Section: Discussionmentioning

confidence: 99%

“…αS oligomeric samples were prepared on the basis of previous protocols (17,21,22,24,25,27,40,62,63). Briefly, 6 mg of lyophilized protein was resuspended in PBS buffer, pH 7.4, to give a final concentration of approximately 800 μM (12 mg/mL) and passed through a 0.22-μm cutoff filter immediately before incubation at 37°C for 20-24 h without agitation or the application of any other process that could induce shear and, hence, accelerate the conversion of monomers and oligomers into fibrils (23,29).…”

Section: Methodsmentioning

confidence: 99%

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Structural characterization of toxic oligomers that are kinetically trapped during α-synuclein fibril formation

Chen

Drakulić

Deas

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

428

661

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We describe the isolation and detailed structural characterization of stable toxic oligomers of α-synuclein that have accumulated during the process of amyloid formation. Our approach has allowed us to identify distinct subgroups of oligomers and to probe their molecular architectures by using cryo-electron microscopy (cryoEM) image reconstruction techniques. Although the oligomers exist in a range of sizes, with different extents and nature of β-sheet content and exposed hydrophobicity, they all possess a hollow cylindrical architecture with similarities to certain types of amyloid fibril, suggesting that the accumulation of at least some forms of amyloid oligomers is likely to be a consequence of very slow rates of rearrangement of their β-sheet structures. Our findings reveal the inherent multiplicity of the process of protein misfolding and the key role the β-sheet geometry acquired in the early stages of the self-assembly process plays in dictating the kinetic stability and the pathological nature of individual oligomeric species.protein misfolding | amyloid aggregation | toxic oligomer | cryoelectron microscopy | neurodegeneration

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Structural characterization of toxic oligomers that are kinetically trapped during α-synuclein fibril formation

Chen

Drakulić

Deas

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

428

661

View full text Add to dashboard Cite

show abstract

“…16 For all Cys-apelin peptides, NPM conjugation in DMF proceeded efficiently at room temperature ( Figure 2), with DMF serving as an excellent co-solvent both for NPM and the apelin peptides. A stoichiometry of 2:1 to 5:1 (NPM:apelin) allowed for robust conjugation, a significantly reduced (although not unprecedented 29 ) stoichiometry relative to typical protocols. [30][31] In the case of Cys-apelin-36, addition of DTT was required, presumably to reduce disulfide-linked dimers and allow for NPM conjugation.…”

Section: Pyrene-apelin Conjugationmentioning

confidence: 99%

Pyrene–Apelin Conjugation Modulates Fluorophore– and Peptide–Micelle Interactions

2017

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Bioactive apelin peptide forms ranging in length from 12 to 55 amino acids bind to and activate the apelin receptor (AR or APJ), a class A G-protein coupled receptor. Apelin-12, -17, and -36 isoforms, named according to length, with an additional N-terminal cysteine residue allowed for regiospecific and efficient conjugation of pyrene-maleimide. Through steady-state fluorescence spectroscopy, the emission properties of pyrene in aqueous buffer were compared to those of the pyrene-apelin conjugates both without and with zwitterionic or anionic micelles. Pyrene photophysics are consistent with an expected partitioning into the hydrophobic micellar cores, while pyrene-apelin conjugation prevented this partitioning. Apelin, conversely, is expected to preferentially interact with anionic micelles; pyrene-apelin conjugates appear to lose preferential interaction. Finally, Förster resonance energy transfer between pyrene and tryptophan residues in the N-terminal tail and first transmembrane segment (the AR55 construct, comprising residues 1-55 of the AR) was consistent with efficient nonspecific pyrene-apelin conjugate binding to micelles rather than direct, specific apelin-AR55 binding. This approach provides a versatile fluorophore conjugation strategy for apelin, particularly valuable given that even a highly hydrophobic fluorophore is not deleterious to peptide behavior in membrane-mimetic micellar systems. Figure S2) demonstrating Cys-apelin-36 expression, SUMO cleavage and purification. Concentration dependent emission spectra of Py-Cys-apelin-17 in buffer and surfactant micelles ( Figure S3). Graphical Abstract

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“…Many of the oligomers show, upon biophysical examination, ordered assemblies with a well-defined pattern of intermolecular contacts and at least some of these contacts involve regions that form a β-sheet core in the fibrillar state, should that conformation be achieved. 135 Thus, while these diverse proteins form very different structures in their soluble state, their fibril states are distinguished by structural commonalities, thought to be due to the ability of the primary sequence to be stabilized by hydrogen bond interactions in the polypeptide, such that β-strands of the oligomer can stack in register and be arranged perpendicular to the long axis of the ultimate fibril to generate a cross-β structure. [136][137][138] The Aβ oligomers characteristic of AD have been studied most intensively and their levels correlate well with disease severity.…”

Section: Pre-amyloid Structure and Toxicitymentioning

confidence: 99%

Proteotoxicity and Cardiac Dysfunction

2013

N Engl J Med

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Baseline physiological function of the mammalian heart is under the constant threat of environmental or intrinsic pathological insults. Cardiomyocyte proteins are thus subject to unremitting pressure to function optimally and this depends upon them assuming and maintaining proper conformation. This review explores the multiple defenses a cell may employ for its proteins to assume and maintain correct protein folding and conformation. There are multiple quality control mechanisms to ensure that nascent polypeptides are properly folded and mature proteins maintain their functional conformation. When proteins do misfold, either in the face of normal or pathologic stimuli or because of intrinsic mutations or post-translational modifications, they must either be refolded correctly or recycled. In the absence of these corrective processes, they may become toxic to the cell. Herein, we explore some of the underlying mechanisms that lead to proteotoxicity. The continued presence and chronic accumulation of misfolded or unfolded proteins can be disastrous in cardiomyocytes as these misfolded proteins can lead to aggregation or the formation of soluble peptides that are proteotoxic. This in turn leads to compromised protein quality control and precipitating a downward spiral of the cell's ability to maintain protein homeostasis. Some underlying mechanisms are discussed and the therapeutic potential of interfering with proteotoxicity in the heart is explored.

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Structural Insights into Amyloid Oligomers of the Parkinson Disease-related Protein α-Synuclein

Cited by 52 publications

References 50 publications

Structural characterization of toxic oligomers that are kinetically trapped during α-synuclein fibril formation

Structural characterization of toxic oligomers that are kinetically trapped during α-synuclein fibril formation

Pyrene–Apelin Conjugation Modulates Fluorophore– and Peptide–Micelle Interactions

Proteotoxicity and Cardiac Dysfunction

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