1
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Guza M, Dzwolak W. Acetone-induced structural variant of insulin amyloid fibrils. Int J Biol Macromol 2024; 257:128680. [PMID: 38071871 DOI: 10.1016/j.ijbiomac.2023.128680] [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: 10/04/2023] [Revised: 12/01/2023] [Accepted: 12/06/2023] [Indexed: 01/27/2024]
Abstract
Self-propagating polymorphism of amyloid fibrils is a distinct manifestation of non-equilibrium conditions under which protein aggregation typically occurs. Structural variants of fibrils can often be accessed through physicochemical perturbations of the de novo aggregation process. On the other hand, tiny changes in the amino acid sequence of the parent protein may also result in structurally distinguishable amyloid fibrils. Here, we show that in the presence of acetone, the low-pH fibrillization pathway of bovine insulin (BI) leads to a new type of amyloid with the infrared features (split amide I' band with the maximum at 1623 cm-1) bearing a striking resemblance to those of the previously reported fibrils from recombinant LysB31-ArgB32 human insulin analog formed in the absence of the co-solvent. Insulin fibrils formed in the presence ([BI-ace]) and absence ([BI]) of acetone cross-seed each other and pass their infrared features to the daughter generations of fibrils. We have used dimethyl sulfoxide (DMSO) coupled to in situ infrared spectroscopy measurements to probe the stability of fibrils against chemical denaturation. While both types of fibrils eventually undergo DMSO-induced disassembly coupled to a β-sheet→coil transition, in the case of [BI-ace] amyloid, the denaturation is preceded by the fibrils transiently acquiring the [BI]-like infrared characteristics. We argue that this effect is caused by DMSO-induced dehydration of [BI-ace]. In support to this hypothesis, we show that, even in the absence of DMSO, the infrared features of [BI-ace] disappear upon drying. We discuss this very peculiar aspect of [BI-ace] fibrils in the context of recently accessed in silico models of plausible structural variants of insulin protofilaments.
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Affiliation(s)
- Marcin Guza
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, 1 Pasteur Str., 02-093 Warsaw, Poland
| | - Wojciech Dzwolak
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, 1 Pasteur Str., 02-093 Warsaw, Poland.
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2
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The current state of amyloidosis therapeutics and the potential role of fluorine in their treatment. Biochimie 2022; 202:123-135. [PMID: 35963462 DOI: 10.1016/j.biochi.2022.08.003] [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: 02/16/2022] [Revised: 07/22/2022] [Accepted: 08/04/2022] [Indexed: 11/22/2022]
Abstract
Amyloidosis, commonly known as amyloid-associated diseases, is characterized by improperly folded proteins accumulating in tissues and eventually causing organ damage, which is linked to several disorders ranging from neurodegenerative to peripheral diseases. It has an enormous societal and financial impact on the global health sector. Due to the complexity of protein misfolding and intertwined aggregation, there are no effective disease-modifying medications at present, and the condition is likely mis/non-diagnosed half of the time. Nonetheless, over the last two decades, substantial research into aggregation processes has revealed the possibilities of new intervention approaches. On the other hand, fluorine has been a rising star in therapeutic development for numerous neurodegenerative illnesses and other peripheral diseases. In this study, we revised and emphasized the possible significance of fluorine-modified therapeutic molecules and fluorine-modified nanoparticles (NPs) in the modulation of amyloidogenic proteins, including insulin, amyloid beta peptide (Aβ), prion protein (PrP), transthyretin (TTR) and Huntingtin (htt).
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3
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Matiiv AB, Trubitsina NP, Matveenko AG, Barbitoff YA, Zhouravleva GA, Bondarev SA. Structure and Polymorphism of Amyloid and Amyloid-Like Aggregates. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:450-463. [PMID: 35790379 DOI: 10.1134/s0006297922050066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 04/08/2022] [Accepted: 04/09/2022] [Indexed: 06/15/2023]
Abstract
Amyloids are protein aggregates with the cross-β structure. The interest in amyloids is explained, on the one hand, by their role in the development of socially significant human neurodegenerative diseases, and on the other hand, by the discovery of functional amyloids, whose formation is an integral part of cellular processes. To date, more than a hundred proteins with the amyloid or amyloid-like properties have been identified. Studying the structure of amyloid aggregates has revealed a wide variety of protein conformations. In the review, we discuss the diversity of protein folds in the amyloid-like aggregates and the characteristic features of amyloid aggregates that determine their unusual properties, including stability and interaction with amyloid-specific dyes. The review also describes the diversity of amyloid aggregates and its significance for living organisms.
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Affiliation(s)
- Anton B Matiiv
- Department of Genetics and Biotechnology, Saint Petersburg State University, Saint Petersburg, 199034, Russia
| | - Nina P Trubitsina
- Department of Genetics and Biotechnology, Saint Petersburg State University, Saint Petersburg, 199034, Russia
| | - Andrew G Matveenko
- Department of Genetics and Biotechnology, Saint Petersburg State University, Saint Petersburg, 199034, Russia
| | - Yury A Barbitoff
- Department of Genetics and Biotechnology, Saint Petersburg State University, Saint Petersburg, 199034, Russia
- Bioinformatics Institute, Saint Petersburg, 197342, Russia
| | - Galina A Zhouravleva
- Department of Genetics and Biotechnology, Saint Petersburg State University, Saint Petersburg, 199034, Russia
- Laboratory of Amyloid Biology, Saint Petersburg State University, Saint Petersburg, 199034, Russia
| | - Stanislav A Bondarev
- Department of Genetics and Biotechnology, Saint Petersburg State University, Saint Petersburg, 199034, Russia.
- Laboratory of Amyloid Biology, Saint Petersburg State University, Saint Petersburg, 199034, Russia
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4
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Zhang Y, Liu Y, Zhao W, Sun Y. Hydroxylated single-walled carbon nanotube inhibits β2m 21-31 fibrillization and disrupts pre-formed proto-fibrils. Int J Biol Macromol 2021; 193:1-7. [PMID: 34687758 DOI: 10.1016/j.ijbiomac.2021.10.103] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/11/2021] [Accepted: 10/14/2021] [Indexed: 11/17/2022]
Abstract
Pathological aggregation of amyloid polypeptides is associated with numerous degenerative diseases. Preventing aggregation and clearing amyloid deposits are considered as promising strategies against amyloidosis. With the capacity of crossing the blood-brain barrier and good biocompatibility, the hydroxylated single-walled carbon nanotube (SWCNT-OH) has been shown with excellent anti-amyloid properties. Here, we systematically studied the SWCNT-OH effects on the fibrillization of the β2m21-31 peptides utilizing all-atom discrete molecular dynamics (DMD) simulation. Our results demonstrated the isolated β2m21-31 peptides first nucleated into unstructured oligomers followed by coil-to-sheet conformational conversions in oligomers with at least six peptides. The elongation and lateral surfaces of the preformed β-sheet could catalyze the other unstructured monomers and small oligomers converted into β-sheet formations via dock-lock fibril growth and secondary nucleation processes. Eventually, the β2m21-31 peptides would self-assemble into well-ordered cross-β structures. Regardless of isolated monomers or well-defined cross-β assemblies, the β2m21-31 would attach on the surfaces of SWCNT-OH adopting unstructured formations indicating the SWCNT-OH not only inhibited the fibrillization of β2m21-31 but also destroyed pre-formed proto-fibrils. Overall, our study displays a complete picture of the fibrillization mechanism of β2m21-31 and the amyloid inhibitory mechanism of SWCNT-OH, offering new insight into the de-novo design of anti-amyloid inhibitors.
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Affiliation(s)
- Yu Zhang
- School of Physical Science and Technology, Ningbo University, Ningbo 315211, China
| | - Yuying Liu
- School of Physical Science and Technology, Ningbo University, Ningbo 315211, China
| | - Wenhui Zhao
- School of Physical Science and Technology, Ningbo University, Ningbo 315211, China
| | - Yunxiang Sun
- School of Physical Science and Technology, Ningbo University, Ningbo 315211, China.
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5
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Ohgi H, Imamura H, Sumi T, Nishikawa K, Koga Y, Westh P, Morita T. Two different regimes in alcohol-induced coil-helix transition: effects of 2,2,2-trifluoroethanol on proteins being either independent of or enhanced by solvent structural fluctuations. Phys Chem Chem Phys 2021; 23:5760-5772. [PMID: 33481971 DOI: 10.1039/d0cp05103a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Inhomogeneous distribution of constituent molecules in a mixed solvent has been known to give remarkable effects on the solute, e.g., conformational changes of biomolecules in an alcohol-water mixture. We investigated the general effects of 2,2,2-trifluoroethanol (TFE) on proteins/peptides in a mixture of water and TFE using melittin as a model protein. Fluctuations and Kirkwood-Buff integrals (KBIs) in the TFE-H2O mixture, quantitative descriptions of inhomogeneity, were determined by small-angle X-ray scattering investigation and compared with those in the aqueous solutions of other alcohols. The concentration fluctuation for the mixtures ranks as methanol < ethanol ≪ TFE < tert-butanol < 1-propanol, indicating that the inhomogeneity of molecular distribution in the TFE-H2O mixture is unexpectedly comparable to those in the series of mono-ols. On the basis of the concentration dependence of KBIs between the TFE molecules, it was found that a strong attraction between the TFE molecules is not necessarily important to induce helix conformation, which is inconsistent with the previously proposed mechanism. To address this issue, by combining the KBIs and the helix contents reported by the experimental spectroscopic studies, we quantitatively evaluated the change in the preferential binding parameter of TFE to melittin attributed to the coil-helix transition. As a result, we found two different regimes on TFE-induced helix formation. In the dilute concentration region of TFE below ∼2 M, where the TFE molecules are not aggregated among themselves, the excess preferential binding of TFE to the helix occurs due to the direct interaction between them, namely independent of the solvent fluctuation. In the higher concentration region above ∼2 M, in addition to the former effect, the excess preferential binding is significantly enhanced by the solvent fluctuation. This scheme should be held as general cosolvent effects of TFE on proteins/peptides.
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Affiliation(s)
- Hiroyo Ohgi
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan.
| | - Hiroshi Imamura
- Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University, Shiga 525-8577, Japan
| | - Tomonari Sumi
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan.
| | - Keiko Nishikawa
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan. and Toyota Physical & Chemical Research Institute, Nagakute, Aichi 480-1192, Japan
| | - Yoshikata Koga
- Department of Chemistry, The University of British Columbia, Vancouver, V6T 1Z1, Canada
| | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800, Kgs, Lyngby, Denmark
| | - Takeshi Morita
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan.
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6
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Current Understanding of the Structure, Stability and Dynamic Properties of Amyloid Fibrils. Int J Mol Sci 2021; 22:ijms22094349. [PMID: 33919421 PMCID: PMC8122407 DOI: 10.3390/ijms22094349] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 04/17/2021] [Accepted: 04/18/2021] [Indexed: 02/07/2023] Open
Abstract
Amyloid fibrils are supramolecular protein assemblies represented by a cross-β structure and fibrous morphology, whose structural architecture has been previously investigated. While amyloid fibrils are basically a main-chain-dominated structure consisting of a backbone of hydrogen bonds, side-chain interactions also play an important role in determining their detailed structures and physicochemical properties. In amyloid fibrils comprising short peptide segments, a steric zipper where a pair of β-sheets with side chains interdigitate tightly is found as a fundamental motif. In amyloid fibrils comprising longer polypeptides, each polypeptide chain folds into a planar structure composed of several β-strands linked by turns or loops, and the steric zippers are formed locally to stabilize the structure. Multiple segments capable of forming steric zippers are contained within a single protein molecule in many cases, and polymorphism appears as a result of the diverse regions and counterparts of the steric zippers. Furthermore, the β-solenoid structure, where the polypeptide chain folds in a solenoid shape with side chains packed inside, is recognized as another important amyloid motif. While side-chain interactions are primarily achieved by non-polar residues in disease-related amyloid fibrils, the participation of hydrophilic and charged residues is prominent in functional amyloids, which often leads to spatiotemporally controlled fibrillation, high reversibility, and the formation of labile amyloids with kinked backbone topology. Achieving precise control of the side-chain interactions within amyloid structures will open up a new horizon for designing useful amyloid-based nanomaterials.
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7
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Hiramatsu T, Yamamoto N, Ha S, Masuda Y, Yasuda M, Ishigaki M, Yuzu K, Ozaki Y, Chatani E. Iodine staining as a useful probe for distinguishing insulin amyloid polymorphs. Sci Rep 2020; 10:16741. [PMID: 33028868 PMCID: PMC7542459 DOI: 10.1038/s41598-020-73460-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 08/27/2020] [Indexed: 01/26/2023] Open
Abstract
It is recently suggested that amyloid polymorphism, i.e., structural diversity of amyloid fibrils, has a deep relationship with pathology. However, its prompt recognition is almost halted due to insufficiency of analytical methods for detecting polymorphism of amyloid fibrils sensitively and quickly. Here, we propose that iodine staining, a historically known reaction that was firstly found by Virchow, can be used as a method for distinguishing amyloid polymorphs. When insulin fibrils were prepared and iodine-stained, they exhibited different colors depending on polymorphs. Each of the colors was inherited to daughter fibrils by seeding reactions. The colors were fundamentally represented as a sum of three absorption bands in visible region between 400 and 750 nm, and the bands showed different titration curves against iodine, suggesting that there are three specific iodine binding sites. The analysis of resonance Raman spectra and polarization microscope suggested that several polyiodide ions composed of I3− and/or I5− were formed on the grooves or the edges of β-sheets. It was concluded that the polyiodide species and conformations formed are sensitive to surface structure of amyloid fibrils, and the resultant differences in color will be useful for detecting polymorphism in a wide range of diagnostic samples.
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Affiliation(s)
- Takato Hiramatsu
- Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo, 657-8501, Japan
| | - Naoki Yamamoto
- School of Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, 329-0498, Japan
| | - Seongmin Ha
- Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo, 657-8501, Japan
| | - Yuki Masuda
- Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo, 657-8501, Japan
| | - Mitsuru Yasuda
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo, 669-1337, Japan
| | - Mika Ishigaki
- Raman Project Center for Medical and Biological Applications, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504, Japan.,Faculty of Life and Environmental Science, Shimane University, 1060 Nishikawatsu, Matsue, Shimane, 690-8504, Japan
| | - Keisuke Yuzu
- Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo, 657-8501, Japan
| | - Yukihiro Ozaki
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo, 669-1337, Japan.,Molecular Photoscience Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo, 657-8501, Japan
| | - Eri Chatani
- Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo, 657-8501, Japan.
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8
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Disentangling the role of solvent polarity and protein solvation in folding and self-assembly of α-lactalbumin. J Colloid Interface Sci 2020; 561:749-761. [DOI: 10.1016/j.jcis.2019.11.051] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 10/29/2019] [Accepted: 11/14/2019] [Indexed: 12/31/2022]
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9
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Khan MS, Bhatt S, Tabrez S, Rehman MT, Alokail MS, AlAjmi MF. Quinoline yellow (food additive) induced conformational changes in lysozyme: a spectroscopic, docking and simulation studies of dye-protein interactions. Prep Biochem Biotechnol 2020; 50:673-681. [PMID: 32101072 DOI: 10.1080/10826068.2020.1725774] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Quinoline yellow (QY) is a synthetic yellow dye widely used as a coloring agent for various foodstuffs. In the current study, we have examined the role of QY on the aggregation propensity of hen egg-white lysozyme (HEWL) under physiological conditions. The dye induced conformational changes in HEWL leading to aggregate formation were identified by circular dichroism (CD), turbidity analysis, fluorescence measurement and microscopic (TEM) imaging. Molecular docking and molecular dynamics simulation studies were also employed to strengthen binding and aggregation results. Our results indicate that 25-100 µM of QY induces aggregation in HEWL, while lower QY concentrations (5 and 10 µM) does not have any effect on the aggregation propensity of HEWL. The kinetics of HEWL aggregation demonstrate nucleation independent aggregation of HEWL without lag phase. On the other hand, far UV-CD analysis illustrated the loss of α-helical structure with the increasing concentration of QY. TEM results also support the formation of aggregate structures in HEWL when exposed to QY. Molecular docking and simulation studies revealed that the HEWL-QY complex is stable as compared to individual entities. In silico analysis also illustrated that QY-induced aggregation of HEWL proceeds through the formation of hydrogen bonds, electrostatic (Pi-Anion) and Pi-Sulfur interactions. The above-mentioned results highlight the possible detrimental effect by food additive dyes, particularly in protein misfolding.
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Affiliation(s)
- Mohd Shahnawaz Khan
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Sheraz Bhatt
- Department of Biochemistry, College of Sciences, Cluster University, Srinagar, India
| | - Shams Tabrez
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Md Tabish Rehman
- Department of Pharmacology, Collage of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Majed Saleh Alokail
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Mohamed F AlAjmi
- Department of Pharmacology, Collage of Pharmacy, King Saud University, Riyadh, Saudi Arabia
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10
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Sakalauskas A, Ziaunys M, Smirnovas V. Concentration-dependent polymorphism of insulin amyloid fibrils. PeerJ 2019; 7:e8208. [PMID: 31844588 PMCID: PMC6910113 DOI: 10.7717/peerj.8208] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 11/13/2019] [Indexed: 01/28/2023] Open
Abstract
Protein aggregation into highly structured fibrils has long been associated with several neurodegenerative disorders, such as Alzheimer's or Parkinson's disease. Polymorphism of amyloid fibrils increases the complexity of disease mechanisms and may be one of the reasons for the slow progress in drug research. Here we report protein concentration as another factor leading to polymorphism of insulin amyloid fibrils. Moreover, our data suggests that insulin amyloid conformation can self-replicate only via elongation, while seed-induced nucleation will lead to environment-defined conformation of fibrils. As similar observations were already described for a couple of other amyloid proteins, we suggest it to be a generic mechanism for self-replication of different amyloid fibril conformations.
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Affiliation(s)
- Andrius Sakalauskas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Mantas Ziaunys
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Vytautas Smirnovas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
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11
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Lin Y, Sahoo BR, Ozawa D, Kinoshita M, Kang J, Lim MH, Okumura M, Huh YH, Moon E, Jang JH, Lee HJ, Ryu KY, Ham S, Won HS, Ryu KS, Sugiki T, Bang JK, Hoe HS, Fujiwara T, Ramamoorthy A, Lee YH. Diverse Structural Conversion and Aggregation Pathways of Alzheimer's Amyloid-β (1-40). ACS NANO 2019; 13:8766-8783. [PMID: 31310506 DOI: 10.1021/acsnano.9b01578] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Complex amyloid aggregation of amyloid-β (1-40) (Aβ1-40) in terms of monomer structures has not been fully understood. Herein, we report the microscopic mechanism and pathways of Aβ1-40 aggregation with macroscopic viewpoints through tuning its initial structure and solubility. Partial helical structures of Aβ1-40 induced by low solvent polarity accelerated cytotoxic Aβ1-40 amyloid fibrillation, while predominantly helical folds did not aggregate. Changes in the solvent polarity caused a rapid formation of β-structure-rich protofibrils or oligomers via aggregation-prone helical structures. Modulation of the pH and salt concentration transformed oligomers to protofibrils, which proceeded to amyloid formation. We reveal diverse molecular mechanisms underlying Aβ1-40 aggregation with conceptual energy diagrams and propose that aggregation-prone partial helical structures are key to inducing amyloidogenesis. We demonstrate that context-dependent protein aggregation is comprehensively understood using the macroscopic phase diagram, which provides general insights into differentiation of amyloid formation and phase separation from unfolded and folded structures.
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Affiliation(s)
- Yuxi Lin
- Department of Chemistry , Sookmyung Women's University , Cheongpa-ro 47-gil 100 , Yongsan-gu, Seoul 04310 , South Korea
| | - Bikash R Sahoo
- Biophysics Program and Department of Chemistry, Biomedical Engineering, and Macromolecular Science and Engineering , University of Michigan , Ann Arbor , Michigan 48109-1055 , United States
| | - Daisaku Ozawa
- Department of Neurotherapeutics , Osaka University Graduate School of Medicine , 2-2 Yamadaoka , Suita , Osaka 565-0871 , Japan
| | - Misaki Kinoshita
- Frontier Research Institute for Interdisciplinary Sciences , Tohoku University , 6-3 Aramaki-Aza-Aoba , Aoba-ku, Sendai 980-8578 , Japan
| | - Juhye Kang
- Department of Chemistry , Korea Advanced Institute of Science and Technology , Daejeon 34141 , South Korea
- Department of Chemistry , Ulsan National Institute of Science and Technology , Ulsan 44919 , South Korea
| | - Mi Hee Lim
- Department of Chemistry , Korea Advanced Institute of Science and Technology , Daejeon 34141 , South Korea
| | - Masaki Okumura
- Frontier Research Institute for Interdisciplinary Sciences , Tohoku University , 6-3 Aramaki-Aza-Aoba , Aoba-ku, Sendai 980-8578 , Japan
| | | | | | | | - Hyun-Ju Lee
- Department of Neural Development and Disease , Korea Brain Research Institute , 61 Cheomdan-ro , Dong-gu, Daegu 41068 , South Korea
| | - Ka-Young Ryu
- Department of Neural Development and Disease , Korea Brain Research Institute , 61 Cheomdan-ro , Dong-gu, Daegu 41068 , South Korea
| | - Sihyun Ham
- Department of Chemistry , Sookmyung Women's University , Cheongpa-ro 47-gil 100 , Yongsan-gu, Seoul 04310 , South Korea
| | - Hyung-Sik Won
- Department of Biotechnology, Research Institute and College of Biomedical and Health Science , Konkuk University , Chungju , Chungbuk 27478 , South Korea
| | | | - Toshihiko Sugiki
- Institute for Protein Research , Osaka University , Yamadaoka 3-2 , Suita , Osaka 565-0871 , Japan
| | | | - Hyang-Sook Hoe
- Department of Neural Development and Disease , Korea Brain Research Institute , 61 Cheomdan-ro , Dong-gu, Daegu 41068 , South Korea
| | - Toshimichi Fujiwara
- Institute for Protein Research , Osaka University , Yamadaoka 3-2 , Suita , Osaka 565-0871 , Japan
| | - Ayyalusamy Ramamoorthy
- Biophysics Program and Department of Chemistry, Biomedical Engineering, and Macromolecular Science and Engineering , University of Michigan , Ann Arbor , Michigan 48109-1055 , United States
| | - Young-Ho Lee
- Institute for Protein Research , Osaka University , Yamadaoka 3-2 , Suita , Osaka 565-0871 , Japan
- Bio-Analytical Science , University of Science and Technology , Daejeon 34113 , South Korea
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12
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Chen Y, Xing Z, Liao D, Qiu F. Neglected Hydrophobicity of Dimethanediyl Group in Peptide Self-Assembly: A Hint from Amyloid-like Peptide GNNQQNY and Its Derivatives. J Phys Chem B 2018; 122:10470-10477. [PMID: 30372075 DOI: 10.1021/acs.jpcb.8b09220] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Besides typical hydrophobic amino acids providing hydrophobic interactions, glutamine as a hydrophilic amino acid has also been known to be an important element in many self-assembling peptides, but it is still not clear how this particular amino acid contributes to the self-assembling process. We supposed that the dimethanediyl group in the side chain of glutamine could provide hydrophobic interaction for peptide self-assembly. To prove this hypothesis, we used the GNNQQNY peptide and its derivatives as examples to show the importance of the dimethanediyl group for peptide self-assembly. We found a very close relationship between the number of dimethanediyl groups, the strength of hydrophobic interaction, and the self-assembling ability of the peptides, indicating the hydrophobicity of the dimethanediyl group and its important role for self-assembly. This new finding might be instructive for clarifying the self-assembling mechanism of many natural peptides, as well as for developing novel self-assembling peptide nanomaterials.
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13
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Sulatskaya AI, Rodina NP, Polyakov DS, Sulatsky MI, Artamonova TO, Khodorkovskii MA, Shavlovsky MM, Kuznetsova IM, Turoverov KK. Structural Features of Amyloid Fibrils Formed from the Full-Length and Truncated Forms of Beta-2-Microglobulin Probed by Fluorescent Dye Thioflavin T. Int J Mol Sci 2018; 19:E2762. [PMID: 30223436 PMCID: PMC6164334 DOI: 10.3390/ijms19092762] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 09/04/2018] [Accepted: 09/13/2018] [Indexed: 12/17/2022] Open
Abstract
The persistence of high concentrations of beta-2-microglobulin (β2M) in the blood of patients with acute renal failure leads to the development of the dialysis-related amyloidosis. This disease manifests in the deposition of amyloid fibrils formed from the various forms of β2M in the tissues and biological fluids of patients. In this paper, the amyloid fibrils formed from the full-length β2M (β2m) and its variants that lack the 6 and 10 N-terminal amino acids of the protein polypeptide chain (ΔN6β2m and ΔN10β2m, respectively) were probed by using the fluorescent dye thioflavin T (ThT). For this aim, the tested solutions were prepared via the equilibrium microdialysis approach. Spectroscopic analysis of the obtained samples allowed us to detect one binding mode (type) of ThT interaction with all the studied variants of β2M amyloid fibrils with affinity ~10⁴ M-1. This interaction can be explained by the dye molecules incorporation into the grooves that were formed by the amino acids side chains of amyloid protofibrils along the long axis of the fibrils. The decrease in the affinity and stoichiometry of the dye interaction with β2M fibrils, as well as in the fluorescence quantum yield and lifetime of the bound dye upon the shortening of the protein amino acid sequence were shown. The observed differences in the ThT-β2M fibrils binding parameters and characteristics of the bound dye allowed to prove not only the difference of the ΔN10β2m fibrils from other β2M fibrils (that can be detected visually, for example, by transmission electron microscopy (TEM), but also the differences between β2m and ΔN6β2m fibrils (that can not be unequivocally confirmed by other approaches). These results prove an essential role of N-terminal amino acids of the protein in the formation of the β2M amyloid fibrils. Information about amyloidogenic protein sequences can be claimed in the development of ways to inhibit β2M fibrillogenesis for the treatment of dialysis-related amyloidosis.
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Affiliation(s)
- Anna I Sulatskaya
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology of the Russian Academy of Science, Tikhoretsky ave. 4, St. Petersburg 194064, Russia.
| | - Natalia P Rodina
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology of the Russian Academy of Science, Tikhoretsky ave. 4, St. Petersburg 194064, Russia.
| | - Dmitry S Polyakov
- Department of Molecular Genetics, Institute of Experimental Medicine, Pavlov str. 12, St. Petersburg 197376, Russia.
- Chair of Medical Genetics, North-Western State Medical University named after I.I. Mechnikov, Piskarevskij prospect 47, St. Petersburg 195067, Russia.
| | - Maksim I Sulatsky
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology of the Russian Academy of Science, Tikhoretsky ave. 4, St. Petersburg 194064, Russia.
| | - Tatyana O Artamonova
- Research Center of Nanobiotechnologies, Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya 29, St. Petersburg 195251, Russia.
| | - Mikhail A Khodorkovskii
- Research Center of Nanobiotechnologies, Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya 29, St. Petersburg 195251, Russia.
| | - Mikhail M Shavlovsky
- Department of Molecular Genetics, Institute of Experimental Medicine, Pavlov str. 12, St. Petersburg 197376, Russia.
- Chair of Medical Genetics, North-Western State Medical University named after I.I. Mechnikov, Piskarevskij prospect 47, St. Petersburg 195067, Russia.
| | - Irina M Kuznetsova
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology of the Russian Academy of Science, Tikhoretsky ave. 4, St. Petersburg 194064, Russia.
| | - Konstantin K Turoverov
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology of the Russian Academy of Science, Tikhoretsky ave. 4, St. Petersburg 194064, Russia.
- Institute of Physics, Nanotechnology and Telecommunications, Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya 29, St. Petersburg 195251, Russia.
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Impact of membrane curvature on amyloid aggregation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1741-1764. [PMID: 29709613 DOI: 10.1016/j.bbamem.2018.04.012] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 04/23/2018] [Accepted: 04/25/2018] [Indexed: 12/11/2022]
Abstract
The misfolding, amyloid aggregation, and fibril formation of intrinsically disordered proteins/peptides (or amyloid proteins) have been shown to cause a number of disorders. The underlying mechanisms of amyloid fibrillation and structural properties of amyloidogenic precursors, intermediates, and amyloid fibrils have been elucidated in detail; however, in-depth examinations on physiologically relevant contributing factors that induce amyloidogenesis and lead to cell death remain challenging. A large number of studies have attempted to characterize the roles of biomembranes on protein aggregation and membrane-mediated cell death by designing various membrane components, such as gangliosides, cholesterol, and other lipid compositions, and by using various membrane mimetics, including liposomes, bicelles, and different types of lipid-nanodiscs. We herein review the dynamic effects of membrane curvature on amyloid generation and the inhibition of amyloidogenic proteins and peptides, and also discuss how amyloid formation affects membrane curvature and integrity, which are key for understanding relationships with cell death. Small unilamellar vesicles with high curvature and large unilamellar vesicles with low curvature have been demonstrated to exhibit different capabilities to induce the nucleation, amyloid formation, and inhibition of amyloid-β peptides and α-synuclein. Polymorphic amyloidogenesis in small unilamellar vesicles was revealed and may be viewed as one of the generic properties of interprotein interaction-dominated amyloid formation. Several mechanical models and phase diagrams are comprehensively shown to better explain experimental findings. The negative membrane curvature-mediated mechanisms responsible for the toxicity of pancreatic β cells by the amyloid aggregation of human islet amyloid polypeptide (IAPP) and binding of the precursors of the semen-derived enhancer of viral infection (SEVI) are also described. The curvature-dependent binding modes of several types of islet amyloid polypeptides with high-resolution NMR structures are also discussed.
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15
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Vetri V, Piccirilli F, Krausser J, Buscarino G, Łapińska U, Vestergaard B, Zaccone A, Foderà V. Ethanol Controls the Self-Assembly and Mesoscopic Properties of Human Insulin Amyloid Spherulites. J Phys Chem B 2018; 122:3101-3112. [DOI: 10.1021/acs.jpcb.8b01779] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Valeria Vetri
- Dipartimento di Fisica e Chimica and Advanced Technologies Network Center (ATEN), Università degli Studi di Palermo, Viale delle Scienze ed.18, Palermo 90128, Italy
| | - Federica Piccirilli
- Dipartimento di Fisica e Chimica and Advanced Technologies Network Center (ATEN), Università degli Studi di Palermo, Viale delle Scienze ed.18, Palermo 90128, Italy
| | - Johannes Krausser
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, U.K
| | - Gianpiero Buscarino
- Dipartimento di Fisica e Chimica and Advanced Technologies Network Center (ATEN), Università degli Studi di Palermo, Viale delle Scienze ed.18, Palermo 90128, Italy
| | - Urszula Łapińska
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
| | | | - Alessio Zaccone
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, U.K
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16
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Katina NS, Grigorashvili EI, Suvorina MY, Ilyina NB, Ryabova NA, Selivanova OM, Surin AK. Amyloid Core Wild-Type Apomyoglobin and Its Mutant Variants Is Formed by Different Regions of the Polypeptide Chain. Mol Biol 2018. [DOI: 10.1134/s0026893318010089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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17
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Terakawa MS, Lee YH, Kinoshita M, Lin Y, Sugiki T, Fukui N, Ikenoue T, Kawata Y, Goto Y. Membrane-induced initial structure of α-synuclein control its amyloidogenesis on model membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:757-766. [PMID: 29273335 DOI: 10.1016/j.bbamem.2017.12.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 12/13/2017] [Accepted: 12/14/2017] [Indexed: 12/01/2022]
Abstract
Amyloid fibrillation causes serious neurodegenerative diseases and amyloidosis; however, the detailed mechanisms by which the structural states of precursor proteins in a lipid membrane-associated environment contribute to amyloidogenesis still remains to be elucidated. We examined the relationship between structural states of intrinsically-disordered wild-type and mutant α-synuclein (αSN) and amyloidogenesis on two-types of model membranes. Highly-unstructured wild-type αSN (αSNWT) and a C-terminally-truncated mutant lacking negative charges (αSN103) formed amyloid fibrils on both types of membranes, the model membrane mimicking presynaptic vesicles (Mimic membrane) and the model membrane of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC membrane). Unstructured αSNWT and αSN103 both bound to Mimic membranes in a helical conformation with similar binding affinity. Promotion and then inhibition of amyloidogenesis of αSNWT were observed as the concentration of Mimic lipids increased. We explain this by the two-state binding model: at lower lipid concentrations, binding of αSNWT to membranes enhances amyloidogenicity by increasing the local concentration of membrane-bound αSN and so promoting amyloid nucleation; at higher lipid concentrations, membrane-bound αSNWT is actually in a sense diluted by increasing the number of model membranes, which blocks amyloid fibrillation due to an insufficient bound population for productive nucleation. Meanwhile, αSN103 formed amyloid fibrils over the whole concentration of Mimic lipids used here without inhibition, revealing the importance of helical structures for binding affinity and negatively charged unstructured C-terminal region for modulating amyloidogenesis. We propose that membrane binding-induced initial conformations of αSN, its overall charge states, and the population of membrane-bound αSN are key determinants of amyloidogenesis on membranes.
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Affiliation(s)
- Mayu S Terakawa
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Young-Ho Lee
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Misaki Kinoshita
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Yuxi Lin
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Toshihiko Sugiki
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Naoya Fukui
- Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, Tottori 680-8552, Japan
| | - Tatsuya Ikenoue
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Yasushi Kawata
- Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, Tottori 680-8552, Japan
| | - Yuji Goto
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
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18
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Salt-regulated reversible fibrillation of Mycobacterium tuberculosis isocitrate lyase: Concurrent restoration of structure and activity. Int J Biol Macromol 2017; 104:89-96. [DOI: 10.1016/j.ijbiomac.2017.06.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Revised: 05/30/2017] [Accepted: 06/02/2017] [Indexed: 02/03/2023]
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19
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Kinetics and polymorphs of yeast prion Sup35NM amyloidogenesis. Int J Biol Macromol 2017; 102:1241-1249. [PMID: 28476595 DOI: 10.1016/j.ijbiomac.2017.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 04/14/2017] [Accepted: 05/01/2017] [Indexed: 11/22/2022]
Abstract
Amyloidogenic proteins often form many types of aggregates, which are a critical determinant of cytotoxicity and tissue specificity. However, the molecular mechanisms underlying the generation of distinct amyloids and their influence on cells remain largely unknown. We herein investigated the polymorphic amyloid formation of the yeast prion protein, Sup35NM, an intrinsically disordered N-terminal fragment of Sup35, under various conditions and its potential relationship to cytotoxicity. Sup35NM aggregated to amyloid fibrils with distinct kinetics, structures, morphologies, tinctorial properties, and conformational stabilities depending on the concentration of NaCl, pH, and temperature, indicating the polymorphic amyloidogenesis of Sup35NM. Detailed kinetic analyses of Sup35NM amyloid formation revealed a strong inverse correlation between the lag time and elongation rate without a correlation between kinetic and structural parameters. These results suggest that kinetic polymorphisms due to distinct nucleation and elongation rates result in structural polymorphs of amyloid fibrils, and also that conditions that enhance or inhibit the nucleation of Sup35NM promote or delay fibril growth. The deleterious effects of polymorphic Sup35NM amyloid fibrils on membrane integrity and cell vitality were minimal. We hypothesize that the innocuous polymorphic nature of Sup35NM amyloid fibrils may be beneficial for gaining time for prion infection prior to cell death.
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20
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Synthetic food additive dye “Tartrazine” triggers amorphous aggregation in cationic myoglobin. Int J Biol Macromol 2017; 98:277-286. [DOI: 10.1016/j.ijbiomac.2017.01.097] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 12/27/2016] [Accepted: 01/23/2017] [Indexed: 12/18/2022]
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21
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Shigeto S, Chang CF, Hiramatsu H. Directly Probing Intermolecular Structural Change of a Core Fragment of β 2-Microglobulin Amyloid Fibrils with Low-Frequency Raman Spectroscopy. J Phys Chem B 2017; 121:490-496. [PMID: 28042925 DOI: 10.1021/acs.jpcb.6b10779] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amyloid fibrils, which are ordered aggregates of proteins or peptides, have attracted keen interest because their deposition causes serious human diseases. Despite many studies utilizing X-ray crystallography, solid-state NMR, and other methods, intermolecular interactions governing the fibril formation remain largely unclear. Here, we used low-frequency Raman (LFR) spectroscopy to investigate the intermolecular β-sheet structure of a core fragment of β2-microglobulin amyloid fibrils, β2m21-29, in aqueous buffer solutions. The LFR spectra (approximately 10-200 cm-1) of β2m21-29 amyloid fibrils measured at different pH values (ranging from 6.8 to 8.0) revealed a broad-spectral pattern with a maximum at ∼80 cm-1 below pH 7.2 and at ∼110 cm-1 above pH 7.4. This observation is attributed to a pH-dependent structural change from an antiparallel to a parallel intermolecular β-sheet structure. Multivariate curve resolution-alternating least-squares (MCR-ALS) analysis enabled us to decompose the apparently monotonous LFR spectra into three distinctly different contributions: intermolecular vibrations of the parallel and antiparallel β-sheets and intramolecular vibrations of the peptide backbone. Peak positions of the obtained LFR bands not only exhibit a much more pronounced difference between the two β-sheets than the conventional amide I band, but they also suggest stronger intermolecular interaction, due presumably to the hydrophobic effect, in the parallel β-sheet than in the antiparallel β-sheet. The present results show that LFR spectroscopy in combination with the MCR-ALS analysis holds promise for real-time tracking of the intermolecular dynamics of amyloid fibril formation under physiological conditions.
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Affiliation(s)
- Shinsuke Shigeto
- Department of Applied Chemistry, National Chiao Tung University , Hsinchu 30010, Taiwan
| | - Chun-Fu Chang
- Department of Applied Chemistry, National Chiao Tung University , Hsinchu 30010, Taiwan
| | - Hirotsugu Hiramatsu
- Graduate School of Pharmaceutical Sciences, Tohoku University , Sendai 980-8578, Japan
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22
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Kinoshita M, Kakimoto E, Terakawa MS, Lin Y, Ikenoue T, So M, Sugiki T, Ramamoorthy A, Goto Y, Lee YH. Model membrane size-dependent amyloidogenesis of Alzheimer's amyloid-β peptides. Phys Chem Chem Phys 2017; 19:16257-16266. [DOI: 10.1039/c6cp07774a] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We herein report the mechanism of amyloid formation of amyloid-β (Aβ) peptides on small (SUV) and large unilamellar vesicles (LUVs), which consist of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipids.
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Affiliation(s)
| | - Erina Kakimoto
- Institute for Protein Research
- Osaka University
- Suita
- Japan
| | - Mayu S. Terakawa
- Institute for Protein Research
- Osaka University
- Suita
- Japan
- Department of Biochemistry
| | - Yuxi Lin
- Institute for Protein Research
- Osaka University
- Suita
- Japan
| | - Tatsuya Ikenoue
- Institute for Protein Research
- Osaka University
- Suita
- Japan
- Department of Chemistry
| | - Masatomo So
- Institute for Protein Research
- Osaka University
- Suita
- Japan
| | | | | | - Yuji Goto
- Institute for Protein Research
- Osaka University
- Suita
- Japan
| | - Young-Ho Lee
- Institute for Protein Research
- Osaka University
- Suita
- Japan
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23
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Narang D, Singh A, Swasthi HM, Mukhopadhyay S. Characterization of Salt-Induced Oligomerization of Human β2-Microglobulin at Low pH. J Phys Chem B 2016; 120:7815-23. [PMID: 27467899 DOI: 10.1021/acs.jpcb.6b05619] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Misfolding and amyloid aggregation of human β2-microglobulin (β2m) have been linked to dialysis-related amyloidosis. Previous studies have shown that in the presence of different salt concentrations and at pH 2.5, β2m assembles into aggregates with distinct morphologies. However, the structural and mechanistic details of the aggregation of β2m, giving rise to different morphologies, are poorly understood. In this work, we have extensively characterized the salt-induced oligomers of the acid-unfolded state of β2m using an array of biophysical tools including steady-state and time-resolved fluorescence, circular dichroism, dynamic light scattering, and atomic force microscopy imaging. Fluorescence studies using the oligomer-sensitive molecular rotor, 4-(dicyanovinyl)-julolidine, in conjunction with the light scattering and cross-linking assay indicated that at low salt (NaCl) concentrations β2m exists as a disordered monomer, capable of transforming into ordered amyloid. In the presence of higher concentrations of salt, β2m aggregates into a larger oligomeric species that does not appear to transform into amyloid fibrils. Site-specific fluorescence experiments using single Trp variants of β2m revealed that the middle region of the protein is incorporated into these oligomers, whereas the C-terminal segment is highly exposed to bulk water. Additionally, stopped-flow kinetic experiments indicated that the formation of hydrophobic core and oligomerization occur concomitantly. Our results revealed the distinct pathways by which β2m assembles into oligomers and fibrils.
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Affiliation(s)
- Dominic Narang
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences and ‡Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) , Mohali, Knowledge City, Sector 81, S.A.S. Nagar, Mohali 140306, Punjab, India
| | - Anubhuti Singh
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences and ‡Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) , Mohali, Knowledge City, Sector 81, S.A.S. Nagar, Mohali 140306, Punjab, India
| | - Hema M Swasthi
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences and ‡Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) , Mohali, Knowledge City, Sector 81, S.A.S. Nagar, Mohali 140306, Punjab, India
| | - Samrat Mukhopadhyay
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences and ‡Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) , Mohali, Knowledge City, Sector 81, S.A.S. Nagar, Mohali 140306, Punjab, India
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24
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Crespo R, Villar-Alvarez E, Taboada P, Rocha FA, Damas AM, Martins PM. What Can the Kinetics of Amyloid Fibril Formation Tell about Off-pathway Aggregation? J Biol Chem 2015; 291:2018-2032. [PMID: 26601940 DOI: 10.1074/jbc.m115.699348] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Indexed: 11/06/2022] Open
Abstract
Some of the most prevalent neurodegenerative diseases are characterized by the accumulation of amyloid fibrils in organs and tissues. Although the pathogenic role of these fibrils has not been completely established, increasing evidence suggests off-pathway aggregation as a source of toxic/detoxicating deposits that still remains to be targeted. The present work is a step toward the development of off-pathway modulators using the same amyloid-specific dyes as those conventionally employed to screen amyloid inhibitors. We identified a series of kinetic signatures revealing the quantitative importance of off-pathway aggregation relative to amyloid fibrillization; these include non-linear semilog plots of amyloid progress curves, highly variable end point signals, and half-life coordinates weakly influenced by concentration. Molecules that attenuate/intensify the magnitude of these signals are considered promising off-pathway inhibitors/promoters. An illustrative example shows that amyloid deposits of lysozyme are only the tip of an iceberg hiding a crowd of insoluble aggregates. Thoroughly validated using advanced microscopy techniques and complementary measurements of dynamic light scattering, CD, and soluble protein depletion, the new analytical tools are compatible with the high-throughput methods currently employed in drug discovery.
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Affiliation(s)
- Rosa Crespo
- From the Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia, Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Eva Villar-Alvarez
- the Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, 15782 Spain, and
| | - Pablo Taboada
- the Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, 15782 Spain, and
| | - Fernando A Rocha
- From the Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia, Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Ana M Damas
- the Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal
| | - Pedro M Martins
- From the Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia, Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal,; the Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal.
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25
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Early aggregation preceding the nucleation of insulin amyloid fibrils as monitored by small angle X-ray scattering. Sci Rep 2015; 5:15485. [PMID: 26503463 PMCID: PMC4621412 DOI: 10.1038/srep15485] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 09/28/2015] [Indexed: 01/09/2023] Open
Abstract
The nucleation event of amyloid fibrils is one of the most crucial processes that dictate the timing and rate of the pathology of diseases; however, information regarding how protein molecules associate to produce fibril nuclei is currently limited. In order to explore this issue in more detail, we performed time-resolved small angle X-ray scattering (SAXS) measurements on insulin fibrillation, in combination with additional multidirectional analyses of thioflavin T fluorescence, FTIR spectroscopy, light scattering, and light transmittance, during the fibrillation process of bovine insulin. SAXS monitoring revealed that insulin molecules associated into rod-like prefibrillar aggregates in the very early stage of the reaction. After the formation of these early aggregates, they appeared to further coalesce mutually to form larger clusters, and the SAXS profiles subsequently showed the further time evolution of conformational development towards mature amyloid fibrils. Distinct types of structural units in terms of shape in a nano-scale order, cross-β content, and thioflavin T fluorescence intensity were observed in a manner that was dependent on the fibrillation pathways. These results suggest the presence of diverse substructures that characterize various fibrillation pathways, and eventually, manifest polymorphisms in mature amyloid fibrils.
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26
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Abstract
Prions are infective proteins, which can self-assemble into different strain conformations, leading to different disease phenotypes. An increasing number of studies suggest that prion-like self-propagation may be a common feature of amyloid-like structures. Thus it is important to unravel every possible factor leading to the formation of different amyloid strains. Here we report on the formation of two types of insulin amyloid-like fibrils with distinct infrared spectroscopic features grown under slightly different pH conditions. Similar to prion strains, both insulin fibril types are able to self-propagate their conformational template under conditions, favoring spontaneous formation of different type fibrils. The low-pH-induced insulin amyloid strain is structurally very similar to previously reported strains formed either in the presence of 20% ethanol, or by modification of the amino acid sequence of insulin. A deeper analysis of literature data in the context of our current findings suggests a shift of the monomer-dimer equilibrium of insulin as a possible factor controlling the formation of different strains.
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27
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Sneideris T, Milto K, Smirnovas V. Polymorphism of amyloid-like fibrils can be defined by the concentration of seeds. PeerJ 2015; 3:e1207. [PMID: 26355941 PMCID: PMC4563235 DOI: 10.7717/peerj.1207] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 08/01/2015] [Indexed: 12/11/2022] Open
Abstract
Prions are infectious proteins where the same protein may express distinct strains. The strains are enciphered by different misfolded conformations. Strain-like phenomena have also been reported in a number of other amyloid-forming proteins. One of the features of amyloid strains is the ability to self-propagate, maintaining a constant set of physical properties despite being propagated under conditions different from those that allowed initial formation of the strain. Here we report a cross-seeding experiment using strains formed under different conditions. Using high concentrations of seeds results in rapid elongation and new fibrils preserve the properties of the seeding fibrils. At low seed concentrations, secondary nucleation plays the major role and new fibrils gain properties predicted by the environment rather than the structure of the seeds. Our findings could explain conformational switching between amyloid strains observed in a wide variety of in vivo and in vitro experiments.
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Affiliation(s)
- Tomas Sneideris
- Department of Biothermodynamics and Drug Design, Vilnius University, Institute of Biotechnology, Vilnius, Lithuania
| | - Katažyna Milto
- Department of Biothermodynamics and Drug Design, Vilnius University, Institute of Biotechnology, Vilnius, Lithuania
| | - Vytautas Smirnovas
- Department of Biothermodynamics and Drug Design, Vilnius University, Institute of Biotechnology, Vilnius, Lithuania
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28
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Choi TS, Lee JW, Jin KS, Kim HI. Amyloid fibrillation of insulin under water-limited conditions. Biophys J 2015; 107:1939-1949. [PMID: 25418175 DOI: 10.1016/j.bpj.2014.09.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 08/01/2014] [Accepted: 09/10/2014] [Indexed: 02/08/2023] Open
Abstract
Amyloid fibrillation in water-organic mixtures has been widely studied to understand the effect of protein-solvent interactions on the fibrillation process. In this study, we monitored insulin fibrillation in formamide and its methyl derivatives (formamide, N-methyl formamide, N,N-dimethyl formamide) in the presence and absence of water. These model solvent systems mimic the cellular environment by providing denaturing conditions and a hydrophobic environment with limited water content. Thioflavin T (ThT) assay revealed that binary mixtures of water with formamide and its methyl derivatives enhanced fibrillation rates and ?-sheet abundance, whereas organic solvents suppressed insulin fibrillation. We utilized solution small-angle x-ray scattering (SAXS) and differential scanning calorimetry (DSC) to investigate the correlation between protein-solvent interactions and insulin fibrillation. SAXS experiments combined with simulated annealing of the protein indicated that the degree of denaturation of the hydrophobic core region at residues B11-B17 determines the fibrillation rate. In addition, DSC experiments suggested a crucial role of hydrophobic interactions in the fibrillation process. These results imply that an environment with limited water, which imitates a lipid membrane system, accelerates protein denaturation and the formation of intermolecular hydrophobic interactions during amyloid fibrillation.
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Affiliation(s)
- Tae Su Choi
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Jong Wha Lee
- Pohang Accelerator Laboratory, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Kyeong Sik Jin
- Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Hugh I Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea; Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea.
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29
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Curtain CC, Kirby NM, Mertens HDT, Barnham KJ, Knott RB, Masters CL, Cappai R, Rekas A, Kenche VB, Ryan T. Alpha-synuclein oligomers and fibrils originate in two distinct conformer pools: a small angle X-ray scattering and ensemble optimisation modelling study. MOLECULAR BIOSYSTEMS 2015; 11:190-6. [DOI: 10.1039/c4mb00356j] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Size exclusion chromatography with small angle X-ray scattering and ensemble optimisation modelling reveals conformers in random pool of α-synuclein.
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Affiliation(s)
- Cyril C. Curtain
- Department of Pathology and Bio21 Molecular Science and Technology Institute
- The University of Melbourne
- Victoria 3010
- Australia
- The University of Melbourne
| | - Nigel M. Kirby
- SAXS/WAXS Beamline
- The Australian Synchrotron
- Clayton
- Australia
| | | | - Kevin J. Barnham
- Department of Pathology and Bio21 Molecular Science and Technology Institute
- The University of Melbourne
- Victoria 3010
- Australia
- The University of Melbourne
| | - Robert B. Knott
- Australian Nuclear Science and Technology Organisation (ANSTO)
- Kirrawee
- Australia
| | - Colin L. Masters
- The University of Melbourne
- Florey Institute of Neuroscience and Mental Health
- Victoria 3010
- Australia
| | - Roberto Cappai
- Department of Pathology and Bio21 Molecular Science and Technology Institute
- The University of Melbourne
- Victoria 3010
- Australia
| | - Agata Rekas
- Australian Nuclear Science and Technology Organisation (ANSTO)
- Kirrawee
- Australia
| | - Vijaya B. Kenche
- The University of Melbourne
- Florey Institute of Neuroscience and Mental Health
- Victoria 3010
- Australia
| | - Timothy Ryan
- The University of Melbourne
- Florey Institute of Neuroscience and Mental Health
- Victoria 3010
- Australia
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30
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Garcia-Pardo J, Graña-Montes R, Fernandez-Mendez M, Ruyra A, Roher N, Aviles FX, Lorenzo J, Ventura S. Amyloid formation by human carboxypeptidase D transthyretin-like domain under physiological conditions. J Biol Chem 2014; 289:33783-96. [PMID: 25294878 DOI: 10.1074/jbc.m114.594804] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein aggregation is linked to a growing list of diseases, but it is also an intrinsic property of polypeptides, because the formation of functional globular proteins comes at the expense of an inherent aggregation propensity. Certain proteins can access aggregation-prone states from native-like conformations without the need to cross the energy barrier for unfolding. This is the case of transthyretin (TTR), a homotetrameric protein whose dissociation into its monomers initiates the aggregation cascade. Domains with structural homology to TTR exist in a number of proteins, including the M14B subfamily carboxypeptidases. We show here that the monomeric transthyretin-like domain of human carboxypeptidase D aggregates under close to physiological conditions into amyloid structures, with the population of folded but aggregation-prone states being controlled by the conformational stability of the domain. We thus confirm that the TTR fold keeps a generic residual aggregation propensity upon folding, resulting from the presence of preformed amyloidogenic β-strands in the native state. These structural elements should serve for functional/structural purposes, because they have not been purged out by evolution, but at the same time they put proteins like carboxypeptidase D at risk of aggregation in biological environments and thus can potentially lead to deposition diseases.
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Affiliation(s)
- Javier Garcia-Pardo
- From the Institut de Biotecnologia i Biomedicina, Departaments de Bioquimica i Biologia Molecular and
| | - Ricardo Graña-Montes
- From the Institut de Biotecnologia i Biomedicina, Departaments de Bioquimica i Biologia Molecular and
| | - Marc Fernandez-Mendez
- From the Institut de Biotecnologia i Biomedicina, Departaments de Bioquimica i Biologia Molecular and
| | - Angels Ruyra
- From the Institut de Biotecnologia i Biomedicina
| | - Nerea Roher
- From the Institut de Biotecnologia i Biomedicina, Biologia Cel·lular, Immunologia i Fisiologia Animal, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Francesc X Aviles
- From the Institut de Biotecnologia i Biomedicina, Departaments de Bioquimica i Biologia Molecular and
| | - Julia Lorenzo
- From the Institut de Biotecnologia i Biomedicina, Departaments de Bioquimica i Biologia Molecular and
| | - Salvador Ventura
- From the Institut de Biotecnologia i Biomedicina, Departaments de Bioquimica i Biologia Molecular and
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31
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Lin Y, Lee YH, Yoshimura Y, Yagi H, Goto Y. Solubility and supersaturation-dependent protein misfolding revealed by ultrasonication. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:1845-1854. [PMID: 24059752 DOI: 10.1021/la403100h] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Although alcohols are useful cosolvents for producing amyloid fibrils, the underlying mechanism of alcohol-dependent fibrillation is unclear. We studied the alcohol-induced fibrillation of hen egg-white lysozyme at various concentrations of ethanol, 2,2,2-trifluoroethanol (TFE), and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP). Under the conditions where the alcohol-denatured lysozyme retained metastability, ultrasonication effectively triggered fibrillation. The optimal alcohol concentration depended on the alcohol species. HFIP showed a sharp maximum at 12-16%. For TFE, a broad maximum at 40-80% was observed. Ethanol exhibited only an increase in fibrillation above 60%. These profiles were opposite to the equilibrium solubility of lysozyme in water/alcohol mixtures. The results indicate that although fibrillation is determined by solubility, supersaturation prevents conformational transitions and ultrasonication is highly effective in minimizing an effect of supersaturation. We propose an alcohol-dependent protein misfolding funnel useful for examining amyloidogenicity. This misfolding funnel will apply to fibrillation under physiological conditions where biological environments play important roles in decreasing the solubility.
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Affiliation(s)
- Yuxi Lin
- Institute for Protein Research, Osaka University , 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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32
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Relini A, Marano N, Gliozzi A. Misfolding of amyloidogenic proteins and their interactions with membranes. Biomolecules 2013; 4:20-55. [PMID: 24970204 PMCID: PMC4030986 DOI: 10.3390/biom4010020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 12/13/2013] [Accepted: 12/17/2013] [Indexed: 01/07/2023] Open
Abstract
In this paper, we discuss amyloidogenic proteins, their misfolding, resulting structures, and interactions with membranes, which lead to membrane damage and subsequent cell death. Many of these proteins are implicated in serious illnesses such as Alzheimer’s disease and Parkinson’s disease. Misfolding of amyloidogenic proteins leads to the formation of polymorphic oligomers and fibrils. Oligomeric aggregates are widely thought to be the toxic species, however, fibrils also play a role in membrane damage. We focus on the structure of these aggregates and their interactions with model membranes. Study of interactions of amlyoidogenic proteins with model and natural membranes has shown the importance of the lipid bilayer in protein misfolding and aggregation and has led to the development of several models for membrane permeabilization by the resulting amyloid aggregates. We discuss several of these models: formation of structured pores by misfolded amyloidogenic proteins, extraction of lipids, interactions with receptors in biological membranes, and membrane destabilization by amyloid aggregates perhaps analogous to that caused by antimicrobial peptides.
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Affiliation(s)
- Annalisa Relini
- Department of Physics, University of Genoa, Genoa 16146, Italy.
| | - Nadia Marano
- Department of Physics, University of Genoa, Genoa 16146, Italy.
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33
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Cobb NJ, Apostol MI, Chen S, Smirnovas V, Surewicz WK. Conformational stability of mammalian prion protein amyloid fibrils is dictated by a packing polymorphism within the core region. J Biol Chem 2013; 289:2643-50. [PMID: 24338015 DOI: 10.1074/jbc.m113.520718] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Mammalian prion strains are believed to arise from the propagation of distinct conformations of the misfolded prion protein PrP(Sc). One key operational parameter used to define differences between strains has been conformational stability of PrP(Sc) as defined by resistance to thermal and/or chemical denaturation. However, the structural basis of these stability differences is unknown. To bridge this gap, we have generated two strains of recombinant human prion protein amyloid fibrils that show dramatic differences in conformational stability and have characterized them by a number of biophysical methods. Backbone amide hydrogen/deuterium exchange experiments revealed that, in sharp contrast to previously studied strains of infectious amyloid formed from the yeast prion protein Sup35, differences in β-sheet core size do not underlie differences in conformational stability between strains of mammalian prion protein amyloid. Instead, these stability differences appear to be dictated by distinct packing arrangements (i.e. steric zipper interfaces) within the amyloid core, as indicated by distinct x-ray fiber diffraction patterns and large strain-dependent differences in hydrogen/deuterium exchange kinetics for histidine side chains within the core region. Although this study was limited to synthetic prion protein amyloid fibrils, a similar structural basis for strain-dependent conformational stability may apply to brain-derived PrP(Sc), especially because large strain-specific differences in PrP(Sc) stability are often observed despite a similar size of the PrP(Sc) core region.
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34
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Torbeev VY, Hilvert D. Both the cis-trans equilibrium and isomerization dynamics of a single proline amide modulate β2-microglobulin amyloid assembly. Proc Natl Acad Sci U S A 2013; 110:20051-6. [PMID: 24262149 PMCID: PMC3864314 DOI: 10.1073/pnas.1310414110] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The human protein β2-microglobulin (β2m) aggregates as amyloid fibrils in patients undergoing long-term hemodialysis. Isomerization of Pro32 from its native cis to a nonnative trans conformation is thought to trigger β2m misfolding and subsequent amyloid assembly. To examine this hypothesis, we systematically varied the free-energy profile of proline cis-trans isomerization by replacing Pro32 with a series of 4-fluoroprolines via total chemical synthesis. We show that β2m's stability, (un)folding, and aggregation properties are all influenced by the rate and equilibrium of Pro32 cis-trans isomerization. As anticipated, the β2m monomer was either stabilized or destabilized by respective incorporation of (2S,4S)-fluoroproline, which favors the native cis amide bond, or the stereoisomeric (2S,4R)-fluoroproline, which disfavors this conformation. However, substitution of Pro32 with 4,4-difluoroproline, which has nearly the same cis-trans preference as proline but an enhanced isomerization rate, caused pronounced destabilization of the protein and increased oligomerization at neutral pH. More remarkably, these subtle alterations in chemical composition--incorporation of one or two fluorine atoms into a single proline residue in the 99 amino acid long protein--modulated the aggregation properties of β2m, inducing the formation of polymorphically distinct amyloid fibrils. These results highlight the importance of conformational dynamics for molecular assembly of an amyloid cross-β structure and provide insights into mechanistic aspects of Pro32 cis-trans isomerism in β2m aggregation.
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Affiliation(s)
| | - Donald Hilvert
- Laboratory of Organic Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland
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35
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Trifluoroethanol modulates amyloid formation by the all α-helical URN1 FF domain. Int J Mol Sci 2013; 14:17830-44. [PMID: 23999589 PMCID: PMC3794755 DOI: 10.3390/ijms140917830] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 08/07/2013] [Accepted: 08/26/2013] [Indexed: 01/11/2023] Open
Abstract
Amyloid fibril formation is implicated in different human diseases. The transition between native α-helices and nonnative intermolecular β-sheets has been suggested to be a trigger of fibrillation in different conformational diseases. The FF domain of the URN1 splicing factor (URN1-FF) is a small all-α protein that populates a molten globule (MG) at low pH. Despite the fact that this conformation maintains most of the domain native secondary structure, it progressively converts into β-sheet enriched and highly ordered amyloid fibrils. In this study, we investigated if 2,2,2-trifluoroethanol (TFE) induced conformational changes that affect URN1-FF amyloid formation. Despite TFE having been shown to induce or increase the aggregation of both globular and disordered proteins at moderate concentrations, we demonstrate here that in the case of URN1-FF it reinforces its intrinsic α-helical structure, which competes the formation of aggregated assemblies. In addition, we show that TFE induces conformational diversity in URN1-FF fibrils, in such a way that the fibrils formed in the presence and absence of the cosolvent represent different polymorphs. It is suggested that the effect of TFE on both the soluble and aggregated states of URN1-FF depends on its ability to facilitate hydrogen bonding.
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36
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Bhat V, Olenick MB, Schuchardt BJ, Mikles DC, Deegan BJ, McDonald CB, Seldeen KL, Kurouski D, Faridi MH, Shareef MM, Gupta V, Lednev IK, Farooq A. Heat-induced fibrillation of BclXL apoptotic repressor. Biophys Chem 2013; 179:12-25. [PMID: 23714425 DOI: 10.1016/j.bpc.2013.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 04/24/2013] [Accepted: 04/30/2013] [Indexed: 12/18/2022]
Abstract
The BclXL apoptotic repressor bears the propensity to associate into megadalton oligomers in solution, particularly under acidic pH. Herein, using various biophysical methods, we analyze the effect of temperature on the oligomerization of BclXL. Our data show that BclXL undergoes irreversible aggregation and assembles into highly-ordered rope-like homogeneous fibrils with length in the order of mm and a diameter in the μm-range under elevated temperatures. Remarkably, the formation of such fibrils correlates with the decay of a largely α-helical fold into a predominantly β-sheet architecture of BclXL in a manner akin to the formation of amyloid fibrils. Further interrogation reveals that while BclXL fibrils formed under elevated temperatures show no observable affinity toward BH3 ligands, they appear to be optimally primed for insertion into cardiolipin bicelles. This salient observation strongly argues that BclXL fibrils likely represent an on-pathway intermediate for insertion into mitochondrial outer membrane during the onset of apoptosis. Collectively, our study sheds light on the propensity of BclXL to form amyloid-like fibrils with important consequences on its mechanism of action in gauging the apoptotic fate of cells in health and disease.
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Affiliation(s)
- Vikas Bhat
- Department of Biochemistry & Molecular Biology, Leonard Miller School of Medicine, University of Miami, Miami, FL 33136, USA
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