1
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Bini M, Tozzini V, Brancolini G. Deconstructing Electrostatics of Functionalized Metal Nanoparticles from Molecular Dynamics Simulations. J Phys Chem B 2023; 127:8226-8241. [PMID: 37714525 PMCID: PMC10544014 DOI: 10.1021/acs.jpcb.3c03481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/31/2023] [Indexed: 09/17/2023]
Abstract
Gold nanoparticles (NPs) with different surface functionalizations can selectively interact with specific proteins, allowing a wide range of possible applications in biotechnology and biomedicine. To prevent their tendency to aggregate and to modulate their interaction with charged biomolecules or substrates (e.g., for biosensing applications), they can be functionalized with charged groups, introducing a mutual interaction which can be modulated by changing the ionic strength of the solvent. In silico modeling of these systems is often addressed with low-resolution models, which must account for these effects in the, often implicit, solvent representation. Here, we present a systematic conformational dynamic characterization of ligand-coated gold nanoparticles with different sizes, charges, and functionalizations by means of atomistic molecular dynamics simulations. Based on these, we deconstruct their electrostatic properties and propose a general representation of their average-long-range interactions extendable to different sizes, charges, and ionic strengths. This study clarifies in detail the role of the different features of the NP (charge, size, structure) and of the ionic strength in determining the details of the interparticle interaction and represents the first step toward a general strategy for the parametrization of NP coarse-grained models able to account for varying ionic strengths.
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2
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Nash S, Vachet RW. Gas-Phase Unfolding of Protein Complexes Distinguishes Conformational Isomers. J Am Chem Soc 2022; 144:22128-22139. [PMID: 36414315 DOI: 10.1021/jacs.2c09573] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Proteins can adopt different conformational states that are important for their biological function and, in some cases, can be responsible for their dysfunction. The essential roles that proteins play in biological systems make distinguishing the structural differences between these conformational states both fundamentally and practically important. Here, we demonstrate that collision-induced unfolding (CIU), in combination with ion mobility-mass spectrometry (IM-MS) measurements, distinguish subtly different conformational states for protein complexes. Using the open and closed states of the β-lactoglobulin (βLG) dimer as a model, we show that these two conformational isomers unfold during collisional activation to generate distinct states that are readily separated by IM-MS. Extensive molecular modeling of the CIU process reproduces the distinct unfolding intermediates and identifies the molecular details that explain why the two conformational states unfold in distinct ways. Strikingly, the open conformational state forms new electrostatic interactions upon collisional heating, while the closed state does not. These newly formed electrostatic interactions involve residues on the loop differentially positioned in the two βLG conformational isomers, highlighting that gas-phase unfolding pathways reflect aspects of solution structure. This combination of experiment and theory provides a path forward for distinguishing subtly different conformational isomers for protein complexes via gas-phase unfolding experiments. Our results also have implications for understanding how protein complexes dissociate in the gas phase, indicating that current models need to be refined to explain protein complex dissociation.
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Affiliation(s)
- Stacey Nash
- Molecular and Cellular Biology Program, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Richard W Vachet
- Molecular and Cellular Biology Program, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States.,Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003 United States
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3
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Ahmad A, Mishra R. Polyol and sugar osmolytes stabilize the molten globule state of α-lactalbumin and inhibit amyloid fibril formation. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2022; 1870:140853. [PMID: 36096464 DOI: 10.1016/j.bbapap.2022.140853] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 08/29/2022] [Accepted: 09/02/2022] [Indexed: 06/15/2023]
Abstract
Protein misfolding and aggregation are associated with several human diseases such as Alzheimer's, Parkinson's, prion related disorders, type-II diabetes, etc. Different strategies using molecular chaperones, synthetic and naturally occurring small molecules, osmolytes, etc. have been used to prevent protein aggregation and amyloid fibril formation. In this study, we have used bovine α-lactalbumin at pH 1.6, 37 °C, and shaking conditions to promote amyloid fibril formation. Polyol and sugar osmolytes like glycerol, sorbitol, and trehalose have been used to inhibit the fibrillation of a number of proteins. In the present work, amyloid fibril formation of α-lactalbumin has been shown by ThT assay and AFM, while changes in the secondary structure during fibrillation has been followed by circular dichroism spectroscopy. Our results show that glycerol, sorbitol, and trehalose affect amyloid fibril formation of α-lactalbumin in a concentration-dependent manner. There is a delay in the lag phase of amyloid fibril formation in sorbitol and trehalose and complete inhibition in 6 M glycerol. Our results indicate that delay in the lag phase and inhibition of amyloid fibril formation are due to the stabilization of molten globule state by these osmolytes. At pH 1.6, the molten globule as well as the amyloid fibrils bind to ANS. However, when pH was shifted from 1.6 to 7, only the oligomeric and the fibrillar species bind to ANS due to refolding of molten globule state. The outcome of this study might be useful in designing small molecules which may stabilize the intermediate states, thus preventing amyloid fibril formation.
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Affiliation(s)
- Aziz Ahmad
- School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Rajesh Mishra
- School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India.
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4
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Maya-Martinez R, Xu Y, Guthertz N, Walko M, Karamanos TK, Sobott F, Breeze AL, Radford SE. Dimers of D76N-β 2-microglobulin display potent antiamyloid aggregation activity. J Biol Chem 2022; 298:102659. [PMID: 36328246 PMCID: PMC9712992 DOI: 10.1016/j.jbc.2022.102659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 10/20/2022] [Accepted: 10/28/2022] [Indexed: 11/05/2022] Open
Abstract
Self-association of WT β2-microglobulin (WT-β2m) into amyloid fibrils is associated with the disorder dialysis related amyloidosis. In the familial variant D76N-β2m, the single amino acid substitution enhances the aggregation propensity of the protein dramatically and gives rise to a disorder that is independent of renal dysfunction. Numerous biophysical and structural studies on WT- and D76N-β2m have been performed in order to better understand the structure and dynamics of the native proteins and their different potentials to aggregate into amyloid. However, the structural properties of transient D76N-β2m oligomers and their role(s) in assembly remained uncharted. Here, we have utilized NMR methods, combined with photo-induced crosslinking, to detect, trap, and structurally characterize transient dimers of D76N-β2m. We show that the crosslinked D76N-β2m dimers have different structures from those previously characterized for the on-pathway dimers of ΔN6-β2m and are unable to assemble into amyloid. Instead, the crosslinked D76N-β2m dimers are potent inhibitors of amyloid formation, preventing primary nucleation and elongation/secondary nucleation when added in substoichiometric amounts with D76N-β2m monomers. The results highlight the specificity of early protein-protein interactions in amyloid formation and show how mapping these interfaces can inform new strategies to inhibit amyloid assembly.
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Affiliation(s)
- Roberto Maya-Martinez
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Yong Xu
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Nicolas Guthertz
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Martin Walko
- Astbury Centre for Structural Molecular Biology, School of Chemistry, University of Leeds, Leeds, United Kingdom
| | - Theodoros K Karamanos
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Frank Sobott
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Alexander L Breeze
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom.
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5
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Bini M, Brancolini G, Tozzini V. Aggregation behavior of nanoparticles: Revisiting the phase diagram of colloids. Front Mol Biosci 2022; 9:986223. [PMID: 36200074 PMCID: PMC9527328 DOI: 10.3389/fmolb.2022.986223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 08/01/2022] [Indexed: 11/16/2022] Open
Abstract
Surface functionalization of metal nanoparticles (NPs), e.g., using peptides and proteins, has recently attracted a considerable attention in the field of design of therapeutics and diagnostics. The possibility of diverse functionalization allows them to selectively interact with proteins, while the metal core ensures solubility, making them tunable therapeutic agents against diseases due to mis-folding or aggregation. On the other hand, their action is limited by possible self-aggregation, which could be, however, prevented based on the full understanding of their phase diagram as a function of the environmental variables (temperature, ionic strength of the solution, concentration) and intrinsic characteristics (size, charge, amount, and type of functional groups). A common modeling strategy to study the phase behavior is to represent the NPs as spheres interacting via effective potentials implicitly accounting for the solvation effects. Their size put the NPs into the class of colloids, albeit with particularly complex interactions including both attractive and repulsive features, and a consequently complex phase diagram. In this work, we review the studies exploring the phases of these systems starting from those with only attractive or repulsive interactions, displaying a simpler disperse-clustered-aggregated transitions. The phase diagram is here interpreted focusing on the universal aspects, i.e., those dependent on the general feature of the potentials, and available data are organized in a parametric phase diagram. We then consider the potentials with competing attractive short range well and average-long-range repulsive tail, better representing the NPs. Through the proper combination of the attractive only and repulsive only potentials, we are able to interpret the appearance of novel phases, characterized by aggregates with different structural characteristics. We identify the essential parameters that stabilize the disperse phase potentially useful to optimize NP therapeutic activity and indicate how to tune the phase behavior by changing environmental conditions or the NP chemical–physical properties.
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Affiliation(s)
| | - Giorgia Brancolini
- Istituto Nanoscienze—CNR, Center S3, Modena, Italy
- *Correspondence: Giorgia Brancolini,
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6
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Bizat N, Parrales V, Laoues S, Normant S, Levavasseur E, Roussel J, Privat N, Gougerot A, Ravassard P, Beaudry P, Brandel JP, Laplanche JL, Haïk S. An in vivo Caenorhabditis elegans model for therapeutic research in human prion diseases. Brain 2021; 144:2745-2758. [PMID: 34687213 DOI: 10.1093/brain/awab152] [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: 11/04/2020] [Revised: 02/11/2021] [Accepted: 02/27/2021] [Indexed: 11/12/2022] Open
Abstract
Human prion diseases are fatal neurodegenerative disorders that include sporadic, infectious and genetic forms. Inherited Creutzfeldt-Jakob disease due to the E200K mutation of the prion protein-coding gene is the most common form of genetic prion disease. The phenotype resembles that of sporadic Creutzfeldt-Jakob disease at both the clinical and pathological levels, with a median disease duration of 4 months. To date, there is no available treatment for delaying the occurrence or slowing the progression of human prion diseases. Existing in vivo models do not allow high-throughput approaches that may facilitate the discovery of compounds targeting pathological assemblies of human prion protein or their effects on neuronal survival. Here, we generated a genetic model in the nematode Caenorhabditis elegans, which is devoid of any homologue of the prion protein, by expressing human prion protein with the E200K mutation in the mechanosensitive neuronal system. Expression of E200K prion protein induced a specific behavioural pattern and neurodegeneration of green fluorescent protein-expressing mechanosensitive neurons, in addition to the formation of intraneuronal inclusions associated with the accumulation of a protease-resistant form of the prion protein. We demonstrated that this experimental system is a powerful tool for investigating the efficacy of anti-prion compounds on both prion-induced neurodegeneration and prion protein misfolding, as well as in the context of human prion protein. Within a library of 320 compounds that have been approved for human use and cross the blood-brain barrier, we identified five molecules that were active against the aggregation of the E200K prion protein and the neurodegeneration it induced in transgenic animals. This model breaks a technological limitation in prion therapeutic research and provides a key tool to study the deleterious effects of misfolded prion protein in a well-described neuronal system.
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Affiliation(s)
- Nicolas Bizat
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne University, Hospital Pitié-Salpêtrière, F-75013 Paris, France.,Faculté de Pharmacie de Paris, Paris University, Paris F-75006, France
| | - Valeria Parrales
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne University, Hospital Pitié-Salpêtrière, F-75013 Paris, France
| | - Sofian Laoues
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne University, Hospital Pitié-Salpêtrière, F-75013 Paris, France
| | - Sébastien Normant
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne University, Hospital Pitié-Salpêtrière, F-75013 Paris, France
| | - Etienne Levavasseur
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne University, Hospital Pitié-Salpêtrière, F-75013 Paris, France
| | - Julian Roussel
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne University, Hospital Pitié-Salpêtrière, F-75013 Paris, France
| | - Nicolas Privat
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne University, Hospital Pitié-Salpêtrière, F-75013 Paris, France
| | - Alexianne Gougerot
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne University, Hospital Pitié-Salpêtrière, F-75013 Paris, France
| | - Philippe Ravassard
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne University, Hospital Pitié-Salpêtrière, F-75013 Paris, France
| | - Patrice Beaudry
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne University, Hospital Pitié-Salpêtrière, F-75013 Paris, France
| | - Jean-Philippe Brandel
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne University, Hospital Pitié-Salpêtrière, F-75013 Paris, France.,AP-HP, Cellule Nationale de Référence des Maladies de Creutzfeldt-Jakob, University Hospital Pitié-Salpêtrière, Paris F-75013, France
| | - Jean-Louis Laplanche
- Faculté de Pharmacie de Paris, Paris University, Paris F-75006, France.,Inserm, UMR-S 1144, Paris F-75006, France
| | - Stéphane Haïk
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne University, Hospital Pitié-Salpêtrière, F-75013 Paris, France.,AP-HP, Cellule Nationale de Référence des Maladies de Creutzfeldt-Jakob, University Hospital Pitié-Salpêtrière, Paris F-75013, France
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7
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Marcinko TM, Drews T, Liu T, Vachet RW. Epigallocatechin-3-gallate Inhibits Cu(II)-Induced β-2-Microglobulin Amyloid Formation by Binding to the Edge of Its β-Sheets. Biochemistry 2020; 59:1093-1103. [PMID: 32100530 DOI: 10.1021/acs.biochem.0c00043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Epigallocatechin-3-gallate (EGCG) is a catechin found in green tea that can inhibit the amyloid formation of a wide variety of proteins. EGCG's ability to prevent or redirect the amyloid formation of so many proteins may reflect a common mechanism of action, and thus, greater molecular-level insight into how it exerts its effect could have broad implications. Here, we investigate the molecular details of EGCG's inhibition of the protein β-2-microglobulin (β2m), which forms amyloids in patients undergoing long-term dialysis treatment. Using size-exclusion chromatography and a collection of mass spectrometry-based techniques, we find that EGCG prevents Cu(II)-induced β2m amyloid formation by diverting the normal progression of preamyloid oligomers toward the formation of spherical, redissolvable aggregates. EGCG exerts its effect by binding with a micromolar affinity (Kd ≈ 5 μM) to the β2m monomer on the edge of two β-sheets near the N-terminus. This interaction destabilizes the preamyloid dimer and prevents the formation of a tetramer species previously shown to be essential for Cu(II)-induced β2m amyloid formation. EGCG's binding at the edge of the β-sheets in β2m is consistent with a previous hypothesis that EGCG generally prevents amyloid formation by binding cross-β-sheet aggregation intermediates.
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Affiliation(s)
- Tyler M Marcinko
- Department of Chemistry, University of Massachusetts-Amherst, 374 Lederle Graduate Research Tower A, 710 North Pleasant Street, Amherst, Massachusetts 01003, United States
| | - Thomas Drews
- Department of Chemistry, University of Massachusetts-Amherst, 374 Lederle Graduate Research Tower A, 710 North Pleasant Street, Amherst, Massachusetts 01003, United States
| | - Tianying Liu
- Department of Chemistry, University of Massachusetts-Amherst, 374 Lederle Graduate Research Tower A, 710 North Pleasant Street, Amherst, Massachusetts 01003, United States
| | - Richard W Vachet
- Department of Chemistry, University of Massachusetts-Amherst, 374 Lederle Graduate Research Tower A, 710 North Pleasant Street, Amherst, Massachusetts 01003, United States
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8
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Marcinko TM, Liang C, Savinov S, Chen J, Vachet RW. Structural Heterogeneity in the Preamyloid Oligomers of β-2-Microglobulin. J Mol Biol 2019; 432:396-409. [PMID: 31711963 DOI: 10.1016/j.jmb.2019.10.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 10/25/2019] [Accepted: 10/30/2019] [Indexed: 11/29/2022]
Abstract
In dialysis patients, the protein β2-microglobulin (β2m) forms amyloid fibrils in a condition known as dialysis-related amyloidosis. To understand the early stages of the amyloid assembly process, we have used native electrospray ionization (ESI) together with ion mobility mass spectrometry (IM-MS) to study soluble preamyloid oligomers. ESI-IM-MS reveals the presence of multiple conformers for the dimer, tetramer, and hexamer that precede the Cu(II)-induced amyloid assembly process, results which are distinct from β2m oligomers formed at low pH. Experimental and computational results indicate that the predominant dimer is a Cu(II)-bound structure with an antiparallel side-by-side configuration. In contrast, tetramers exist in solution in both Cu(II)-bound and Cu(II)-free forms. Selective depletion of Cu(II)-bound species results in two primary conformers-one that is compact and another that is more expanded. Molecular modeling and molecular dynamics simulations identify models for these two tetrameric conformers with unique interactions and interfaces that enthalpically compensate for the loss of Cu(II). Unlike with other amyloid systems in which conformational heterogeneity is often associated with different amyloid morphologies or off-pathway events, conformational heterogeneity in the tetramer seems to be a necessary aspect of Cu(II)-induced amyloid formation by β2m. Moreover, the Cu(II)-free models represent a new advance in our understanding of Cu(II) release in Cu(II)-induced amyloid formation, laying a foundation for further mechanistic studies as well as development of new inhibition strategies.
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Affiliation(s)
- Tyler M Marcinko
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, United States
| | - Chungwen Liang
- Computational and Modeling Core Facility, Institute for Applied Life Sciences, Amherst, MA 01003, United States
| | - Sergey Savinov
- Computational and Modeling Core Facility, Institute for Applied Life Sciences, Amherst, MA 01003, United States; Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003, United States
| | - Jianhen Chen
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, United States; Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003, United States
| | - Richard W Vachet
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, United States.
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9
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Brancolini G, Tozzini V. Building Minimalist Models for Functionalized Metal Nanoparticles. Front Mol Biosci 2019; 6:50. [PMID: 31312634 PMCID: PMC6614485 DOI: 10.3389/fmolb.2019.00050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 06/17/2019] [Indexed: 01/11/2023] Open
Affiliation(s)
| | - Valentina Tozzini
- Istituto Nanoscienze-CNR and NEST-Scuola Normale Superiore, Pisa, Italy
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10
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Multiscale modeling of proteins interaction with functionalized nanoparticles. Curr Opin Colloid Interface Sci 2019. [DOI: 10.1016/j.cocis.2018.12.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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11
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Giorgetti S, Greco C, Tortora P, Aprile FA. Targeting Amyloid Aggregation: An Overview of Strategies and Mechanisms. Int J Mol Sci 2018; 19:E2677. [PMID: 30205618 PMCID: PMC6164555 DOI: 10.3390/ijms19092677] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 09/02/2018] [Accepted: 09/05/2018] [Indexed: 12/26/2022] Open
Abstract
Amyloids result from the aggregation of a set of diverse proteins, due to either specific mutations or promoting intra- or extra-cellular conditions. Structurally, they are rich in intermolecular β-sheets and are the causative agents of several diseases, both neurodegenerative and systemic. It is believed that the most toxic species are small aggregates, referred to as oligomers, rather than the final fibrillar assemblies. Their mechanisms of toxicity are mostly mediated by aberrant interactions with the cell membranes, with resulting derangement of membrane-related functions. Much effort is being exerted in the search for natural antiamyloid agents, and/or in the development of synthetic molecules. Actually, it is well documented that the prevention of amyloid aggregation results in several cytoprotective effects. Here, we portray the state of the art in the field. Several natural compounds are effective antiamyloid agents, notably tetracyclines and polyphenols. They are generally non-specific, as documented by their partially overlapping mechanisms and the capability to interfere with the aggregation of several unrelated proteins. Among rationally designed molecules, we mention the prominent examples of β-breakers peptides, whole antibodies and fragments thereof, and the special case of drugs with contrasting transthyretin aggregation. In this framework, we stress the pivotal role of the computational approaches. When combined with biophysical methods, in several cases they have helped clarify in detail the protein/drug modes of interaction, which makes it plausible that more effective drugs will be developed in the future.
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Affiliation(s)
- Sofia Giorgetti
- Department of Molecular Medicine, Institute of Biochemistry, University of Pavia, Via Taramelli 3b, 27100 Pavia, Italy.
| | - Claudio Greco
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milano, Italy.
| | - Paolo Tortora
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy.
- Milan Center for Neuroscience (Neuro-MI), 20126 Milano, Italy.
| | - Francesco Antonio Aprile
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK.
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12
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Limpikirati P, Liu T, Vachet RW. Covalent labeling-mass spectrometry with non-specific reagents for studying protein structure and interactions. Methods 2018; 144:79-93. [PMID: 29630925 PMCID: PMC6051898 DOI: 10.1016/j.ymeth.2018.04.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 04/03/2018] [Accepted: 04/04/2018] [Indexed: 12/13/2022] Open
Abstract
Using mass spectrometry (MS) to obtain information about a higher order structure of protein requires that a protein's structural properties are encoded into the mass of that protein. Covalent labeling (CL) with reagents that can irreversibly modify solvent accessible amino acid side chains is an effective way to encode structural information into the mass of a protein, as this information can be read-out in a straightforward manner using standard MS-based proteomics techniques. The differential reactivity of proteins under two or more conditions can be used to distinguish protein topologies, conformations, and/or binding sites. CL-MS methods have been effectively used for the structural analysis of proteins and protein complexes, particularly for systems that are difficult to study by other more traditional biochemical techniques. This review provides an overview of the non-specific CL approaches that have been combined with MS with a particular emphasis on the reagents that are commonly used, including hydroxyl radicals, carbenes, and diethylpyrocarbonate. We describe the reagent and protein factors that affect the reactivity of amino acid side chains. We also include details about experimental design and workflow, data analysis, recent applications, and some future prospects of CL-MS methods.
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Affiliation(s)
| | - Tianying Liu
- Department of Chemistry, University of Massachusetts Amherst, MA 01003, United States
| | - Richard W Vachet
- Department of Chemistry, University of Massachusetts Amherst, MA 01003, United States.
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13
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Mahdavimehr M, Meratan AA, Ghobeh M, Ghasemi A, Saboury AA, Nemat-Gorgani M. Inhibition of HEWL fibril formation by taxifolin: Mechanism of action. PLoS One 2017; 12:e0187841. [PMID: 29131828 PMCID: PMC5683630 DOI: 10.1371/journal.pone.0187841] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 10/26/2017] [Indexed: 12/31/2022] Open
Abstract
Among therapeutic approaches for amyloid-related diseases, attention has recently turned to the use of natural products as effective anti-aggregation compounds. Although a wealth of in vitro and in vivo evidence indicates some common inhibitory activity of these compounds, they don't generally suggest the same mechanism of action. Here, we show that taxifolin, a ubiquitous bioactive constituent of foods and herbs, inhibits formation of HEWL amyloid fibrils and their related toxicity by causing formation of very large globular, chain-like aggregates. A range of amyloid-specific techniques were employed to characterize this process. We found that taxifolin exerts its effect by binding to HEWL prefibrillar species, rather than by stabilizing the molecule in its native-like state. Furthermore, it's binding results in diverting the amyloid pathway toward formation of very large globular, chain-like aggregates with low β-sheet content and reduced solvent-exposed hydrophobic patches. ThT fluorescence measurements show that the binding capacity of taxifolin is significantly reduced, upon generation of large protofibrillar aggregates at the end of growth phase. We believe these results may help design promising inhibitors of protein aggregation for amyloid-related diseases.
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Affiliation(s)
- Mohsen Mahdavimehr
- Department of Biological Sciences, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran
| | - Ali Akbar Meratan
- Department of Biological Sciences, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran
- * E-mail:
| | - Maryam Ghobeh
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Atiyeh Ghasemi
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Ali Akbar Saboury
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Mohsen Nemat-Gorgani
- Stanford Genome Technology Center, Stanford University, Palo Alto, California, United States of America
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Liu T, Marcinko TM, Kiefer PA, Vachet RW. Using Covalent Labeling and Mass Spectrometry To Study Protein Binding Sites of Amyloid Inhibiting Molecules. Anal Chem 2017; 89:11583-11591. [PMID: 29028328 PMCID: PMC5677544 DOI: 10.1021/acs.analchem.7b02915] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Amyloid aggregates are associated with several debilitating diseases, and there are numerous efforts to develop small molecule treatments against these diseases. One challenge associated with these efforts is determining protein binding site information for potential therapeutics because amyloid-forming proteins rapidly form oligomers and aggregates, making traditional protein structural analysis techniques challenging. Using β-2-microglobulin (β2m) as a model amyloid-forming protein along with two recently identified small molecule amyloid inhibitors (i.e., rifamycin SV and doxycycline), we demonstrate that covalent labeling and mass spectrometry (MS) can be used to map small-molecule binding sites for a rapidly aggregating protein. Specifically, three different covalent labeling reagents, namely diethylpyrocarbonate, 2,3-butanedione, and the reagent pair EDC/GEE, are used together to pinpoint the binding sites of rifamycin SV, doxycycline, and another molecule, suramin, which binds but does not inhibit Cu(II)-induced β2m amyloid formation. The labeling results reveal binding sites that are consistent with the known effects of these molecules on β2m amyloid formation and are in general agreement with molecular docking results. We expect that this combined covalent labeling approach will be applicable to other protein/small molecule systems that are difficult to study by traditional means.
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Affiliation(s)
- Tianying Liu
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Tyler M. Marcinko
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Patrick A. Kiefer
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Richard W. Vachet
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
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