1
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Brandner S, Habeck T, Lermyte F. New Insights into the Intrinsic Electron-Based Dissociation Behavior of Cytochrome c Oligomers. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:1908-1916. [PMID: 37227392 DOI: 10.1021/jasms.3c00106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Between 2003 and 2017, four reports were published that demonstrated the intrinsic ability of the native iron-containing proteins cytochrome c and ferritin to undergo radical-based backbone fragmentation in the gas phase without the introduction of exogenous electrons. For cytochrome c in particular, this effect has so far only been reported to occur in the ion source, preventing the in-depth study of reactions occurring after gas-phase isolation of specific precursors. Here, we report the first observation of this intrinsic native electron capture dissociation behavior after quadrupole isolation of specific charge states of the cytochrome c dimer and trimer, providing direct experimental support for key aspects of the mechanism proposed 20 years ago. Furthermore, we provide evidence that, in contrast to some earlier proposals, these oligomeric states are formed in bulk solution rather than during the electrospray ionization process and that the observed fragmentation site preferences can be rationalized through the structure and interactions within these native oligomers rather than the monomer. We also show that the observed fragmentation pattern─and indeed, whether or not fragmentation occurs─is highly sensitive to the provenance and history of the protein samples, to the extent that samples can show distinct fragmentation behavior despite behaving identically in ion mobility experiments. This rather underexplored method therefore represents an exquisitely sensitive conformational probe and will hopefully receive more attention from the biomolecular mass spectrometry community in the future.
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Affiliation(s)
- Sarah Brandner
- Department of Chemistry, Clemens-Schöpf Institute of Organic Chemistry and Biochemistry, Technical University of Darmstadt, Peter-Grünberg-Strasse 4, 64287 Darmstadt, Germany
| | - Tanja Habeck
- Department of Chemistry, Clemens-Schöpf Institute of Organic Chemistry and Biochemistry, Technical University of Darmstadt, Peter-Grünberg-Strasse 4, 64287 Darmstadt, Germany
| | - Frederik Lermyte
- Department of Chemistry, Clemens-Schöpf Institute of Organic Chemistry and Biochemistry, Technical University of Darmstadt, Peter-Grünberg-Strasse 4, 64287 Darmstadt, Germany
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2
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Sedov I, Khaibrakhmanova D. Molecular Mechanisms of Inhibition of Protein Amyloid Fibril Formation: Evidence and Perspectives Based on Kinetic Models. Int J Mol Sci 2022; 23:ijms232113428. [PMID: 36362217 PMCID: PMC9657184 DOI: 10.3390/ijms232113428] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 10/29/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022] Open
Abstract
Inhibition of fibril formation is considered a possible treatment strategy for amyloid-related diseases. Understanding the molecular nature of inhibitor action is crucial for the design of drug candidates. In the present review, we describe the common kinetic models of fibril formation and classify known inhibitors by the mechanism of their interactions with the aggregating protein and its oligomers. This mechanism determines the step or steps of the aggregation process that become inhibited and the observed changes in kinetics and equilibrium of fibril formation. The results of numerous studies indicate that possible approaches to antiamyloid inhibitor discovery include the search for the strong binders of protein monomers, cappers blocking the ends of the growing fibril, or the species absorbing on the surface of oligomers preventing nucleation. Strongly binding inhibitors stabilizing the native state can be promising for the structured proteins while designing the drug candidates targeting disordered proteins is challenging.
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Affiliation(s)
- Igor Sedov
- Chemical Institute, Kazan Federal University, Kremlevskaya 18, 420008 Kazan, Russia
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111 Kazan, Russia
- Sirius University of Science and Technology, 1 Olympic Ave, 354340 Sochi, Russia
- Correspondence: ; Tel.: +7-9600503916
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3
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Cawood EE, Karamanos TK, Wilson AJ, Radford SE. Visualizing and trapping transient oligomers in amyloid assembly pathways. Biophys Chem 2020; 268:106505. [PMID: 33220582 PMCID: PMC8188297 DOI: 10.1016/j.bpc.2020.106505] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 10/29/2020] [Accepted: 11/01/2020] [Indexed: 12/31/2022]
Abstract
Oligomers which form during amyloid fibril assembly are considered to be key contributors towards amyloid disease. However, understanding how such intermediates form, their structure, and mechanisms of toxicity presents significant challenges due to their transient and heterogeneous nature. Here, we discuss two different strategies for addressing these challenges: use of (1) methods capable of detecting lowly-populated species within complex mixtures, such as NMR, single particle methods (including fluorescence and force spectroscopy), and mass spectrometry; and (2) chemical and biological tools to bias the amyloid energy landscape towards specific oligomeric states. While the former methods are well suited to following the kinetics of amyloid assembly and obtaining low-resolution structural information, the latter are capable of producing oligomer samples for high-resolution structural studies and inferring structure-toxicity relationships. Together, these different approaches should enable a clearer picture to be gained of the nature and role of oligomeric intermediates in amyloid formation and disease. Methods to study structure, toxicity, and kinetics of transient amyloid oligomers. NMR and single particle methods can characterize lowly-populated oligomers. Chemical tools/antibodies stabilize oligomers for structural and toxicity studies A combination of methods is needed to fully characterize amyloid assembly pathways.
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Affiliation(s)
- Emma E Cawood
- Astbury Centre for Structural Molecular Biology, School of Chemistry, University of Leeds, LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, UK
| | - Theodoros K Karamanos
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, UK; Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Andrew J Wilson
- Astbury Centre for Structural Molecular Biology, School of Chemistry, University of Leeds, LS2 9JT, UK.
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, UK.
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4
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Loureiro RJS, Faísca PFN. The Early Phase of β2-Microglobulin Aggregation: Perspectives From Molecular Simulations. Front Mol Biosci 2020; 7:578433. [PMID: 33134317 PMCID: PMC7550760 DOI: 10.3389/fmolb.2020.578433] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/08/2020] [Indexed: 11/24/2022] Open
Abstract
Protein β2-microglobulin is the causing agent of two amyloidosis, dialysis related amyloidosis (DRA), affecting the bones and cartilages of individuals with chronic renal failure undergoing long-term hemodialysis, and a systemic amyloidosis, found in one French family, which impairs visceral organs. The protein’s small size and its biomedical significance attracted the attention of theoretical scientists, and there are now several studies addressing its aggregation mechanism in the context of molecular simulations. Here, we review the early phase of β2-microglobulin aggregation, by focusing on the identification and structural characterization of monomers with the ability to trigger aggregation, and initial small oligomers (dimers, tetramers, hexamers etc.) formed in the so-called nucleation phase. We focus our analysis on results from molecular simulations and integrate our views with those coming from in vitro experiments to provide a broader perspective of this interesting field of research. We also outline directions for future computer simulation studies.
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Affiliation(s)
- Rui J S Loureiro
- Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, University of Lisboa, Lisbon, Portugal
| | - Patrícia F N Faísca
- Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, University of Lisboa, Lisbon, Portugal.,Department of Physics, Faculty of Sciences, University of Lisboa, Lisbon, Portugal
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5
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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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6
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Raimondi S, Porcari R, Mangione PP, Verona G, Marcoux J, Giorgetti S, Taylor GW, Ellmerich S, Ballico M, Zanini S, Pardon E, Al-Shawi R, Simons JP, Corazza A, Fogolari F, Leri M, Stefani M, Bucciantini M, Gillmore JD, Hawkins PN, Valli M, Stoppini M, Robinson CV, Steyaert J, Esposito G, Bellotti V. A specific nanobody prevents amyloidogenesis of D76N β 2-microglobulin in vitro and modifies its tissue distribution in vivo. Sci Rep 2017; 7:46711. [PMID: 28429761 PMCID: PMC5399440 DOI: 10.1038/srep46711] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/23/2017] [Indexed: 11/24/2022] Open
Abstract
Systemic amyloidosis is caused by misfolding and aggregation of globular proteins in vivo for which effective treatments are urgently needed. Inhibition of protein self-aggregation represents an attractive therapeutic strategy. Studies on the amyloidogenic variant of β2-microglobulin, D76N, causing hereditary systemic amyloidosis, have become particularly relevant since fibrils are formed in vitro in physiologically relevant conditions. Here we compare the potency of two previously described inhibitors of wild type β2-microglobulin fibrillogenesis, doxycycline and single domain antibodies (nanobodies). The β2-microglobulin -binding nanobody, Nb24, more potently inhibits D76N β2-microglobulin fibrillogenesis than doxycycline with complete abrogation of fibril formation. In β2-microglobulin knock out mice, the D76N β2-microglobulin/ Nb24 pre-formed complex, is cleared from the circulation at the same rate as the uncomplexed protein; however, the analysis of tissue distribution reveals that the interaction with the antibody reduces the concentration of the variant protein in the heart but does not modify the tissue distribution of wild type β2-microglobulin. These findings strongly support the potential therapeutic use of this antibody in the treatment of systemic amyloidosis.
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Affiliation(s)
- Sara Raimondi
- Department of Molecular Medicine, Institute of Biochemistry, University of Pavia, Via Taramelli 3b, 27100 Pavia, Italy
| | - Riccardo Porcari
- Wolfson Drug Discovery Unit, Centre for Amyloidosis and Acute Phase Proteins, Division of Medicine, University College London, London NW3 2PF, UK
| | - P Patrizia Mangione
- Department of Molecular Medicine, Institute of Biochemistry, University of Pavia, Via Taramelli 3b, 27100 Pavia, Italy.,Wolfson Drug Discovery Unit, Centre for Amyloidosis and Acute Phase Proteins, Division of Medicine, University College London, London NW3 2PF, UK
| | - Guglielmo Verona
- Wolfson Drug Discovery Unit, Centre for Amyloidosis and Acute Phase Proteins, Division of Medicine, University College London, London NW3 2PF, UK
| | - Julien Marcoux
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Sofia Giorgetti
- Department of Molecular Medicine, Institute of Biochemistry, University of Pavia, Via Taramelli 3b, 27100 Pavia, Italy
| | - Graham W Taylor
- Wolfson Drug Discovery Unit, Centre for Amyloidosis and Acute Phase Proteins, Division of Medicine, University College London, London NW3 2PF, UK
| | - Stephan Ellmerich
- Wolfson Drug Discovery Unit, Centre for Amyloidosis and Acute Phase Proteins, Division of Medicine, University College London, London NW3 2PF, UK
| | - Maurizio Ballico
- Science and Math Division, New York University at Abu Dhabi, Abu Dhabi, UAE
| | - Stefano Zanini
- Science and Math Division, New York University at Abu Dhabi, Abu Dhabi, UAE
| | - Els Pardon
- Structural Biology Research Centre, VIB, Pleinlaan 2, 1050, Brussel, Belgium.,Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussel, Belgium
| | - Raya Al-Shawi
- Centre for Biomedical Science, Division of Medicine, University College London, London NW3 2PF, UK
| | - J Paul Simons
- Wolfson Drug Discovery Unit, Centre for Amyloidosis and Acute Phase Proteins, Division of Medicine, University College London, London NW3 2PF, UK
| | - Alessandra Corazza
- Department of Medical and Biological Sciences (DSMB), University of Udine, Piazzale Kolbe 4, 33100 Udine, Italy.,Istituto Nazionale Biostrutture e Biosistemi, Viale Medaglie d'Oro 305, 00136 Roma, Italy
| | - Federico Fogolari
- Istituto Nazionale Biostrutture e Biosistemi, Viale Medaglie d'Oro 305, 00136 Roma, Italy.,Department of Mathematics, Computer Science and Physics, University of Udine, Piazzale Kolbe 4, 33100 Udine, Italy
| | - Manuela Leri
- Department of Biomedical, Experimental and Clinical Sciences 'Mario Serio', University of Florence, Viale Morgagni 50, 50134 Florence, Italy
| | - Massimo Stefani
- Department of Biomedical, Experimental and Clinical Sciences 'Mario Serio', University of Florence, Viale Morgagni 50, 50134 Florence, Italy.,Research Centre for Molecular Basis of Neurodegeneration, 50134 Florence, Italy
| | - Monica Bucciantini
- Department of Biomedical, Experimental and Clinical Sciences 'Mario Serio', University of Florence, Viale Morgagni 50, 50134 Florence, Italy.,Research Centre for Molecular Basis of Neurodegeneration, 50134 Florence, Italy
| | - Julian D Gillmore
- National Amyloidosis Centre, University College London, London NW3 2PF, UK
| | - Philip N Hawkins
- National Amyloidosis Centre, University College London, London NW3 2PF, UK
| | - Maurizia Valli
- Department of Molecular Medicine, Institute of Biochemistry, University of Pavia, Via Taramelli 3b, 27100 Pavia, Italy
| | - Monica Stoppini
- Department of Molecular Medicine, Institute of Biochemistry, University of Pavia, Via Taramelli 3b, 27100 Pavia, Italy
| | - Carol V Robinson
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Jan Steyaert
- Structural Biology Research Centre, VIB, Pleinlaan 2, 1050, Brussel, Belgium.,Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussel, Belgium
| | - Gennaro Esposito
- Science and Math Division, New York University at Abu Dhabi, Abu Dhabi, UAE.,Istituto Nazionale Biostrutture e Biosistemi, Viale Medaglie d'Oro 305, 00136 Roma, Italy.,Department of Mathematics, Computer Science and Physics, University of Udine, Piazzale Kolbe 4, 33100 Udine, Italy
| | - Vittorio Bellotti
- Department of Molecular Medicine, Institute of Biochemistry, University of Pavia, Via Taramelli 3b, 27100 Pavia, Italy.,Wolfson Drug Discovery Unit, Centre for Amyloidosis and Acute Phase Proteins, Division of Medicine, University College London, London NW3 2PF, UK
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7
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Scarff CA, Ashcroft AE, Radford SE. Characterization of Amyloid Oligomers by Electrospray Ionization-Ion Mobility Spectrometry-Mass Spectrometry (ESI-IMS-MS). Methods Mol Biol 2016; 1345:115-32. [PMID: 26453209 DOI: 10.1007/978-1-4939-2978-8_8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Soluble oligomers formed during the self-assembly of amyloidogenic peptide and protein species are generally thought to be highly toxic. Consequently, thorough characterization of these species is of much interest in the quest for effective therapeutics and for an enhanced understanding of amyloid fibrillation pathways. The structural characterization of oligomeric species, however, is challenging as they are often transiently and lowly populated, and highly heterogeneous. Electrospray ionization-ion mobility spectrometry-mass spectrometry (ESI-IMS-MS) is a powerful technique which is able to detect individual ion species populated within a complex heterogeneous mixture and characterize them in terms of shape, stoichiometry, ligand binding capability, and relative stability. Herein, we describe the use of ESI-IMS-MS to characterize the size and shape of oligomers of beta-2-microglobulin through use of data calibration and the derivation of models. This enables information about the range of oligomeric species populated en route to amyloid formation and the mode of oligomer growth to be obtained.
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Affiliation(s)
- Charlotte A Scarff
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Alison E Ashcroft
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK.
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Astbury Building, Room 10.122a, Leeds, LS2 9JT, UK.
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8
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Koroleva ON, Dubrovin EV, Tolstova AP, Kuzmina NV, Laptinskaya TV, Yaminsky IV, Drutsa VL. A hypothetical hierarchical mechanism of the self-assembly of the Escherichia coli RNA polymerase σ(70) subunit. SOFT MATTER 2016; 12:1974-1982. [PMID: 26758573 DOI: 10.1039/c5sm02934a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Diverse morphology of aggregates of amyloidogenic proteins has been attracting much attention in the last few years, and there is still no complete understanding of the relationships between various types of aggregates. In this work, we propose the model, which universally explains the formation of morphologically different (wormlike and rodlike) aggregates on the example of a σ(70) subunit of RNA polymerase, which has been recently shown to form amyloid fibrils. Aggregates were studied using AFM in solution and depolarized dynamic light scattering. The obtained results demonstrate comparably low Young's moduli of the wormlike structures (7.8-12.3 MPa) indicating less structured aggregation of monomeric proteins than that typical for β-sheet formation. To shed light on the molecular interaction of the protein during the aggregation, early stages of fibrillization of the σ(70) subunit were modeled using all-atom molecular dynamics. Simulations have shown that the σ(70) subunit is able to form quasi-symmetric extended dimers, which may further interact with each other and grow linearly. The proposed general model explains different pathways of σ(70) subunit aggregation and may be valid for other amyloid proteins.
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Affiliation(s)
- O N Koroleva
- Faculty of Chemistry, Lomonosov Moscow State University, Leninskie gory, 1/3, Moscow, 119991 Russian Federation
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9
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Young LM, Saunders JC, Mahood RA, Revill CH, Foster RJ, Ashcroft AE, Radford SE. ESI-IMS-MS: A method for rapid analysis of protein aggregation and its inhibition by small molecules. Methods 2016; 95:62-9. [PMID: 26007606 PMCID: PMC4769093 DOI: 10.1016/j.ymeth.2015.05.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 03/26/2015] [Accepted: 05/07/2015] [Indexed: 11/21/2022] Open
Abstract
Electrospray ionisation-ion mobility spectrometry-mass spectrometry (ESI-IMS-MS) is a powerful method for the study of conformational changes in protein complexes, including oligomeric species populated during protein self-aggregation into amyloid fibrils. Information on the mass, stability, cross-sectional area and ligand binding capability of each transiently populated intermediate, present in the heterogeneous mixture of assembling species, can be determined individually in a single experiment in real-time. Determining the structural characterisation of oligomeric species and alterations in self-assembly pathways observed in the presence of small molecule inhibitors is of great importance, given the urgent demand for effective therapeutics. Recent studies have demonstrated the capability of ESI-IMS-MS to identify small molecule modulators of amyloid assembly and to determine the mechanism by which they interact (positive, negative, non-specific binding, or colloidal) in a high-throughput format. Here, we demonstrate these advances using self-assembly of Aβ40 as an example, and reveal two new inhibitors of Aβ40 fibrillation.
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Affiliation(s)
- Lydia M Young
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom; School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, United Kingdom.
| | - Janet C Saunders
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom; School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, United Kingdom.
| | - Rachel A Mahood
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom; School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, United Kingdom.
| | - Charlotte H Revill
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom; School of Chemistry, University of Leeds, LS2 9JT, United Kingdom.
| | - Richard J Foster
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom; School of Chemistry, University of Leeds, LS2 9JT, United Kingdom.
| | - Alison E Ashcroft
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom; School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, United Kingdom.
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom; School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, United Kingdom.
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10
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Hall Z, Schmidt C, Politis A. Uncovering the Early Assembly Mechanism for Amyloidogenic β2-Microglobulin Using Cross-linking and Native Mass Spectrometry. J Biol Chem 2015; 291:4626-37. [PMID: 26655720 PMCID: PMC4813486 DOI: 10.1074/jbc.m115.691063] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Indexed: 12/14/2022] Open
Abstract
β2-Microglobulin (β2m), a key component of the major histocompatibility class I complex, can aggregate into fibrils with severe clinical consequences. As such, investigating the structural aspects of the formation of oligomeric intermediates of β2m and their subsequent progression toward fibrillar aggregates is of great importance. However, β2m aggregates are challenging targets in structural biology, primarily due to their inherent transient and heterogeneous nature. Here we study the oligomeric distributions and structures of the early intermediates of amyloidogenic β2m and its truncated variant ΔN6-β2m. We established compact oligomers for both variants by integrating advanced mass spectrometric techniques with available electron microscopy maps and atomic level structures from NMR spectroscopy and x-ray crystallography. Our results revealed a stepwise assembly mechanism by monomer addition and domain swapping for the oligomeric species of ΔN6-β2m. The observed structural similarity and common oligomerization pathway between the two variants is likely to enable ΔN6-β2m to cross-seed β2m fibrillation and allow the formation of mixed fibrils. We further determined the key subunit interactions in ΔN6-β2m tetramer, revealing the importance of a domain-swapped hinge region for formation of higher order oligomers. Overall, we deliver new mechanistic insights into β2m aggregation, paving the way for future studies on the mechanisms and cause of amyloid fibrillation.
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Affiliation(s)
- Zoe Hall
- From the Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, United Kingdom, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom, and
| | - Carla Schmidt
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom, and
| | - Argyris Politis
- Department of Chemistry, King's College London, 7 Trinity Street, London SE1 1DB, United Kingdom
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11
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Phillips AS, Gomes AF, Kalapothakis JMD, Gillam JE, Gasparavicius J, Gozzo FC, Kunath T, MacPhee C, Barran PE. Conformational dynamics of α-synuclein: insights from mass spectrometry. Analyst 2015; 140:3070-81. [DOI: 10.1039/c4an02306d] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Different mass spectrometry approaches are combined to investigate the conformational flexibility of α-synuclein.
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Affiliation(s)
- Ashley S. Phillips
- Manchester Institute of Biotechnology
- University of Manchester
- Manchester
- UK
| | - Alexandre F. Gomes
- Dalton Mass Spectrometry Laboratory
- University of Campinas – UNICAMP
- Brazil
| | | | - Jay E. Gillam
- School of Physics and Astronomy
- University of Edinburgh
- Edinburgh
- UK
| | | | - Fabio C. Gozzo
- Dalton Mass Spectrometry Laboratory
- University of Campinas – UNICAMP
- Brazil
| | - Tilo Kunath
- MRC Centre for Regenerative Medicine
- University of Edinburgh
- Edinburgh
- UK
| | - Cait MacPhee
- School of Physics and Astronomy
- University of Edinburgh
- Edinburgh
- UK
| | - Perdita E. Barran
- Manchester Institute of Biotechnology
- University of Manchester
- Manchester
- UK
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12
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Sitkiewicz E, Kłoniecki M, Poznański J, Bal W, Dadlez M. Factors Influencing Compact–Extended Structure Equilibrium in Oligomers of Aβ1–40 Peptide—An Ion Mobility Mass Spectrometry Study. J Mol Biol 2014; 426:2871-85. [DOI: 10.1016/j.jmb.2014.05.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 05/08/2014] [Accepted: 05/15/2014] [Indexed: 12/15/2022]
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13
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Lanucara F, Holman SW, Gray CJ, Eyers CE. The power of ion mobility-mass spectrometry for structural characterization and the study of conformational dynamics. Nat Chem 2014; 6:281-94. [DOI: 10.1038/nchem.1889] [Citation(s) in RCA: 655] [Impact Index Per Article: 65.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 02/11/2014] [Indexed: 02/07/2023]
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14
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Snijder J, Heck AJR. Analytical approaches for size and mass analysis of large protein assemblies. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2014; 7:43-64. [PMID: 25014341 DOI: 10.1146/annurev-anchem-071213-020015] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Analysis of the size and mass of nanoparticles, whether they are natural biomacromolecular or synthetic supramolecular assemblies, is an important step in the characterization of such molecular species. In recent years, electrospray ionization (ESI) has emerged as a technology through which particles with masses up to 100 MDa can be ionized and transferred into the gas phase, preparing them for accurate mass analysis. Here we review currently used methodologies, with a clear focus on native mass spectrometry (MS). Additional complementary methodologies are also covered, including ion-mobility analysis, nanomechanical mass sensors, and charge-detection MS. The literature discussed clearly demonstrates the great potential of ESI-based methodologies for the size and mass analysis of nanoparticles, including very large naturally occurring protein assemblies. The analytical approaches discussed are powerful tools in not only structural biology, but also nanotechnology.
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Affiliation(s)
- Joost Snijder
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, the Netherlands; ,
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15
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Leney AC, Pashley CL, Scarff CA, Radford SE, Ashcroft AE. Insights into the role of the beta-2 microglobulin D-strand in amyloid propensity revealed by mass spectrometry. MOLECULAR BIOSYSTEMS 2013; 10:412-20. [PMID: 24336936 PMCID: PMC4006425 DOI: 10.1039/c3mb70420c] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Characterising the differences between oligomers formed from the amyloidogenic protein β2-microglobulin and its mutant H51A using ESI-IMS-MS.
In vivo beta-2 microglobulin (β2m) forms amyloid fibrils that are associated with the disease dialysis-related amyloidosis. Here, electrospray ionisation-ion mobility spectrometry-mass spectrometry has been used to compare the oligomers formed from wild-type β2m with those formed from a variant of the protein containing a single point mutation in the D strand, H51A, during in vitro fibril assembly. Using the amyloid-binding fluorescent dye, Thioflavin T, to monitor fibrillation kinetics, H51A was shown to exhibit a two-fold increase in the lag-time of fibril formation. Despite this, comparison of the oligomeric species observed during the lag-time of self-aggregation indicated that H51A had a higher population of oligomers, and formed oligomers of higher order, than wild-type β2m. The cross-sectional areas of the oligomers arising from H51A and wild-type protein were indistinguishable, although the H51A oligomers were shown to have a significantly higher kinetic stability on account of their reluctance to undergo sub-unit exchange when mixed with 15N-labelled protein. Together the data reveal a significant effect of His51, and thus that of the D-strand sequence, on amyloid formation. The results also highlight the power of mass spectrometry in probing complex biochemical mechanisms in real-time.
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Affiliation(s)
- Aneika C Leney
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
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16
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Zhong Y, Feng J, Ruotolo BT. Robotically assisted titration coupled to ion mobility-mass spectrometry reveals the interface structures and analysis parameters critical for multiprotein topology mapping. Anal Chem 2013; 85:11360-8. [PMID: 24164205 DOI: 10.1021/ac402276k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Multiprotein complexes have three-dimensional shapes and dynamic functions that impact almost every aspect of biochemistry. Despite this, our ability to rapidly assess the structures of such macromolecules lags significantly behind high-throughput efforts to identify their function, especially in the context of human disease. Here, we describe results obtained by coupling ion mobility-mass spectrometry with automated robotic sampling of different solvent compositions. This combination of technologies has allowed us to explore an extensive set of solution conditions for a group of eight protein homotetramers, representing a broad sample of protein structure and stability space. We find that altering solution ionic strength in concert with dimethylsulfoxide content is sufficient to disrupt the protein-protein interfaces of all of the complexes studied here. Ion mobility measurements captured for both intact assemblies and subcomplexes match expected values from available X-ray structures in all cases save two. For these exceptions, we find that distorted subcomplexes result from extreme disruption conditions, and are accompanied by small shifts in intact tetramers size, thus enabling the removal of distorted subcomplex data in downstream models. Furthermore, we find strong correlations between the relative intensities of disrupted protein tetramers and the relative number and type of interactions present at interfaces as a function of disrupting agent added. In most cases, this correlation appears strong enough to quantify various types of protein interfacial interactions within unknown proteins following appropriate calibration.
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Affiliation(s)
- Yueyang Zhong
- Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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17
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Mass spectrometry coupled experiments and protein structure modeling methods. Int J Mol Sci 2013; 14:20635-57. [PMID: 24132151 PMCID: PMC3821635 DOI: 10.3390/ijms141020635] [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: 07/30/2013] [Revised: 09/17/2013] [Accepted: 09/19/2013] [Indexed: 01/02/2023] Open
Abstract
With the accumulation of next generation sequencing data, there is increasing interest in the study of intra-species difference in molecular biology, especially in relation to disease analysis. Furthermore, the dynamics of the protein is being identified as a critical factor in its function. Although accuracy of protein structure prediction methods is high, provided there are structural templates, most methods are still insensitive to amino-acid differences at critical points that may change the overall structure. Also, predicted structures are inherently static and do not provide information about structural change over time. It is challenging to address the sensitivity and the dynamics by computational structure predictions alone. However, with the fast development of diverse mass spectrometry coupled experiments, low-resolution but fast and sensitive structural information can be obtained. This information can then be integrated into the structure prediction process to further improve the sensitivity and address the dynamics of the protein structures. For this purpose, this article focuses on reviewing two aspects: the types of mass spectrometry coupled experiments and structural data that are obtainable through those experiments; and the structure prediction methods that can utilize these data as constraints. Also, short review of current efforts in integrating experimental data in the structural modeling is provided.
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Gillam JE, MacPhee CE. Modelling amyloid fibril formation kinetics: mechanisms of nucleation and growth. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:373101. [PMID: 23941964 DOI: 10.1088/0953-8984/25/37/373101] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Amyloid and amyloid-like fibrils are self-assembling protein nanostructures, of interest for their robust material properties and inherent biological compatibility as well as their putative role in a number of debilitating mammalian disorders. Understanding fibril formation is essential to the development of strategies to control, manipulate or prevent fibril growth. As such, this area of research has attracted significant attention over the last half century. This review describes a number of different models that have been formulated to describe the kinetics of fibril assembly. We describe the macroscopic implications of mechanisms in which secondary processes such as secondary nucleation, fragmentation or branching dominate the assembly pathway, compared to mechanisms dominated by the influence of primary nucleation. We further describe how experimental data can be analysed with respect to the predictions of kinetic models.
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Affiliation(s)
- J E Gillam
- School of Physics and Astronomy, The University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, UK
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19
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The role of initial oligomers in amyloid fibril formation by human stefin B. Int J Mol Sci 2013; 14:18362-84. [PMID: 24013380 PMCID: PMC3794784 DOI: 10.3390/ijms140918362] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 08/21/2013] [Accepted: 08/22/2013] [Indexed: 02/03/2023] Open
Abstract
Oligomers are commonly observed intermediates at the initial stages of amyloid fibril formation. They are toxic to neurons and cause decrease in neural transmission and long-term potentiation. We describe an in vitro study of the initial steps in amyloid fibril formation by human stefin B, which proved to be a good model system. Due to relative stability of the initial oligomers of stefin B, electrospray ionization mass spectrometry (ESI MS) could be applied in addition to size exclusion chromatography (SEC). These two techniques enabled us to separate and detect distinguished oligomers from the monomers: dimers, trimers, tetramers, up to decamers. The amyloid fibril formation process was followed at different pH and temperatures, including such conditions where the process was slow enough to detect the initial oligomeric species at the very beginning of the lag phase and those at the end of the lag phase. Taking into account the results of the lower-order oligomers transformations early in the process, we were able to propose an improved model for the stefin B fibril formation.
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Scarff CA, Sicorello A, Tomé RJ, Macedo-Ribeiro S, Ashcroft AE, Radford SE. A tale of a tail: Structural insights into the conformational properties of the polyglutamine protein ataxin-3. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2013; 345-347:63-70. [PMID: 25844046 PMCID: PMC4375668 DOI: 10.1016/j.ijms.2012.08.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 08/22/2012] [Accepted: 08/23/2012] [Indexed: 05/24/2023]
Abstract
Ataxin-3 is the protein responsible for the neurodegenerative polyglutamine disease Spinocerebellar ataxia type 3. Full structural characterisation of ataxin-3 is required to aid in understanding the mechanism of disease. Despite extensive study, little is known about the conformational properties of the full-length protein, in either its non-expanded healthy or expanded pathogenic forms, particularly since its polyglutamine-containing region has denied structural elucidation. In this work, travelling-wave ion mobility spectrometry-mass spectrometry and limited proteolysis have been used to compare the conformational properties of full-length non-expanded ataxin-3 (14Q) and its isolated N-terminal Josephin domain (JD). Limited proteolysis experiments have confirmed that the JD is stable, being extremely resistant to trypsin digestion, with the exception of the α2/α3 hairpin which is flexible and exposed to protease cleavage in solution. The C-terminal region of ataxin-3 which contains the glutamine-rich sequences is largely unstructured, showing little resistance to limited proteolysis. Using ion mobility spectrometry-mass spectrometry we show that ataxin-3 (14Q) adopts a wide range of conformational states in vitro conferred by the flexibility of its C-terminal tail and the α2/α3 hairpin of the N-terminal JD. This study highlights how the power of MS-based approaches to protein structural characterisation can be particularly useful when the target protein is aggregation-prone and has intrinsically unordered regions.
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Affiliation(s)
- Charlotte A. Scarff
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Alessandro Sicorello
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Ricardo J.L. Tomé
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Sandra Macedo-Ribeiro
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Alison E. Ashcroft
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Sheena E. Radford
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
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21
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Woods L, Radford S, Ashcroft A. Advances in ion mobility spectrometry-mass spectrometry reveal key insights into amyloid assembly. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1834:1257-68. [PMID: 23063533 PMCID: PMC3787735 DOI: 10.1016/j.bbapap.2012.10.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 09/27/2012] [Accepted: 10/02/2012] [Indexed: 10/28/2022]
Abstract
Interfacing ion mobility spectrometry to mass spectrometry (IMS-MS) has enabled mass spectrometric analyses to extend into an extra dimension, providing unrivalled separation and structural characterization of lowly populated species in heterogeneous mixtures. One biological system that has benefitted significantly from such advances is that of amyloid formation. Using IMS-MS, progress has been made into identifying transiently populated monomeric and oligomeric species for a number of different amyloid systems and has led to an enhanced understanding of the mechanism by which small molecules modulate amyloid formation. This review highlights recent advances in this field, which have been accelerated by the commercial availability of IMS-MS instruments. This article is part of a Special Issue entitled: Mass spectrometry in structural biology.
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Affiliation(s)
| | - S.E. Radford
- Astbury Centre for Structural Molecular Biology & School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, UK
| | - A.E. Ashcroft
- Astbury Centre for Structural Molecular Biology & School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, UK
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22
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Young L, Ndlovu H, Knapman TW, Harris SA, Radford SE, Ashcroft AE. Monitoring oligomer formation from self-aggregating amylin peptides using ESI-IMS-MS. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/s12127-012-0115-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Hyung SJ, Ruotolo BT. Integrating mass spectrometry of intact protein complexes into structural proteomics. Proteomics 2012; 12:1547-64. [PMID: 22611037 DOI: 10.1002/pmic.201100520] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
MS analysis of intact protein complexes has emerged as an established technology for assessing the composition and connectivity within dynamic, heterogeneous multiprotein complexes at low concentrations and in the context of mixtures. As this technology continues to move forward, one of the main challenges is to integrate the information content of such intact protein complex measurements with other MS approaches in structural biology. Methods such as H/D exchange, oxidative foot-printing, chemical cross-linking, affinity purification, and ion mobility separation add complementary information that allows access to every level of protein structure and organization. Here, we survey the structural information that can be retrieved by such experiments, demonstrate the applicability of integrative MS approaches in structural proteomics, and look to the future to explore upcoming innovations in this rapidly advancing area.
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Affiliation(s)
- Suk-Joon Hyung
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
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24
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Ma B, Nussinov R. Selective molecular recognition in amyloid growth and transmission and cross-species barriers. J Mol Biol 2012; 421:172-84. [PMID: 22119878 PMCID: PMC6407624 DOI: 10.1016/j.jmb.2011.11.023] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2011] [Revised: 11/10/2011] [Accepted: 11/13/2011] [Indexed: 11/23/2022]
Abstract
Mutual conformational selection and population shift followed by minor induced-fit optimization is the key mechanism in biomolecular recognition, and monomers and small oligomers binding to amyloid seeds in fibril growth is a molecular recognition event. Here, we describe amyloid aggregation, preferred species, cross-species barriers and transmission within the broad framework of molecular recognition. Cross-seeding of amyloid species is governed by conformational selection of compatible (complementary) states. If the dominant conformations of two species are similar, they can cross-seed each other; on the other hand, if they are sufficiently different, they will grow into different fibrils, reflecting species barriers. Such a scenario has recently been observed for the tau protein, which has four repeats. While a construct consisting of repeats 1, 3 and 4 can serve as a seed for the entire four-repeat tau segment, the inverse does not hold. On the other hand, the tau protein repeats with the characteristic U-turn shape can cross-seed Alzheimer's amyloid β and, similarly, the islet amyloid polypeptide. Within this framework, we suggest that the so-called "central dogma" of amyloid formation, where aggregation takes place through nonspecific backbone hydrogen bonding interactions, which are common to all peptides and proteins, is a simple reflection of the heterogeneous, polymorphic free-energy landscape of amyloid species. Here, we review available data and make some propositions addressing this key problem. In particular, we argue that recent theoretical and experimental observations support the key role of selective molecular recognition in amyloidosis and in determining cross-species barriers and transmission.
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Affiliation(s)
- Buyong Ma
- Basic Science Program, SAIC-Frederick, Inc. Center for Cancer Research Nanobiology Program NCI-Frederick, Frederick, MD 21702
| | - Ruth Nussinov
- Basic Science Program, SAIC-Frederick, Inc. Center for Cancer Research Nanobiology Program NCI-Frederick, Frederick, MD 21702
- Sackler Inst. of Molecular Medicine Department of Human Genetics and Molecular Medicine Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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