1
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Cory MB, Jones CM, Shaffer KD, Venkatesh Y, Giannakoulias S, Perez RM, Lougee MG, Hummingbird E, Pagar VV, Hurley CM, Li A, Mach RH, Kohli RM, Petersson EJ. FRETing about the details: Case studies in the use of a genetically encoded fluorescent amino acid for distance-dependent energy transfer. Protein Sci 2023; 32:e4633. [PMID: 36974585 PMCID: PMC10108435 DOI: 10.1002/pro.4633] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 03/22/2023] [Accepted: 03/24/2023] [Indexed: 03/29/2023]
Abstract
Förster resonance energy transfer (FRET) is a valuable method for monitoring protein conformation and biomolecular interactions. Intrinsically fluorescent amino acids that can be genetically encoded, such as acridonylalanine (Acd), are particularly useful for FRET studies. However, quantitative interpretation of FRET data to derive distance information requires careful use of controls and consideration of photophysical effects. Here we present two case studies illustrating how Acd can be used in FRET experiments to study small molecule induced conformational changes and multicomponent biomolecular complexes.
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Affiliation(s)
- Michael B. Cory
- Graduate Group in Biochemistry and BiophysicsPerelman School of Medicine, University of PennsylvaniaPhiladelphiaPennsylvania19104USA
| | - Chloe M. Jones
- Graduate Group in Biochemistry and BiophysicsPerelman School of Medicine, University of PennsylvaniaPhiladelphiaPennsylvania19104USA
| | - Kyle D. Shaffer
- Department of ChemistrySchool of Arts and Sciences, University of PennsylvaniaPhiladelphiaPennsylvania19104USA
| | - Yarra Venkatesh
- Department of ChemistrySchool of Arts and Sciences, University of PennsylvaniaPhiladelphiaPennsylvania19104USA
| | - Sam Giannakoulias
- Department of ChemistrySchool of Arts and Sciences, University of PennsylvaniaPhiladelphiaPennsylvania19104USA
| | - Ryann M. Perez
- Department of ChemistrySchool of Arts and Sciences, University of PennsylvaniaPhiladelphiaPennsylvania19104USA
| | - Marshall G. Lougee
- Department of ChemistrySchool of Arts and Sciences, University of PennsylvaniaPhiladelphiaPennsylvania19104USA
| | - Eshe Hummingbird
- Department of ChemistrySchool of Arts and Sciences, University of PennsylvaniaPhiladelphiaPennsylvania19104USA
| | - Vinayak V. Pagar
- Department of ChemistrySchool of Arts and Sciences, University of PennsylvaniaPhiladelphiaPennsylvania19104USA
| | - Christina M. Hurley
- Graduate Group in Biochemistry and BiophysicsPerelman School of Medicine, University of PennsylvaniaPhiladelphiaPennsylvania19104USA
| | - Allen Li
- Department of ChemistrySchool of Arts and Sciences, University of PennsylvaniaPhiladelphiaPennsylvania19104USA
| | - Robert H. Mach
- Department of RadiologyPerelman School of Medicine, University of PennsylvaniaPhiladelphiaPennsylvania19104USA
| | - Rahul M. Kohli
- Department of Biochemistry and BiophysicsPerelman School of Medicine, University of PennsylvaniaPhiladelphiaPennsylvania19104USA
- Department of MedicinePerelman School of Medicine, University of PennsylvaniaPhiladelphiaPennsylvania19104USA
| | - E. James Petersson
- Department of ChemistrySchool of Arts and Sciences, University of PennsylvaniaPhiladelphiaPennsylvania19104USA
- Department of Biochemistry and BiophysicsPerelman School of Medicine, University of PennsylvaniaPhiladelphiaPennsylvania19104USA
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2
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Pancoe SX, Wang YJ, Shimogawa M, Perez RM, Giannakoulias S, Petersson EJ. Effects of Mutations and Post-Translational Modifications on α-Synuclein In Vitro Aggregation. J Mol Biol 2022; 434:167859. [PMID: 36270580 PMCID: PMC9922159 DOI: 10.1016/j.jmb.2022.167859] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 11/06/2022]
Abstract
Fibrillar aggregates of the α-synuclein (αS) protein are the hallmark of Parkinson's Disease and related neurodegenerative disorders. Characterization of the effects of mutations and post-translational modifications (PTMs) on the αS aggregation rate can provide insight into the mechanism of fibril formation, which remains elusive in spite of intense study. A comprehensive collection (375 examples) of mutant and PTM aggregation rate data measured using the fluorescent probe thioflavin T is presented, as well as a summary of the effects of fluorescent labeling on αS aggregation (20 examples). A curated set of 131 single mutant de novo aggregation experiments are normalized to wild type controls and analyzed in terms of structural data for the monomer and fibrillar forms of αS. These tabulated data serve as a resource to the community to help in interpretation of aggregation experiments and to potentially be used as inputs for computational models of aggregation.
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Affiliation(s)
- Samantha X Pancoe
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA
| | - Yanxin J Wang
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA
| | - Marie Shimogawa
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA
| | - Ryann M Perez
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA
| | - Sam Giannakoulias
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA
| | - E James Petersson
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA.
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3
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Pan B, Shimogawa M, Zhao J, Rhoades E, Kashina A, Petersson EJ. Cysteine-Based Mimic of Arginylation Reproduces Neuroprotective Effects of the Authentic Post-Translational Modification on α-Synuclein. J Am Chem Soc 2022; 144:7911-7918. [PMID: 35451816 PMCID: PMC9922158 DOI: 10.1021/jacs.2c02499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Arginylation is an understudied post-translational modification (PTM) involving the transfer of arginine to aspartate or glutamate sidechains in a protein. Among the targets of this PTM is α-synuclein (αS), a neuronal protein involved in regulating synaptic vesicles. The aggregation of αS is implicated in neurodegenerative diseases, particularly in Parkinson's disease, and arginylation has been found to protect against this pathological process. Arginylated αS has been studied through semisynthesis involving multipart native chemical ligation (NCL), but this can be very labor-intensive with low yields. Here, we present a facile way to introduce a mimic of the arginylation modification into a protein of interest, compatible with orthogonal installation of labels such as fluorophores. We synthesize bromoacetyl arginine and react it with recombinant, site-specific cysteine mutants of αS. We validate the mimic by testing the vesicle binding affinity of mimic-arginylated αS, as well as its aggregation kinetics and monomer incorporation into fibrils, and comparing these results to those of authentically arginylated αS produced through NCL. In cultured neurons, we compare the fibril seeding capabilities of preformed fibrils carrying a small percentage of arginylated αS. We find that, consistent with authentically arginylated αS, mimic-arginylated αS does not perturb the protein's native function but alters aggregation kinetics and monomer incorporation. Both mimic and authentically modified αS suppress aggregation in neuronal cells. Our results provide further insight into the neuroprotective effects of αS arginylation, and our alternative strategy to generate arginylated αS enables the study of this PTM in proteins not accessible through NCL.
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Affiliation(s)
- Buyan Pan
- Department of Chemistry; University of Pennsylvania; 231 South 34th Street; Philadelphia, Pennsylvania 19104, USA
| | - Marie Shimogawa
- Department of Chemistry; University of Pennsylvania; 231 South 34th Street; Philadelphia, Pennsylvania 19104, USA
| | - Jun Zhao
- Department of Biomedical Sciences; University of Pennsylvania School of Veterinary Medicine; 3800 Spruce Street; Philadelphia, Pennsylvania, 19104, USA
| | - Elizabeth Rhoades
- Department of Chemistry; University of Pennsylvania; 231 South 34th Street; Philadelphia, Pennsylvania 19104, USA
| | - Anna Kashina
- Department of Biomedical Sciences; University of Pennsylvania School of Veterinary Medicine; 3800 Spruce Street; Philadelphia, Pennsylvania, 19104, USA
| | - E. James Petersson
- Department of Chemistry; University of Pennsylvania; 231 South 34th Street; Philadelphia, Pennsylvania 19104, USA
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4
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Shimogawa M, Petersson EJ. New strategies for fluorescently labeling proteins in the study of amyloids. Curr Opin Chem Biol 2021; 64:57-66. [PMID: 34091264 PMCID: PMC8585672 DOI: 10.1016/j.cbpa.2021.04.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 04/18/2021] [Accepted: 04/20/2021] [Indexed: 01/25/2023]
Abstract
Amyloid proteins are widely studied, both for their unusual biophysical properties and their association with disorders such as Alzheimer's and Parkinson's disease. Fluorescence-based methods using site-specifically labeled proteins can provide information on the details of their structural dynamics and their roles in specific biological processes. Here, we describe the application of different labeling methods and novel fluorescent probe strategies to the study of amyloid proteins, both for in vitro biophysical experiments and for in vivo imaging. These labeling tools can be elegantly used to answer important questions on the function and pathology of amyloid proteins.
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Affiliation(s)
- Marie Shimogawa
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA, 19104, USA
| | - E James Petersson
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA, 19104, USA.
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5
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Jones CM, Robkis DM, Blizzard RJ, Munari M, Venkatesh Y, Mihaila TS, Eddins AJ, Mehl RA, Zagotta WN, Gordon SE, Petersson EJ. Genetic encoding of a highly photostable, long lifetime fluorescent amino acid for imaging in mammalian cells. Chem Sci 2021; 12:11955-11964. [PMID: 34976337 PMCID: PMC8634729 DOI: 10.1039/d1sc01914g] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 07/18/2021] [Indexed: 01/28/2023] Open
Abstract
Acridonylalanine (Acd) is a fluorescent amino acid that is highly photostable, with a high quantum yield and long fluorescence lifetime in water. These properties make it superior to existing genetically encodable fluorescent amino acids for monitoring protein interactions and conformational changes through fluorescence polarization or lifetime experiments, including fluorescence lifetime imaging microscopy (FLIM). Here, we report the genetic incorporation of Acd using engineered pyrrolysine tRNA synthetase (RS) mutants that allow for efficient Acd incorporation in both E. coli and mammalian cells. We compare protein yields and amino acid specificity for these Acd RSs to identify an optimal construct. We also demonstrate the use of Acd in FLIM, where its long lifetime provides strong contrast compared to endogenous fluorophores and engineered fluorescent proteins, which have lifetimes less than 5 ns.
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Affiliation(s)
- Chloe M Jones
- Department of Chemistry, University of Pennsylvania 231 South 34th Street Philadelphia PA 19104 USA
- Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania 3700 Hamilton Walk Philadelphia PA 19104 USA
| | - D Miklos Robkis
- Department of Chemistry, University of Pennsylvania 231 South 34th Street Philadelphia PA 19104 USA
- Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania 3700 Hamilton Walk Philadelphia PA 19104 USA
| | - Robert J Blizzard
- Department of Biochemistry and Biophysics, Oregon State University 2011 Ag Life Sciences Building Corvallis Oregon 97331 USA
| | - Mika Munari
- Department of Physiology and Biophysics, University of Washington 1705 NE Pacific St., Box 357290 Seattle WA 98195 USA
| | - Yarra Venkatesh
- Department of Chemistry, University of Pennsylvania 231 South 34th Street Philadelphia PA 19104 USA
| | - Tiberiu S Mihaila
- Department of Chemistry, University of Pennsylvania 231 South 34th Street Philadelphia PA 19104 USA
| | - Alex J Eddins
- Department of Biochemistry and Biophysics, Oregon State University 2011 Ag Life Sciences Building Corvallis Oregon 97331 USA
| | - Ryan A Mehl
- Department of Biochemistry and Biophysics, Oregon State University 2011 Ag Life Sciences Building Corvallis Oregon 97331 USA
| | - William N Zagotta
- Department of Physiology and Biophysics, University of Washington 1705 NE Pacific St., Box 357290 Seattle WA 98195 USA
| | - Sharona E Gordon
- Department of Physiology and Biophysics, University of Washington 1705 NE Pacific St., Box 357290 Seattle WA 98195 USA
| | - E James Petersson
- Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania 3700 Hamilton Walk Philadelphia PA 19104 USA
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6
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Caminati G, Martina MR, Menichetti S, Procacci P. Blocking the FKBP12 induced dendrimeric burst in aberrant aggregation of α-synuclein by using the ElteN378 synthetic inhibitor. J Enzyme Inhib Med Chem 2019; 34:1711-1715. [PMID: 31547734 PMCID: PMC6764402 DOI: 10.1080/14756366.2019.1667342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
α-Synuclein (α-syn), a disordered cytoplasmatic protein, plays a fundamental role in the pathogenesis of Parkinson’s disease (PD). Here, we have shown, using photophysical measurements, that addition of FKBP12 to α-syn solutions, dramatically accelerates protein aggregation, leading to an explosion of dendritic structures revealed by fluorescence and phase-contrast microscopy. We have further demonstrated that this aberrant α-syn aggregation can be blocked using a recently discovered non-immunosuppressive synthetic inhibitor of FKBP12, ElteN378. The role of FKBP12 and of ElteN378 in the α-syn aggregation mechanism has been elucidated using molecular dynamics simulations based on an effective coarse-grained model. The reported data not only reveal a new potent synthetic drug as a candidate for early stage treatment of α-syn dependent neurodegenerations but also pave the way to a deeper understanding of the mechanism of action of FKBP12 on α-syn oligomeric aggregation, a topic which is still controversial.
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Affiliation(s)
- Gabriella Caminati
- Department of Chemistry "Ugo Schiff", University of Florence , Sesto Fiorentino , Italy.,Center for Colloid and Surface Science (CSGI), University of Florence , Sesto Fiorentino , Italy
| | - Maria Raffaella Martina
- Department of Chemistry "Ugo Schiff", University of Florence , Sesto Fiorentino , Italy.,Center for Colloid and Surface Science (CSGI), University of Florence , Sesto Fiorentino , Italy
| | - Stefano Menichetti
- Center for Colloid and Surface Science (CSGI), University of Florence , Sesto Fiorentino , Italy
| | - Piero Procacci
- Center for Colloid and Surface Science (CSGI), University of Florence , Sesto Fiorentino , Italy
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7
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Mizuguchi C, Nakagawa M, Namba N, Sakai M, Kurimitsu N, Suzuki A, Fujita K, Horiuchi S, Baba T, Ohgita T, Nishitsuji K, Saito H. Mechanisms of aggregation and fibril formation of the amyloidogenic N-terminal fragment of apolipoprotein A-I. J Biol Chem 2019; 294:13515-13524. [PMID: 31341020 DOI: 10.1074/jbc.ra119.008000] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 07/20/2019] [Indexed: 01/26/2023] Open
Abstract
The N-terminal (1-83) fragment of the major constituent of plasma high-density lipoprotein, apolipoprotein A-I (apoA-I), strongly tends to form amyloid fibrils, leading to systemic amyloidosis. Here, using a series of deletion variants, we examined the roles of two major amyloidogenic segments (residues 14-22 and 50-58) in the aggregation and fibril formation of an amyloidogenic G26R variant of the apoA-I 1-83 fragment (apoA-I 1-83/G26R). Thioflavin T fluorescence assays and atomic force microscopy revealed that elimination of residues 14-22 completely inhibits fibril formation of apoA-I 1-83/G26R, whereas Δ32-40 and Δ50-58 variants formed fibrils with markedly reduced nucleation and fibril growth rates. CD measurements revealed structural transitions from random coil to β-sheet structures in all deletion variants except for the Δ14-22 variant, indicating that residues 14-22 are critical for the β-transition and fibril formation. Thermodynamic analysis of the kinetics of fibril formation by apoA-I 1-83/G26R indicated that both nucleation and fibril growth are enthalpically unfavorable, whereas entropically, nucleation is favorable, but fibril growth is unfavorable. Interestingly, the nucleation of the Δ50-58 variant was entropically unfavorable, indicating that residues 50-58 entropically promote the nucleation step in fibril formation of apoA-I 1-83/G26R. Moreover, a residue-level structural investigation of apoA-I 1-83/G26R fibrils with site-specific pyrene labeling indicated that the two amyloidogenic segments are in close proximity to form an amyloid core structure, whereas the N- and C-terminal tail regions are excluded from the amyloid core. These results provide critical insights into the aggregation mechanism and fibril structure of the amyloidogenic N-terminal fragment of apoA-I.
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Affiliation(s)
- Chiharu Mizuguchi
- Department of Biophysical Chemistry, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan
| | - Miho Nakagawa
- Department of Biophysical Chemistry, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan
| | - Norihiro Namba
- Department of Biophysical Chemistry, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan
| | - Misae Sakai
- Department of Biophysical Chemistry, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan
| | - Naoko Kurimitsu
- Department of Biophysical Chemistry, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan
| | - Ayane Suzuki
- Department of Biophysical Chemistry, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan
| | - Kaho Fujita
- Department of Biophysical Chemistry, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan
| | - Sayaka Horiuchi
- Department of Biophysical Chemistry, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan
| | - Teruhiko Baba
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba 305-8565, Japan
| | - Takashi Ohgita
- Department of Biophysical Chemistry, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan
| | - Kazuchika Nishitsuji
- Department of Biochemistry, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan
| | - Hiroyuki Saito
- Department of Biophysical Chemistry, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan.
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8
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Jun JV, Haney CM, Karpowicz RJ, Giannakoulias S, Lee VMY, Petersson EJ, Chenoweth DM. A "Clickable" Photoconvertible Small Fluorescent Molecule as a Minimalist Probe for Tracking Individual Biomolecule Complexes. J Am Chem Soc 2019; 141:1893-1897. [PMID: 30657670 DOI: 10.1021/jacs.8b13094] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Photoconvertible fluorophores can enable the visualization and tracking of a specific biomolecules, complexes, and cellular compartments with precise spatiotemporal control. The field of photoconvertible probes is dominated by fluorescent protein variants, which can introduce perturbations to the target biomolecules due to their large size. Here, we present a photoconvertible small molecule, termed CPX, that can be conjugated to any target through azide-alkyne cycloaddition ("click" reaction). To demonstrate its utility, we have applied CPX to study (1) trafficking of biologically relevant synthetic vesicles and (2) intracellular processes involved in transmission of α-synuclein (αS) pathology. Our results demonstrate that CPX can serve as a minimally perturbing probe for tracking the dynamics of biomolecules.
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Affiliation(s)
- Joomyung V Jun
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Conor M Haney
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Richard J Karpowicz
- Department of Pathology and Laboratory Medicine , Center for Neurodegenerative Disease Research, University of Pennsylvania , 3600 Spruce Street , Philadelphia , Pennsylvania 19104 , United States
| | - Sam Giannakoulias
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Virginia M-Y Lee
- Department of Pathology and Laboratory Medicine , Center for Neurodegenerative Disease Research, University of Pennsylvania , 3600 Spruce Street , Philadelphia , Pennsylvania 19104 , United States
| | - E James Petersson
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - David M Chenoweth
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
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9
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Flynn JD, Jiang Z, Lee JC. Segmental 13 C-Labeling and Raman Microspectroscopy of α-Synuclein Amyloid Formation. Angew Chem Int Ed Engl 2018; 57:17069-17072. [PMID: 30371967 PMCID: PMC6688611 DOI: 10.1002/anie.201809865] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/05/2018] [Indexed: 01/05/2023]
Abstract
Mapping conformational changes of α-synuclein (α-syn) from soluble, unstructured monomers to β-sheet- rich aggregates is crucial towards understanding amyloid formation. Raman microspectroscopy is now used to spatially resolve conformational heterogeneity of amyloid aggregates and monitor amyloid formation of segmentally 13 C-labeled α-syn in real-time. As the 13 C-isotope shifts the amide-I stretching frequency to lower energy, the ligated construct, 13 C1-8612 CS87C-140 -α-syn, exhibits two distinct bands allowing for simultaneous detection of secondary structural changes in N-terminal 1-86 and C-terminal 87-140 residues. The disordered-to-β-sheet conformational change is first observed for the N-terminal followed by the C-terminal region. Finally, Raman spectroscopic changes occurred prior to Thioflavin T fluorescence enhancement, indicating that the amide-I band is a superior probe of amyloid formation.
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Affiliation(s)
- Jessica D. Flynn
- National Heart, Lung, and Blood Institute, National
Institutes of Health, Bethesda, MD 20892, United States
| | - Zhiping Jiang
- National Heart, Lung, and Blood Institute, National
Institutes of Health, Bethesda, MD 20892, United States
| | - Jennifer C. Lee
- National Heart, Lung, and Blood Institute, National
Institutes of Health, Bethesda, MD 20892, United States
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10
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Flynn JD, Jiang Z, Lee JC. Segmental
13
C‐Labeling and Raman Microspectroscopy of α‐Synuclein Amyloid Formation. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201809865] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jessica D. Flynn
- National Heart, Lung, and Blood Institute National Institutes of Health Bethesda MD 20892 USA
| | - Zhiping Jiang
- National Heart, Lung, and Blood Institute National Institutes of Health Bethesda MD 20892 USA
| | - Jennifer C. Lee
- National Heart, Lung, and Blood Institute National Institutes of Health Bethesda MD 20892 USA
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11
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Hsieh CJ, Ferrie JJ, Xu K, Lee I, Graham TJA, Tu Z, Yu J, Dhavale D, Kotzbauer P, Petersson EJ, Mach RH. Alpha Synuclein Fibrils Contain Multiple Binding Sites for Small Molecules. ACS Chem Neurosci 2018; 9:2521-2527. [PMID: 29750499 DOI: 10.1021/acschemneuro.8b00177] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The fibrillary aggregation of the protein alpha synuclein (Asyn) is a hallmark of Parkinson's disease, and the identification of small molecule binding sites on fibrils is essential to the development of diagnostic imaging probes. A series of molecular modeling, photoaffinity labeling, mass spectrometry, and radioligand binding studies were conducted on Asyn fibrils. The results of these studies revealed the presence of three different binding sites within fibrillar Asyn capable of binding small molecules with moderate to high affinity. A knowledge of the amino acid residues in these binding sites will be important in the design of high affinity probes capable of imaging fibrillary species of Asyn.
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Affiliation(s)
- Chia-Ju Hsieh
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - John J. Ferrie
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Kuiying Xu
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Iljung Lee
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Thomas J. A. Graham
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Zhude Tu
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Jennifer Yu
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Dhruva Dhavale
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Paul Kotzbauer
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - E. James Petersson
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Robert H. Mach
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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