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Dolui S, Roy A, Pal U, Kundu S, Pandit E, N Ratha B, Pariary R, Saha A, Bhunia A, Maiti NC. Raman Spectroscopic Insights of Phase-Separated Insulin Aggregates. ACS PHYSICAL CHEMISTRY AU 2024; 4:268-280. [PMID: 38800728 PMCID: PMC11117687 DOI: 10.1021/acsphyschemau.3c00065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/30/2024] [Accepted: 01/31/2024] [Indexed: 05/29/2024]
Abstract
Phase-separated protein accumulation through the formation of several aggregate species is linked to the pathology of several human disorders and diseases. Our current investigation envisaged detailed Raman signature and structural intricacy of bovine insulin in its various forms of aggregates produced in situ at an elevated temperature (60 °C). The amide I band in the Raman spectrum of the protein in its native-like conformation appeared at 1655 cm-1 and indicated the presence of a high content of α-helical structure as prepared freshly in acidic pH. The disorder content (turn and coils) also was predominately present in both the monomeric and oligomeric states and was confirmed by the presence shoulder amide I maker band at ∼1680 cm-1. However, the band shifted to ∼1671 cm-1 upon the transformation of the protein solution into fibrillar aggregates as produced for a longer time of incubation. The protein, however, maintained most of its helical conformation in the oligomeric phase; the low-frequency backbone α-helical conformation signal at ∼935 cm-1 was similar to that of freshly prepared aqueous protein solution enriched in helical conformation. The peak intensity was significantly weak in the fibrillar aggregates, and it appeared as a good Raman signature to follow the phase separation and the aggregation behavior of insulin and similar other proteins. Tyrosine phenoxy moieties in the protein may maintained its H-bond donor-acceptor integrity throughout the course of fibril formation; however, it entered in more hydrophobic environment in its journey of fibril formation. In addition, it was noticed that oligomeric bovine insulin maintained the orientation/conformation of the disulfide bonds. However, in the fibrillar state, the disulfide linkages became more strained and preferred to maintain a single conformation state.
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Affiliation(s)
- Sandip Dolui
- Structural
Biology and Bioinformatics Division, Indian
Institute of Chemical Biology, Council of Scientific and Industrial
Research, 4, Raja S.C. Mullick Road, Kolkata 700032, India
| | - Anupam Roy
- Structural
Biology and Bioinformatics Division, Indian
Institute of Chemical Biology, Council of Scientific and Industrial
Research, 4, Raja S.C. Mullick Road, Kolkata 700032, India
| | - Uttam Pal
- Structural
Biology and Bioinformatics Division, Indian
Institute of Chemical Biology, Council of Scientific and Industrial
Research, 4, Raja S.C. Mullick Road, Kolkata 700032, India
| | - Shubham Kundu
- Structural
Biology and Bioinformatics Division, Indian
Institute of Chemical Biology, Council of Scientific and Industrial
Research, 4, Raja S.C. Mullick Road, Kolkata 700032, India
| | - Esha Pandit
- Structural
Biology and Bioinformatics Division, Indian
Institute of Chemical Biology, Council of Scientific and Industrial
Research, 4, Raja S.C. Mullick Road, Kolkata 700032, India
| | - Bhisma N Ratha
- Department
of Chemical Sciences, Bose Institute, Unified Academic Campus, Salt Lake,
Sector V, Kolkata 700091, India
| | - Ranit Pariary
- Department
of Chemical Sciences, Bose Institute, Unified Academic Campus, Salt Lake,
Sector V, Kolkata 700091, India
| | - Achintya Saha
- Department
of Chemical Technology, University of Calcutta, 92 Acharya Prafulla Chandra Road, Calcutta 700009, India
| | - Anirban Bhunia
- Department
of Chemical Sciences, Bose Institute, Unified Academic Campus, Salt Lake,
Sector V, Kolkata 700091, India
| | - Nakul C. Maiti
- Structural
Biology and Bioinformatics Division, Indian
Institute of Chemical Biology, Council of Scientific and Industrial
Research, 4, Raja S.C. Mullick Road, Kolkata 700032, India
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2
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Ye S, Zhong K, Huang Y, Zhang G, Sun C, Jiang J. Artificial Intelligence-based Amide-II Infrared Spectroscopy Simulation for Monitoring Protein Hydrogen Bonding Dynamics. J Am Chem Soc 2024; 146:2663-2672. [PMID: 38240637 DOI: 10.1021/jacs.3c12258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
The structurally sensitive amide II infrared (IR) bands of proteins provide valuable information about the hydrogen bonding of protein secondary structures, which is crucial for understanding protein dynamics and associated functions. However, deciphering protein structures from experimental amide II spectra relies on time-consuming quantum chemical calculations on tens of thousands of representative configurations in solvent water. Currently, the accurate simulation of amide II spectra for whole proteins remains a challenge. Here, we present a machine learning (ML)-based protocol designed to efficiently simulate the amide II IR spectra of various proteins with an accuracy comparable to experimental results. This protocol stands out as a cost-effective and efficient alternative for studying protein dynamics, including the identification of secondary structures and monitoring the dynamics of protein hydrogen bonding under different pH conditions and during protein folding process. Our method provides a valuable tool in the field of protein research, focusing on the study of dynamic properties of proteins, especially those related to hydrogen bonding, using amide II IR spectroscopy.
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Affiliation(s)
- Sheng Ye
- School of Artificial Intelligence, Anhui University, Hefei, Anhui 230601, People's Republic of China
| | - Kai Zhong
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747AG, Netherlands
| | - Yan Huang
- Key Laboratory of Precision and Intelligent Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Guozhen Zhang
- Hefei National Research Center of Physical Sciences at the Microscale, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Changyin Sun
- School of Artificial Intelligence, Anhui University, Hefei, Anhui 230601, People's Republic of China
| | - Jun Jiang
- Key Laboratory of Precision and Intelligent Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
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3
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Slekiene N, Snitka V, Bruzaite I, Ramanavicius A. Influence of TiO 2 and ZnO Nanoparticles on α-Synuclein and β-Amyloid Aggregation and Formation of Protein Fibrils. MATERIALS (BASEL, SWITZERLAND) 2022; 15:7664. [PMID: 36363256 PMCID: PMC9653647 DOI: 10.3390/ma15217664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 10/26/2022] [Accepted: 10/27/2022] [Indexed: 06/16/2023]
Abstract
The most common neurological disorders, i.e., Parkinson's disease (PD) and Alzheimer's disease (AD), are characterized by degeneration of cognitive functions due to the loss of neurons in the central nervous system. The aggregation of amyloid proteins is an important pathological feature of neurological disorders.The aggregation process involves a series of complex structural transitions from monomeric to the formation of fibrils. Despite its potential importance in understanding the pathobiology of PD and AD diseases, the details of the aggregation process are still unclear. Nanoparticles (NPs) absorbed by the human circulatory system can interact with amyloid proteins in the human brain and cause PD. In this work, we report the study of the interaction between TiO2 nanoparticles (TiO2-NPs) and ZnO nanoparticles (ZnO-NPs) on the aggregation kinetics of β-amyloid fragment 1-40 (βA) and α-synuclein protein using surface-enhanced Raman spectroscopy (SERS) and tip-enhanced Raman spectroscopy (TERS). The characterizations of ZnO-NPs and TiO2-NPs were evaluated by X-ray diffraction (XRD) spectrum, atomic force microscopy (AFM), and UV-Vis spectroscopy. The interaction of nanoparticles with amyloid proteins was investigated by SERS. Our study showed that exposure of amyloid protein molecules to TiO2-NPs and ZnO-NPs after incubation at 37 °C caused morphological changes and stimulated aggregation and fibrillation. In addition, significant differences in the intensity and location of active Raman frequencies in the amide I domain were found. The principal component analysis (PCA) results show that the effect of NPs after incubation at 4 °C does not cause changes in βA structure.
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Affiliation(s)
- Nora Slekiene
- Pharmacy Center, Institute of Biomedical Sciences, Faculty of Medicine, University of Vilnius, M.K. Čiurlionio g. 21/27, LT-03101 Vilnius, Lithuania
| | - Valentinas Snitka
- Research Center for Microsystems and Nanotechnology, Kaunas University of Technology, 65 Studentu Str., LT-51369 Kaunas, Lithuania
| | - Ingrida Bruzaite
- Department of Chemistry and Bioengineering, Faculty of Fundamental Sciences, Vilnius Gediminas Technical University, Sauletekio Av. 11, LT-10223 Vilnius, Lithuania
- Laboratory of Electrochemical Energy Conversion, State Research Institute Centre for Physical Sciences and Technology, Sauletekio Av. 3, LT-10257 Vilnius, Lithuania
| | - Arunas Ramanavicius
- Department of Physical Chemistry, Faculty of Chemistry and Geosciences, Vilnius University, 24 Naugarduko Str., LT-03225 Vilnius, Lithuania
- Laboratory of Nanotechnology, State Research Institute Centre for Physical Sciences and Technology, Sauletekio Av. 3, LT-10257 Vilnius, Lithuania
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4
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Hilt S, Liu R, Maezawa I, Rojalin T, Aung HH, Budamagunta M, Slez R, Gong Q, Carney RP, Voss JC. Novel Stilbene-Nitroxyl Hybrid Compounds Display Discrete Modulation of Amyloid Beta Toxicity and Structure. Front Chem 2022; 10:896386. [PMID: 35720993 PMCID: PMC9204515 DOI: 10.3389/fchem.2022.896386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 04/21/2022] [Indexed: 11/13/2022] Open
Abstract
Several neurodegenerative diseases are driven by misfolded proteins that assemble into soluble aggregates. These "toxic oligomers" have been associated with a plethora of cellular dysfunction and dysregulation, however the structural features underlying their toxicity are poorly understood. A major impediment to answering this question relates to the heterogeneous nature of the oligomers, both in terms of structural disorder and oligomer size. This not only complicates elucidating the molecular etiology of these disorders, but also the druggability of these targets as well. We have synthesized a class of bifunctional stilbenes to modulate both the conformational toxicity within amyloid beta oligomers (AβO) and the oxidative stress elicited by AβO. Using a neuronal culture model, we demonstrate this bifunctional approach has the potential to counter the molecular pathogenesis of Alzheimer's disease in a powerful, synergistic manner. Examination of AβO structure by various biophysical tools shows that each stilbene candidate uniquely alters AβO conformation and toxicity, providing insight towards the future development of structural correctors for AβO. Correlations of AβO structural modulation and bioactivity displayed by each provides insights for future testing in vivo. The multi-target activity of these hybrid molecules represents a highly advantageous feature for disease modification in Alzheimer's, which displays a complex, multifactorial etiology. Importantly, these novel small molecules intervene with intraneuronal AβO, a necessary feature to counter the cycle of dysregulation, oxidative stress and inflammation triggered during the earliest stages of disease progression.
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Affiliation(s)
- Silvia Hilt
- Department of Biochemistry and Molecular Medicine, University of California, Davis, Davis, CA, United States
| | - Ruiwu Liu
- Department of Biochemistry and Molecular Medicine, University of California, Davis, Davis, CA, United States
| | - Izumi Maezawa
- M.I.N.D. Institute and Department of Pathology and Laboratory Medicine, University of California, Davis, Davis, CA, United States
| | - Tatu Rojalin
- Department of Biomedical Engineering, University of California, Davis, Davis, CA, United States
| | - Hnin H. Aung
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, Davis, CA, United States
- Research Division, California Air Resource Board, Sacramento, CA, United States
| | - Madhu Budamagunta
- Department of Biochemistry and Molecular Medicine, University of California, Davis, Davis, CA, United States
| | - Ryan Slez
- Department of Biochemistry and Molecular Medicine, University of California, Davis, Davis, CA, United States
| | - Qizhi Gong
- Department of Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Randy P. Carney
- Department of Biomedical Engineering, University of California, Davis, Davis, CA, United States
| | - John C. Voss
- Department of Biochemistry and Molecular Medicine, University of California, Davis, Davis, CA, United States
- Paramag Biosciences Inc., Davis, CA, United States
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5
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Das A, Korn A, Carroll A, Carver JA, Maiti S. Application of the Double-Mutant Cycle Strategy to Protein Aggregation Reveals Transient Interactions in Amyloid-β Oligomers. J Phys Chem B 2021; 125:12426-12435. [PMID: 34748334 DOI: 10.1021/acs.jpcb.1c05829] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Transient oligomeric intermediates in the peptide or protein aggregation pathway are suspected to be the key toxic species in many amyloid diseases, but deciphering their molecular nature has remained a challenge. Here we show that the strategy of "double-mutant cycles", used effectively in probing protein-folding intermediates, can reveal transient interactions during protein aggregation. It does so by comparing the changes in thermodynamic parameters between the wild type, and single and double mutants. We demonstrate the strategy by probing the possible transient salt bridge partner of lysine 28 (K28) in the oligomeric states of amyloid β-40 (Aβ40), the putative toxic species in Alzheimer's disease. In mature fibrils, the binding partner is aspartate 23. This interaction differentiates Aβ40 from the more toxic Aβ42, where K28's binding partner is the C-terminal carboxylate. We selectively acetylated K28 and amidated the C-terminus of Aβ40, creating four distinct variants. Spectroscopic measurements of the kinetics and thermodynamics of aggregation show that K28 and the C-terminus interact transiently in the early phases of the Aβ40 aggregation pathway. Hydrogen-deuterium exchange mass spectrometry (using a simple analysis method that we introduce here that takes into account the isotopic mass distribution) supports this interpretation. It is also supported by cellular toxicity measurements, suggesting possible similarities in the mechanisms of toxicity of Aβ40 oligomers (which are more toxic than Aβ40 fibrils) and Aβ42. Our results show that double-mutant cycles can be a powerful tool for probing transient interactions during protein aggregation.
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Affiliation(s)
- Anirban Das
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Alexander Korn
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstr. 16-18, D-04107 Leipzig, Germany
| | - Adam Carroll
- Research School of Chemistry, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - John A Carver
- Research School of Chemistry, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Sudipta Maiti
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
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6
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Ghosh S, Verma S. Carvedilol inhibits Aβ 25-35 fibrillation by intervening the early stage helical intermediate formation: A biophysical investigation. Int J Biol Macromol 2021; 188:263-271. [PMID: 34371042 DOI: 10.1016/j.ijbiomac.2021.08.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 07/16/2021] [Accepted: 08/03/2021] [Indexed: 12/28/2022]
Abstract
Self-assembly of disordered amyloid-beta (Aβ) peptides results in highly ordered amyloid fibrils. The structural information of the early-stage events and also in the presence of inhibitors is of great significance. It is challenging to acquire due to the nature of the amyloids and experimental constraints. Here, we demonstrate the cascade of aggregation (early to late) of the Aβ25-35 peptide in the absence and presence of carvedilol, a nonselective β-adrenergic receptor blocker. The aggregation process of Aβ25-35 peptide is monitored using Thioflavin T (ThT) fluorescence, dynamic light scattering (DLS), circular dichroism (CD), Raman spectroscopic techniques, and imaging experiments. We find that the Aβ25-35 peptide undergoes an early-stage (3-6 h) helical intermediate formation across the fibrillation pathway using CD and Raman measurements. Carvedilol obstructs the helical intermediate formation of Aβ25-35 peptide resulting in inhibition. CD spectra and deconvolution of the Raman bands suggest the β-sheet formation (24-100 h) in the absence of carvedilol. Spectroscopic results indicate a disordered structure for the peptide in the presence of carvedilol (24-100 h). Electron microscopy (EM) shows the formation of polymorphic fibrils for the peptide alone and non-amyloidal aggregates in the presence of carvedilol. Molecular docking study suggests that the plausible mode of interaction with carvedilol involves the C-terminal residues of the peptide.
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Affiliation(s)
- Sudeshna Ghosh
- Department of Chemistry, Indian Institute of Technology Kanpur, UP 208016, India.
| | - Sandeep Verma
- Department of Chemistry, Indian Institute of Technology Kanpur, UP 208016, India.
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7
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Saini R, Shuaib S, Goyal D, Goyal B. Impact of Mutations on the Conformational Transition from α-Helix to β-Sheet Structures in Arctic-Type Aβ 40: Insights from Molecular Dynamics Simulations. ACS OMEGA 2020; 5:23219-23228. [PMID: 32954172 PMCID: PMC7495726 DOI: 10.1021/acsomega.0c02983] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 08/13/2020] [Indexed: 05/13/2023]
Abstract
The amyloid-β (Aβ) protein aggregation into toxic oligomers and fibrils has been recognized as a key player in the pathogenesis of Alzheimer's disease. Recent experiments reported that a double alanine mutation (L17A/F19A) in the central hydrophobic core (CHC) region of [G22]Aβ40 (familial Arctic mutation) diminished the self-assembly propensity of [G22]Aβ40. However, the molecular mechanism behind the decreased aggregation tendency of [A17/A19/G22]Aβ40 is not well understood. Herein, we carried out molecular dynamics simulations to elucidate the structure and dynamics of [G22]Aβ40 and [A17/A19/G22]Aβ40. The results for the secondary structure analysis reveal a significantly increased amount of the helical content in the CHC and C-terminal region of [A17/A19/G22]Aβ40 as compared to [G22]Aβ40. The bending free-energy analysis of D23-K28 salt bridge suggests that the double alanine mutation in the CHC region of [G22]Aβ40 has the potential to reduce the fibril formation rate by 0.57 times of [G22]Aβ40. Unlike [G22]Aβ40, [A17/A19/G22]Aβ40 largely sampled helical conformation, as determined by the minimum energy conformations extracted from the free-energy landscape. The present study provided atomic level details into the experimentally observed diminished aggregation tendency of [A17/A19/G22]Aβ40 as compared to [G22]Aβ40.
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Affiliation(s)
- Rajneet
Kaur Saini
- Department
of Chemistry, Faculty of Basic and Applied Sciences, Sri Guru Granth Sahib World University, Fatehgarh Sahib 140406, Punjab, India
| | - Suniba Shuaib
- Department
of Chemistry, Faculty of Basic and Applied Sciences, Sri Guru Granth Sahib World University, Fatehgarh Sahib 140406, Punjab, India
| | - Deepti Goyal
- Department
of Chemistry, Faculty of Basic and Applied Sciences, Sri Guru Granth Sahib World University, Fatehgarh Sahib 140406, Punjab, India
| | - Bhupesh Goyal
- School
of Chemistry & Biochemistry, Thapar
Institute of Engineering & Technology, Patiala 147004, Punjab, India
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8
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Dolui S, Mondal A, Roy A, Pal U, Das S, Saha A, Maiti NC. Order, Disorder, and Reorder State of Lysozyme: Aggregation Mechanism by Raman Spectroscopy. J Phys Chem B 2019; 124:50-60. [PMID: 31820990 DOI: 10.1021/acs.jpcb.9b09139] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lysozyme, like many other well-folded globular proteins, under stressful conditions produces nanoscale oligomer assembly and amyloid-like fibrillar aggregates. With engaging Raman microscopy, we made a critical structural analysis of oligomer and other assembly structures of lysozyme obtained from hen egg white and provided a quantitative estimation of a protein secondary structure in different states of its fibrillation. A strong amide I Raman band at 1660 cm-1 and a N-Cα-C stretching band at ∼930 cm-1 clearly indicated the presence of a substantial amount of α-helical folds of the protein in its oligomeric assembly state. In addition, analysis of the amide III region and Raman difference spectra suggested an ample presence of a PPII-like secondary structure in these oligomers without causing major loss of α-helical folds, which is found in the case of monomeric samples. Circular dichroism study also revealed the presence of typical α-helical folds in the oligomeric state. Nonetheless, most of the Raman bands associated with aromatic residues and disulfide (-S-S-) linkages broadened in the oligomeric state and indicated a collapse in the tertiary structure. In the fibrillar state of assembly, the amide I band became much sharper and enriched with the β-sheet secondary structure. Also, the disulfide bond vibration in matured fibrils became much weaker compared to monomer and oligomers and thus confirmed certain loss/cleavage of this bond during fibrillation. The Raman band of tryptophan and tyrosine residues indicated that some of these residues experienced a greater hydrophobic microenvironment in the fibrillar state than the protein in the oligomeric state of the assembly structure.
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Affiliation(s)
- Sandip Dolui
- Structural Biology and Bioinformatics Division , Indian Institute of Chemical Biology, Council of Scientific and Industrial Research , 4, Raja S.C. Mullick Road , Kolkata 700032 , India
| | - Animesh Mondal
- Structural Biology and Bioinformatics Division , Indian Institute of Chemical Biology, Council of Scientific and Industrial Research , 4, Raja S.C. Mullick Road , Kolkata 700032 , India
| | - Anupam Roy
- Structural Biology and Bioinformatics Division , Indian Institute of Chemical Biology, Council of Scientific and Industrial Research , 4, Raja S.C. Mullick Road , Kolkata 700032 , India
| | - Uttam Pal
- Structural Biology and Bioinformatics Division , Indian Institute of Chemical Biology, Council of Scientific and Industrial Research , 4, Raja S.C. Mullick Road , Kolkata 700032 , India
| | - Supriya Das
- Structural Biology and Bioinformatics Division , Indian Institute of Chemical Biology, Council of Scientific and Industrial Research , 4, Raja S.C. Mullick Road , Kolkata 700032 , India
| | - Achintya Saha
- Department of Chemical Technology , University of Calcutta , 92 Acharya Prafulla Chandra Road , Calcutta 700009 , India
| | - Nakul C Maiti
- Structural Biology and Bioinformatics Division , Indian Institute of Chemical Biology, Council of Scientific and Industrial Research , 4, Raja S.C. Mullick Road , Kolkata 700032 , India
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9
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Devitt G, Rice W, Crisford A, Nandhakumar I, Mudher A, Mahajan S. Conformational Evolution of Molecular Signatures during Amyloidogenic Protein Aggregation. ACS Chem Neurosci 2019; 10:4593-4611. [PMID: 31661242 DOI: 10.1021/acschemneuro.9b00451] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Aggregation is a pathological hallmark of proteinopathies such as Alzheimer's disease and results in the deposition of β-sheet-rich amyloidogenic protein aggregates. Such proteinopathies can be classified by the identity of one or more aggregated proteins, with recent evidence also suggesting that distinct molecular conformers (strains) of the same protein can be observed in different diseases, as well is in subtypes of the same disease. Therefore, methods for the quantification of pathological changes in protein conformation are central to understanding and treating proteinopathies. In this work, the evolution of Raman spectroscopic molecular signatures of three conformationally distinct proteins, bovine serum albumin (α-helical-rich), β2-microglobulin (β-sheet-rich), and tau (natively disordered), was assessed during aggregation into oligomers and fibrils. The morphological evolution was tracked using atomic force microscopy and corresponding conformational changes were assessed by their Raman signatures acquired in both wet and dried conditions. A deconvolution model was developed which allowed us to quantify the conformation of the nonregular protein tau, as well as for the oligomeric and fibrillar species of each of the proteins. Principle component analysis of the fingerprint region allowed further identification of the distinguishing spectral features and unsupervised distinction. While an increase in β-sheet is seen on aggregation, crucially, however, each protein also retains a significant proportion of its native monomeric structure after aggregation. Thus, spectral analysis of each aggregated species, oligomeric, as well as fibrillar, for each protein resulted in a unique and quantitative "conformational fingerprint". This approach allowed us to provide the first differential detection of both oligomers and fibrils of the three different amyloidogenic proteins, including tau, whose aggregates have never before been interrogated using spontaneous Raman spectroscopy. Quantitative "conformational fingerprinting" by Raman spectroscopy thus demonstrates its huge potential and utility in understanding proteinopathic disease mechanisms and for providing strain-specific early diagnostic markers and targets for disease-modifying therapies.
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10
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Salimi A, Li H, Shi H, Lee JY. Intrinsic origin of amyloid aggregation: Behavior of histidine (εεε) and (δδδ) tautomer homodimers of Aβ (1–40). Biochim Biophys Acta Gen Subj 2019; 1863:795-801. [DOI: 10.1016/j.bbagen.2019.02.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 02/08/2019] [Accepted: 02/11/2019] [Indexed: 02/08/2023]
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11
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Tan J, Zhang J, Luo Y, Ye S. Misfolding of a Human Islet Amyloid Polypeptide at the Lipid Membrane Populates through β-Sheet Conformers without Involving α-Helical Intermediates. J Am Chem Soc 2019; 141:1941-1948. [PMID: 30621387 DOI: 10.1021/jacs.8b08537] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Amyloid formation has been implicated in many fatal diseases, but its mechanism remains to be clarified due to a lack of effective methods that can capture the transient intermediates. Here, we experimentally demonstrate that sum frequency generation vibrational spectroscopy can unambiguously discriminate the intermediates during amyloid formation at the lipid membrane in situ and in real time by combining the chiral amide I and achiral amide II and amide III spectral signals of the protein backbone. Such a combination can directly identify the formation of β-hairpin-like monomers and β-sheet oligomers and fibrils. A strong correlation between the amide II signals and the formation of β-sheet oligomers and fibrils was found. With this approach, the structural evolution of human islet amyloid polypeptides (hIAPP) at negative lipid bilayers was elucidated. It was firmly confirmed that hIAPP populates through β-sheet conformers without involving α-helical intermediates. The membrane-associated assembly of hIAPP proceeds by assembling with a β-hairpin-like monomer at the lipid bilayer surface, rather than by inserting the preassembled β-sheet oligomers in solution. This newly established protocol is ready to be utilized in revealing the mechanism of amyloid aggregation at the lipid membrane.
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Affiliation(s)
- Junjun Tan
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , 230026 , China
| | - Jiahui Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , 230026 , China
| | - Yi Luo
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , 230026 , China
| | - Shuji Ye
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , 230026 , China
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12
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Dolui S, Roy A, Pal U, Saha A, Maiti NC. Structural Insight of Amyloidogenic Intermediates of Human Insulin. ACS OMEGA 2018; 3:2452-2462. [PMID: 30023834 PMCID: PMC6045404 DOI: 10.1021/acsomega.7b01776] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Accepted: 02/16/2018] [Indexed: 05/27/2023]
Abstract
Engaging Raman spectroscopy as a primary tool, we investigated the early events of insulin fibrilization and determined the structural content present in oligomer and protofibrils that are formed as intermediates in the fibril formation pathway. Insulin oligomer, as obtained upon incubation of zinc-free insulin at 60 °C, was mostly spherical in shape, with a diameter of 3-5 nm. Longer incubation produced "necklace"-like beaded protofibrillar assembly species. These intermediates eventually transformed into 5-8 nm thick fibers with smooth surface texture. A broad amide I band in the Raman spectrum of insulin monomer appeared at 1659 cm-1, with a shoulder band at 1676 cm-1. This signature suggested the presence of major helical and extended secondary structure of the protein backbone. In the oligomeric state, the protein maintained its helical imprint (∼50%) and no substantial increment of the compact cross-β-sheet structure was observed. A nonamide helix signature band at 940 cm-1 was present in the oligomeric state, and it was weakened in the fibrillar structure. The 1-anilino-8-naphthalene-sulfonate binding study strongly suggested that a collapse in the tertiary structure, not the major secondary structural realignment, was the dominant factor in the formation of oligomers. In the fibrillar state, the contents of helical and disordered secondary structures decreased significantly and the β-sheet amount increased to ∼62%. The narrow amide I Raman band at 1674 cm-1 in the fibrillar state connoted the formation of vibrationally restricted highly organized β-sheet structure with quaternary realignment into steric-zipped species.
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Affiliation(s)
- Sandip Dolui
- Structural
Biology and Bioinformatics Division, Indian
Institute of Chemical Biology, Council of Scientific and Industrial
Research, 4, Raja S.C. Mullick Road, Kolkata 700032, India
| | - Anupam Roy
- Structural
Biology and Bioinformatics Division, Indian
Institute of Chemical Biology, Council of Scientific and Industrial
Research, 4, Raja S.C. Mullick Road, Kolkata 700032, India
| | - Uttam Pal
- Chemical
Sciences Division, Saha Institute of Nuclear
Physics, 1/AF Bidhannagar, Kolkata 700064, India
| | - Achintya Saha
- Department
of Chemical Technology, University of Calcutta, 92 Acharya Prafulla Chandra Road, Calcutta 700009, India
| | - Nakul C. Maiti
- Structural
Biology and Bioinformatics Division, Indian
Institute of Chemical Biology, Council of Scientific and Industrial
Research, 4, Raja S.C. Mullick Road, Kolkata 700032, India
| |
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