1
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Alfano C, Fichou Y, Huber K, Weiss M, Spruijt E, Ebbinghaus S, De Luca G, Morando MA, Vetri V, Temussi PA, Pastore A. Molecular Crowding: The History and Development of a Scientific Paradigm. Chem Rev 2024; 124:3186-3219. [PMID: 38466779 PMCID: PMC10979406 DOI: 10.1021/acs.chemrev.3c00615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 02/13/2024] [Accepted: 02/26/2024] [Indexed: 03/13/2024]
Abstract
It is now generally accepted that macromolecules do not act in isolation but "live" in a crowded environment, that is, an environment populated by numerous different molecules. The field of molecular crowding has its origins in the far 80s but became accepted only by the end of the 90s. In the present issue, we discuss various aspects that are influenced by crowding and need to consider its effects. This Review is meant as an introduction to the theme and an analysis of the evolution of the crowding concept through time from colloidal and polymer physics to a more biological perspective. We introduce themes that will be more thoroughly treated in other Reviews of the present issue. In our intentions, each Review may stand by itself, but the complete collection has the aspiration to provide different but complementary perspectives to propose a more holistic view of molecular crowding.
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Affiliation(s)
- Caterina Alfano
- Structural
Biology and Biophysics Unit, Fondazione
Ri.MED, 90100 Palermo, Italy
| | - Yann Fichou
- CNRS,
Bordeaux INP, CBMN UMR 5248, IECB, University
of Bordeaux, F-33600 Pessac, France
| | - Klaus Huber
- Department
of Chemistry, University of Paderborn, 33098 Paderborn, Germany
| | - Matthias Weiss
- Experimental
Physics I, Physics of Living Matter, University
of Bayreuth, 95440 Bayreuth, Germany
| | - Evan Spruijt
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Simon Ebbinghaus
- Lehrstuhl
für Biophysikalische Chemie and Research Center Chemical Sciences
and Sustainability, Research Alliance Ruhr, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Giuseppe De Luca
- Dipartimento
di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy
| | | | - Valeria Vetri
- Dipartimento
di Fisica e Chimica − Emilio Segrè, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy
| | | | - Annalisa Pastore
- King’s
College London, Denmark
Hill Campus, SE5 9RT London, United Kingdom
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2
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Hunt NT. Biomolecular infrared spectroscopy: making time for dynamics. Chem Sci 2024; 15:414-430. [PMID: 38179520 PMCID: PMC10763549 DOI: 10.1039/d3sc05223k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 11/24/2023] [Indexed: 01/06/2024] Open
Abstract
Time resolved infrared spectroscopy of biological molecules has provided a wealth of information relating to structural dynamics, conformational changes, solvation and intermolecular interactions. Challenges still exist however arising from the wide range of timescales over which biological processes occur, stretching from picoseconds to minutes or hours. Experimental methods are often limited by vibrational lifetimes of probe groups, which are typically on the order of picoseconds, while measuring an evolving system continuously over some 18 orders of magnitude in time presents a raft of technological hurdles. In this Perspective, a series of recent advances which allow biological molecules and processes to be studied over an increasing range of timescales, while maintaining ultrafast time resolution, will be reviewed, showing that the potential for real-time observation of biomolecular function draws ever closer, while offering a new set of challenges to be overcome.
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Affiliation(s)
- Neil T Hunt
- Department of Chemistry and York Biomedical Research Institute, University of York Heslington York YO10 5DD UK
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3
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Unnikrishnan AC, Balamurugan K, Shanmugam G. Structural Insights into the Amyloid Fibril Polymorphism Using an Isotope-Edited Vibrational Circular Dichroism Study at the Amino Acid Residue Level. J Phys Chem B 2023; 127:7674-7684. [PMID: 37667494 DOI: 10.1021/acs.jpcb.3c03437] [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: 09/06/2023]
Abstract
Polymorphism is common in both in vitro and in vivo amyloid fibrils formed by the same peptide/protein. However, the differences in their self-assembled structures at the amino acid level remain poorly understood. In this study, we utilized isotope-edited vibrational circular dichroism (VCD) on a well-known amyloidogenic peptide fragment (N22FGAIL27) of human islet amyloid polypeptide (IAPf) to investigate the structural polymorphism. Two individual isotope-labeled IAPf peptides were used, with a 13C label on the carbonyl group of phenylalanine (IAPf-F) and glycine (IAPf-G). We compared the amyloid-like nanofibril of IAPf induced by solvent casting (fibril B) with our previous report on the same IAPf peptide fibril but with a different fibril morphology (fibril A) formed in an aqueous buffer solution. Fibril B consisted of entangled, laterally fused amyloid-like nanofibrils with a relatively shorter diameter (15-50 nm) and longer length (several microns), while fibril A displayed nanofibrils with a higher diameter (30-60 nm) and shorter length (500 nm-2 μm). The isotope-edited VCD analysis indicated that fibrils B consisted of anti-parallel β-sheet arrangements with glycine residues in the registry and phenylalanine residues out of the registry, which was significantly different from fibrils A, where a mixture of parallel β-sheet and turn structure with the registry at phenylalanine and glycine residues was observed. The VCD analysis, therefore, suggests that polymorphism in amyloid-like fibrils can be attributed to the difference in the packing/arrangement of the individual β-strands in the β-sheet and the difference in the amino acid registry. Our findings provide insights into the structural aspects of fibril polymorphism related to various amyloid diseases and may aid in designing amyloid fibril inhibitors for therapeutic purposes.
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Affiliation(s)
- Anagha C Unnikrishnan
- Organic & Bioorganic Chemistry Laboratory, Council of Scientific and Industrial Research (CSIR)─Central Leather Research Institute (CLRI), Adyar, Chennai 600020, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Kanagasabai Balamurugan
- Centre for High Computing, Council of Scientific and Industrial Research (CSIR)─Central Leather Research Institute (CLRI), Adyar, Chennai 600020, India
| | - Ganesh Shanmugam
- Organic & Bioorganic Chemistry Laboratory, Council of Scientific and Industrial Research (CSIR)─Central Leather Research Institute (CLRI), Adyar, Chennai 600020, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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4
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Bian Y, Li Y, Liu K, He H, Feng Y, Yu X. Dendric nanostructures for SARS-CoV-2 proteins detection based on surface enhanced infrared absorption spectroscopy. JOURNAL OF BIOPHOTONICS 2023; 16:e202200277. [PMID: 36419375 DOI: 10.1002/jbio.202200277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 11/10/2022] [Accepted: 11/21/2022] [Indexed: 06/16/2023]
Abstract
Infrared spectroscopy is a non-destructive and rapid characterization tool that can distinguish different viral proteins by spectral details. However, traditional infrared spectroscopy has insufficient absorption signal intensity contrast when measuring low-concentration samples. In this work, surface enhanced infrared absorption (SEIRA) spectroscopy is proposed by deploying a novel nanostructure array as SEIRA substrates. An array of gold dendric nanostructures are designed and fabricated with a precision resonance control to achieve surface enhancement covering a broadband molecular "finger-print" region. The spectral positions of the multiple resonances accurately correspond to the characteristic absorption peaks of the SARS-CoV-2 proteins. An approach for SARS-CoV-2 protein detection based on SEIRA spectroscopy is then proposed. A low concentration detection of 40 μg/ml diluted SARS-CoV-2 nucleocapsid protein is experimentally demonstrated and the enhancement factor (EF) achieved is in good agreement with simulation results. The SEIRA methodology based on broadband resonance nanostructure design provides a systematic approach for sensitive, non-destructive and rapid protein molecular detection, which could be extended to various kind of molecular characterization and biomedical diagnostics.
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Affiliation(s)
- Yupei Bian
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
| | - Yang Li
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
| | - Kang Liu
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
| | - Houshu He
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
| | - Yingmei Feng
- Beijing Youan Hospital, Capital Medical University, Beijing, China
| | - Xia Yu
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
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5
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Zhu M, Zeng L, Li Z, Wang C, Wu L, Jiang X. Revealing the Nanoarchitectonics of Amyloid β-Aggregation on Two-Dimensional Biomimetic Membranes by Surface-Enhanced Infrared Absorption Spectroscopy. ChemistryOpen 2023; 12:e202200253. [PMID: 36744594 PMCID: PMC9906390 DOI: 10.1002/open.202200253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/13/2023] [Indexed: 02/07/2023] Open
Abstract
The in vivo folding of amyloid β (Aβ) is influenced by many factors among which biomembrane interfaces play an important role. Here, using surface-enhanced infrared absorption (SEIRA) spectroscopy and atomic force microscopy (AFM), the adsorption, structure, and morphology of Aβ42 aggregating on different two-dimensional interfaces were investigated. Results show that interfaces facilitate the aggregation of Aβ42 and are conducive to the formation of homogeneous aggregates, while the aggregates vary on different interfaces. On hydrophobic interfaces, strong hydrophobic interactions with the C-terminus of Aβ42 result in the formation of small oligomers with a small proportion of the β-sheet structure. On hydrophilic interfaces, hydrogen-bonding interactions and electrostatic interactions promote the formation of large aggregate particles with β-sheet structure. The hydration repulsion plays an important role in the interaction of Aβ42 with interfaces. These findings help to understand the nature of Aβ42 adsorption and aggregation on the biomembrane interface and the origin of heterogeneity and polymorphism of Aβ42 aggregates.
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Affiliation(s)
- Manyu Zhu
- State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchunJilin130022P. R. China
- School of Applied Chemistry and EngineeringUniversity of Science & Technology of ChinaHefeiAnhui230026P. R. China
| | - Li Zeng
- State Key Laboratory of Environmental Chemistry and EcotoxicologyResearch Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing100085P. R. China
| | - Zihao Li
- State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchunJilin130022P. R. China
- School of Applied Chemistry and EngineeringUniversity of Science & Technology of ChinaHefeiAnhui230026P. R. China
| | - Chen Wang
- State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchunJilin130022P. R. China
- School of Applied Chemistry and EngineeringUniversity of Science & Technology of ChinaHefeiAnhui230026P. R. China
| | - Lie Wu
- State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchunJilin130022P. R. China
| | - Xiue Jiang
- State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchunJilin130022P. R. China
- School of Applied Chemistry and EngineeringUniversity of Science & Technology of ChinaHefeiAnhui230026P. R. China
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6
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Rutherford SH, Baker MJ, Hunt NT. 2D-IR spectroscopy of proteins in H 2O-A Perspective. J Chem Phys 2023; 158:030901. [PMID: 36681646 DOI: 10.1063/5.0129480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The form of the amide I infrared absorption band provides a sensitive probe of the secondary structure and dynamics of proteins in the solution phase. However, the frequency coincidence of the amide I band with the bending vibrational mode of H2O has necessitated the widespread use of deuterated solvents. Recently, it has been demonstrated that ultrafast 2D-IR spectroscopy allows the detection of the protein amide I band in H2O-based fluids, meaning that IR methods can now be applied to study proteins in physiologically relevant solvents. In this perspective, we describe the basis of the 2D-IR method for observing the protein amide I band in H2O and show how this development has the potential to impact areas ranging from our fundamental appreciation of protein structural dynamics to new applications for 2D-IR spectroscopy in the analytical and biomedical sciences. In addition, we discuss how the spectral response of water, rather than being a hindrance, now provides a basis for new approaches to data pre-processing, standardization of 2D-IR data collection, and signal quantification. Ultimately, we visualize a direction of travel toward the creation of 2D-IR spectral libraries that can be linked to advanced computational methods for use in high-throughput protein screening and disease diagnosis.
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Affiliation(s)
- Samantha H Rutherford
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Technology and Innovation Centre, 99 George Street, Glasgow G1 1RD, United Kingdom
| | - Matthew J Baker
- School of Medicine, Faculty of Clinical Biomedical Sciences, University of Central Lancashire, Preston PR1 2HE, United Kingdom
| | - Neil T Hunt
- Department of Chemistry and York Biomedical Research Institute, University of York, York YO10 5DD, United Kingdom
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7
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Watson MD, Lee JC. Genetically Encoded Aryl Alkyne for Raman Spectral Imaging of Intracellular α-Synuclein Fibrils. J Mol Biol 2023; 435:167716. [PMID: 35792158 PMCID: PMC9805477 DOI: 10.1016/j.jmb.2022.167716] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 06/28/2022] [Accepted: 06/29/2022] [Indexed: 02/04/2023]
Abstract
α-Synuclein (α-syn) is an intrinsically disordered protein involved in a group of diseases collectively termed synucleinopathies, characterized by the aggregation of α-syn to form insoluble, β-sheet-rich amyloid fibrils. Amyloid fibrils are thought to contribute to disease progression through cell-to-cell transmission, templating and propagating intracellular amyloid formation. Raman spectral imaging offers a direct characterization of protein secondary structure via the amide-I backbone vibration; however, specific detection of α-syn conformational changes against the background of other cellular components presents a challenge. Here, we demonstrate the ability to unambiguously identify cellularly internalized α-syn fibrils by coupling Raman spectral imaging with the use of a genetically encoded aryl alkyne, 4-ethynyl-l-phenylalanine (FCC), through amber codon suppression. The alkyne stretch (CC) of FCC provides a spectrally unique molecular vibration without interference from native biomolecules. Cellular uptake of FCC-α-syn fibrils formed in vitro was visualized in cultured human SH-SY5Y neuroblastoma cells by Raman spectral imaging. Fibrils appear as discrete cytosolic clusters of varying sizes, found often at the cellular periphery. Raman spectra of internalized fibrils exhibit frequency shifts and spectral narrowing relative to in vitro fibrils, highlighting the environmental sensitivity of the alkyne vibration. Interestingly, spectral analysis reveals variations in lipid and protein recruitment to these aggregates, and in some cases, secondary structural changes in the fibrils are observed. This work sets the groundwork for future Raman spectroscopic investigations using a similar approach of an evolved aminoacyl-tRNA synthetase/tRNA pair to incorporate FCC into endogenous amyloidogenic proteins to monitor their aggregation in cells.
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Affiliation(s)
- Matthew D Watson
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, United States
| | - Jennifer C Lee
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, United States.
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8
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Dicke SS, Maj M, Fields CR, Zanni MT. Metastable intermediate during hIAPP aggregation catalyzed by membranes as detected with 2D IR spectroscopy. RSC Chem Biol 2022; 3:931-940. [PMID: 35866164 PMCID: PMC9257649 DOI: 10.1039/d2cb00028h] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 05/24/2022] [Indexed: 11/26/2022] Open
Abstract
The aggregation of human islet amyloid polypeptide (hIAPP) into amyloid fibrils involves formation of oligomeric intermediates that are thought to be the cytotoxic species responsible for β-cell dysfunction in type 2 diabetes. hIAPP oligomers permeating or disrupting the cellular membrane may be one mechanism of toxicity and so measuring the structural kinetics of aggregation in the presence of membranes is of much interest. In this study, we use 2D IR spectroscopy and 13C18O isotope labeling to study the secondary structure of the oligomeric intermediates formed in solution and in the presence of phospholipid vesicles at sites L12A13, L16V17, G24A25 and V32G33. Pairs of labels monitor the couplings between associated polypeptides and the dihedral angles between adjacent residues. In solution, the L12A13 residues form an oligomeric β-sheet in addition to an α-helix whereas with the phospholipid vesicles they are α-helical throughout the aggregation process. In both solution and with DOPC vesicles, L16V17 and V32G33 have disordered structures until fibrils are formed. Similarly, under both conditions, G24A25 exhibits 3-state kinetics, created by an oligomeric intermediate with a well-defined β-sheet structure. Amyloid fibril formation is often thought to involve intermediates with exceedingly low populations that are difficult to detect experimentally. These experiments establish that amyloid fibril formation of hIAPP when catalyzed by membranes includes a metastable intermediate and that this intermediate has a similar structure at G24A25 in the FGAIL region as the corresponding intermediate in solution, thought to be the toxic species. 2D IR and 13C18O isotope labeling establish that amyloid formation of hIAPP catalyzed by membranes includes a metastable intermediate with a similar structure at G24A25 in the FGAIL region as the corresponding intermediate in solution.![]()
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Affiliation(s)
- Sidney S Dicke
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
| | - Michał Maj
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA .,Formally at Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
| | - Caitlyn R Fields
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
| | - Martin T Zanni
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
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9
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Dicke SS, Alperstein AM, Schueler KL, Stapleton DS, Simonett SP, Fields CR, Chalyavi F, Keller MP, Attie AD, Zanni MT. Application of 2D IR Bioimaging: Hyperspectral Images of Formalin-Fixed Pancreatic Tissues and Observation of Slow Protein Degradation. J Phys Chem B 2021; 125:9517-9525. [PMID: 34396779 PMCID: PMC8769495 DOI: 10.1021/acs.jpcb.1c05554] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We used two-dimensional IR bioimaging to study the structural heterogeneity of formalin-fixed mouse pancreas. Images were generated from the hyperspectral data sets by plotting quantities associated with the amide I vibrational mode, which is created by the backbone carbonyl stretch. Images that measure the fundamental vibrational frequencies, cross peaks, and anharmonic shifts are presented. Histograms are generated for each quantity, providing averaged values and distributions around the mean that serve as metrics for protein structures. Images were generated from tissue that had been stored in a formalin fixation for 3, 8, and 48 weeks. Over this period, all three metrics show that that the β-sheet content of the samples increased, consistent with protein aggregation. Our results indicate that formalin fixation does not entirely arrest the degradation of a protein structure in pancreas tissue.
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Affiliation(s)
- Sidney S Dicke
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Ariel M Alperstein
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Kathryn L Schueler
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States
| | - Donald S Stapleton
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States
| | - Shane P Simonett
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States
| | - Caitlyn R Fields
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Farzaneh Chalyavi
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Mark P Keller
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States
| | - Alan D Attie
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States
| | - Martin T Zanni
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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10
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Tumbic GW, Hossan MY, Thielges MC. Protein Dynamics by Two-Dimensional Infrared Spectroscopy. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2021; 14:299-321. [PMID: 34314221 PMCID: PMC8713465 DOI: 10.1146/annurev-anchem-091520-091009] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Proteins function as ensembles of interconverting structures. The motions span from picosecond bond rotations to millisecond and longer subunit displacements. Characterization of functional dynamics on all spatial and temporal scales remains challenging experimentally. Two-dimensional infrared spectroscopy (2D IR) is maturing as a powerful approach for investigating proteins and their dynamics. We outline the advantages of IR spectroscopy, describe 2D IR and the information it provides, and introduce vibrational groups for protein analysis. We highlight example studies that illustrate the power and versatility of 2D IR for characterizing protein dynamics and conclude with a brief discussion of the outlook for biomolecular 2D IR.
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Affiliation(s)
- Goran W Tumbic
- Department of Chemistry, Indiana University, Bloomington, Indiana 47401, USA;
| | - Md Yeathad Hossan
- Department of Chemistry, Indiana University, Bloomington, Indiana 47401, USA;
| | - Megan C Thielges
- Department of Chemistry, Indiana University, Bloomington, Indiana 47401, USA;
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11
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Watson MD, Lee JC. Coupling chemical biology and vibrational spectroscopy for studies of amyloids in vitro and in cells. Curr Opin Chem Biol 2021; 64:90-97. [PMID: 34186291 DOI: 10.1016/j.cbpa.2021.05.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 05/04/2021] [Accepted: 05/18/2021] [Indexed: 01/21/2023]
Abstract
Amyloid diseases are characterized by the aggregation of various proteins to form insoluble β-sheet-rich fibrils leading to cell death. Vibrational spectroscopies have emerged as attractive methods to study this process because of the rich structural information that can be extracted without large, perturbative probes. Importantly, specific vibrations such as the amide-I band directly report on secondary structure changes, which are key features of amyloid formation. Beyond intrinsic vibrations, the incorporation of unnatural vibrational probes can improve sensitivity for secondary structure determination (e.g. isotopic labeling), can provide residue-specific information of the surrounding polarity (e.g. unnatural amino acid), and are translatable into cellular studies. Here, we review the latest studies that have leveraged tools from chemical biology for the incorporation of novel vibrational probes into amyloidogenic proteins for both mechanistic and cellular studies.
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Affiliation(s)
- Matthew D Watson
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jennifer C Lee
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
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12
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Edun DN, Flanagan MR, Serrano AL. Does liquid-liquid phase separation drive peptide folding? Chem Sci 2020; 12:2474-2479. [PMID: 34164013 PMCID: PMC8179267 DOI: 10.1039/d0sc04993j] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 12/28/2020] [Indexed: 12/13/2022] Open
Abstract
Proline-arginine (PR) dipeptide repeats have been shown to undergo liquid-liquid phase separation and are an example of a growing number of intrinsically disordered proteins that can assemble into membraneless organelles. These structures have been posited as nucleation sites for pathogenic protein aggregation. As such, a better understanding of the effects that the increased local concentration and volumetric crowding within droplets have on peptide secondary structure is necessary. Herein we use Fourier transform infrared (FTIR) and two-dimensional infrared (2DIR) spectroscopy to show that formation of droplets by PR20 accompanies changes in the amide-I spectra consistent with folding into poly-proline helical structures.
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Affiliation(s)
- Dean N Edun
- Department of Chemistry and Biochemistry, University of Notre Dame Notre Dame Indiana 46556 USA
| | - Meredith R Flanagan
- Department of Chemistry and Biochemistry, University of Notre Dame Notre Dame Indiana 46556 USA
| | - Arnaldo L Serrano
- Department of Chemistry and Biochemistry, University of Notre Dame Notre Dame Indiana 46556 USA
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