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Langeland J, Lindkvist TT, Kjær C, Nielsen SB. Gas-phase Förster resonance energy transfer in mass-selected and trapped ions. MASS SPECTROMETRY REVIEWS 2024; 43:477-499. [PMID: 36514825 DOI: 10.1002/mas.21828] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 10/21/2022] [Accepted: 11/25/2022] [Indexed: 06/17/2023]
Abstract
Förster Resonance Energy transfer (FRET) is a nonradiative process that may occur from an electronically excited donor to an acceptor when the emission spectrum of the donor overlaps with the absorption spectrum of the acceptor. FRET experiments have been done in the gas phase based on specially designed mass-spectroscopy setups with the goal to obtain structural information on biomolecular ions labeled with a FRET pair (i.e., donor and acceptor dyes) and to shed light on the energy-transfer process itself. Ions are accumulated in a radio-frequency ion trap or a Penning trap where mass selection of those of interest takes place, followed by photoexcitation. Gas-phase FRET is identified from detection of emitted light either from the donor, the acceptor, or both, or from a fragmentation channel that is specific to the acceptor when electronically excited. The challenge associated with the first approach is the collection and detection of photons emitted from a thin ion cloud that is not easily accessible while the second approach relies both on the photophysical and chemical behavior of the acceptor. In this review, we present the different instrumentation used for gas-phase FRET, including a discussion of advantages and disadvantages, and examples on how the technique has provided important structural information that is not easily obtainable otherwise. Furthermore, we describe how the spectroscopic properties of the dyes are affected by nearby electric fields, which is readily discernable from experiments on simple model systems with alkyl or π-conjugated bridges. Such spectral changes can have a significant effect on the FRET efficiency. Ideas for new directions are presented at the end with special focus on cold-ion spectroscopy.
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Affiliation(s)
- Jeppe Langeland
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | | | - Christina Kjær
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
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2
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Ji X, Wang N, Wang J, Wang T, Huang X, Hao H. Non-destructive real-time monitoring and investigation of the self-assembly process using fluorescent probes. Chem Sci 2024; 15:3800-3830. [PMID: 38487216 PMCID: PMC10935763 DOI: 10.1039/d3sc06527h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 01/22/2024] [Indexed: 03/17/2024] Open
Abstract
Self-assembly has been considered as a strategy to construct superstructures with specific functions, which has been widely used in many different fields, such as bionics, catalysis, and pharmacology. A detailed and in-depth analysis of the self-assembly mechanism is beneficial for directionally and accurately regulating the self-assembly process of substances. Fluorescent probes exhibit unique advantages of sensitivity, non-destructiveness, and real-time self-assembly tracking, compared with traditional methods. In this work, the design principle of fluorescent probes with different functions and their applications for the detection of thermodynamic and kinetic parameters during the self-assembly process were systematically reviewed. Their efficiency, limitations and advantages are also discussed. Furthermore, the promising perspectives of fluorescent probes for investigating the self-assembly process are also discussed and suggested.
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Affiliation(s)
- Xiongtao Ji
- National Engineering Research Center of Industrial Crystallization Technology, School of Chemical Engineering and Technology, Tianjin University Tianjin 300072 China
| | - Na Wang
- National Engineering Research Center of Industrial Crystallization Technology, School of Chemical Engineering and Technology, Tianjin University Tianjin 300072 China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin 300072 China
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University Tianjin 300072 China +86-22-27374971 +86-22-27405754
| | - Jingkang Wang
- National Engineering Research Center of Industrial Crystallization Technology, School of Chemical Engineering and Technology, Tianjin University Tianjin 300072 China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin 300072 China
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University Tianjin 300072 China +86-22-27374971 +86-22-27405754
| | - Ting Wang
- National Engineering Research Center of Industrial Crystallization Technology, School of Chemical Engineering and Technology, Tianjin University Tianjin 300072 China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin 300072 China
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University Tianjin 300072 China +86-22-27374971 +86-22-27405754
| | - Xin Huang
- National Engineering Research Center of Industrial Crystallization Technology, School of Chemical Engineering and Technology, Tianjin University Tianjin 300072 China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin 300072 China
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University Tianjin 300072 China +86-22-27374971 +86-22-27405754
| | - Hongxun Hao
- National Engineering Research Center of Industrial Crystallization Technology, School of Chemical Engineering and Technology, Tianjin University Tianjin 300072 China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin 300072 China
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University Tianjin 300072 China +86-22-27374971 +86-22-27405754
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3
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Wu R, Metternich JB, Kamenik AS, Tiwari P, Harrison JA, Kessen D, Akay H, Benzenberg LR, Chan TWD, Riniker S, Zenobi R. Determining the gas-phase structures of α-helical peptides from shape, microsolvation, and intramolecular distance data. Nat Commun 2023; 14:2913. [PMID: 37217470 PMCID: PMC10203302 DOI: 10.1038/s41467-023-38463-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 04/19/2023] [Indexed: 05/24/2023] Open
Abstract
Mass spectrometry is a powerful technique for the structural and functional characterization of biomolecules. However, it remains challenging to accurately gauge the gas-phase structure of biomolecular ions and assess to what extent native-like structures are maintained. Here we propose a synergistic approach which utilizes Förster resonance energy transfer and two types of ion mobility spectrometry (i.e., traveling wave and differential) to provide multiple constraints (i.e., shape and intramolecular distance) for structure-refinement of gas-phase ions. We add microsolvation calculations to assess the interaction sites and energies between the biomolecular ions and gaseous additives. This combined strategy is employed to distinguish conformers and understand the gas-phase structures of two isomeric α-helical peptides that might differ in helicity. Our work allows more stringent structural characterization of biologically relevant molecules (e.g., peptide drugs) and large biomolecular ions than using only a single structural methodology in the gas phase.
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Affiliation(s)
- Ri Wu
- Laboratorium für Organische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland
| | - Jonas B Metternich
- Laboratorium für Organische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland
| | - Anna S Kamenik
- Laboratorium für Physikalische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland
| | - Prince Tiwari
- Laboratorium für Organische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Forschungsstrasse 111, 5232, Villigen PSI, Switzerland
| | - Julian A Harrison
- Laboratorium für Organische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland
| | - Dennis Kessen
- Laboratorium für Organische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland
- University of Münster, MEET Battery Research Center, Corrensstrasse 46, 48149, Münster, Germany
| | - Hasan Akay
- Laboratorium für Organische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland
| | - Lukas R Benzenberg
- Laboratorium für Organische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland
| | - T-W Dominic Chan
- Department of Chemistry, The Chinese University of Hong Kong, Hong Kong SAR, People's Republic of China
| | - Sereina Riniker
- Laboratorium für Physikalische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland.
| | - Renato Zenobi
- Laboratorium für Organische Chemie, D-CHAB, ETH Zürich, 8093, Zurich, Switzerland.
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4
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Wu R, Benzenberg LR, Svingou D, Zenobi R. The Structure of Cyclic Neuropeptide Somatostatin and Octapeptide Octreotide in the Presence of Copper Ions: Insights from Transition Metal Ion FRET and Native Ion Mobility-Mass Spectrometry. J Am Chem Soc 2023; 145:10542-10547. [PMID: 37146120 DOI: 10.1021/jacs.2c13613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The conformation and function of somatostatin (SST), a cyclic neuropeptide, was recently found to be altered in the presence of Cu(II) ions, which leads to self-aggregation and loss of biological function as a neurotransmitter. However, the impact of Cu(II) ions on the structure and function of SST is not fully understood. In this work, transition metal ion Förster resonance energy transfer (tmFRET) and native ion mobility-mass spectrometry (IM-MS) were utilized to study the structures of well-defined gas-phase ions of SST and of a smaller analogue, octreotide (OCT). The tmFRET results suggest two binding sites of Cu(II) ions in both native-like SST and OCT ions, either in close proximity to the disulfide bond or complexed by two aromatic residues, consistent with results obtained from collision-induced dissociation (CID). The former binding site was reported to initiate aggregation of SST, while the latter binding site could directly affect the essential motif for receptor binding and therefore impair the biological function of SST and OCT when bound to SST receptors. Our results demonstrate that tmFRET is capable of locating transition metal ion binding sites in neuropeptides. Furthermore, multiple distance constraints (tmFRET) and global shape (IM-MS) provide additional structural insights of SST and OCT ions upon metal binding, which is related to the self-aggregation mechanisms and overall biological functions.
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Affiliation(s)
- Ri Wu
- Laboratorium für Organische Chemie, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Lukas R Benzenberg
- Laboratorium für Organische Chemie, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Despoina Svingou
- Laboratorium für Organische Chemie, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Renato Zenobi
- Laboratorium für Organische Chemie, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
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Hou N, Zhao X, Han Z, Jiang X, Fang Y, Chen Y, Li D. Dodecenylsuccinic anhydride-modified oxalate decarboxylase loaded with magnetic nano-Fe 3O 4@SiO 2 for demulsification of oil-in-water emulsions. CHEMOSPHERE 2022; 308:136595. [PMID: 36167213 DOI: 10.1016/j.chemosphere.2022.136595] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 09/19/2022] [Accepted: 09/21/2022] [Indexed: 06/16/2023]
Abstract
The inability to demulsify oil-in-water emulsions via green and efficient processes is a challenging problem in many industrial processes. As a novel biodemulsifier, protein demulsifiers display excellent dispersibility and stability, but their demulsification mechanisms are not clear, which severely restricts their large-scale production and application. In this study, the demulsification mechanism of the high-efficiency protein biodemulsifier oxalate decarboxylase (Bacm OxdC), which is secreted by the Bacillus mojavensis XH1 strain, for an oil-in-water emulsion was analyzed. The results showed that Bacm OxdC was spontaneously adsorbed at the oil-water interface and turned its hydrophobic amino acids outward to increase its hydrophobicity and break the emulsified system. Furthermore, it effectively reduced the oil-water interfacial tension and interfacial film strength, thereby reducing the oil-water interfacial energy and finally enabling demulsification. To further improve the demulsification efficiency and reusability, Fe3O4@SiO2@OxdC-DDSA was prepared. This method provided a magnetic response for Bacm OxdC and enabled efficient demulsification. The demulsification rate of Fe3O4@SiO2@OxdC-DDSA reached 98.1% at 24 h, which was 30.7% higher than that of the original Bacm OxdC. After three cycles, the demulsification rate still reached 89.3%, proving it has excellent recyclability. This work is the first study on the demulsification mechanism of protein biodemulsifiers and provides useful insights into the demulsification mechanism of biodemulsifiers for oil-in-water emulsions. In addition, a promising high-efficiency modification technique for protein biodemulsifiers was proposed, which provided information for the development of biodemulsifiers for oil-water separation.
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Affiliation(s)
- Ning Hou
- College of Resources and Environment, Northeast Agricultural University, No. 600 Changjiang Street, Harbin, Heilongjiang, 150030, PR China
| | - Xin Zhao
- College of Resources and Environment, Northeast Agricultural University, No. 600 Changjiang Street, Harbin, Heilongjiang, 150030, PR China
| | - Ziyi Han
- College of Resources and Environment, Northeast Agricultural University, No. 600 Changjiang Street, Harbin, Heilongjiang, 150030, PR China
| | - Xinxin Jiang
- College of Resources and Environment, Northeast Agricultural University, No. 600 Changjiang Street, Harbin, Heilongjiang, 150030, PR China
| | - Yongping Fang
- College of Resources and Environment, Northeast Agricultural University, No. 600 Changjiang Street, Harbin, Heilongjiang, 150030, PR China
| | - Yun Chen
- College of Resources and Environment, Northeast Agricultural University, No. 600 Changjiang Street, Harbin, Heilongjiang, 150030, PR China
| | - Dapeng Li
- College of Resources and Environment, Northeast Agricultural University, No. 600 Changjiang Street, Harbin, Heilongjiang, 150030, PR China.
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6
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Huang Z, Kayanattil M, Hayes SA, Miller RJD. Picosecond infrared laser driven sample delivery for simultaneous liquid-phase and gas-phase electron diffraction studies. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2022; 9:054301. [PMID: 36124204 PMCID: PMC9482465 DOI: 10.1063/4.0000159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/12/2022] [Indexed: 06/15/2023]
Abstract
Here, we report on a new approach based on laser driven molecular beams that provides simultaneously nanoscale liquid droplets and gas-phase sample delivery for femtosecond electron diffraction studies. The method relies on Picosecond InfraRed Laser (PIRL) excitation of vibrational modes to strongly drive phase transitions under energy confinement by a mechanism referred to as Desorption by Impulsive Vibrational Excitation (DIVE). This approach is demonstrated using glycerol as the medium with selective excitation of the OH stretch region for energy deposition. The resulting plume was imaged with both an ultrafast electron gun and a pulsed bright-field optical microscope to characterize the sample source simultaneously under the same conditions with time synchronization equivalent to sub-micrometer spatial resolution in imaging the plume dynamics. The ablation front gives the expected isolated gas phase, whereas the trailing edge of the plume is found to consist of nanoscale liquid droplets to thin films depending on the excitation conditions. Thus, it is possible by adjusting the timing to go continuously from probing gas phase to solution phase dynamics in a single experiment with 100% hit rates and very low sample consumption (<100 nl per diffraction image). This approach will be particularly interesting for biomolecules that are susceptible to denaturation in turbulent flow, whereas PIRL-DIVE has been shown to inject molecules as large as proteins into the gas phase fully intact. This method opens the door as a general approach to atomically resolving solution phase chemistry as well as conformational dynamics of large molecular systems and allow separation of the solvent coordinate on the dynamics of interest.
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Affiliation(s)
- Zhipeng Huang
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Meghanad Kayanattil
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Stuart A. Hayes
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - R. J. Dwayne Miller
- Departments of Chemistry and Physics, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 1H6, Canada
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7
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Wu R, Metternich JB, Tiwari P, Zenobi R. Adapting a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer for Gas-Phase Fluorescence Spectroscopy Measurement of Trapped Biomolecular Ions. Anal Chem 2021; 93:15626-15632. [PMID: 34784193 DOI: 10.1021/acs.analchem.1c02858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Gas-phase fluorescence spectroscopy is still in its infancy, which demands further instrumental developments. In this study, a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS), equipped with a lab-developed data acquisition system, was coupled to a tunable femtosecond laser and a state-of-the-art optical system for fluorescence studies of mass-selected ions. For excitation, a laser beam was focused (beam size < 1.0 mm) into the cylindrical ICR cell. A wire mesh replaced the back trapping plate, allowing ∼10% of the fluorescence emitted from trapped ions to be collected by a lens installed beside the wire mesh. The collected fluorescence light was then transmitted outside of the mass spectrometer via fiber optics. A novel accumulation during detection (ADD) scheme was developed to increase the duty cycle of gas-phase fluorescence spectroscopy experiments. With ADD, >90% duty cycle for mass spectrometry and fluorescence experiments could be achieved. This instrument was able to perform fluorescence experiments on various ions, from simple rhodamine dyes to large biomolecules (i.e., peptides and proteins) labeled with dyes of various optical properties. A fluorescence lifetime measurement of trapped rhodamine 6G cations was also performed, yielding a value of 5.97 ± 0.23 ns. This setup has a broad mass range and decent fluorescence spectroscopy performance (i.e., the emission spectrum of rhodamine 6G can be acquired with good S/N in a minute). Finally, this setup also allows more challenging gas-phase fluorescence spectroscopy experiments, for example, of low quantum yield fluorophores and large biomolecules in their native state that appear at high m/z, which may not be doable with quadrupole ion traps (QIT).
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Affiliation(s)
- Ri Wu
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Jonas B Metternich
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Prince Tiwari
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Renato Zenobi
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
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8
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Britt HM, Cragnolini T, Thalassinos K. Integration of Mass Spectrometry Data for Structural Biology. Chem Rev 2021; 122:7952-7986. [PMID: 34506113 DOI: 10.1021/acs.chemrev.1c00356] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Mass spectrometry (MS) is increasingly being used to probe the structure and dynamics of proteins and the complexes they form with other macromolecules. There are now several specialized MS methods, each with unique sample preparation, data acquisition, and data processing protocols. Collectively, these methods are referred to as structural MS and include cross-linking, hydrogen-deuterium exchange, hydroxyl radical footprinting, native, ion mobility, and top-down MS. Each of these provides a unique type of structural information, ranging from composition and stoichiometry through to residue level proximity and solvent accessibility. Structural MS has proved particularly beneficial in studying protein classes for which analysis by classic structural biology techniques proves challenging such as glycosylated or intrinsically disordered proteins. To capture the structural details for a particular system, especially larger multiprotein complexes, more than one structural MS method with other structural and biophysical techniques is often required. Key to integrating these diverse data are computational strategies and software solutions to facilitate this process. We provide a background to the structural MS methods and briefly summarize other structural methods and how these are combined with MS. We then describe current state of the art approaches for the integration of structural MS data for structural biology. We quantify how often these methods are used together and provide examples where such combinations have been fruitful. To illustrate the power of integrative approaches, we discuss progress in solving the structures of the proteasome and the nuclear pore complex. We also discuss how information from structural MS, particularly pertaining to protein dynamics, is not currently utilized in integrative workflows and how such information can provide a more accurate picture of the systems studied. We conclude by discussing new developments in the MS and computational fields that will further enable in-cell structural studies.
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Affiliation(s)
- Hannah M Britt
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, United Kingdom
| | - Tristan Cragnolini
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, United Kingdom.,Institute of Structural and Molecular Biology, Birkbeck College, University of London, London WC1E 7HX, United Kingdom
| | - Konstantinos Thalassinos
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, United Kingdom.,Institute of Structural and Molecular Biology, Birkbeck College, University of London, London WC1E 7HX, United Kingdom
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9
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Tiwari P, Wu R, Metternich JB, Zenobi R. Transition Metal Ion FRET in the Gas Phase: A 10-40 Å Range Molecular Ruler for Mass-Selected Biomolecular Ions. J Am Chem Soc 2021; 143:11291-11295. [PMID: 34291949 DOI: 10.1021/jacs.1c01915] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Structural studies of mass-selected biomolecules in the gas phase can reveal their intrinsic properties and provide useful benchmarks for biomolecular modeling. Here, we report the first evidence of transition metal ion FRET (tmFRET) in the gas phase and its application to measure short (10-40 Å) biomolecular backbone distances. The measured FRET efficiencies in rhodamine dye (donor) labeled helical peptides complexed with Cu2+ ions (acceptor) decreased with increasing donor - acceptor distances, confirming the occurrence of tmFRET. The distances estimated for similar peptide sequences from the FRET efficiencies were consistently longer in the gas phase compared to those reported in solution, indicating an expanded structure and a possible loss of helicity.
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Affiliation(s)
- Prince Tiwari
- Department of Chemistry and Applied Biosciences, ETH Zürich Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Ri Wu
- Department of Chemistry and Applied Biosciences, ETH Zürich Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Jonas B Metternich
- Department of Chemistry and Applied Biosciences, ETH Zürich Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Renato Zenobi
- Department of Chemistry and Applied Biosciences, ETH Zürich Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
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10
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Tiwari P, Czar MF, Zenobi R. Fluorescence-Based Detection of the Desolvation Process of Protein Ions Generated in an Aqueous Electrospray Plume. Anal Chem 2021; 93:3635-3642. [PMID: 33557519 DOI: 10.1021/acs.analchem.0c05396] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new experimental setup to study laser-induced fluorescence from analytes at different locations in an electrospray plume has been developed. The high fluorescence collection efficiency (∼2%) of the setup, along with a sensitive charge coupled device (CCD) detector, enabled the study of low ion concentrations (down to ∼fM) in the plume. The use of small electrospray tip inner diameters (<1 μm) facilitated the fast desolvation of gaseous protein ions in an aqueous electrospray plume. Fluorescence spectra were acquired from specific locations along the plume axis in different aqueous electrospray plumes with three different analytes: a rhodamine dye and two proteins (ubiquitin and apomyoglobin) labeled with rhodamine dyes. To confirm the presence of gaseous ions, pure gas-phase fluorescence spectra were acquired in the vacuum of a modified ion trap mass spectrometer. These spectra were used to fit to confirm the presence of gaseous species in the corresponding spectra obtained from the electrospray plume. This study shows that with small inner diameter spray capillaries, gaseous protein ions generated at atmospheric pressure in an electrospray plume can be detected with fluorescence-based techniques. Fluorescence measurements can be used to study their structure in the electrospray plume, and the dynamics as they transition from solution to the gas phase and in the early stages after desolvation from charged droplets. Other techniques can also be applied to further study gaseous biomolecular structures under ambient conditions immediately after desolvation.
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Affiliation(s)
- Prince Tiwari
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093Zürich, Switzerland
| | - Martin F Czar
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093Zürich, Switzerland
| | - Renato Zenobi
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093Zürich, Switzerland
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11
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Tiwari P, Metternich JB, Czar MF, Zenobi R. Breaking the Brightness Barrier: Design and Characterization of a Selected-Ion Fluorescence Measurement Setup with High Optical Detection Efficiency. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:187-197. [PMID: 33236907 DOI: 10.1021/jasms.0c00264] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A quadrupole ion trap (QIT) mass spectrometer has been modified and coupled with tunable laser excitation and highly sensitive fluorescence detection systems to perform fluorescence studies on mass-selected ions. Gaseous ions, generated using nanoelectrospray ionization (nano-ESI), are trapped in the QIT that allows optical access for laser irradiation. The emitted fluorescence is collected from a 5.0 mm diameter hole drilled into the ring electrode of the QIT and is directed toward the detection setup. Due to the small inner diameter (7.07 mm) of the ring electrode and a relatively large opening for fluorescence collection, a fluorescence collection efficiency of 2.3% is achieved. After some losses in transmission, around 1.8% of the emitted fluorescence reaches the detectors, more than any other similar instrument reported in the literature. This improved fluorescence collection translates to a much shorter measurement time for a fluorescence signal. Another key feature of this setup is the ability to perform a variety of fluorescence experiments on trapped ions including excitation and emission spectroscopy, lifetime measurement, and ion imaging. The capabilities of the instrument are demonstrated by measuring fluorescence spectra of dyes and biomolecules labeled with dyes in a range of different excitation and emission wavelengths, quantum yields, m/z, and different polarities. A fluorescence lifetime measurement and ion image of trapped rhodamine 6G cations are also shown. With a wide array of functionality and high fluorescence detection performance, this setup provides an opportunity to study biomolecular structures and photophysics of fluorophores in well-controlled environments.
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Affiliation(s)
- Prince Tiwari
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Jonas B Metternich
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Martin F Czar
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
| | - Renato Zenobi
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland
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12
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Stockett MH, Kjær C, Daly S, Bieske EJ, Verlet JRR, Nielsen SB, Bull JN. Photophysics of Isolated Rose Bengal Anions. J Phys Chem A 2020; 124:8429-8438. [PMID: 32966075 DOI: 10.1021/acs.jpca.0c07123] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dye molecules based on the xanthene moiety are widely used as fluorescent probes in bioimaging and technological applications due to their large absorption cross-section for visible light and high fluorescence quantum yield. These applications require a clear understanding of the dye's inherent photophysics and the effect of a condensed-phase environment. Here, the gas-phase photophysics of the rose bengal doubly deprotonated dianion [RB - 2H]2-, deprotonated monoanion [RB - H]-, and doubly deprotonated radical anion [RB - 2H]•- is investigated using photodetachment, photoelectron, and dispersed fluorescence action spectroscopies, and tandem ion mobility spectrometry (IMS) coupled with laser excitation. For [RB - 2H]2-, photodetachment action spectroscopy reveals a clear band in the visible (450-580 nm) with vibronic structure. Electron affinity and repulsive Coulomb barrier (RCB) properties of the dianion are characterized using frequency-resolved photoelectron spectroscopy, revealing a decreased RCB compared with that of fluorescein dianions due to electron delocalization over halogen atoms. Monoanions [RB - H]- and [RB - 2H]•- differ in nominal mass by 1 Da but are difficult to study individually using action spectroscopies that isolate target ions using low-resolution mass spectrometry. This work shows that the two monoanions are readily distinguished and probed using the IMS-photo-IMS and photo-IMS-photo-IMS strategies, providing distinct but overlapping photodissociation action spectra in the visible spectral range. Gas-phase fluorescence was not detected from photoexcited [RB - 2H]2- due to rapid electron ejection. However, both [RB - H]- and [RB - 2H]•- show a weak fluorescence signal. The [RB - H]- action spectra show a large Stokes shift of ∼1700 cm-1, while the [RB - 2H]•- action spectra show no appreciable Stokes shift. This difference is explained by considering geometries of the ground and fluorescing states.
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Affiliation(s)
- Mark H Stockett
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - Christina Kjær
- Department of Physics and Astronomy, Aarhus University, Aarhus 8000, Denmark
| | - Steven Daly
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumiére Matiére UMR 5306, F-69100 Villeurbanne, France
| | - Evan J Bieske
- School of Chemistry, University of Melbourne, Parkville VIC 3010, Australia
| | - Jan R R Verlet
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | | | - James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, United Kingdom
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13
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Brodbelt JS, Morrison LJ, Santos I. Ultraviolet Photodissociation Mass Spectrometry for Analysis of Biological Molecules. Chem Rev 2020; 120:3328-3380. [PMID: 31851501 PMCID: PMC7145764 DOI: 10.1021/acs.chemrev.9b00440] [Citation(s) in RCA: 139] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The development of new ion-activation/dissociation methods continues to be one of the most active areas of mass spectrometry owing to the broad applications of tandem mass spectrometry in the identification and structural characterization of molecules. This Review will showcase the impact of ultraviolet photodissociation (UVPD) as a frontier strategy for generating informative fragmentation patterns of ions, especially for biological molecules whose complicated structures, subtle modifications, and large sizes often impede molecular characterization. UVPD energizes ions via absorption of high-energy photons, which allows access to new dissociation pathways relative to more conventional ion-activation methods. Applications of UVPD for the analysis of peptides, proteins, lipids, and other classes of biologically relevant molecules are emphasized in this Review.
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Affiliation(s)
- Jennifer S. Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Lindsay J. Morrison
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Inês Santos
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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14
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Czar MF, Breitgoff FD, Sahoo D, Sajid M, Ramezanian N, Polyhach Y, Jeschke G, Godt A, Zenobi R. Linear and Kinked Oligo(phenyleneethynylene)s as Ideal Molecular Calibrants for Förster Resonance Energy Transfer. J Phys Chem Lett 2019; 10:6942-6947. [PMID: 31633356 DOI: 10.1021/acs.jpclett.9b02621] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We show that oligo(phenyleneethynylene)s (oligoPEs) are ideal spacers for calibrating dye pairs used for Förster resonance energy transfer (FRET). Ensemble FRET measurements on linear and kinked diads with such spacers show the expected distance and orientation dependence of FRET. Measured FRET efficiencies match excellently with those predicted using a harmonic segmented chain model, which was validated by end-to-end distance distributions obtained from pulsed electron paramagnetic resonance measurements on spin-labeled oligoPEs with comparable label distances.
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Affiliation(s)
- Martin F Czar
- Department of Chemistry and Applied Biosciences , ETH Zurich , CH-8093 Zurich , Switzerland
| | - Frauke D Breitgoff
- Department of Chemistry and Applied Biosciences , ETH Zurich , CH-8093 Zurich , Switzerland
| | - Dhananjaya Sahoo
- Faculty of Chemistry and Center for Molecular Materials (CM2) , Bielefeld University , Universitätsstraße 25 , 33615 Bielefeld , Germany
| | - Muhammad Sajid
- Faculty of Chemistry and Center for Molecular Materials (CM2) , Bielefeld University , Universitätsstraße 25 , 33615 Bielefeld , Germany
| | - Navid Ramezanian
- Faculty of Chemistry and Center for Molecular Materials (CM2) , Bielefeld University , Universitätsstraße 25 , 33615 Bielefeld , Germany
| | - Yevhen Polyhach
- Department of Chemistry and Applied Biosciences , ETH Zurich , CH-8093 Zurich , Switzerland
| | - Gunnar Jeschke
- Department of Chemistry and Applied Biosciences , ETH Zurich , CH-8093 Zurich , Switzerland
| | - Adelheid Godt
- Faculty of Chemistry and Center for Molecular Materials (CM2) , Bielefeld University , Universitätsstraße 25 , 33615 Bielefeld , Germany
| | - Renato Zenobi
- Department of Chemistry and Applied Biosciences , ETH Zurich , CH-8093 Zurich , Switzerland
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15
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Soorkia S, Jouvet C, Grégoire G. UV Photoinduced Dynamics of Conformer-Resolved Aromatic Peptides. Chem Rev 2019; 120:3296-3327. [DOI: 10.1021/acs.chemrev.9b00316] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Satchin Soorkia
- Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Univ. Paris-Sud, Université Paris-Saclay, F-91405 Orsay, France
| | - Christophe Jouvet
- CNRS, Aix Marseille Université, PIIM UMR 7345, 13397, Marseille, France
| | - Gilles Grégoire
- Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Univ. Paris-Sud, Université Paris-Saclay, F-91405 Orsay, France
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16
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Choi CM, Kulesza A, Daly S, MacAleese L, Antoine R, Dugourd P, Chirot F. Ion mobility resolved photo-fragmentation to discriminate protomers. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2019; 33 Suppl 1:28-34. [PMID: 29885203 DOI: 10.1002/rcm.8202] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 06/01/2018] [Accepted: 06/04/2018] [Indexed: 06/08/2023]
Abstract
RATIONALE Among the sources of structural diversity in biomolecular ions, the co-existence of protomers is particularly difficult to take into account, which in turn complicates structural interpretation of gas-phase data. METHODS We investigated the sensitivity of gas-phase photo-fragmentation measurements and ion mobility spectrometry (IMS) to the protonation state of a model peptide derivatized with chromophores. Accessible interconversion pathways between the different identified conformers were probed by tandem ion mobility measurement. Furthermore, the excitation coupling between the chromophores has been probed through photo-fragmentation measurements on mobility-selected ions. All results were interpreted based on molecular dynamics simulations. RESULTS We show that protonation can significantly affect the photo-fragmentation yields. Especially, conformers with very close collision cross sections (CCSs) may display dramatically different photo-fragmentation yields in relation with different protonation patterns. CONCLUSIONS We show that, even if precise structure assignment based on molecular modeling is in principle difficult for large biomolecular assemblies, the combination of photo-fragmentation and IMS can help to identify the signature of protomer co-existence for a population of biomolecular ions in the gas phase. Such spectroscopic data are particularly suitable to follow conformational changes.
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Affiliation(s)
- Chang Min Choi
- Mass Spectrometry and Advanced Instrumentation Research Group, Div. of Scientific Instrumentation, Korea Basic Science Institute, Cheongju, Republic of Korea
| | - Alexander Kulesza
- CNRS, UMR5306 Institut Lumière Matière, Univ Lyon, Université Claude Bernard Lyon 1, 69622, Villeurbanne cedex, France
| | - Steven Daly
- CNRS, UMR5306 Institut Lumière Matière, Univ Lyon, Université Claude Bernard Lyon 1, 69622, Villeurbanne cedex, France
| | - Luke MacAleese
- CNRS, UMR5306 Institut Lumière Matière, Univ Lyon, Université Claude Bernard Lyon 1, 69622, Villeurbanne cedex, France
| | - Rodolphe Antoine
- CNRS, UMR5306 Institut Lumière Matière, Univ Lyon, Université Claude Bernard Lyon 1, 69622, Villeurbanne cedex, France
| | - Philippe Dugourd
- CNRS, UMR5306 Institut Lumière Matière, Univ Lyon, Université Claude Bernard Lyon 1, 69622, Villeurbanne cedex, France
| | - Fabien Chirot
- CNRS, Ens de Lyon, UMR5280 Institut Sciences Analytiques, Univ Lyon, Université Claude Bernard Lyon 1, 69100, Villeurbanne, France
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17
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Daly S, MacAleese L, Dugourd P, Chirot F. Combining Structural Probes in the Gas Phase - Ion Mobility-Resolved Action-FRET. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:133-139. [PMID: 29038996 DOI: 10.1007/s13361-017-1824-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 09/15/2017] [Accepted: 09/27/2017] [Indexed: 06/07/2023]
Abstract
In the context of native mass spectrometry, the development of gas-phase structural probes sensitive to the different levels of structuration of biomolecular assemblies is necessary to push forward conformational studies. In this paper, we provide the first example of the combination of ion mobility (IM) and Förster resonance energy transfer (FRET) measurements within the same experimental setup. The possibility to obtain mass- and mobility-resolved FRET measurements is demonstrated on a model peptide and applied to monitor the collision-induced unfolding of ubiquitin. Graphical Abstract ᅟ.
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Affiliation(s)
- Steven Daly
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière UMR 5306, F-69100, Villeurbanne, France
- Université de Bordeaux, INSERM U1212, CNRS UMR 5320, ARNA Laboratory, IECB, F-33600, Pessac, France
| | - Luke MacAleese
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière UMR 5306, F-69100, Villeurbanne, France
| | - Philippe Dugourd
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière UMR 5306, F-69100, Villeurbanne, France
| | - Fabien Chirot
- Univ Lyon, Université Claude Bernard Lyon 1, Ens de Lyon, CNRS, Institut des Sciences Analytiques UMR 5280, 5 rue de la Doua, F-69100, Villeurbanne, France.
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18
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Honma K. Laser-induced- and dispersed-fluorescence studies of rhodamine 590 and 640 ions formed by electrospray ionization: observation of fluorescence from highly-excited vibrational levels of S1 states. Phys Chem Chem Phys 2018; 20:26859-26869. [DOI: 10.1039/c8cp04067b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fluorescence spectra of vibrationally very “hot” S1 states were observed for the first time under gas phase conditions.
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Affiliation(s)
- Kenji Honma
- Graduate School of Material Science
- University of Hyogo
- Hyogo
- Japan
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19
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Laszlo KJ, Munger EB, Bush MF. Effects of Solution Structure on the Folding of Lysozyme Ions in the Gas Phase. J Phys Chem B 2017; 121:2759-2766. [PMID: 28301724 PMCID: PMC5486214 DOI: 10.1021/acs.jpcb.7b00783] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The fidelity between the structures of proteins in solution and protein ions in the gas phase is critical to experiments that use gas-phase measurements to infer structures in solution. Here we generate ions of lysozyme, a 129-residue protein whose native tertiary structure contains four internal disulfide bonds, from three solutions that preserve varying extents of the original native structure. We then use cation-to-anion proton-transfer reactions (CAPTR) to reduce the charge states of those ions in the gas phase and ion mobility to probe their structures. The collision cross section (Ω) distributions of each CAPTR product depends to varying extents on the original solution, the charge state of the product, and the charge state of the precursor. For example, the Ω distributions of the 6+ ions depend strongly on the original solutions conditions and to a lesser extent on the charge state of the precursor. Energy-dependent experiments suggest that very different structures are accessible to disulfide-reduced and disulfide-intact ions, but similar Ω distributions are formed at high energy for disulfide-intact ions from denaturing and from aqueous conditions. The Ω distributions of the 3+ ions are all similar but exhibit subtle differences that depend more strongly on the original solutions conditions than other factors. More generally, these results suggest that specific CAPTR products may be especially sensitive to specific elements of structure in solution.
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Affiliation(s)
- Kenneth J. Laszlo
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Eleanor B. Munger
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Matthew F. Bush
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
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20
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Pinheiro S, Curutchet C. Can Förster Theory Describe Stereoselective Energy Transfer Dynamics in a Protein-Ligand Complex? J Phys Chem B 2017; 121:2265-2278. [PMID: 28235382 DOI: 10.1021/acs.jpcb.7b00217] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Förster resonance energy transfer (FRET) reactions involving ligands and aromatic amino acids can substantially impact the fluorescence properties of a protein-ligand complex, an impact intimately related to the corresponding binding mode. Structural characterization of such binding events in terms of intermolecular distances can be done through the well-known R-6 distance-dependent Förster rate expression. However, such an interpretation suffers from uncertainties underlying Förster theory in the description of the electronic coupling that promotes FRET, mostly related to the dipole-dipole orientation factor, dielectric screening effects, and deviations from the ideal dipole approximation. Here, we investigate how Förster approximations impact the prediction of energy transfer dynamics in the complex between flurbiprofen (FBP) and human serum albumin (HSA), as well as a model FBP-Trp dyad, in which recent observation of enantioselective fluorescence quenching has been ascribed to energy transfer from FBP to Trp. To this end, we combine classical molecular dynamics simulations with polarizable quantum mechanics/molecular mechanics calculations that allow overcoming Förster approximations. On the basis of our results, we discuss the potential of structure-based simulations in the characterization of drug-binding events through fluorescence techniques. Overall, we find an excellent agreement between theory and experiment both in terms of enantioselectivity and FRET times, thus strongly supporting the reliability of the binding modes proposed for the (S) and (R) enantiomers of FBP. In particular, we show that the dynamic quenching arises from a small fraction of drug bound to the secondary site of HSA at the interface between subdomains IIA and IIB, whereas the enantioselectivity arises from the larger flexibility of the (S)-FBP enantiomer in the binding pocket.
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Affiliation(s)
- Silvana Pinheiro
- Departament de Farmàcia i Tecnologia Farmacèutica i Fisicoquímica and Institut de Biomedicina (IBUB), Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona , Av. Joan XXIII s/n, Barcelona 08028, Spain
| | - Carles Curutchet
- Departament de Farmàcia i Tecnologia Farmacèutica i Fisicoquímica and Institut de Biomedicina (IBUB), Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona , Av. Joan XXIII s/n, Barcelona 08028, Spain
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21
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Adam PR, Barta ML, Dickenson NE. Characterization of Type Three Secretion System Translocator Interactions with Phospholipid Membranes. Methods Mol Biol 2017; 1531:81-91. [PMID: 27837483 DOI: 10.1007/978-1-4939-6649-3_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
In vitro characterization of type III secretion system (T3SS) translocator proteins has proven challenging due to complex purification schemes and their hydrophobic nature that often requires detergents to provide protein solubility and stability. Here, we provide experimental details for several techniques that overcome these hurdles, allowing for the direct characterization of the Shigella translocator protein IpaB with respect to phospholipid membrane interaction. The techniques specifically discussed in this chapter include membrane interaction/liposome flotation, liposome sensitive fluorescence quenching, and protein-mediated liposome disruption assays. These assays have provided valuable insight into the role of IpaB in T3SS-mediated phospholipid membrane interactions by Shigella and should readily extend to other members of this important class of proteins.
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Affiliation(s)
- Philip R Adam
- Kansas Department of Health and Environment Laboratories, Topeka, KS, 66620, USA
| | - Michael L Barta
- Higuchi Biosciences Center, University of Kansas, Lawrence, KS, 66047, USA
| | - Nicholas E Dickenson
- Department of Chemistry and Biochemistry, Utah State University, 300 Old Main Hill, Logan, UT, 84322, USA.
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22
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Hendricks NG, Julian RR. Leveraging ultraviolet photodissociation and spectroscopy to investigate peptide and protein three-dimensional structure with mass spectrometry. Analyst 2016; 141:4534-40. [DOI: 10.1039/c6an01020b] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recent advances in mass spectrometry and lasers have facilitated the development of novel experiments combining the benefits of both technologies.
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Affiliation(s)
| | - Ryan R. Julian
- Department of Chemistry
- University of California
- Riverside
- USA
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