1
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Schramm HM, Cabrera ER, Greer C, Clowers BH. A Modular Variable Temperature FT-IMS Instrument Optimized for Gas-Phase Ion Chemistry Applications. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024. [PMID: 38994799 DOI: 10.1021/jasms.4c00183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/13/2024]
Abstract
The latest iteration of modular, open-source rolled ion mobility spectrometers was characterized and tailored for heated ion chemistry experiments. Because the nature of ion-neutral interactions is innately linked to the temperature of the drift cell, heated IMS experiments explicitly probe the fundamental characteristics of these collisions. While classic mobility experiments examine ions through inert buffer gases, doping the drift cell with reactive vapor enables desolvated chemical reactions to be studied. By using materials with minimal outgassing and ensuring the isolation of the drift tube from the surrounding ambient conditions, an open-source drift cell outfitted with heating components enables investigations of chemical reactions as a function of temperature. We show here that elevated temperatures facilitate an increase in deuterium incorporation and allow for hydrogen/deuterium exchanges otherwise unattainable under ambient conditions. While the initial fast exchanges get faster as temperature is increased, the slow rate which rises from the kinetic nonlinearity though to be attributed to ion-neutral clustering, remains constant with no change in mobility shifts. Additionally, we show the analytical merit of multiplexing mobility data by comparing the performance of traditional signal-averaging and FT-IMS modes.
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Affiliation(s)
- Haley M Schramm
- Department of Chemistry, Washington State University, Pullman, Washington 99163, United States
| | - Elvin R Cabrera
- Department of Chemistry, Washington State University, Pullman, Washington 99163, United States
| | - Cullen Greer
- Department of Chemistry, Washington State University, Pullman, Washington 99163, United States
| | - Brian H Clowers
- Department of Chemistry, Washington State University, Pullman, Washington 99163, United States
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2
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Kang WY, Mondal A, Bonney JR, Perez A, Prentice BM. Structural Elucidation of Ubiquitin via Gas-Phase Ion/Ion Cross-Linking Reactions Using Sodium-Cationized Reagents Coupled with Infrared Multiphoton Dissociation. Anal Chem 2024; 96:8518-8527. [PMID: 38711366 PMCID: PMC11161031 DOI: 10.1021/acs.analchem.4c00442] [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] [Indexed: 05/08/2024]
Abstract
Accurate structural determination of proteins is critical to understanding their biological functions and the impact of structural disruption on disease progression. Gas-phase cross-linking mass spectrometry (XL-MS) via ion/ion reactions between multiply charged protein cations and singly charged cross-linker anions has previously been developed to obtain low-resolution structural information on proteins. This method significantly shortens experimental time relative to conventional solution-phase XL-MS but has several technical limitations: (1) the singly deprotonated N-hydroxysulfosuccinimide (sulfo-NHS)-based cross-linker anions are restricted to attachment at neutral amine groups of basic amino acid residues and (2) analyzing terminal cross-linked fragment ions is insufficient to unambiguously localize sites of linker attachment. Herein, we demonstrate enhanced structural information for alcohol-denatured A-state ubiquitin obtained from an alternative gas-phase XL-MS approach. Briefly, singly sodiated ethylene glycol bis(sulfosuccinimidyl succinate) (sulfo-EGS) cross-linker anions enable covalent cross-linking at both ammonium and amine groups. Additionally, covalently modified internal fragment ions, along with terminal b-/y-type counterparts, improve the determination of linker attachment sites. Molecular dynamics simulations validate experimentally obtained gas-phase conformations of denatured ubiquitin. This method has identified four cross-linking sites across 8+ ubiquitin, including two new sites in the N-terminal region of the protein that were originally inaccessible in prior gas-phase XL approaches. The two N-terminal cross-linking sites suggest that the N-terminal half of ubiquitin is more compact in gas-phase conformations. By comparison, the two C-terminal linker sites indicate the signature transformation of this region of the protein from a native to a denatured conformation. Overall, the results suggest that the solution-phase secondary structures of the A-state ubiquitin are conserved in the gas phase. This method also provides sufficient sensitivity to differentiate between two gas-phase conformers of the same charge state with subtle structural variations.
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Affiliation(s)
| | - Arup Mondal
- Department of Chemistry, University of Florida
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3
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Peters-Clarke TM, Coon JJ, Riley NM. Instrumentation at the Leading Edge of Proteomics. Anal Chem 2024; 96:7976-8010. [PMID: 38738990 DOI: 10.1021/acs.analchem.3c04497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Affiliation(s)
- Trenton M Peters-Clarke
- Department of Chemistry, University of Wisconsin─Madison, Madison, Wisconsin 53706, United States
- Department of Biomolecular Chemistry, University of Wisconsin─Madison, Madison, Wisconsin 53706, United States
| | - Joshua J Coon
- Department of Chemistry, University of Wisconsin─Madison, Madison, Wisconsin 53706, United States
- Department of Biomolecular Chemistry, University of Wisconsin─Madison, Madison, Wisconsin 53706, United States
- Morgridge Institute for Research, Madison, Wisconsin 53715, United States
| | - Nicholas M Riley
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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4
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Brandner S, Habeck T, Lermyte F. New Insights into the Intrinsic Electron-Based Dissociation Behavior of Cytochrome c Oligomers. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:1908-1916. [PMID: 37227392 DOI: 10.1021/jasms.3c00106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Between 2003 and 2017, four reports were published that demonstrated the intrinsic ability of the native iron-containing proteins cytochrome c and ferritin to undergo radical-based backbone fragmentation in the gas phase without the introduction of exogenous electrons. For cytochrome c in particular, this effect has so far only been reported to occur in the ion source, preventing the in-depth study of reactions occurring after gas-phase isolation of specific precursors. Here, we report the first observation of this intrinsic native electron capture dissociation behavior after quadrupole isolation of specific charge states of the cytochrome c dimer and trimer, providing direct experimental support for key aspects of the mechanism proposed 20 years ago. Furthermore, we provide evidence that, in contrast to some earlier proposals, these oligomeric states are formed in bulk solution rather than during the electrospray ionization process and that the observed fragmentation site preferences can be rationalized through the structure and interactions within these native oligomers rather than the monomer. We also show that the observed fragmentation pattern─and indeed, whether or not fragmentation occurs─is highly sensitive to the provenance and history of the protein samples, to the extent that samples can show distinct fragmentation behavior despite behaving identically in ion mobility experiments. This rather underexplored method therefore represents an exquisitely sensitive conformational probe and will hopefully receive more attention from the biomolecular mass spectrometry community in the future.
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Affiliation(s)
- Sarah Brandner
- Department of Chemistry, Clemens-Schöpf Institute of Organic Chemistry and Biochemistry, Technical University of Darmstadt, Peter-Grünberg-Strasse 4, 64287 Darmstadt, Germany
| | - Tanja Habeck
- Department of Chemistry, Clemens-Schöpf Institute of Organic Chemistry and Biochemistry, Technical University of Darmstadt, Peter-Grünberg-Strasse 4, 64287 Darmstadt, Germany
| | - Frederik Lermyte
- Department of Chemistry, Clemens-Schöpf Institute of Organic Chemistry and Biochemistry, Technical University of Darmstadt, Peter-Grünberg-Strasse 4, 64287 Darmstadt, Germany
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5
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Liu Z, Chen X, Yang S, Tian R, Wang F. Integrated mass spectrometry strategy for functional protein complex discovery and structural characterization. Curr Opin Chem Biol 2023; 74:102305. [PMID: 37071953 DOI: 10.1016/j.cbpa.2023.102305] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 03/10/2023] [Accepted: 03/15/2023] [Indexed: 04/20/2023]
Abstract
The discovery of functional protein complex and the interrogation of the complex structure-function relationship (SFR) play crucial roles in the understanding and intervention of biological processes. Affinity purification-mass spectrometry (AP-MS) has been proved as a powerful tool in the discovery of protein complexes. However, validation of these novel protein complexes as well as elucidation of their molecular interaction mechanisms are still challenging. Recently, native top-down MS (nTDMS) is rapidly developed for the structural analysis of protein complexes. In this review, we discuss the integration of AP-MS and nTDMS in the discovery and structural characterization of functional protein complexes. Further, we think the emerging artificial intelligence (AI)-based protein structure prediction is highly complementary to nTDMS and can promote each other. We expect the hybridization of integrated structural MS with AI prediction to be a powerful workflow in the discovery and SFR investigation of functional protein complexes.
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Affiliation(s)
- Zheyi Liu
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiong Chen
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen 518055, China
| | - Shirui Yang
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ruijun Tian
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Fangjun Wang
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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6
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Cabrera ER, Laganowsky A, Clowers BH. FTflow: An Open-Source Python GUI for FT-IM-MS Experiments. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:790-793. [PMID: 36854177 PMCID: PMC10370402 DOI: 10.1021/jasms.2c00352] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
As part of a larger effort to aid in seamless integration of Fourier-based multiplexed ion mobility with a range mass analyzers, we have developed an all-in-one graphical user interface tool for FT-IM-MS data analysis that runs directly within a web browser. This tool, FTflow, accepts mzML files and displays necessary information such as mass spectra and extracted ion chromatograms in order to reconstruct arrival time distributions. It also extracts the corresponding mobility-related information (e.g., Ko and CCS) for each of the target ion populations. Furthermore, input fields for experimental conditions are clearly laid out for users and ease-of-use. With flexibility in mind, the processing scripts and GUI interface are written entirely in Python and allows users the option to modify source code to fit their specific needs. While the intention for this tool is to be a starting point for exploratory analysis of FT-IM-MS data, it has the capability to be adapted for use in more automated data processing pipelines through direct access of core processing routines.
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Affiliation(s)
- Elvin R. Cabrera
- Department of Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University, College Station, TX 77843, USA
| | - Brian H. Clowers
- Department of Chemistry, Washington State University, Pullman, WA 99164, USA
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7
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Christofi E, Barran P. Ion Mobility Mass Spectrometry (IM-MS) for Structural Biology: Insights Gained by Measuring Mass, Charge, and Collision Cross Section. Chem Rev 2023; 123:2902-2949. [PMID: 36827511 PMCID: PMC10037255 DOI: 10.1021/acs.chemrev.2c00600] [Citation(s) in RCA: 38] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
The investigation of macromolecular biomolecules with ion mobility mass spectrometry (IM-MS) techniques has provided substantial insights into the field of structural biology over the past two decades. An IM-MS workflow applied to a given target analyte provides mass, charge, and conformation, and all three of these can be used to discern structural information. While mass and charge are determined in mass spectrometry (MS), it is the addition of ion mobility that enables the separation of isomeric and isobaric ions and the direct elucidation of conformation, which has reaped huge benefits for structural biology. In this review, where we focus on the analysis of proteins and their complexes, we outline the typical features of an IM-MS experiment from the preparation of samples, the creation of ions, and their separation in different mobility and mass spectrometers. We describe the interpretation of ion mobility data in terms of protein conformation and how the data can be compared with data from other sources with the use of computational tools. The benefit of coupling mobility analysis to activation via collisions with gas or surfaces or photons photoactivation is detailed with reference to recent examples. And finally, we focus on insights afforded by IM-MS experiments when applied to the study of conformationally dynamic and intrinsically disordered proteins.
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Affiliation(s)
- Emilia Christofi
- Michael Barber Centre for Collaborative Mass Spectrometry, Manchester Institute of Biotechnology, University of Manchester, Princess Street, Manchester M1 7DN, United Kingdom
| | - Perdita Barran
- Michael Barber Centre for Collaborative Mass Spectrometry, Manchester Institute of Biotechnology, University of Manchester, Princess Street, Manchester M1 7DN, United Kingdom
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8
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Depraz Depland A, Stroganova I, Wootton CA, Rijs AM. Developments in Trapped Ion Mobility Mass Spectrometry to Probe the Early Stages of Peptide Aggregation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:193-204. [PMID: 36633834 PMCID: PMC9896548 DOI: 10.1021/jasms.2c00253] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 11/15/2022] [Accepted: 12/16/2022] [Indexed: 06/17/2023]
Abstract
Ion mobility mass spectrometry (IM-MS) has proven to be an excellent method to characterize the structure of amyloidogenic protein and peptide aggregates, which are formed in coincidence with the development of neurodegenerative diseases. However, it remains a challenge to obtain detailed structural information on all conformational intermediates, originating from the early onset of those pathologies, due to their complex and heterogeneous environment. One way to enhance the insights and the identification of these early stage oligomers is by employing high resolution ion mobility mass spectrometry experiments. This would allow us to enhance the mobility separation and MS characterization. Trapped ion mobility spectrometry (TIMS) is an ion mobility technique known for its inherently high resolution and has successfully been applied to the analysis of protein conformations among others. To obtain conformational information on fragile peptide aggregates, the instrumental parameters of the TIMS-Quadrupole-Time-of-Flight mass spectrometer (TIMS-qToF-MS) have to be optimized to allow the study of intact aggregates and ensure their transmission toward the detector. Here, we investigate the suitability and application of TIMS to probe the aggregation process, targeting the well-characterized M307-N319 peptide segment of the TDP-43 protein, which is involved in the development of amyotrophic lateral sclerosis. By studying the influence of key parameters over the full mass spectrometer, such as source temperature, applied voltages or RFs among others, we demonstrate that by using an optimized instrumental method TIMS can be used to probe peptide aggregation.
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Affiliation(s)
- Agathe Depraz Depland
- Division
of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life
Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands
| | - Iuliia Stroganova
- Division
of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life
Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands
| | | | - Anouk M. Rijs
- Division
of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life
Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands
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9
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Fouque KJD, Miller SA, Pham K, Bhanu NV, Cintron-Diaz YL, Leyva D, Kaplan D, Voinov VG, Ridgeway ME, Park MA, Garcia BA, Fernandez-Lima F. Top-"Double-Down" Mass Spectrometry of Histone H4 Proteoforms: Tandem Ultraviolet-Photon and Mobility/Mass-Selected Electron Capture Dissociations. Anal Chem 2022; 94:15377-15385. [PMID: 36282112 PMCID: PMC11037235 DOI: 10.1021/acs.analchem.2c03147] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Post-translational modifications (PTMs) on intact histones play a major role in regulating chromatin dynamics and influence biological processes such as DNA transcription, replication, and repair. The nature and position of each histone PTM is crucial to decipher how this information is translated into biological response. In the present work, the potential of a novel tandem top-"double-down" approach─ultraviolet photodissociation followed by mobility and mass-selected electron capture dissociation and mass spectrometry (UVPD-TIMS-q-ECD-ToF MS/MS)─is illustrated for the characterization of HeLa derived intact histone H4 proteoforms. The comparison between q-ECD-ToF MS/MS spectra and traditional Fourier-transform-ion cyclotron resonance-ECD MS/MS spectra of a H4 standard showed a similar sequence coverage (∼75%) with significant faster data acquisition in the ToF MS/MS platform (∼3 vs ∼15 min). Multiple mass shifts (e.g., 14 and 42 Da) were observed for the HeLa derived H4 proteoforms for which the top-down UVPD and ECD fragmentation analysis were consistent in detecting the presence of acetylated PTMs at the N-terminus and Lys5, Lys8, Lys12, and Lys16 residues, as well as methylated, dimethylated, and trimethylated PTMs at the Lys20 residue with a high sequence coverage (∼90%). The presented top-down results are in good agreement with bottom-up TIMS ToF MS/MS experiments and allowed for additional description of PTMs at the N-terminus. The integration of a 213 nm UV laser in the present platform allowed for UVPD events prior to the ion mobility-mass precursor separation for collision-induced dissociation (CID)/ECD-ToF MS. Selected c305+ UVPD fragments, from different H4 proteoforms (e.g., Ac + Me2, 2Ac + Me2 and 3Ac + Me2), exhibited multiple IMS bands for which similar CID/ECD fragmentation patterns per IMS band pointed toward the presence of conformers, adopting the same PTM distribution, with a clear assignment of the PTM localization for each of the c305+ UVPD fragment H4 proteoforms. These results were consistent with the biological "zip" model, where acetylation proceeds in the Lys16 to Lys5 direction. This novel platform further enhances the structural toolbox with alternative fragmentation mechanisms (UVPD, CID, and ECD) in tandem with fast, high-resolution mobility separations and shows great promise for global proteoform analysis.
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Affiliation(s)
- Kevin Jeanne Dit Fouque
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, United States
| | - Samuel A. Miller
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, United States
| | - Khoa Pham
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, United States
| | - Natarajan V. Bhanu
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, United States
| | - Yarixa L. Cintron-Diaz
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, United States
| | - Dennys Leyva
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, United States
| | | | | | | | - Melvin A. Park
- Bruker Daltonics Inc., Billerica, MA 01821, United States
| | - Benjamin A. Garcia
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, United States
| | - Francisco Fernandez-Lima
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, United States
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10
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Theisen A, Wootton CA, Haris A, Morgan TE, Lam YPY, Barrow MP, O’Connor PB. Enhancing Biomolecule Analysis and 2DMS Experiments by Implementation of (Activated Ion) 193 nm UVPD on a FT-ICR Mass Spectrometer. Anal Chem 2022; 94:15631-15638. [DOI: 10.1021/acs.analchem.2c02354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Alina Theisen
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | | | - Anisha Haris
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Tomos E. Morgan
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Yuko P. Y. Lam
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Mark P. Barrow
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Peter B. O’Connor
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
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11
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Cabrera ER, Clowers BH. Considerations for Generating Frequency Modulation Waveforms for Fourier Transform-Ion Mobility Experiments. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:1858-1864. [PMID: 36066398 PMCID: PMC10370403 DOI: 10.1021/jasms.2c00168] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
By casting the information regarding an ion population's mobility in the frequency domain, the coupling of time-dispersive ion mobility techniques is now imminently compatible with slower mass analyzers such as ion traps. Recent reports have detailed the continued progress toward maximizing the efficiency of the Fourier transform ion mobility-mass spectrometry (FT-IM-MS) experiments, but few reports have outlined the intersection between the practical considerations of implementation against the theoretical limits imposed by traditional signal processing techniques. One of the important concerns for Fourier-based multiplexing experiments is avoiding signal aliasing as a product of undersampled signals that may occur during data acquisition. In addition to traditional considerations such as detector sampling frequency, the limitations (i.e., maximum measurable drift time) imposed by experimental mass scan duration and the frequency sweep used for ion gate modulation must also be assessed. This work aims to connect the fundamental underpinnings of FT-IM-MS experiments and the associated experimental parameters that are encountered when coupling the comparatively fast separations in the mobility domain with the slower m/z scanning common for ion-trap mass analyzers. In addition to stating the relevant theory that applies to the FT-IM-MS experiment, this report highlights how aliased signals will manifest post Fourier transform in reconstructed arrival time distributions and calculated mobilities.
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Affiliation(s)
- Elvin R. Cabrera
- Department of Chemistry, Washington State University, Pullman, WA 99164, United States
| | - Brian H. Clowers
- Department of Chemistry, Washington State University, Pullman, WA 99164, United States
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12
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Sipe SN, Jeanne Dit Fouque K, Garabedian A, Leng F, Fernandez-Lima F, Brodbelt JS. Exploring the Conformations and Binding Location of HMGA2·DNA Complexes Using Ion Mobility Spectrometry and 193 nm Ultraviolet Photodissociation Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:1092-1102. [PMID: 35687872 PMCID: PMC9274541 DOI: 10.1021/jasms.2c00083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Although it is widely accepted that protein function is largely dependent on its structure, intrinsically disordered proteins (IDPs) lack defined structure but are essential in proper cellular processes. Mammalian high mobility group proteins (HMGA) are one such example of IDPs that perform a number of crucial nuclear activities and have been highly studied due to their involvement in the proliferation of a variety of disease and cancers. Traditional structural characterization methods have had limited success in understanding HMGA proteins and their ability to coordinate to DNA. Ion mobility spectrometry and mass spectrometry provide insights into the diversity and heterogeneity of structures adopted by IDPs and are employed here to interrogate HMGA2 in its unbound states and bound to two DNA hairpins. The broad distribution of collision cross sections observed for the apo-protein are restricted when HMGA2 is bound to DNA, suggesting that increased protein organization is promoted in the holo-form. Ultraviolet photodissociation was utilized to probe the changes in structures for the compact and elongated structures of HMGA2 by analyzing backbone cleavage propensities and solvent accessibility based on charge-site analysis, which revealed a spectrum of conformational possibilities. Namely, preferential binding of the DNA hairpins with the second of three AT-hooks of HMGA2 is suggested based on the suppression of backbone fragmentation and distribution of DNA-containing protein fragments.
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Affiliation(s)
- Sarah N Sipe
- Department of Chemistry, University of Texas, Austin, Texas 78712 United States
| | - Kevin Jeanne Dit Fouque
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Alyssa Garabedian
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Fenfei Leng
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
- Biomolecular Sciences Institute, Florida International University, Miami, Florida 33199, United States
| | - Francisco Fernandez-Lima
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
- Biomolecular Sciences Institute, Florida International University, Miami, Florida 33199, United States
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas, Austin, Texas 78712 United States
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13
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Miller SA, Fouque KJD, Ridgeway ME, Park MA, Fernandez-Lima F. Trapped Ion Mobility Spectrometry, Ultraviolet Photodissociation, and Time-of-Flight Mass Spectrometry for Gas-Phase Peptide Isobars/Isomers/Conformers Discrimination. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:1267-1275. [PMID: 35658468 PMCID: PMC9262853 DOI: 10.1021/jasms.2c00091] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Trapped ion mobility spectrometry (TIMS) when coupled with mass spectrometry (MS) offers great advantages for the separation of isobaric, isomeric, and/or conformeric species. In the present work, we report the advantages of coupling TIMS with a low-cost, ultraviolet photodissociation (UVPD) linear ion trap operated at few mbars prior to time-of-flight (ToF) MS analysis for the effective characterization of isobaric, isomeric, and/or conformeric species based on mobility-selected fragmentation patterns. These three traditional challenges to MS-based separations are illustrated for the case of biologically relevant model systems: H3.1 histone tail PTM isobars (K4Me3/K18Ac), lanthipeptide regioisomers (overlapping/nonoverlapping ring patterns), and a model peptide conformer (angiotensin I). The sequential nature of the TIMS operation allows for effective synchronization with the ToF MS scans, in addition to parallel operation between the TIMS and the UVPD trap. Inspection of the mobility-selected UVPD MS spectra showed that for all three cases considered, unique fragmentation patterns (fingerprints) were observed per mobility band. Different from other IMS-UVPD implementations, the higher resolution of the TIMS device allowed for high mobility resolving power (R > 100) and effective mobility separation. The mobility selected UVPD MS provided high sequence coverage (>85%) with a fragmentation efficiency up to ∼40%.
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Affiliation(s)
- Samuel A. Miller
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, United States
| | - Kevin Jeanne Dit Fouque
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, United States
- Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, United States
| | | | - Melvin A. Park
- Bruker Daltonics Inc., Billerica, MA 01821, United States
| | - Francisco Fernandez-Lima
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, United States
- Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, United States
- Corresponding Author: Francisco Fernandez-Lima,
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14
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Sipe SN, Sanders JD, Reinecke T, Clowers BH, Brodbelt JS. Separation and Collision Cross Section Measurements of Protein Complexes Afforded by a Modular Drift Tube Coupled to an Orbitrap Mass Spectrometer. Anal Chem 2022; 94:9434-9441. [PMID: 35736993 PMCID: PMC9302900 DOI: 10.1021/acs.analchem.2c01653] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
New developments in analytical technologies and biophysical methods have advanced the characterization of increasingly complex biomolecular assemblies using native mass spectrometry (MS). Ion mobility methods, in particular, have enabled a new dimension of structural information and analysis of proteins, allowing separation of conformations and providing size and shape insights based on collision cross sections (CCSs). Based on the concepts of absorption-mode Fourier transform (aFT) multiplexing ion mobility spectrometry (IMS), here, a modular drift tube design proves capable of separating native-like proteins up to 148 kDa with resolution up to 45. Coupled with high-resolution Orbitrap MS, binding of small ligands and cofactors can be resolved in the mass domain and correlated to changes in structural heterogeneity observed in the ion-neutral CCS distributions. We also demonstrate the ability to rapidly determine accurate CCSs for proteins with 1-min aFT-IMS-MS sweeps without the need for calibrants or correction factors.
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Affiliation(s)
- Sarah N. Sipe
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - James D. Sanders
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Tobias Reinecke
- Department of Chemistry, Washington State University, Pullman, Washington 99164, United States
| | - Brian H. Clowers
- Department of Chemistry, Washington State University, Pullman, Washington 99164, United States
| | - Jennifer S. Brodbelt
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
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15
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Sipe SN, Lancaster EB, Butalewicz JP, Whitman CP, Brodbelt JS. Symmetry of 4-Oxalocrotonate Tautomerase Trimers Influences Unfolding and Fragmentation in the Gas Phase. J Am Chem Soc 2022; 144:12299-12309. [PMID: 35767842 DOI: 10.1021/jacs.2c03564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The recent discovery of asymmetric arrangements of trimers in the tautomerase superfamily (TSF) adds structural diversity to this already mechanistically diverse superfamily. Classification of asymmetric trimers has previously been determined using X-ray crystallography. Here, native mass spectrometry (MS) and ultraviolet photodissociation (UVPD) are employed as an integrated strategy for more rapid and sensitive differentiation of symmetric and asymmetric trimers. Specifically, the unfolding of symmetric and asymmetric trimers initiated by collisional heating was probed using UVPD, which revealed unique gas-phase unfolding pathways. Variations in UVPD patterns from native-like, compact trimeric structures to unfolded, extended conformations indicate a rearrangement of higher-order structure in the asymmetric trimers that are believed to be stabilized by salt-bridge triads, which are absent from the symmetric trimers. Consequently, the symmetric trimers were found to be less stable in the gas phase, resulting in enhanced UVPD fragmentation overall and a notable difference in higher-order re-structuring based on the extent of hydrogen migration of protein fragments. The increased stability of the asymmetric trimers may justify their evolution and concomitant diversification of the TSF. Facilitating the classification of TSF members as symmetric or asymmetric trimers assists in delineating the evolutionary history of the TSF.
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Affiliation(s)
- Sarah N Sipe
- Department of Chemistry, University of Texas, Austin, Texas 78712, United States
| | - Emily B Lancaster
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, University of Texas, Austin, Texas 78712, United States
| | - Jamie P Butalewicz
- Department of Chemistry, University of Texas, Austin, Texas 78712, United States
| | - Christian P Whitman
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, University of Texas, Austin, Texas 78712, United States.,Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712, United States
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas, Austin, Texas 78712, United States
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16
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Liu R, Xia S, Li H. Native top-down mass spectrometry for higher-order structural characterization of proteins and complexes. MASS SPECTROMETRY REVIEWS 2022:e21793. [PMID: 35757976 DOI: 10.1002/mas.21793] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
Progress in structural biology research has led to a high demand for powerful and yet complementary analytical tools for structural characterization of proteins and protein complexes. This demand has significantly increased interest in native mass spectrometry (nMS), particularly native top-down mass spectrometry (nTDMS) in the past decade. This review highlights recent advances in nTDMS for structural research of biological assemblies, with a particular focus on the extra multi-layers of information enabled by TDMS. We include a short introduction of sample preparation and ionization to nMS, tandem fragmentation techniques as well as mass analyzers and software/analysis pipelines used for nTDMS. We highlight unique structural information offered by nTDMS and examples of its broad range of applications in proteins, protein-ligand interactions (metal, cofactor/drug, DNA/RNA, and protein), therapeutic antibodies and antigen-antibody complexes, membrane proteins, macromolecular machineries (ribosome, nucleosome, proteosome, and viruses), to endogenous protein complexes. The challenges, potential, along with perspectives of nTDMS methods for the analysis of proteins and protein assemblies in recombinant and biological samples are discussed.
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Affiliation(s)
- Ruijie Liu
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Shujun Xia
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Huilin Li
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
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17
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Snyder DT, Harvey SR, Wysocki VH. Surface-induced Dissociation Mass Spectrometry as a Structural Biology Tool. Chem Rev 2022; 122:7442-7487. [PMID: 34726898 PMCID: PMC9282826 DOI: 10.1021/acs.chemrev.1c00309] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Native mass spectrometry (nMS) is evolving into a workhorse for structural biology. The plethora of online and offline preparation, separation, and purification methods as well as numerous ionization techniques combined with powerful new hybrid ion mobility and mass spectrometry systems has illustrated the great potential of nMS for structural biology. Fundamental to the progression of nMS has been the development of novel activation methods for dissociating proteins and protein complexes to deduce primary, secondary, tertiary, and quaternary structure through the combined use of multiple MS/MS technologies. This review highlights the key features and advantages of surface collisions (surface-induced dissociation, SID) for probing the connectivity of subunits within protein and nucleoprotein complexes and, in particular, for solving protein structure in conjunction with complementary techniques such as cryo-EM and computational modeling. Several case studies highlight the significant role SID, and more generally nMS, will play in structural elucidation of biological assemblies in the future as the technology becomes more widely adopted. Cases are presented where SID agrees with solved crystal or cryoEM structures or provides connectivity maps that are otherwise inaccessible by "gold standard" structural biology techniques.
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Affiliation(s)
- Dalton T. Snyder
- Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, OH 43210
| | - Sophie R. Harvey
- Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, OH 43210,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
| | - Vicki H. Wysocki
- Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, OH 43210,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210,Corresponding author:
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18
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Vallejo DD, Rojas Ramírez C, Parson KF, Han Y, Gadkari VV, Ruotolo BT. Mass Spectrometry Methods for Measuring Protein Stability. Chem Rev 2022; 122:7690-7719. [PMID: 35316030 DOI: 10.1021/acs.chemrev.1c00857] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mass spectrometry is a central technology in the life sciences, providing our most comprehensive account of the molecular inventory of the cell. In parallel with developments in mass spectrometry technologies targeting such assessments of cellular composition, mass spectrometry tools have emerged as versatile probes of biomolecular stability. In this review, we cover recent advancements in this branch of mass spectrometry that target proteins, a centrally important class of macromolecules that accounts for most biochemical functions and drug targets. Our efforts cover tools such as hydrogen-deuterium exchange, chemical cross-linking, ion mobility, collision induced unfolding, and other techniques capable of stability assessments on a proteomic scale. In addition, we focus on a range of application areas where mass spectrometry-driven protein stability measurements have made notable impacts, including studies of membrane proteins, heat shock proteins, amyloidogenic proteins, and biotherapeutics. We conclude by briefly discussing the future of this vibrant and fast-moving area of research.
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Affiliation(s)
- Daniel D Vallejo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Carolina Rojas Ramírez
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Kristine F Parson
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Yilin Han
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Varun V Gadkari
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Brandon T Ruotolo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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19
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Cabrera ER, Clowers BH. Synchronized Stepped Frequency Modulation for Multiplexed Ion Mobility Measurements. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:557-564. [PMID: 35108007 PMCID: PMC9264663 DOI: 10.1021/jasms.1c00365] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Implementation of frequency-encoded multiplexing for ion mobility spectrometry (e.g., Fourier transform ion mobility spectrometry (FT-IMS)) has facilitated the direct coupling of drift tube ion mobility instrumentation with ion-trap mass analyzers despite their duty cycle mismatch. Traditionally, FT-IMS experiments have been carried out to utilize continuous linear frequency sweeps that are independent of the scan rate of the ion-trap mass analyzer, thus creating a situation where multiple frequencies are swept over two sequential mass scans. This in turn creates a degree of ambiguity in which the ion current derived from a single modulation frequency cannot be assigned to a single data point in the frequency-modulated signal. In an effort to eliminate this ambiguity, this work describes a discrete stepwise function to modulate the ion gates of the IMS while synchronization between the generated frequencies and the scan rate of the linear ion trap is achieved. While the number of individual frequencies used in the stepped frequency sweeps is less than in continuous linear modulation experiments, there is no loss in performance and high levels of precision are maintained across differing combinations of terminal frequencies and scan lengths. Furthermore, the frequency-scan synchronization enables further data-processing techniques such as linear averaging of the frequency modulated signal to drastically improve signal-to-noise ratio for both high and low intensity analytes.
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20
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Liu FC, Ridgeway ME, Winfred JSRV, Polfer NC, Lee J, Theisen A, Wootton CA, Park MA, Bleiholder C. Tandem-trapped ion mobility spectrometry/mass spectrometry coupled with ultraviolet photodissociation. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2021; 35:e9192. [PMID: 34498312 PMCID: PMC9195479 DOI: 10.1002/rcm.9192] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/02/2021] [Accepted: 09/03/2021] [Indexed: 05/05/2023]
Abstract
RATIONALE Tandem-ion mobility spectrometry/mass spectrometry methods have recently gained traction for the structural characterization of proteins and protein complexes. However, ion activation techniques currently coupled with tandem-ion mobility spectrometry/mass spectrometry methods are limited in their ability to characterize structures of proteins and protein complexes. METHODS Here, we describe the coupling of the separation capabilities of tandem-trapped ion mobility spectrometry/mass spectrometry (tTIMS/MS) with the dissociation capabilities of ultraviolet photodissociation (UVPD) for protein structure analysis. RESULTS We establish the feasibility of dissociating intact proteins by UV irradiation at 213 nm between the two TIMS devices in tTIMS/MS and at pressure conditions compatible with ion mobility spectrometry (2-3 mbar). We validate that the fragments produced by UVPD under these conditions result from a radical-based mechanism in accordance with prior literature on UVPD. The data suggest stabilization of fragment ions produced from UVPD by collisional cooling due to the elevated pressures used here ("UVnoD2"), which otherwise do not survive to detection. The data account for a sequence coverage for the protein ubiquitin comparable to recent reports, demonstrating the analytical utility of our instrument in mobility-separating fragment ions produced from UVPD. CONCLUSIONS The data demonstrate that UVPD carried out at elevated pressures of 2-3 mbar yields extensive fragment ions rich in information about the protein and that their exhaustive analysis requires IMS separation post-UVPD. Therefore, because UVPD and tTIMS/MS each have been shown to be valuable techniques on their own merit in proteomics, our contribution here underscores the potential of combining tTIMS/MS with UVPD for structural proteomics.
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Affiliation(s)
- Fanny C. Liu
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4389, USA
| | - Mark E. Ridgeway
- Bruker Daltonics, Inc., 40 Manning Rd., Billerica, MA 01821, USA
| | | | - Nicolas C. Polfer
- Athénée de Luxembourg, 24 boulevard Pierre Dupont, L-1430 Luxembourg, Grand-Duchy of Luxembourg
| | - Jusung Lee
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4389, USA
| | | | | | - Melvin A. Park
- Bruker Daltonics, Inc., 40 Manning Rd., Billerica, MA 01821, USA
- Correspondence to: ,
| | - Christian Bleiholder
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4389, USA
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4389, USA
- Correspondence to: ,
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21
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Evaluating the Performance of 193 nm Ultraviolet Photodissociation for Tandem Mass Tag Labeled Peptides. ANALYTICA 2021. [DOI: 10.3390/analytica2040014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Despite the successful application of tandem mass tags (TMT) for peptide quantitation, missing reporter ions in higher energy collisional dissociation (HCD) spectra remains a challenge for consistent quantitation, especially for peptides with labile post-translational modifications. Ultraviolet photodissociation (UVPD) is an alternative ion activation method shown to provide superior coverage for sequencing of peptides and intact proteins. Here, we optimized and evaluated 193 nm UVPD for the characterization of TMT-labeled model peptides, HeLa proteome, and N-glycopeptides from model proteins. UVPD yielded the same TMT reporter ions as HCD, at m/z 126–131. Additionally, UVPD produced a wide range of fragments that yielded more complete characterization of glycopeptides and less frequent missing TMT reporter ion channels, whereas HCD yielded a strong tradeoff between characterization and quantitation of TMT-labeled glycopeptides. However, the lower fragmentation efficiency of UVPD yielded fewer peptide identifications than HCD. Overall, 193 nm UVPD is a valuable tool that provides an alternative to HCD for the quantitation of large and highly modified peptides with labile PTMs. Continued development of instrumentation specific to UVPD will yield greater fragmentation efficiency and fulfil the potential of UVPD to be an all-in-one spectrum ion activation method for broad use in the field of proteomics.
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22
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Al-Jabiry A, Palmer M, Langridge J, Bellamy-Carter J, Robinson D, Oldham NJ. Combined Chemical Modification and Collision Induced Unfolding Using Native Ion Mobility-Mass Spectrometry Provides Insights into Protein Gas-Phase Structure. Chemistry 2021; 27:13783-13792. [PMID: 34289194 DOI: 10.1002/chem.202101857] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Indexed: 11/10/2022]
Abstract
Native mass spectrometry is now an important tool in structural biology. Thus, the nature of higher protein structure in the vacuum of the mass spectrometer is an area of significant interest. One of the major goals in the study of gas-phase protein structure is to elucidate the stabilising role of interactions at the level of individual amino acid residues. A strategy combining protein chemical modification together with collision induced unfolding (CIU) was developed and employed to probe the structure of compact protein ions produced by native electrospray ionisation. Tractable chemical modification was used to alter the properties of amino acid residues, and ion mobility-mass spectrometry (IM-MS) utilised to monitor the extent of unfolding as a function of modification. From these data the importance of specific intramolecular interactions for the stability of compact gas-phase protein structure can be inferred. Using this approach, and aided by molecular dynamics simulations, an important stabilising interaction between K6 and H68 in the protein ubiquitin was identified, as was a contact between the N-terminus and E22 in a ubiquitin binding protein UBA2.
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Affiliation(s)
- Asia Al-Jabiry
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Martin Palmer
- Waters Corporation, Stamford Avenue Altrincham Road, Wilmslow, Cheshire, SK9 4AX, UK
| | - James Langridge
- Waters Corporation, Stamford Avenue Altrincham Road, Wilmslow, Cheshire, SK9 4AX, UK
| | | | - David Robinson
- School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK
| | - Neil J Oldham
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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23
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Becher S, Wang H, Leeming MG, Donald WA, Heiles S. Influence of protein ion charge state on 213 nm top-down UVPD. Analyst 2021; 146:3977-3987. [PMID: 34009215 DOI: 10.1039/d1an00571e] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ultraviolet photodissociation (UVPD) is a powerful and rapidly developing method in top-down proteomics. Sequence coverages can exceed those obtained with collision- and electron-induced fragmentation methods. Because of the recent interest in UVPD, factors that influence protein fragmentation and sequence coverage are actively debated in the literature. Here, we performed top-down 213 nm UVPD experiments on a 7 T Fourier-transform ion cyclotron resonance mass spectrometer (FT-ICR MS) for the model proteins ubiquitin, myoglobin and cytochrome c that were electrosprayed from native, denaturing and supercharging solutions in order to investigate the effect of protein charge states on UVPD fragments. By performing UVPD in ultrahigh vacuum, factors associated with collisional cooling and any ion activation during transfer between mass analyzers can be largely eliminated. Sequence coverage increased from <10% for low charge states to >60% for high charge states for all three proteins. This trend is influenced by the overall charge state, i.e., charges per number of amino acid residues, and to a lesser degree by associated structural changes of protein ions of different charge states based on comparisons to published collision-cross section measurements. To rationalize this finding, and correlate sequence ion formation and identity with the number and location of protons, UVPD results were compared to protonation sites predicted based on electrostatic modelling. Assuming confined protonation sites, these results indicate the presence of two general fragmentation types; i.e., charge remote and charge directed. For moderately high protein charge states, fragment ions mostly originate in regions between likely protonation sites (charge remote), whereas sequence ions of highly charge protein ions occur either near backbone amide protonation sites at low-basicity residues (charge directed) or at charge remote sites (i.e., high-basicity residues). Overall, our results suggest that top-down 213 UVPD performance in the zero-pressure limit depends strongly on protein charge states and protonation sites can influence the location of backbone cleavages.
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Affiliation(s)
- Simon Becher
- Institute of Inorganic and Analytical Chemistry, Justus Liebig University Giessen, 35392 Giessen, Germany.
| | - Huixin Wang
- Mark Wainwright Analytical Centre, University of New South Wales, New South Wales, Australia
| | - Michael G Leeming
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - William A Donald
- School of Chemistry, University of New South Wales, Sydney, New South Wales, Australia
| | - Sven Heiles
- Institute of Inorganic and Analytical Chemistry, Justus Liebig University Giessen, 35392 Giessen, Germany.
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24
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Yin V, Konermann L. Probing the Effects of Heterogeneous Oxidative Modifications on the Stability of Cytochrome c in Solution and in the Gas Phase. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:73-83. [PMID: 32401029 DOI: 10.1021/jasms.0c00089] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Covalent modifications by reactive oxygen species can modulate the function and stability of proteins. Thermal unfolding experiments in solution are a standard tool for probing oxidation-induced stability changes. Complementary to such solution investigations, the stability of electrosprayed protein ions can be assessed in the gas phase by collision-induced unfolding (CIU) and ion-mobility spectrometry. A question that remains to be explored is whether oxidation-induced stability alterations in solution are mirrored by the CIU behavior of gaseous protein ions. Here, we address this question using chloramine-T-oxidized cytochrome c (CT-cyt c) as a model system. CT-cyt c comprises various proteoforms that have undergone MetO formation (+16 Da) and Lys carbonylation (LysCH2-NH2 → LysCHO, -1 Da). We found that CT-cyt c in solution was destabilized, with a ∼5 °C reduced melting temperature compared to unmodified controls. Surprisingly, CIU experiments revealed the opposite trend, i.e., a stabilization of CT-cyt c in the gas phase. To pinpoint the source of this effect, we performed proteoform-resolved CIU on CT-cyt c fractions that had been separated by cation exchange chromatography. In this way, it was possible to identify MetO formation at residue 80 as the key modification responsible for stabilization in the gas phase. Possibly, this effect is caused by newly formed contacts of the sulfoxide with aromatic residues in the protein core. Overall, our results demonstrate that oxidative modifications can affect protein stability in solution and in the gas phase very differently.
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Affiliation(s)
- Victor Yin
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
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25
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Lermyte F, Theisen A, O'Connor PB. Solution Condition-Dependent Formation of Gas-Phase Protomers of Alpha-Synuclein in Electrospray Ionization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:364-372. [PMID: 33237779 DOI: 10.1021/jasms.0c00373] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
One of the main characteristics of biomolecular ions in mass spectrometry is their net charge, and a range of approaches exist to either increase or decrease this quantity in the gas phase. In the context of small molecules, it is well known that, in addition to the charge state, the charge site also has a profound effect on an ion's gas-phase behavior; however, this effect has been far less explored for peptides and intact proteins. Methods exist to determine charge sites of protein ions, and others have observed that the interplay of electrostatic repulsion and inherent basicity leads to different sites gaining or losing a charge depending on the total net charge. Here, we report two distinct protonation site isomers ("protomers") of α-synuclein occurring at the same charge state. The protomers showed important differences in their gas-phase fragmentation behavior and were furthermore distinguishable by ion mobility spectrometry. One protomer was produced under standard electrospray conditions, while the other was observed after addition of 10% dimethyl sulfoxide to the protein solution. Charge sites for both protomers were determined using ultraviolet photodissociation.
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Affiliation(s)
- Frederik Lermyte
- Department of Chemistry, Technical University of Darmstadt, 64287 Darmstadt, Germany
- School of Engineering, University of Warwick, Coventry CV4 7AL, U.K
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Alina Theisen
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Peter B O'Connor
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
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26
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Bellamy‐Carter J, O'Grady L, Passmore M, Jenner M, Oldham NJ. Decoding Protein Gas‐Phase Stability with Alanine Scanning and Collision‐Induced Unfolding Ion Mobility Mass Spectrometry. ACTA ACUST UNITED AC 2020. [DOI: 10.1002/anse.202000019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
| | - Louisa O'Grady
- School of Chemistry University of Nottingham University Park Nottingham NG7 2RD UK
| | - Munro Passmore
- Department of Chemistry University of Warwick Coventry CV4 7AL UK
| | - Matthew Jenner
- Department of Chemistry University of Warwick Coventry CV4 7AL UK
- Warwick Integrative Synthetic Biology Centre University of Warwick Coventry CV4 7AL UK
| | - Neil J. Oldham
- School of Chemistry University of Nottingham University Park Nottingham NG7 2RD UK
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27
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Stiving AQ, Harvey SR, Jones BJ, Bellina B, Brown JM, Barran PE, Wysocki VH. Coupling 193 nm Ultraviolet Photodissociation and Ion Mobility for Sequence Characterization of Conformationally-Selected Peptides. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:2313-2320. [PMID: 32959654 PMCID: PMC8127984 DOI: 10.1021/jasms.0c00259] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Ultraviolet photodissociation (UVPD) has emerged as a useful technique for characterizing peptide, protein, and protein complex primary and secondary structure. 193 nm UVPD, specifically, enables extensive covalent fragmentation of the peptide backbone without the requirement of a specific side chain chromophore and with no precursor charge state dependence. We have modified a commercial quadrupole-ion mobility-time-of-flight (Q-IM-TOF) mass spectrometer to include 193 nm UVPD following ion mobility. Ion mobility (IM) is a gas-phase separation technique that enables separation of ions by their size, shape, and charge, providing an orthogonal dimension of separation to mass analysis. Following instrument modifications, we characterized the performance of, and information that could be generated from, this new setup using the model peptides substance P, melittin, and insulin chain B. These experiments show extensive fragmentation across the peptide backbone and a variety of ion types as expected from 193 nm UVPD. Additionally, y-2 ions (along with complementary a+2 and b+2 ions) N-terminal to proline were observed. Combining the IM separation and mobility gating capabilities with UVPD, we demonstrate the ability to accomplish both mass- and mobility-selection of bradykinin des-Arg9 and des-Arg1 peptides followed by complete sequence characterization by UVPD. The new capabilities of this modified instrument demonstrate the utility of combining IM with UVPD because isobaric species cannot be independently selected with a traditional quadrupole alone.
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Affiliation(s)
- Alyssa Q Stiving
- Department of Chemistry and Biochemistry and Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Sophie R Harvey
- Department of Chemistry and Biochemistry and Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Benjamin J Jones
- Department of Chemistry and Biochemistry and Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Bruno Bellina
- Michael Barber Centre for Collaborative Mass Spectrometry, Manchester Institute of Biotechnology, and Photon Science Institute, University of Manchester, 131 Princess Street, Manchester, M1 7DN, United Kingdom
| | | | - Perdita E Barran
- Michael Barber Centre for Collaborative Mass Spectrometry, Manchester Institute of Biotechnology, and Photon Science Institute, University of Manchester, 131 Princess Street, Manchester, M1 7DN, United Kingdom
| | - Vicki H Wysocki
- Department of Chemistry and Biochemistry and Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, Ohio 43210, United States
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Zhou M, Lantz C, Brown KA, Ge Y, Paša-Tolić L, Loo JA, Lermyte F. Higher-order structural characterisation of native proteins and complexes by top-down mass spectrometry. Chem Sci 2020; 11:12918-12936. [PMID: 34094482 PMCID: PMC8163214 DOI: 10.1039/d0sc04392c] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 10/05/2020] [Indexed: 12/11/2022] Open
Abstract
In biology, it can be argued that if the genome contains the script for a cell's life cycle, then the proteome constitutes an ensemble cast of actors that brings these instructions to life. Their interactions with each other, co-factors, ligands, substrates, and so on, are key to understanding nearly any biological process. Mass spectrometry is well established as the method of choice to determine protein primary structure and location of post-translational modifications. In recent years, top-down fragmentation of intact proteins has been increasingly combined with ionisation of noncovalent assemblies under non-denaturing conditions, i.e., native mass spectrometry. Sequence, post-translational modifications, ligand/metal binding, protein folding, and complex stoichiometry can thus all be probed directly. Here, we review recent developments in this new and exciting field of research. While this work is written primarily from a mass spectrometry perspective, it is targeted to all bioanalytical scientists who are interested in applying these methods to their own biochemistry and chemical biology research.
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Affiliation(s)
- Mowei Zhou
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory Richland WA 99354 USA
| | - Carter Lantz
- Department of Chemistry and Biochemistry, Department of Biological Chemistry, University of California-Los Angeles Los Angeles CA 90095 USA
| | - Kyle A Brown
- Department of Chemistry, University of Wisconsin-Madison Madison WI 53706 USA
| | - Ying Ge
- Department of Chemistry, University of Wisconsin-Madison Madison WI 53706 USA
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison Madison WI 53706 USA
| | - Ljiljana Paša-Tolić
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory Richland WA 99354 USA
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, Department of Biological Chemistry, University of California-Los Angeles Los Angeles CA 90095 USA
| | - Frederik Lermyte
- Department of Chemistry, Institute of Chemistry and Biochemistry, Technical University of Darmstadt 64287 Darmstadt Germany
- Mass Spectrometry Laboratory, MolSys Research Unit, University of Liège 4000 Liège Belgium
- School of Engineering, University of Warwick Coventry CV4 7AL UK
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29
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Du Y, Zhao F, Xing J, Cui M, Liu Z. Investigation of interactions between cytochrome c and ginsenosides by native mass spectrometry and molecular docking simulations. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34:e8853. [PMID: 32511843 DOI: 10.1002/rcm.8853] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 05/22/2020] [Accepted: 06/03/2020] [Indexed: 06/11/2023]
Abstract
RATIONALE Ginsenosides are considered to be the main functional components in ginseng and possess various important pharmacological activities. The study of the interactions between ginsenosides and proteins is indispensable for understanding the pharmacological activities of ginsenosides. In this work, the interactions of ginsenosides with cytochrome c (cyt c) were investigated by native mass spectrometry and molecular docking simulations. METHODS The interactions of four ginsenosides (Rb1 , Rb3 , Rf, Rg1 ) and cyt c in NH4 OAc solution were investigated by electrospray ionization linear ion trap mass spectrometry (ESI-LTQ-MS). Molecular docking simulations of cyt c complexes were carried out by AutoDock. RESULTS The native mass spectrometry results showed that the four ginsenosides were directly bound to cyt c, with stoichiometric ratios of 1:1 and 2:1 in NH4 OAc. The order of relative binding abilities of ginsenosides to cyt c obtained by ESI-MS was Rb1 > Rb3 > Rf > Rg1 , which was consistent with the docking results. Moreover, molecular docking simulations also indicated potential binding sites of cyt c and ginsenosides. Hydrogen-bond interaction played a very important role in cyt c binding with ginsenosides. CONCLUSIONS It has been demonstrated that native MS is a useful tool to investigate the interactions of ginsenosides with cyt c. Molecular docking is a good complement to ESI analysis, and can provide information on potential binding sites of cyt c-ginsenoside complexess. This strategy will be helpful to further understand the interactions of proteins and small molecules.
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Affiliation(s)
- Yang Du
- National Center for Mass Spectrometry in Changchun, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, China
- University of Science and Technology of China, Hefei, Anhui, 230029, China
| | - Fengjiao Zhao
- National Center for Mass Spectrometry in Changchun, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, China
- University of Science and Technology of China, Hefei, Anhui, 230029, China
| | - Junpeng Xing
- National Center for Mass Spectrometry in Changchun, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, China
| | - Meng Cui
- National Center for Mass Spectrometry in Changchun, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, China
- University of Science and Technology of China, Hefei, Anhui, 230029, China
| | - Zhiqiang Liu
- National Center for Mass Spectrometry in Changchun, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, China
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30
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Allison TM, Barran P, Benesch JLP, Cianferani S, Degiacomi MT, Gabelica V, Grandori R, Marklund EG, Menneteau T, Migas LG, Politis A, Sharon M, Sobott F, Thalassinos K. Software Requirements for the Analysis and Interpretation of Native Ion Mobility Mass Spectrometry Data. Anal Chem 2020; 92:10881-10890. [PMID: 32649184 DOI: 10.1021/acs.analchem.9b05792] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The past few years have seen a dramatic increase in applications of native mass and ion mobility spectrometry, especially for the study of proteins and protein complexes. This increase has been catalyzed by the availability of commercial instrumentation capable of carrying out such analyses. As in most fields, however, the software to process the data generated from new instrumentation lags behind. Recently, a number of research groups have started addressing this by developing software, but further improvements are still required in order to realize the full potential of the data sets generated. In this perspective, we describe practical aspects as well as challenges in processing native mass spectrometry (MS) and ion mobility-MS data sets and provide a brief overview of currently available tools. We then set out our vision of future developments that would bring the community together and lead to the development of a common platform to expedite future computational developments, provide standardized processing approaches, and serve as a location for the deposition of data for this emerging field. This perspective has been written by members of the European Cooperation in Science and Technology Action on Native MS and Related Methods for Structural Biology (EU COST Action BM1403) as an introduction to the software tools available in this area. It is intended to serve as an overview for newcomers and to stimulate discussions in the community on further developments in this field, rather than being an in-depth review. Our complementary perspective (http://dx.doi.org/10.1021/acs.analchem.9b05791) focuses on computational approaches used in this field.
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Affiliation(s)
- Timothy M Allison
- School of Physical and Chemical Sciences, Biomolecular Interaction Centre, University of Canterbury, Christchurch 8140, New Zealand
| | - Perdita Barran
- Michael Barber Centre for Collaborative Mass Spectrometry, Manchester Institute of Biotechnology, School of Chemistry, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Justin L P Benesch
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, South Parks Road, Oxford OX1 3TA, United Kingdom
| | - Sarah Cianferani
- Laboratoire de Spectrométrie de Masse BioOrganique (LSMBO), Université de Strasbourg, CNRS, IPHC UMR 7178, 67000 Strasbourg, France
| | - Matteo T Degiacomi
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, South Parks Road, Oxford OX1 3TA, United Kingdom.,Department of Physics, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | - Valerie Gabelica
- University of Bordeaux, INSERM and CNRS, ARNA Laboratory, IECB site, 2 Rue Robert Escarpit, 33600 Pessac, France
| | - Rita Grandori
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, 20126 Milan, Italy
| | - Erik G Marklund
- Department of Chemistry - BMC, Uppsala University, Box 576, 75123 Uppsala, Sweden
| | - Thomas Menneteau
- Division of Biosciences, Institute of Structural and Molecular Biology, University College of London, Gower Street, London WC1E 6BT, United Kingdom
| | - Lukasz G Migas
- Michael Barber Centre for Collaborative Mass Spectrometry, Manchester Institute of Biotechnology, School of Chemistry, University of Manchester, Manchester M1 7DN, United Kingdom
| | - Argyris Politis
- Department of Chemistry, King's College London, 7 Trinity Street, London SE1 1DB, United Kingdom
| | - Michal Sharon
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Frank Sobott
- Biomolecular & Analytical Mass Spectrometry, Department of Chemistry, University of Antwerp, 2020 Antwerp, Belgium.,School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Konstantinos Thalassinos
- Division of Biosciences, Institute of Structural and Molecular Biology, University College of London, Gower Street, London WC1E 6BT, United Kingdom.,Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, Malet Street, London WC1E 7HX, United Kingdom
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31
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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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32
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Williams JP, Morrison LJ, Brown JM, Beckman JS, Voinov VG, Lermyte F. Top-Down Characterization of Denatured Proteins and Native Protein Complexes Using Electron Capture Dissociation Implemented within a Modified Ion Mobility-Mass Spectrometer. Anal Chem 2020; 92:3674-3681. [PMID: 31999103 DOI: 10.1021/acs.analchem.9b04763] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Electron-based fragmentation methods have revolutionized biomolecular mass spectrometry, in particular native and top-down protein analysis. Here, we report the use of a new electromagnetostatic cell to perform electron capture dissociation (ECD) within a quadrupole/ion mobility/time-of-flight mass spectrometer. This cell was installed between the ion mobility and time-of-flight regions of the instrument, and fragmentation was fast enough to be compatible with mobility separation. The instrument was already fitted with electron transfer dissociation (ETD) between the quadrupole and mobility regions prior to modification. We show excellent fragmentation efficiency for denatured peptides and proteins without the need to trap ions in the gas phase. Additionally, we demonstrate native top-down backbone fragmentation of noncovalent protein complexes, leading to comparable sequence coverage to what was achieved using the instrument's existing ETD capabilities. Limited collisional ion activation of the hemoglobin tetramer before ECD was reflected in the observed fragmentation pattern, and complementary ion mobility measurements prior to ECD provided orthogonal evidence of monomer unfolding within this complex. The approach demonstrated here provides a powerful platform for both top-down proteomics and mass spectrometry-based structural biology studies.
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Affiliation(s)
- Jonathan P Williams
- Waters Corporation, Stamford Avenue, Altrincham Road, Wilmslow SK9 4AX, United Kingdom
| | - Lindsay J Morrison
- Waters Corporation, Stamford Avenue, Altrincham Road, Wilmslow SK9 4AX, United Kingdom
| | - Jeffery M Brown
- Waters Corporation, Stamford Avenue, Altrincham Road, Wilmslow SK9 4AX, United Kingdom
| | - Joseph S Beckman
- e-MSion Inc., 2121 NE Jack London Drive, Corvallis, Oregon 97330, United States.,Linus Pauling Institute and the Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, United States
| | - Valery G Voinov
- e-MSion Inc., 2121 NE Jack London Drive, Corvallis, Oregon 97330, United States.,Linus Pauling Institute and the Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, United States
| | - Frederik Lermyte
- School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom.,Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
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33
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Affiliation(s)
| | | | - Jennifer S. Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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34
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Zhou M, Liu W, Shaw JB. Charge Movement and Structural Changes in the Gas-Phase Unfolding of Multimeric Protein Complexes Captured by Native Top-Down Mass Spectrometry. Anal Chem 2020; 92:1788-1795. [PMID: 31869201 DOI: 10.1021/acs.analchem.9b03469] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The extent to which noncovalent protein complexes retain native structure in the gas phase is highly dependent on experimental conditions. Energetic collisions with background gas can cause structural changes ranging from unfolding to subunit dissociation. Additionally, recent studies have highlighted the role of charge in such structural changes, but the mechanism is not completely understood. In this study, native top down (native TD) mass spectrometry was used to probe gas-phase structural changes of alcohol dehydrogenase (ADH, 4mer) under varying degrees of in-source activation. Changes in covalent backbone fragments produced by electron capture dissociation (ECD) or 193 nm ultraviolet photodissociation (UVPD) were attributed to structural changes of the ADH 4mer. ECD fragments indicated unfolding started at the N-terminus, and the charge states of UVPD fragments enabled monitoring of charge migration to the unfolded regions. Interestingly, UVPD fragments also indicated that the charge at the "unfolding" N-terminus of ADH decreased at high in-source activation energies after the initial increase. We proposed a possible "refolding-after-unfolding" mechanism, as further supported by monitoring hydrogen elimination from radical a-ions produced by UVPD at the N-terminus of ADH. However, "refolding-after-unfolding" with increasing in-source activation was not observed for charge-reduced ADH, which likely adopted compact structures that are resistant to both charge migration and unfolding. When combined, these results support a charge-directed unfolding mechanism for protein complexes. Overall, an experimental framework was outlined for utilizing native TD to generate structure-informative mass spectral signatures for protein complexes that complement other structure characterization techniques, such as ion mobility and computational modeling.
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Affiliation(s)
- Mowei Zhou
- Environmental Molecular Sciences Laboratory , Pacific Northwest National Laboratory , 3335 Innovation Boulevard , Richland , Washington 99354 , United States
| | - Weijing Liu
- Environmental Molecular Sciences Laboratory , Pacific Northwest National Laboratory , 3335 Innovation Boulevard , Richland , Washington 99354 , United States
| | - Jared B Shaw
- Environmental Molecular Sciences Laboratory , Pacific Northwest National Laboratory , 3335 Innovation Boulevard , Richland , Washington 99354 , United States
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35
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Chea EE, Deredge DJ, Jones LM. Insights on the Conformational Ensemble of Cyt C Reveal a Compact State during Peroxidase Activity. Biophys J 2019; 118:128-137. [PMID: 31810655 DOI: 10.1016/j.bpj.2019.11.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 10/29/2019] [Accepted: 11/11/2019] [Indexed: 12/19/2022] Open
Abstract
Cytochrome c (cyt c) is known for its role in the electron transport chain but transitions to a peroxidase-active state upon exposure to oxidative species. The peroxidase activity ultimately results in the release of cyt c into the cytosol for the engagement of apoptosis. The accumulation of oxidative modifications that accompany the onset of the peroxidase function are well-characterized. However, the concurrent structural and conformational transitions of cyt c remain undercharacterized. Fast photochemical oxidation of proteins (FPOP) coupled with mass spectrometry is a protein footprinting technique used to structurally characterize proteins. FPOP coupled with native ion mobility separation shows that exposure to H2O2 results in the accumulation of a compact state of cyt c. Subsequent top-down fragmentation to localize FPOP modifications reveals changes in heme coordination between conformers. A time-resolved functional assay suggests that this compact conformer is peroxidase active. Altogether, combining FPOP, ion mobility separation, and top-down and bottom-up mass spectrometry allows us to discern individual conformations in solution and obtain a better understanding of the conformational ensemble and structural transitions of cyt c as it transitions from a respiratory role to a proapoptotic role.
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Affiliation(s)
- Emily E Chea
- Department of Pharmaceutical Sciences, University of Maryland Baltimore, Baltimore, Maryland
| | - Daniel J Deredge
- Department of Pharmaceutical Sciences, University of Maryland Baltimore, Baltimore, Maryland
| | - Lisa M Jones
- Department of Pharmaceutical Sciences, University of Maryland Baltimore, Baltimore, Maryland.
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36
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Zheng S, Yuan S, Hou Z, Li G, Chen Y, Pan Y, Liu Y, Huang G. Charge-dependent modulation of specific and nonspecific protein-metal ion interactions in nanoelectrospray ionization mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2019; 33:1502-1511. [PMID: 31151135 DOI: 10.1002/rcm.8493] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 05/21/2019] [Accepted: 05/22/2019] [Indexed: 06/09/2023]
Abstract
RATIONALE Previous studies found that charge state could affect both specific and nonspecific binding of protein-metal ion interactions in nanoelectrospray ionization mass spectrometry (nESI-MS). However, the two kinds of interactions have been studied individually in spite of the problem that they often coexist in the same system. Thus, it is necessary to study the effects of charge state on specific and nonspecific protein-metal ion interactions in one system to reveal more accurate binding state. METHODS The HIV-1 nucleocapsid protein (NCp7(31-55)) which can bind specifically and nonspecifically to Zn2+ served as the model to show the charge-dependent protein-metal ion interactions. Hydrogen/deuterium exchange (HDX) and photodissociation (PD) were used to demonstrate that specific binding state was correlated with protein structure. In addition to NCp7(31-55), three other model proteins were used to investigate the reason for the charge-dependent nonspecific binding. RESULTS For specific binding, we proposed that protein ions with different charge states had different conformations. The HDX results showed that labile protons in the NCp7(31-55)-Zn complex were exchanged in a charge-state-dependent way. The PD experiments revealed differential fragment yields for different charge states. For nonspecific binding, higher charge states had more Zn2+ additions, but less SO4 2- additions. The effects of charge states on nonspecific binding levels were entirely the opposite for Zn2+ and SO4 2- . These results could reveal that the nonspecific binding was caused by electrostatic interaction. CONCLUSIONS For specific binding, NCp7(31-55) with lower charge states have folding and undenatured structures. The binding states of lower charge states can better reflect more native binding states. For nonspecific binding, when multiple metal ions adduct to proteins, the proteins have more net positive charges, which tend to generate higher charge ions during electrospray.
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Affiliation(s)
- Shihui Zheng
- Department of Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Siming Yuan
- Department of Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Zhuanghao Hou
- Department of Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Gongyu Li
- Department of Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Yuting Chen
- Department of Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Yang Pan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui, 230029, P. R. China
| | - Yangzhong Liu
- Department of Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Guangming Huang
- Department of Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui, 230029, P. R. China
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Sipe SN, Brodbelt JS. Impact of charge state on 193 nm ultraviolet photodissociation of protein complexes. Phys Chem Chem Phys 2019; 21:9265-9276. [PMID: 31016301 DOI: 10.1039/c9cp01144g] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
As applications in mass spectrometry continue to expand into the field of structural biology, there have been an increasing number of studies on noncovalent biological assemblies. Ensuring that protein complexes maintain native-like conformations and architectures during the transition from solution to the gas phase is a key aim. Probing composition and arrangement of subunits of multi-charged complexes via tandem mass spectrometry (MS/MS) may lead to protein unfolding and the redistribution of charges on the constituent subunits, leading to asymmetric charge partitioning and ejection of a high-charged monomer. Additionally, the overall dissociation efficiency of many ion activation methods is often suppressed for low charge states, hindering the effectiveness of MS/MS for complexes that have low charge density. Ultraviolet photodissociation (UVPD) of proteins using 193 nm photons is a high-energy alternative to collisional activation and demonstrates little to no charge state dependence. Here the symmetry of charge partitioning upon UVPD is evaluated for an array of multimeric protein complexes as a function of initial charge state. The results demonstrate that high laser energies (3 mJ) for UVPD induces more symmetric charge partitioning and ejection of low-charged, presumably compact monomers than higher-energy collisional dissociation (HCD).
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Affiliation(s)
- Sarah N Sipe
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA.
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