1
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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] [Grants] [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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2
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Liu FC, Ridgeway ME, Wootton CA, Theisen A, Panczyk EM, Meier F, Park MA, Bleiholder C. Top-Down Protein Analysis by Tandem-Trapped Ion Mobility Spectrometry/Mass Spectrometry (Tandem-TIMS/MS) Coupled with Ultraviolet Photodissociation (UVPD) and Parallel Accumulation/Serial Fragmentation (PASEF) MS/MS Analysis. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:2232-2246. [PMID: 37638640 PMCID: PMC11162218 DOI: 10.1021/jasms.3c00187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/29/2023]
Abstract
"Top-down" proteomics analyzes intact proteins and identifies proteoforms by their intact mass as well as the observed fragmentation pattern in tandem mass spectrometry (MS/MS) experiments. Recently, hybrid ion mobility spectrometry-mass spectrometry (IM/MS) methods have gained traction for top-down experiments, either by allowing top-down analysis of individual isomers or alternatively by improving signal/noise and dynamic range for fragment ion assignment. We recently described the construction of a tandem-trapped ion mobility spectrometer/mass spectrometer (tandem-TIMS/MS) coupled with an ultraviolet (UV) laser and demonstrated a proof-of-principle for top-down analysis by UV photodissociation (UVPD) at 2-3 mbar. The present work builds on this with an exploration of a top-down method that couples tandem-TIMS/MS with UVPD and parallel-accumulation serial fragmentation (PASEF) MS/MS analysis. We first survey types and structures of UVPD-specific fragment ions generated in the 2-3 mbar pressure regime of our instrument. Notably, we observe UVPD-induced fragment ions with multiple conformations that differ from those produced in the absence of UV irradiation. Subsequently, we discuss how MS/MS spectra of top-down fragment ions lend themselves ideally for probability-based scoring methods developed in the bottom-up proteomics field and how the ability to record automated PASEF-MS/MS spectra resolves ambiguities in the assignment of top-down fragment ions. Finally, we describe the coupling of tandem-TIMS/MS workflows with UVPD and PASEF-MS/MS analysis for native top-down protein analysis.
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Affiliation(s)
- Fanny C. Liu
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32304, USA
| | | | | | | | | | - Florian Meier
- Functional Proteomics, Jena University Hospital, 07747 Jena, Germany
| | | | - Christian Bleiholder
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32304, USA
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3
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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: 43] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [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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4
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Lanzillotti M, Brodbelt JS. Comparison of Top-Down Protein Fragmentation Induced by 213 and 193 nm UVPD. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:279-285. [PMID: 36594540 DOI: 10.1021/jasms.2c00288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The growing interest in advancing tandem mass spectrometry strategies for top-down proteomics has motivated efforts to optimize ion activation strategies for intact proteins, including the comparison of 193 and 213 nm wavelengths for ultraviolet photodissociation (UVPD). The present study focuses on the performance and outcomes of UVPD for five proteins, ubiquitin, cytochrome C, frataxin, myoglobin, and carbonic anhydrase, with an emphasis on evaluating the similarities and differences in fragmentation promoted by UVPD using 193 nm versus 213 nm photons. Mass spectra were collected as a function of the number of laser pulses, and precursor depletion levels were monitored and controlled to provide consistent energy deposition between 213 and 193 nm UVPD. Fragment ions were confirmed on the basis of their isotopic distributions in m/z space to preserve both charge state and abundance information and were classified on the basis of ion type and frequency. A large portion of the total fragment ion abundance was attributable to preferential cleavages, particularly ones adjacent to proline residues. These cleavages were examined on the basis of the backbone site and abundances, revealing that a and y-2 ions N-terminal to proline residues appeared at disproportionately high abundances in 213 nm UVPD spectra as compared to 193 nm UVPD spectra, highlighting one notable difference in the top-down spectra. We theorize that these fragments are formed more efficiently in 213 nm UVPD than in 193 nm UVPD due to increased absorption of 213 nm photons at the proline amide bond.
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Affiliation(s)
- Michael Lanzillotti
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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5
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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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6
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Liu FC, Kirk SR, Caldwell KA, Pedrete T, Meier F, Bleiholder C. Tandem Trapped Ion Mobility Spectrometry/Mass Spectrometry (tTIMS/MS) Reveals Sequence-Specific Determinants of Top-Down Protein Fragment Ion Cross Sections. Anal Chem 2022; 94:8146-8155. [PMID: 35621336 PMCID: PMC10032035 DOI: 10.1021/acs.analchem.1c05171] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Top-down proteomics provides a straightforward approach to the level of proteoforms but remains technologically challenging. Using ion mobility spectrometry/mass spectrometry (IMS/MS) to separate top-down fragment ions improves signal/noise and dynamic range. Such applications, however, do not yet leverage the primary information obtained from IMS/MS, which is the characterization of the fragment ion structure by the measured momentum transfer cross sections. Here, we perform top-down analysis of intact proteins and assemblies using our tandem trapped ion mobility spectrometer/mass spectrometer (tTIMS/MS) and compile over 1400 cross section values of fragment ions. Our analysis reveals that most fragment ions exhibit multiple, stable conformations similar to those of intact polypeptides and proteins. The data further indicate that the conformational heterogeneity is strongly influenced by the amino acid sequences of the fragment ions. Moreover, time-resolved tTIMS/MS experiments reveal that conformations of top-down fragment ions can be metastable on the timescale of ion mobility measurements. Taken together, our analysis indicates that top-down fragment ions undergo a folding process in the gas phase and that this folding process can lead to kinetic trapping of intermediate states in ion mobility measurements. Hence, because the folding free energy surface of a polypeptide ion is encoded by its amino acid sequence and charge state, our analysis suggests that cross sections can be exploited as sequence-specific determinants of top-down fragment ions.
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Affiliation(s)
- Fanny C. Liu
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4390, USA
| | - Samuel R. Kirk
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4390, USA
| | - Kirsten A. Caldwell
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4390, USA
| | - Thais Pedrete
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4390, USA
| | - Florian Meier
- Functional Proteomics, Jena University Hospital, 07747 Jena, Germany
| | - Christian Bleiholder
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4390, USA
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4390, USA
- Corresponding Author
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7
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Liu FC, Ridgeway ME, Park MA, Bleiholder C. Tandem-trapped ion mobility spectrometry/mass spectrometry ( tTIMS/MS): a promising analytical method for investigating heterogenous samples. Analyst 2022; 147:2317-2337. [PMID: 35521797 PMCID: PMC9914546 DOI: 10.1039/d2an00335j] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Ion mobility spectrometry/mass spectrometry (IMS/MS) is widely used to study various levels of protein structure. Here, we review the current state of affairs in tandem-trapped ion mobility spectrometry/mass spectrometry (tTIMS/MS). Two different tTIMS/MS instruments are discussed in detail: the first tTIMS/MS instrument, constructed from coaxially aligning two TIMS devices; and an orthogonal tTIMS/MS configuration that comprises an ion trap for irradiation of ions with UV photons. We discuss the various workflows the two tTIMS/MS setups offer and how these can be used to study primary, tertiary, and quaternary structures of protein systems. We also discuss, from a more fundamental perspective, the processes that lead to denaturation of protein systems in tTIMS/MS and how to soften the measurement so that biologically meaningful structures can be characterised with tTIMS/MS. We emphasize the concepts underlying tTIMS/MS to underscore the opportunities tandem-ion mobility spectrometry methods offer for investigating heterogeneous samples.
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Affiliation(s)
- Fanny C Liu
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4390, USA.
| | | | | | - Christian Bleiholder
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4390, USA.
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4390, USA
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8
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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: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [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
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9
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Sanders JD, Shields SW, Escobar EE, Lanzillotti MB, Butalewicz JP, James VK, Blevins MS, Sipe SN, Brodbelt JS. Enhanced Ion Mobility Separation and Characterization of Isomeric Phosphatidylcholines Using Absorption Mode Fourier Transform Multiplexing and Ultraviolet Photodissociation Mass Spectrometry. Anal Chem 2022; 94:4252-4259. [PMID: 35239318 DOI: 10.1021/acs.analchem.1c04711] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The structural diversity of phospholipids plays a critical role in cellular membrane dynamics, energy storage, and cellular signaling. Despite its importance, the extent of this diversity has only recently come into focus, largely owing to advances in separation science and mass spectrometry methodology and instrumentation. Characterization of glycerophospholipid (GP) isomers differing only in their acyl chain configurations and locations of carbon-carbon double bonds (C═C) remains challenging due to the need for both effective separation of isomers and advanced tandem mass spectrometry (MS/MS) technologies capable of double-bond localization. Drift tube ion mobility spectrometry (DTIMS) coupled with MS can provide both fast separation and accurate determination of collision cross section (CCS) of molecules but typically lacks the resolving power needed to separate phospholipid isomers. Ultraviolet photodissociation (UVPD) can provide unambiguous double-bond localization but is challenging to implement on the timescales of modern commercial drift tube time-of-flight mass spectrometers. Here, we present a novel method for coupling DTIMS with a UVPD-enabled Orbitrap mass spectrometer using absorption mode Fourier transform multiplexing that affords simultaneous localization of double bonds and accurate CCS measurements even when isomers cannot be fully resolved in the mobility dimension. This method is demonstrated on two- and three-component mixtures and shown to provide CCS measurements that differ from those obtained by individual analysis of each component by less than 1%.
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Affiliation(s)
- James D Sanders
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Samuel W Shields
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Edwin E Escobar
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Michael B Lanzillotti
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Jamie P Butalewicz
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Virginia K James
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Molly S Blevins
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Sarah N Sipe
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Jennifer S Brodbelt
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
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10
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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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11
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Blevins MS, Walker JN, Schaub JM, Finkelstein IJ, Brodbelt JS. Characterization of the T4 gp32-ssDNA complex by native, cross-linking, and ultraviolet photodissociation mass spectrometry. Chem Sci 2021; 12:13764-13776. [PMID: 34760161 PMCID: PMC8549804 DOI: 10.1039/d1sc02861h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 09/23/2021] [Indexed: 12/28/2022] Open
Abstract
Protein-DNA interactions play crucial roles in DNA replication across all living organisms. Here, we apply a suite of mass spectrometry (MS) tools to characterize a protein-ssDNA complex, T4 gp32·ssDNA, with results that both support previous studies and simultaneously uncover novel insight into this non-covalent biological complex. Native mass spectrometry of the protein reveals the co-occurrence of Zn-bound monomers and homodimers, while addition of differing lengths of ssDNA generates a variety of protein:ssDNA complex stoichiometries (1 : 1, 2 : 1, 3 : 1), indicating sequential association of gp32 monomers with ssDNA. Ultraviolet photodissociation (UVPD) mass spectrometry allows characterization of the binding site of the ssDNA within the protein monomer via analysis of holo ions, i.e. ssDNA-containing protein fragments, enabling interrogation of disordered regions of the protein which are inaccessible via traditional crystallographic techniques. Finally, two complementary cross-linking (XL) approaches, bottom-up analysis of the crosslinked complexes as well as MS1 analysis of the intact complexes, are used to showcase the absence of ssDNA binding with the intact cross-linked homodimer and to generate two homodimer gp32 model structures which highlight that the homodimer interface overlaps with the monomer ssDNA-binding site. These models suggest that the homodimer may function in a regulatory capacity by controlling the extent of ssDNA binding of the protein monomer. In sum, this work underscores the utility of a multi-faceted mass spectrometry approach for detailed investigation of non-covalent protein-DNA complexes.
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Affiliation(s)
- Molly S Blevins
- Department of Chemistry, University of Texas at Austin Austin TX 78712 USA
| | - Jada N Walker
- Department of Chemistry, University of Texas at Austin Austin TX 78712 USA
| | - Jeffrey M Schaub
- Department of Molecular Biosciences, University of Texas at Austin Austin TX 78712 USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences, University of Texas at Austin Austin TX 78712 USA
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12
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Bennett JL, Nguyen GTH, Donald WA. Protein-Small Molecule Interactions in Native Mass Spectrometry. Chem Rev 2021; 122:7327-7385. [PMID: 34449207 DOI: 10.1021/acs.chemrev.1c00293] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Small molecule drug discovery has been propelled by the continual development of novel scientific methodologies to occasion therapeutic advances. Although established biophysical methods can be used to obtain information regarding the molecular mechanisms underlying drug action, these approaches are often inefficient, low throughput, and ineffective in the analysis of heterogeneous systems including dynamic oligomeric assemblies and proteins that have undergone extensive post-translational modification. Native mass spectrometry can be used to probe protein-small molecule interactions with unprecedented speed and sensitivity, providing unique insights into polydisperse biomolecular systems that are commonly encountered during the drug discovery process. In this review, we describe potential and proven applications of native MS in the study of interactions between small, drug-like molecules and proteins, including large multiprotein complexes and membrane proteins. Approaches to quantify the thermodynamic and kinetic properties of ligand binding are discussed, alongside a summary of gas-phase ion activation techniques that have been used to interrogate the structure of protein-small molecule complexes. We additionally highlight some of the key areas in modern drug design for which native mass spectrometry has elicited significant advances. Future developments and applications of native mass spectrometry in drug discovery workflows are identified, including potential pathways toward studying protein-small molecule interactions on a whole-proteome scale.
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Affiliation(s)
- Jack L Bennett
- School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Giang T H Nguyen
- School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - William A Donald
- School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia
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13
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Panczyk EM, Snyder DT, Ridgeway ME, Somogyi Á, Park MA, Wysocki VH. Surface-Induced Dissociation of Protein Complexes Selected by Trapped Ion Mobility Spectrometry. Anal Chem 2021; 93:5513-5520. [PMID: 33751887 DOI: 10.1021/acs.analchem.0c05373] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Native mass spectrometry (nMS), particularly in conjunction with gas-phase ion mobility spectrometry measurements, has proven useful as a structural biology tool for evaluating the stoichiometry, conformation, and topology of protein complexes. Here, we demonstrate the combination of trapped ion mobility spectrometry (TIMS) and surface-induced dissociation (SID) on a Bruker SolariX XR 15 T FT-ICR mass spectrometer for the structural analysis of protein complexes. We successfully performed SID on mobility-selected protein complexes, including the streptavidin tetramer and cholera toxin B with bound ligands. Additionally, TIMS-SID was employed on a mixture of the peptides desArg1 and desArg9 bradykinin to mobility-separate and identify the individual peptides. Importantly, results show that native-like conformations can be maintained throughout the TIMS analysis. The TIMS-SID spectra are analogous to SID spectra acquired using quadrupole mass selection, indicating little measurable, if any, structural rearrangement during mobility selection. Mobility parking was used on the ion or mobility of interest and 50-200 SID mass spectra were averaged. High-quality TIMS-SID spectra were acquired over a period of 2-10 min, comparable to or slightly longer than SID coupled with ion mobility on various instrument platforms in our laboratory. The ultrahigh resolving power of the 15 T FT-ICR allowed for the identification and relative quantification of overlapping SID fragments with the same nominal m/z based on isotope patterns, and it shows promise as a platform to probe small mass differences, such as protein/ligand binding or post-translational modifications. These results represent the potential of TIMS-SID-MS for the analysis of both protein complexes and peptides.
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Affiliation(s)
- Erin M Panczyk
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.,Resource for Native MS Guided Structural Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Dalton T Snyder
- Resource for Native MS Guided Structural Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Mark E Ridgeway
- Bruker Daltonics Inc., Billerica, Massachusetts 01821, United States
| | - Árpád Somogyi
- Resource for Native MS Guided Structural Biology, The Ohio State University, Columbus, Ohio 43210, United States.,Campus Chemical Instrument Center, Mass Spectrometry and Proteomics, The Ohio State University, Columbus, Ohio 43210, United States
| | - Melvin A Park
- Bruker Daltonics Inc., Billerica, Massachusetts 01821, United States
| | - Vicki H Wysocki
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.,Resource for Native MS Guided Structural Biology, The Ohio State University, Columbus, Ohio 43210, United States.,Campus Chemical Instrument Center, Mass Spectrometry and Proteomics, The Ohio State University, Columbus, Ohio 43210, United States
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