1
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Matney R, Gadkari VV. Recent advances in gas phase unfolding: Instrumentation and applications. JOURNAL OF MASS SPECTROMETRY : JMS 2024; 59:e5059. [PMID: 38894609 DOI: 10.1002/jms.5059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 05/11/2024] [Accepted: 05/13/2024] [Indexed: 06/21/2024]
Abstract
Broader adoption of native mass spectrometry (MS) and ion mobility-mass spectrometry (IM-MS) has propelled the development of several techniques which take advantage of the selectivity, sensitivity, and speed of MS to make measurements of complex biological molecules in the gas phase. One such method, collision induced unfolding (CIU), has risen to prominence in recent years, due to its well documented capability to detect shifts in structural stability of biological molecules in response to external stimuli (e.g., mutations, stress, non-covalent interactions, sample conditions etc.). This increase in reported CIU measurements is enabled partly due to advances in IM-MS instrumentation by vendors, and also innovative method development by researchers. This perspective highlights a few of these advances and concludes with a look forward toward the future of the gas phase unfolding field.
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Affiliation(s)
- Rowan Matney
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Varun V Gadkari
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
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2
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Zangl R, Soravia S, Saft M, Löffler JG, Schulte J, Rosner CJ, Bredenbeck J, Essen LO, Morgner N. Time-Resolved Ion Mobility Mass Spectrometry to Solve Conformational Changes in a Cryptochrome. J Am Chem Soc 2024; 146:14468-14478. [PMID: 38757172 DOI: 10.1021/jacs.3c13818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
Many biological mechanisms rely on the precise control of conformational changes in proteins. Understanding such dynamic processes requires methods for determining structures and their temporal evolution. In this study, we introduce a novel approach to time-resolved ion mobility mass spectrometry. We validated the method on a simple photoreceptor model and applied it to a more complex system, the animal-like cryptochrome from Chlamydomonas reinhardtii (CraCRY), to determine the role of specific amino acids affecting the conformational dynamics as reaction to blue light activation. In our setup, using a high-power LED mounted in the source region of an ion mobility mass spectrometer, we allow a time-resolved evaluation of mass and ion mobility spectra. Cryptochromes like CraCRY are a widespread type of blue light photoreceptors and mediate various light-triggered biological functions upon excitation of their inbuilt flavin chromophore. Another hallmark of cryptochromes is their flexible carboxy-terminal extension (CTE), whose structure and function as well as the details of its interaction with the photolyase homology region are not yet fully understood and differ among different cryptochromes types. Here, we addressed the highly conserved C-terminal domain of CraCRY, to study the effects of single mutations on the structural transition of the C-terminal helix α22 and the attached CTE upon lit-state formation. We show that D321, the putative proton acceptor of the terminal proton-coupled electron transfer event from Y373, is essential for triggering the large-scale conformational changes of helix α22 and the CTE in the lit state, while D323 influences the timing.
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Affiliation(s)
- Rene Zangl
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt Max-von-Laue-Str. 9, 60438 Frankfurt/Main, Germany
| | - Sejla Soravia
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt Max-von-Laue-Str. 9, 60438 Frankfurt/Main, Germany
| | - Martin Saft
- Department of Chemistry, Philipps University Marburg Hans-Meerwein-Str. 4, 35032 Marburg, Germany
| | - Jan Gerrit Löffler
- Institute of Biophysics, Goethe University Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt/Main, Germany
| | - Jonathan Schulte
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt Max-von-Laue-Str. 9, 60438 Frankfurt/Main, Germany
| | - Christian Joshua Rosner
- Department of Chemistry, Philipps University Marburg Hans-Meerwein-Str. 4, 35032 Marburg, Germany
| | - Jens Bredenbeck
- Institute of Biophysics, Goethe University Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt/Main, Germany
| | - Lars-Oliver Essen
- Department of Chemistry, Philipps University Marburg Hans-Meerwein-Str. 4, 35032 Marburg, Germany
| | - Nina Morgner
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt Max-von-Laue-Str. 9, 60438 Frankfurt/Main, Germany
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3
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Zhu Y, Yun SD, Zhang T, Chang JY, Stover L, Laganowsky A. Native mass spectrometry of proteoliposomes containing integral and peripheral membrane proteins. Chem Sci 2023; 14:14243-14255. [PMID: 38098719 PMCID: PMC10718073 DOI: 10.1039/d3sc04938h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 11/18/2023] [Indexed: 12/17/2023] Open
Abstract
Cellular membranes are critical to the function of membrane proteins, whether they are associated (peripheral) or embedded (integral) within the bilayer. While detergents have contributed to our understanding of membrane protein structure and function, there remains challenges in characterizing protein-lipid interactions within the context of an intact membrane. Here, we developed a method to prepare proteoliposomes for native mass spectrometry (MS) studies. We first use native MS to detect the encapsulation of soluble proteins within liposomes. We then find the peripheral Gβ1γ2 complex associated with the membrane can be ejected and analyzed using native MS. Four different integral membrane proteins (AmtB, AqpZ, TRAAK, and TREK2), all of which have previously been characterized in detergent, eject from the proteoliposomes as intact complexes bound to lipids that have been shown to tightly associate in detergent, drawing a correlation between the two approaches. We also show the utility of more complex lipid environments, such as a brain polar lipid extract, and show TRAAK ejects from liposomes of this extract bound to lipids. These findings underscore the capability to eject protein complexes from membranes bound to both lipids and metal ions, and this approach will be instrumental in the identification of key protein-lipid interactions.
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Affiliation(s)
- Yun Zhu
- Department of Chemistry, Texas A&M University College Station TX 77843 USA
| | - Sangho D Yun
- Department of Chemistry, Texas A&M University College Station TX 77843 USA
| | - Tianqi Zhang
- Department of Chemistry, Texas A&M University College Station TX 77843 USA
| | - Jing-Yuan Chang
- Department of Chemistry, Texas A&M University College Station TX 77843 USA
| | - Lauren Stover
- Department of Chemistry, Texas A&M University College Station TX 77843 USA
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University College Station TX 77843 USA
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4
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Levesque I, Juliano BR, Parson KF, Ruotolo BT. A Critical Evaluation of Detergent Exchange Methodologies for Membrane Protein Native Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:2662-2671. [PMID: 37956121 DOI: 10.1021/jasms.3c00230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Membrane proteins (MPs) play many critical roles in cellular physiology and constitute the majority of current pharmaceutical targets. However, MPs are comparatively understudied relative to soluble proteins due to the challenges associated with their solubilization in membrane mimetics. Native mass spectrometry (nMS) has emerged as a useful technique to probe the structures of MPs. Typically, nMS studies using MPs have employed detergent micelles to solubilize the MP. Oftentimes, the detergent micelle that the MP was purified in will be exchanged into another detergent prior to analysis by nMS. While methodologies for performing detergent exchange have been extensively described in prior reports, the effectiveness of these protocols remains understudied. Here, we present a critical analysis of detergent exchange efficacy using several model transmembrane proteins and a variety of commonly used detergents, evaluating the completeness of the exchange using a battery of existing protocols. Our data include results for octyl glucoside (OG), octaethylene glycol monododecyl ether (C12E8), and tetraethylene glycol monooctyl ether (C8E4), and these data demonstrate that existing protocols are insufficient and yield incomplete exchange for the proteins under the conditions probed here. In some cases, our data indicate that up to 99% of the measured detergent corresponds to the original pre-exchange detergent rather than the desired post-exchange detergent. We conclude by discussing the need for new detergent exchange methodologies alongside improved exchange yield expectations for studying the potential influence of detergents on MP structures.
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Affiliation(s)
- Iliana Levesque
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Brock R Juliano
- 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
| | - Brandon T Ruotolo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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5
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Juliano BR, Keating JW, Ruotolo BT. Infrared Photoactivation Enables Improved Native Top-Down Mass Spectrometry of Transmembrane Proteins. Anal Chem 2023; 95:13361-13367. [PMID: 37610409 PMCID: PMC11081007 DOI: 10.1021/acs.analchem.3c02788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Membrane proteins are often challenging targets for native top-down mass spectrometry experimentation. The requisite use of membrane mimetics to solubilize such proteins necessitates the application of supplementary activation methods to liberate protein ions prior to sequencing, which typically limits the sequence coverage achieved. Recently, infrared photoactivation has emerged as an alternative to collisional activation for the liberation of membrane proteins from surfactant micelles. However, much remains unknown regarding the mechanism by which IR activation liberates membrane protein ions from such micelles, the extent to which such methods can improve membrane protein sequence coverage, and the degree to which such approaches can be extended to support native proteomics. Here, we describe experiments designed to evaluate and probe infrared photoactivation for membrane protein sequencing, proteoform identification, and native proteomics applications. Our data reveal that infrared photoactivation can dissociate micelles composed of a variety of detergent classes, without the need for a strong IR chromophore by leveraging the relatively weak association energies of such detergent clusters in the gas phase. Additionally, our data illustrate how IR photoactivation can be extended to include membrane mimetics beyond micelles and liberate proteins from nanodiscs, liposomes, and bicelles. Finally, our data quantify the improvements in membrane protein sequence coverage produced through the use of IR photoactivation, which typically leads to membrane protein sequence coverage values ranging from 40 to 60%.
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Affiliation(s)
- Brock R Juliano
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Joseph W Keating
- 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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6
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Lutomski CA, El‐Baba TJ, Hinkle JD, Liko I, Bennett JL, Kalmankar NV, Dolan A, Kirschbaum C, Greis K, Urner LH, Kapoor P, Yen H, Pagel K, Mullen C, Syka JEP, Robinson CV. Infrared Multiphoton Dissociation Enables Top-Down Characterization of Membrane Protein Complexes and G Protein-Coupled Receptors. Angew Chem Int Ed Engl 2023; 62:e202305694. [PMID: 37329506 PMCID: PMC7615181 DOI: 10.1002/anie.202305694] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 05/20/2023] [Accepted: 06/15/2023] [Indexed: 06/19/2023]
Abstract
Membrane proteins are challenging to analyze by native mass spectrometry (MS) as their hydrophobic nature typically requires stabilization in detergent micelles that are removed prior to analysis via collisional activation. There is however a practical limit to the amount of energy which can be applied, which often precludes subsequent characterization by top-down MS. To overcome this barrier, we have applied a modified Orbitrap Eclipse Tribrid mass spectrometer coupled to an infrared laser within a high-pressure linear ion trap. We show how tuning the intensity and time of incident photons enables liberation of membrane proteins from detergent micelles. Specifically, we relate the ease of micelle removal to the infrared absorption of detergents in both condensed and gas phases. Top-down MS via infrared multiphoton dissociation (IRMPD), results in good sequence coverage enabling unambiguous identification of membrane proteins and their complexes. By contrasting and comparing the fragmentation patterns of the ammonia channel with two class A GPCRs, we identify successive cleavage of adjacent amino acids within transmembrane domains. Using gas-phase molecular dynamics simulations, we show that areas prone to fragmentation maintain aspects of protein structure at increasing temperatures. Altogether, we propose a rationale to explain why and where in the protein fragment ions are generated.
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Affiliation(s)
- Corinne A. Lutomski
- Physical and Theoretical Chemistry Laboratory, Department of ChemistryUniversity of OxfordOxfordOX1 3QUUK
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin BuildingUniversity of OxfordOxfordOX1 3QUUK
| | - Tarick J. El‐Baba
- Physical and Theoretical Chemistry Laboratory, Department of ChemistryUniversity of OxfordOxfordOX1 3QUUK
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin BuildingUniversity of OxfordOxfordOX1 3QUUK
| | | | | | - Jack L. Bennett
- Physical and Theoretical Chemistry Laboratory, Department of ChemistryUniversity of OxfordOxfordOX1 3QUUK
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin BuildingUniversity of OxfordOxfordOX1 3QUUK
| | - Neha V. Kalmankar
- Physical and Theoretical Chemistry Laboratory, Department of ChemistryUniversity of OxfordOxfordOX1 3QUUK
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin BuildingUniversity of OxfordOxfordOX1 3QUUK
| | - Andrew Dolan
- Physical and Theoretical Chemistry Laboratory, Department of ChemistryUniversity of OxfordOxfordOX1 3QUUK
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin BuildingUniversity of OxfordOxfordOX1 3QUUK
| | - Carla Kirschbaum
- Institute of Chemistry and BiochemistryFreie Universität BerlinBerlin14195Germany
- Fritz Haber Institute of the Max Planck SocietyBerlin14195Germany
| | - Kim Greis
- Institute of Chemistry and BiochemistryFreie Universität BerlinBerlin14195Germany
- Fritz Haber Institute of the Max Planck SocietyBerlin14195Germany
| | - Leonhard H. Urner
- Institute of Chemistry and BiochemistryFreie Universität BerlinBerlin14195Germany
- Fritz Haber Institute of the Max Planck SocietyBerlin14195Germany
- Department of Chemistry and Chemical BiologyTU Dortmund UniversityDortmund44227Germany
| | | | - Hsin‐Yung Yen
- OMass TherapeuticsOxfordOX4 2GXUK
- Institute of Biological ChemistryAcademia SinicaTaipei115Taiwan
| | - Kevin Pagel
- Institute of Chemistry and BiochemistryFreie Universität BerlinBerlin14195Germany
- Fritz Haber Institute of the Max Planck SocietyBerlin14195Germany
| | | | | | - Carol V. Robinson
- Physical and Theoretical Chemistry Laboratory, Department of ChemistryUniversity of OxfordOxfordOX1 3QUUK
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin BuildingUniversity of OxfordOxfordOX1 3QUUK
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7
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Lutomski CA, El‐Baba TJ, Hinkle JD, Liko I, Bennett JL, Kalmankar NV, Dolan A, Kirschbaum C, Greis K, Urner LH, Kapoor P, Yen H, Pagel K, Mullen C, Syka JEP, Robinson CV. Infrared Multiphoton Dissociation Enables Top-Down Characterization of Membrane Protein Complexes and G Protein-Coupled Receptors. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 135:e202305694. [PMID: 38516403 PMCID: PMC10953453 DOI: 10.1002/ange.202305694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Indexed: 03/23/2024]
Abstract
Membrane proteins are challenging to analyze by native mass spectrometry (MS) as their hydrophobic nature typically requires stabilization in detergent micelles that are removed prior to analysis via collisional activation. There is however a practical limit to the amount of energy which can be applied, which often precludes subsequent characterization by top-down MS. To overcome this barrier, we have applied a modified Orbitrap Eclipse Tribrid mass spectrometer coupled to an infrared laser within a high-pressure linear ion trap. We show how tuning the intensity and time of incident photons enables liberation of membrane proteins from detergent micelles. Specifically, we relate the ease of micelle removal to the infrared absorption of detergents in both condensed and gas phases. Top-down MS via infrared multiphoton dissociation (IRMPD), results in good sequence coverage enabling unambiguous identification of membrane proteins and their complexes. By contrasting and comparing the fragmentation patterns of the ammonia channel with two class A GPCRs, we identify successive cleavage of adjacent amino acids within transmembrane domains. Using gas-phase molecular dynamics simulations, we show that areas prone to fragmentation maintain aspects of protein structure at increasing temperatures. Altogether, we propose a rationale to explain why and where in the protein fragment ions are generated.
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Affiliation(s)
- Corinne A. Lutomski
- Physical and Theoretical Chemistry Laboratory, Department of ChemistryUniversity of OxfordOxfordOX1 3QUUK
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin BuildingUniversity of OxfordOxfordOX1 3QUUK
| | - Tarick J. El‐Baba
- Physical and Theoretical Chemistry Laboratory, Department of ChemistryUniversity of OxfordOxfordOX1 3QUUK
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin BuildingUniversity of OxfordOxfordOX1 3QUUK
| | | | | | - Jack L. Bennett
- Physical and Theoretical Chemistry Laboratory, Department of ChemistryUniversity of OxfordOxfordOX1 3QUUK
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin BuildingUniversity of OxfordOxfordOX1 3QUUK
| | - Neha V. Kalmankar
- Physical and Theoretical Chemistry Laboratory, Department of ChemistryUniversity of OxfordOxfordOX1 3QUUK
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin BuildingUniversity of OxfordOxfordOX1 3QUUK
| | - Andrew Dolan
- Physical and Theoretical Chemistry Laboratory, Department of ChemistryUniversity of OxfordOxfordOX1 3QUUK
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin BuildingUniversity of OxfordOxfordOX1 3QUUK
| | - Carla Kirschbaum
- Institute of Chemistry and BiochemistryFreie Universität BerlinBerlin14195Germany
- Fritz Haber Institute of the Max Planck SocietyBerlin14195Germany
| | - Kim Greis
- Institute of Chemistry and BiochemistryFreie Universität BerlinBerlin14195Germany
- Fritz Haber Institute of the Max Planck SocietyBerlin14195Germany
| | - Leonhard H. Urner
- Institute of Chemistry and BiochemistryFreie Universität BerlinBerlin14195Germany
- Fritz Haber Institute of the Max Planck SocietyBerlin14195Germany
- Department of Chemistry and Chemical BiologyTU Dortmund UniversityDortmund44227Germany
| | | | - Hsin‐Yung Yen
- OMass TherapeuticsOxfordOX4 2GXUK
- Institute of Biological ChemistryAcademia SinicaTaipei115Taiwan
| | - Kevin Pagel
- Institute of Chemistry and BiochemistryFreie Universität BerlinBerlin14195Germany
- Fritz Haber Institute of the Max Planck SocietyBerlin14195Germany
| | | | | | - Carol V. Robinson
- Physical and Theoretical Chemistry Laboratory, Department of ChemistryUniversity of OxfordOxfordOX1 3QUUK
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin BuildingUniversity of OxfordOxfordOX1 3QUUK
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8
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Wang Q, Xu T, Fang F, Wang Q, Lundquist P, Sun L. Capillary Zone Electrophoresis-Tandem Mass Spectrometry for Top-Down Proteomics of Mouse Brain Integral Membrane Proteins. Anal Chem 2023; 95:12590-12594. [PMID: 37595263 PMCID: PMC10540247 DOI: 10.1021/acs.analchem.3c02346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/20/2023]
Abstract
Mass spectrometry (MS)-based top-down characterization of integral membrane proteins (IMPs) is crucial for understanding their functions in biological processes. However, it is technically challenging due to their low solubility in typical MS-compatible buffers. In this work, for the first time, we developed an efficient capillary zone electrophoresis (CZE)-tandem MS (MS/MS) method for the top-down proteomics (TDP) of IMPs enriched from mouse brains. Our technique employs a sample buffer containing 30% (v/v) formic acid and 60% (v/v) methanol for solubilizing IMPs and utilizes a separation buffer of 30% (v/v) acetic acid and 30% (v/v) methanol for maintaining the solubility of IMPs during CZE separation. Single-shot CZE-MS/MS identified 51 IMP proteoforms from the mouse brain sample. Coupling size exclusion chromatography (SEC) to CZE-MS/MS enabled the identification of 276 IMP proteoforms from the mouse brain sample containing 1-4 transmembrane domains. This proof-of-concept work demonstrates the high potential of CZE-MS/MS for the large-scale TDP of IMPs.
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Affiliation(s)
- Qianjie Wang
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
- Plant Resilience Institute, Michigan State University, East Lansing, Michigan 48824, United States
| | - Tian Xu
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| | - Fei Fang
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| | - Qianyi Wang
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
| | - Peter Lundquist
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
- Plant Resilience Institute, Michigan State University, East Lansing, Michigan 48824, United States
| | - Liangliang Sun
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48824, United States
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9
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Zhu Y, Odenkirk MT, Qiao P, Zhang T, Schrecke S, Zhou M, Marty MT, Baker ES, Laganowsky A. Combining native mass spectrometry and lipidomics to uncover specific membrane protein-lipid interactions from natural lipid sources. Chem Sci 2023; 14:8570-8582. [PMID: 37593000 PMCID: PMC10430552 DOI: 10.1039/d3sc01482g] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 07/19/2023] [Indexed: 08/19/2023] Open
Abstract
While it is known that lipids play an essential role in regulating membrane protein structure and function, it remains challenging to identify specific protein-lipid interactions. Here, we present an innovative approach that combines native mass spectrometry (MS) and lipidomics to identify lipids retained by membrane proteins from natural lipid extracts. Our results reveal that the bacterial ammonia channel (AmtB) enriches specific cardiolipin (CDL) and phosphatidylethanolamine (PE) from natural headgroup extracts. When the two extracts are mixed, AmtB retains more species, wherein selectivity is tuned to bias headgroup selection. Using a series of natural headgroup extracts, we show TRAAK, a two-pore domain K+ channel (K2P), retains specific acyl chains that is independent of the headgroup. A brain polar lipid extract was then combined with the K2Ps, TRAAK and TREK2, to understand lipid specificity. More than a hundred lipids demonstrated affinity for each protein, and both channels were found to retain specific fatty acids and lysophospholipids known to stimulate channel activity, even after several column washes. Natural lipid extracts provide the unique opportunity to not only present natural lipid diversity to purified membrane proteins but also identify lipids that may be important for membrane protein structure and function.
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Affiliation(s)
- Yun Zhu
- Department of Chemistry, Texas A&M University College Station TX 77843 USA
| | - Melanie T Odenkirk
- Department of Chemistry, North Carolina State University Raleigh NC 27695 USA
| | - Pei Qiao
- Department of Chemistry, Texas A&M University College Station TX 77843 USA
| | - Tianqi Zhang
- Department of Chemistry, Texas A&M University College Station TX 77843 USA
| | - Samantha Schrecke
- Department of Chemistry, Texas A&M University College Station TX 77843 USA
| | - Ming Zhou
- Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine Houston TX 77030 USA
| | - Michael T Marty
- Department of Chemistry and Biochemistry, The University of Arizona Tucson AZ 85721 USA
| | - Erin S Baker
- Department of Chemistry, University of North Carolina Chapel Hill NC 27514 USA
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University College Station TX 77843 USA
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10
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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: 32] [Impact Index Per Article: 32.0] [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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11
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Gadkari VV, Juliano BR, Mallis CS, May JC, Kurulugama RT, Fjeldsted JC, McLean JA, Russell DH, Ruotolo BT. Performance evaluation of in-source ion activation hardware for collision-induced unfolding of proteins and protein complexes on a drift tube ion mobility-mass spectrometer. Analyst 2023; 148:391-401. [PMID: 36537590 PMCID: PMC10103148 DOI: 10.1039/d2an01452a] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Native ion mobility-mass spectrometry (IM-MS) has emerged as an information-rich technique for gas phase protein structure characterization; however, IM resolution is currently insufficient for the detection of subtle structural differences in large biomolecules. This challenge has spurred the development of collision-induced unfolding (CIU) which utilizes incremental gas phase activation to unfold a protein in order to expand the number of measurable descriptors available for native protein ions. Although CIU is now routinely used in native mass spectrometry studies, the interlaboratory reproducibility of CIU has not been established. Here we evaluate the reproducibility of the CIU data produced across three laboratories (University of Michigan, Texas A&M University, and Vanderbilt University). CIU data were collected for a variety of protein ions ranging from 8.6-66 kDa. Within the same laboratory, the CIU fingerprints were found to be repeatable with root mean square deviation (RMSD) values of less than 5%. Collision cross section (CCS) values of the CIU intermediates were consistent across the laboratories, with most features exhibiting an interlaboratory reproducibility of better than 1%. In contrast, the activation potentials required to induce protein CIU transitions varied between the three laboratories. To address these differences, three source assemblies were constructed with an updated ion activation hardware design utilizing higher mechanical tolerance specifications. The production-grade assemblies were found to produce highly consistent CIU data for intact antibodies, exhibiting high precision ion CCS and CIU transition values, thus opening the door to establishing databases of CIU fingerprints to support future biomolecular classification efforts.
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Affiliation(s)
- Varun V Gadkari
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.
| | - Brock R Juliano
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.
| | - Christopher S Mallis
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA
| | - Jody C May
- Center for Innovative Technology, Department of Chemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, USA
| | | | | | - John A McLean
- Center for Innovative Technology, Department of Chemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, USA
| | - David H Russell
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA
| | - Brandon T Ruotolo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.
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12
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Ma X. Recent Advances in Mass Spectrometry-Based Structural Elucidation Techniques. Molecules 2022; 27:molecules27196466. [PMID: 36235003 PMCID: PMC9572214 DOI: 10.3390/molecules27196466] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/23/2022] [Accepted: 09/26/2022] [Indexed: 11/17/2022] Open
Abstract
Mass spectrometry (MS) has become the central technique that is extensively used for the analysis of molecular structures of unknown compounds in the gas phase. It manipulates the molecules by converting them into ions using various ionization sources. With high-resolution MS, accurate molecular weights (MW) of the intact molecular ions can be measured so that they can be assigned a molecular formula with high confidence. Furthermore, the application of tandem MS has enabled detailed structural characterization by breaking the intact molecular ions and protonated or deprotonated molecules into key fragment ions. This approach is not only used for the structural elucidation of small molecules (MW < 2000 Da), but also crucial biopolymers such as proteins and polypeptides; therefore, MS has been extensively used in multiomics studies for revealing the structures and functions of important biomolecules and their interactions with each other. The high sensitivity of MS has enabled the analysis of low-level analytes in complex matrices. It is also a versatile technique that can be coupled with separation techniques, including chromatography and ion mobility, and many other analytical instruments such as NMR. In this review, we aim to focus on the technical advances of MS-based structural elucidation methods over the past five years, and provide an overview of their applications in complex mixture analysis. We hope this review can be of interest for a wide range of audiences who may not have extensive experience in MS-based techniques.
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Affiliation(s)
- Xin Ma
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Dr NW, Atlanta, GA 30332, USA
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13
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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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14
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Phetsanthad A, Li G, Jeon CK, Ruotolo BT, Li L. Comparing Selected-Ion Collision Induced Unfolding with All Ion Unfolding Methods for Comprehensive Protein Conformational Characterization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:944-951. [PMID: 35508074 PMCID: PMC9167759 DOI: 10.1021/jasms.2c00004] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Structural analysis by native ion mobility-mass spectrometry provides a direct means to characterize protein interactions, stability, and other biophysical properties of disease-associated biomolecules. Such information is often extracted from collision-induced unfolding (CIU) experiments, performed by ramping a voltage used to accelerate ions entering a trap cell prior to an ion mobility separator. Traditionally, to simplify data analysis and achieve confident ion identification, precursor ion selection with a quadrupole is performed prior to collisional activation. Only one charge state can be selected at one time, leading to an imbalance between the total time required to survey CIU data across all protein charge states and the resulting structural analysis efficiency. Furthermore, the arbitrary selection of a single charge state can inherently bias CIU analyses. We herein aim to compare two conformation sampling methods for protein gas-phase unfolding: (1) traditional quadrupole selection-based CIU and (2) nontargeted, charge selection-free and shotgun workflow, all ion unfolding (AIU). Additionally, we provide a new data interpretation method that integrates across all charge states to project collisional cross section (CCS) data acquired over a range of activation voltages to produce a single unfolding fingerprint, regardless of charge state distributions. We find that AIU in combination with CCS accumulation across all charges offers an opportunity to maximize protein conformational information with minimal time cost, where additional benefits include (1) an improved signal-to-noise ratios for unfolding fingerprints and (2) a higher tolerance to charge state shifts induced by either operating parameters or other factors that affect protein ionization efficiency.
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Affiliation(s)
- Ashley Phetsanthad
- Department of Chemistry and School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705 USA
| | - Gongyu Li
- Research Center for Analytical Science and Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry, Nankai University, Tianjin 300071, China
- Corresponding authors: Prof. Dr. Gongyu Li, ; Prof. Dr. Lingjun Li,
| | - Chae Kyung Jeon
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Brandon T. Ruotolo
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Lingjun Li
- Department of Chemistry and School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705 USA
- Corresponding authors: Prof. Dr. Gongyu Li, ; Prof. Dr. Lingjun Li,
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15
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Abstract
Native mass spectrometry (nMS) has emerged as an important tool in studying the structure and function of macromolecules and their complexes in the gas phase. In this review, we cover recent advances in nMS and related techniques including sample preparation, instrumentation, activation methods, and data analysis software. These advances have enabled nMS-based techniques to address a variety of challenging questions in structural biology. The second half of this review highlights recent applications of these technologies and surveys the classes of complexes that can be studied with nMS. Complementarity of nMS to existing structural biology techniques and current challenges in nMS are also addressed.
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Affiliation(s)
- Kelly R Karch
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA;
- Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, Ohio, USA
| | - Dalton T Snyder
- Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, Ohio, USA
| | - Sophie R Harvey
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA;
- Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, Ohio, USA
| | - Vicki H Wysocki
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA;
- Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, Ohio, USA
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16
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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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17
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Gavriilidou AFM, Sokratous K, Yen HY, De Colibus L. High-Throughput Native Mass Spectrometry Screening in Drug Discovery. Front Mol Biosci 2022; 9:837901. [PMID: 35495635 PMCID: PMC9047894 DOI: 10.3389/fmolb.2022.837901] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 02/15/2022] [Indexed: 12/15/2022] Open
Abstract
The design of new therapeutic molecules can be significantly informed by studying protein-ligand interactions using biophysical approaches directly after purification of the protein-ligand complex. Well-established techniques utilized in drug discovery include isothermal titration calorimetry, surface plasmon resonance, nuclear magnetic resonance spectroscopy, and structure-based drug discovery which mainly rely on protein crystallography and, more recently, cryo-electron microscopy. Protein-ligand complexes are dynamic, heterogeneous, and challenging systems that are best studied with several complementary techniques. Native mass spectrometry (MS) is a versatile method used to study proteins and their non-covalently driven assemblies in a native-like folded state, providing information on binding thermodynamics and stoichiometry as well as insights on ternary and quaternary protein structure. Here, we discuss the basic principles of native mass spectrometry, the field’s recent progress, how native MS is integrated into a drug discovery pipeline, and its future developments in drug discovery.
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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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Verteporfin is a Substrate-Selective γ-Secretase Inhibitor that Binds the Amyloid Precursor Protein Transmembrane Domain. J Biol Chem 2022; 298:101792. [PMID: 35247387 PMCID: PMC8968665 DOI: 10.1016/j.jbc.2022.101792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/22/2022] [Accepted: 02/26/2022] [Indexed: 11/23/2022] Open
Abstract
This work reports substrate-selective inhibition of a protease with broad substrate specificity based on direct binding of a small molecule inhibitor to the substrate. The target for these studies was γ-secretase protease, which cleaves dozens of different single span membrane protein substrates, including both the C99 domain of the human amyloid precursor protein and the Notch receptor. Substrate-specific inhibition of C99 cleavage is desirable to reduce production of the amyloid-β polypeptide without inhibiting Notch cleavage, a major source of toxicity associated with broad specificity γ-secretase inhibitors. In order to identify a C99-selective inhibitors of the human γ-secretase, we conducted an NMR-based screen of FDA-approved drugs against C99 in model membranes. From this screen, we identified the small molecule verteporfin with these properties. We observed that verteporfin formed a direct 1:1 complex with C99, with a KD of 15-47 μM (depending on the membrane mimetic used), and that it did not bind the transmembrane domain of the Notch-1 receptor. Biochemical assays showed that direct binding of verteporfin to C99 inhibits γ-secretase cleavage of C99 with IC50 values in the range of 15- 164 μM, while Notch-1 cleavage was inhibited only at higher concentrations, and likely via a mechanism that does not involve binding to Notch-1. This work documents a robust NMR-based approach to discovery of small molecule binders to single-span membrane proteins and confirmed that it is possible to inhibit γ-secretase in a substrate-specific manner.
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20
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Qiao P, Schrecke S, Walker T, McCabe JW, Lyu J, Zhu Y, Zhang T, Kumar S, Clemmer D, Russell DH, Laganowsky A. Entropy in the Molecular Recognition of Membrane Protein-Lipid Interactions. J Phys Chem Lett 2021; 12:12218-12224. [PMID: 34928154 PMCID: PMC8905501 DOI: 10.1021/acs.jpclett.1c03750] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Understanding the molecular driving forces that underlie membrane protein-lipid interactions requires the characterization of their binding thermodynamics. Here, we employ variable-temperature native mass spectrometry to determine the thermodynamics of lipid binding events to the human G-protein-gated inward rectifier potassium channel, Kir3.2. The channel displays distinct thermodynamic strategies to engage phosphatidylinositol (PI) and phosphorylated forms thereof. The addition of a 4'-phosphate to PI results in an increase in favorable entropy. PI with two or more phosphates exhibits more complex binding, where lipids appear to bind two nonidentical sites on Kir3.2. Remarkably, the interaction of 4,5-bisphosphate PI with Kir3.2 is solely driven by a large, favorable change in entropy. Installment of a 3'-phosphate to PI(4,5)P2 results in an altered thermodynamic strategy. The acyl chain of the lipid has a marked impact on binding thermodynamics and, in some cases, enthalpy becomes favorable.
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Affiliation(s)
- Pei Qiao
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, United States
| | - Samantha Schrecke
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Thomas Walker
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Jacob W McCabe
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Jixing Lyu
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Yun Zhu
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Tianqi Zhang
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Smriti Kumar
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - David Clemmer
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - David H Russell
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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21
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Qiao P, Schrecke S, Lyu J, Zhu Y, Zhang T, Benavides A, Laganowsky A. Insight into the Phospholipid-Binding Preferences of Kir3.4. Biochemistry 2021; 60:3813-3821. [PMID: 34846128 DOI: 10.1021/acs.biochem.1c00615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The G-protein-gated inwardly rectifying potassium channel 4 (Kir3.4) subunit forms functional tetramers. Previous studies have established that phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) is required for Kir3.4 function. However, the binding preferences of Kir3.4 for the headgroup and acyl chains of phosphorylated phosphatidylinositides (PIPs) and other lipids are not well understood. Here, the interactions between full-length, human Kir3.4 and lipids are characterized using native mass spectrometry (MS) in conjunction with a soluble fluorescent lipid-binding assay. Kir3.4 displays binding preferences for PIPs, and, in some cases, the degree of binding is influenced by the type of acyl chains. The interactions between Kir3.4 and PIPs are weaker in comparison to full-length, human Kir3.2. The binding of PI(4,5)P2 modified with a fluorophore to Kir3.2 can be enhanced by other lipids, such as phosphatidylcholine. Introduction of S143T, a mutation that enhances Kir3.4 activity, results in an overall reduction in the channel binding PIPs. In contrast, the D223N mutant of Kir3.4 that mimics the sodium-bound state exhibited stronger binding for PI(4,5)P2, particularly for those with 18:0-20:4 acyl chains. Taken together, these results provide additional insight into the interaction between Kir3.4 and lipids that are important for channel function.
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Affiliation(s)
- Pei Qiao
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, United States
| | - Samantha Schrecke
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Jixing Lyu
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Yun Zhu
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Tianqi Zhang
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Amanda Benavides
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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22
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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: 31] [Impact Index Per Article: 10.3] [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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23
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Meier F, Park MA, Mann M. Trapped Ion Mobility Spectrometry and Parallel Accumulation-Serial Fragmentation in Proteomics. Mol Cell Proteomics 2021; 20:100138. [PMID: 34416385 PMCID: PMC8453224 DOI: 10.1016/j.mcpro.2021.100138] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/05/2021] [Accepted: 08/11/2021] [Indexed: 12/14/2022] Open
Abstract
Recent advances in efficiency and ease of implementation have rekindled interest in ion mobility spectrometry, a technique that separates gas phase ions by their size and shape and that can be hybridized with conventional LC and MS. Here, we review the recent development of trapped ion mobility spectrometry (TIMS) coupled to TOF mass analysis. In particular, the parallel accumulation-serial fragmentation (PASEF) operation mode offers unique advantages in terms of sequencing speed and sensitivity. Its defining feature is that it synchronizes the release of ions from the TIMS device with the downstream selection of precursors for fragmentation in a TIMS quadrupole TOF configuration. As ions are compressed into narrow ion mobility peaks, the number of peptide fragment ion spectra obtained in data-dependent or targeted analyses can be increased by an order of magnitude without compromising sensitivity. Taking advantage of the correlation between ion mobility and mass, the PASEF principle also multiplies the efficiency of data-independent acquisition. This makes the technology well suited for rapid proteome profiling, an increasingly important attribute in clinical proteomics, as well as for ultrasensitive measurements down to single cells. The speed and accuracy of TIMS and PASEF also enable precise measurements of collisional cross section values at the scale of more than a million data points and the development of neural networks capable of predicting them based only on peptide sequences. Peptide collisional cross section values can differ for isobaric sequences or positional isomers of post-translational modifications. This additional information may be leveraged in real time to direct data acquisition or in postprocessing to increase confidence in peptide identifications. These developments make TIMS quadrupole TOF PASEF a powerful and expandable platform for proteomics and beyond.
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Affiliation(s)
- Florian Meier
- Department Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany; Functional Proteomics, Jena University Hospital, Jena, Germany.
| | - Melvin A Park
- Bruker Daltonics Inc, Billerica, Massachusetts, USA.
| | - Matthias Mann
- Department Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany.
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24
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Ion mobility-mass spectrometry reveals the role of peripheral myelin protein dimers in peripheral neuropathy. Proc Natl Acad Sci U S A 2021; 118:2015331118. [PMID: 33893233 DOI: 10.1073/pnas.2015331118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Peripheral myelin protein (PMP22) is an integral membrane protein that traffics inefficiently even in wild-type (WT) form, with only 20% of the WT protein reaching its final plasma membrane destination in myelinating Schwann cells. Misfolding of PMP22 has been identified as a key factor in multiple peripheral neuropathies, including Charcot-Marie-Tooth disease and Dejerine-Sottas syndrome. While biophysical analyses of disease-associated PMP22 mutants show altered protein stabilities, leading to reduced surface trafficking and loss of PMP22 function, it remains unclear how destabilization of PMP22 mutations causes mistrafficking. Here, native ion mobility-mass spectrometry (IM-MS) is used to compare the gas phase stabilities and abundances for an array of mutant PM22 complexes. We find key differences in the PMP22 mutant stabilities and propensities to form homodimeric complexes. Of particular note, we observe that severely destabilized forms of PMP22 exhibit a higher propensity to dimerize than WT PMP22. Furthermore, we employ lipid raft-mimicking SCOR bicelles to study PMP22 mutants, and find that the differences in dimer abundances are amplified in this medium when compared to micelle-based data, with disease mutants exhibiting up to 4 times more dimer than WT when liberated from SCOR bicelles. We combine our findings with previous cellular data to propose that the formation of PMP22 dimers from destabilized monomers is a key element of PMP22 mistrafficking.
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25
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Kalenius E, Malola S, Matus MF, Kazan R, Bürgi T, Häkkinen H. Experimental Confirmation of a Topological Isomer of the Ubiquitous Au 25(SR) 18 Cluster in the Gas Phase. J Am Chem Soc 2021; 143:1273-1277. [PMID: 33444006 PMCID: PMC8023650 DOI: 10.1021/jacs.0c11509] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
![]()
High-resolution electrospray ionization
ion mobility mass spectrometry
has revealed a gas-phase isomer of the ubiquitous, extremely well-studied
Au25(SR)18 cluster both in anionic and cationic
form. The relative abundance of the isomeric structures can be controlled
by in-source activation. The measured collision cross section of the
new isomer agrees extremely well with a recent theoretical prediction
(MatusM. F.; et al. Chem. Commun.2020, 56, 8087) corresponding to a Au25(SR)18– isomer that is energetically close and topologically connected to
the known ground-state structure via a simple rotation of the gold
core without breaking any Au–S bonds. The results imply that
the structural dynamics leading to isomerization of thiolate-protected
gold clusters may play an important role in their gas-phase reactions
and that isomerization could be controlled by external stimuli.
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Affiliation(s)
- Elina Kalenius
- Department of Chemistry, Nanoscience Center, University of Jyväskylä, FI-40014 Jyväskylä, Finland
| | - Sami Malola
- Department of Physics, Nanoscience Center, University of Jyväskylä, FI-40014 Jyväskylä, Finland
| | - María Francisca Matus
- Department of Physics, Nanoscience Center, University of Jyväskylä, FI-40014 Jyväskylä, Finland
| | - Rania Kazan
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - Thomas Bürgi
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - Hannu Häkkinen
- Department of Chemistry, Nanoscience Center, University of Jyväskylä, FI-40014 Jyväskylä, Finland.,Department of Physics, Nanoscience Center, University of Jyväskylä, FI-40014 Jyväskylä, Finland
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26
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Affiliation(s)
- James E. Keener
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Guozhi Zhang
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Michael T. Marty
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
- Bio5 Institute, University of Arizona, Tucson, AZ 85721, USA
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27
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Fantin SM, Huang H, Sanders CR, Ruotolo BT. Collision-Induced Unfolding Differentiates Functional Variants of the KCNQ1 Voltage Sensor Domain. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:2348-2355. [PMID: 32960579 PMCID: PMC8106873 DOI: 10.1021/jasms.0c00288] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The KCNQ1 voltage-gated potassium channel regulates the repolarization of cardiac cells, and a plurality of point mutations in its voltage-sensing domain (VSD) are associated with toxic gain or loss of pore function, resulting in disease. As is the case with many disease-associated membrane proteins, there are hundreds of human variants of interest identified for KCNQ1; however, a significant portion of these variants have not been characterized in relation to their functional and disease associations. Additionally, as the VSD consists of four transmembrane helices, studies into dynamic structural differences among KCNQ1 VSD variants are hindered by the current limitations and deficits in the high-resolution structure determination of membrane proteins. Here, we use native ion mobility-mass spectrometry and collision-induced unfolding (CIU) to address the need for a high throughput-compatible method for the structural characterization of membrane protein variants of unknown significance using the KCNQ1 VSD as a model system. We perform CIU on wild-type and three mutant KCNQ1 VSD forms associated with the toxic gain or loss of function and show through both automated feature detection and comprehensive difference analysis of the CIU data sets that the variants are clearly grouped by function and disease association. We also construct a classification scheme based on the CIU data sets, which is able to differentiate the variant functional groups and classify a recently characterized variant to its correct grouping. Further, we probe the stability of the KCNQ1 VSD variants when liberated from C12E8 micelles at pH 8.0 and find preliminary evidence that the R231C mutation associated with the gain of the pore function is destabilized relative to the wild-type and loss of function variants.
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Affiliation(s)
- Sarah M. Fantin
- University of Michigan Department of Chemistry, Ann Arbor, Michigan 48109, United States
| | - Hui Huang
- Vanderbilt University, Department of Biochemistry, Nashville, Tennessee 37232, United States
| | - Charles R. Sanders
- Vanderbilt University, Department of Biochemistry, Nashville, Tennessee 37232, United States
| | - Brandon T. Ruotolo
- University of Michigan Department of Chemistry, Ann Arbor, Michigan 48109, United States
- Corresponding Author:
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28
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Deslignière E, Ehkirch A, Botzanowski T, Beck A, Hernandez-Alba O, Cianférani S. Toward Automation of Collision-Induced Unfolding Experiments through Online Size Exclusion Chromatography Coupled to Native Mass Spectrometry. Anal Chem 2020; 92:12900-12908. [DOI: 10.1021/acs.analchem.0c01426] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Evolène Deslignière
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, CNRS, IPHC UMR 7178, 67000 Strasbourg, France
| | - Anthony Ehkirch
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, CNRS, IPHC UMR 7178, 67000 Strasbourg, France
| | - Thomas Botzanowski
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, CNRS, IPHC UMR 7178, 67000 Strasbourg, France
| | - Alain Beck
- IRPF—Centre d’Immunologie Pierre-Fabre (CIPF), 74160 Saint-Julien-en-Genevois, France
| | - Oscar Hernandez-Alba
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, CNRS, IPHC UMR 7178, 67000 Strasbourg, France
| | - Sarah Cianférani
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, CNRS, IPHC UMR 7178, 67000 Strasbourg, France
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29
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Lyu J, Liu Y, McCabe JW, Schrecke S, Fang L, Russell DH, Laganowsky A. Discovery of Potent Charge-Reducing Molecules for Native Ion Mobility Mass Spectrometry Studies. Anal Chem 2020; 92:11242-11249. [PMID: 32672445 DOI: 10.1021/acs.analchem.0c01826] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
There is growing interest in the characterization of protein complexes and their interactions with ligands using native ion mobility mass spectrometry. A particular challenge, especially for membrane proteins, is preserving noncovalent interactions and maintaining native-like structures. Different approaches have been developed to minimize activation of protein complexes by manipulating charge on protein complexes in solution and the gas-phase. Here, we report the utility of polyamines that have exceptionally high charge-reducing potencies with some molecules requiring 5-fold less than trimethylamine oxide to elicit the same effect. The charge-reducing molecules do not adduct to membrane protein complexes and are also compatible with ion-mobility mass spectrometry, paving the way for improved methods of charge reduction.
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Affiliation(s)
- Jixing Lyu
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Yang Liu
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Jacob W McCabe
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Samantha Schrecke
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Lei Fang
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - David H Russell
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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30
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Gault J, Liko I, Landreh M, Shutin D, Bolla JR, Jefferies D, Agasid M, Yen HY, Ladds MJGW, Lane DP, Khalid S, Mullen C, Remes PM, Huguet R, McAlister G, Goodwin M, Viner R, Syka JEP, Robinson CV. Combining native and 'omics' mass spectrometry to identify endogenous ligands bound to membrane proteins. Nat Methods 2020; 17:505-508. [PMID: 32371966 PMCID: PMC7332344 DOI: 10.1038/s41592-020-0821-0] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 03/25/2020] [Indexed: 02/08/2023]
Abstract
Ligands bound to protein assemblies provide critical information for function, yet are often difficult to capture and define. Here we develop a top-down method, 'nativeomics', unifying 'omics' (lipidomics, proteomics, metabolomics) analysis with native mass spectrometry to identify ligands bound to membrane protein assemblies. By maintaining the link between proteins and ligands, we define the lipidome/metabolome in contact with membrane porins and a mitochondrial translocator to discover potential regulators of protein function.
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Affiliation(s)
- Joseph Gault
- Department of Chemistry, University of Oxford, Oxford, UK.
| | - Idlir Liko
- Department of Chemistry, University of Oxford, Oxford, UK
- OMass Therapeutics, Oxford, UK
| | - Michael Landreh
- Department of Microbiology, Tumor and Cell Biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Denis Shutin
- Department of Chemistry, University of Oxford, Oxford, UK
| | | | | | - Mark Agasid
- Department of Chemistry, University of Oxford, Oxford, UK
| | | | - Marcus J G W Ladds
- Department of Microbiology, Tumor and Cell Biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - David P Lane
- Department of Microbiology, Tumor and Cell Biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Syma Khalid
- School of Chemistry, University of Southampton, Southampton, UK
| | | | | | | | | | | | - Rosa Viner
- Thermo Fisher Scientific, San Jose, CA, USA
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