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Bolla JR, Agasid MT, Mehmood S, Robinson CV. Membrane Protein-Lipid Interactions Probed Using Mass Spectrometry. Annu Rev Biochem 2019; 88:85-111. [PMID: 30901263 DOI: 10.1146/annurev-biochem-013118-111508] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Membrane proteins that exist in lipid bilayers are not isolated molecular entities. The lipid molecules that surround them play crucial roles in maintaining their full structural and functional integrity. Research directed at investigating these critical lipid-protein interactions is developing rapidly. Advancements in both instrumentation and software, as well as in key biophysical and biochemical techniques, are accelerating the field. In this review, we provide a brief outline of structural techniques used to probe protein-lipid interactions and focus on the molecular aspects of these interactions obtained from native mass spectrometry (native MS). We highlight examples in which lipids have been shown to modulate membrane protein structure and show how native MS has emerged as a complementary technique to X-ray crystallography and cryo-electron microscopy. We conclude with a short perspective on future developments that aim to better understand protein-lipid interactions in the native environment.
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Affiliation(s)
- Jani Reddy Bolla
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom;
| | - Mark T Agasid
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom;
| | - Shahid Mehmood
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom;
| | - Carol V Robinson
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom;
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52
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Majmudar JD, Feng X, Fox NG, Nabhan JF, Towle T, Ma T, Gooch R, Bulawa C, Yue WW, Martelli A. 4'-Phosphopantetheine and long acyl chain-dependent interactions are integral to human mitochondrial acyl carrier protein function. MEDCHEMCOMM 2019; 10:209-220. [PMID: 30881609 DOI: 10.1039/c8md00489g] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 12/23/2018] [Indexed: 11/21/2022]
Abstract
The mitochondrial acyl carrier protein (human ACPM, yeast Acp1) is an essential mitochondrial protein. Through binding of nascent acyl chains on the serine (S112)-bound 4'-phosphopantetheine (4'-PP) cofactor, ACPM is involved in mitochondrial fatty acid synthesis and lipoic acid biogenesis. Recently, yeast Acp1 was found to interact with several mitochondrial complexes, including the iron-sulfur (Fe-S) cluster biosynthesis and respiratory complexes, via the binding to LYRM proteins, a family of proteins involved in assembly/stability of complexes. Importantly, the interaction of LYRM proteins with Acp1 was shown to be essential in maintaining integrity of mitochondrial complexes. In human, recent structures show that ACPM binding to LYRM proteins involves acyl chains attached to the 4'-PP cofactor. Here, we performed an detailed characterization of the mitochondrial interactome of human ACPM by mass spectrometry (MS) and demonstrate the crucial role of the 4'-PP cofactor in most of ACPM interactions. Specifically, we show that ACPM interacts with endogenous Fe-S cluster complex components through binding of the LYRM protein ISD11/LYRM4. Using knockdown experiments, we further determine that ACPM is essential for the stability of mitochondrial respiratory complexes I, II and III, as well as the Fe-S cluster biosynthesis complex. Finally, using native MS and a top-down MS approach, we show that C14, C16 and C18 3-keto-acyl chains on ACPM are implicated in binding to ISD11 through analysis of the recombinant ACPM-ISD11 complex. Taken together, our data provide novel understanding of the role of 4'-PP- and long acyl chains-dependent interactions in human ACPM function.
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Affiliation(s)
- Jaimeen D Majmudar
- Chemical Biology, Medicine Design , Worldwide Research and Development , Pfizer Inc. , 610 Main Street , Cambridge , MA 02139 , USA .
| | - Xidong Feng
- Discovery Sciences , Worldwide Research and Development , Pfizer Inc. , Eastern Point Road , Groton , CT 06340 , USA
| | - Nicholas G Fox
- Structural Genomics Consortium , Nuffield Department of Clinical Medicine , University of Oxford , OX3 7DQ , UK
| | - Joseph F Nabhan
- Rare Disease Research Unit , Worldwide Research and Development , Pfizer Inc. , 610 Main Street , Cambridge , MA 02139 , USA .
| | - Theresa Towle
- Rare Disease Research Unit , Worldwide Research and Development , Pfizer Inc. , 610 Main Street , Cambridge , MA 02139 , USA .
| | - Tiffany Ma
- Rare Disease Research Unit , Worldwide Research and Development , Pfizer Inc. , 610 Main Street , Cambridge , MA 02139 , USA .
| | - Renea Gooch
- Rare Disease Research Unit , Worldwide Research and Development , Pfizer Inc. , 610 Main Street , Cambridge , MA 02139 , USA .
| | - Christine Bulawa
- Rare Disease Research Unit , Worldwide Research and Development , Pfizer Inc. , 610 Main Street , Cambridge , MA 02139 , USA .
| | - Wyatt W Yue
- Structural Genomics Consortium , Nuffield Department of Clinical Medicine , University of Oxford , OX3 7DQ , UK
| | - Alain Martelli
- Rare Disease Research Unit , Worldwide Research and Development , Pfizer Inc. , 610 Main Street , Cambridge , MA 02139 , USA .
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53
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Poltash ML, McCabe JW, Patrick JW, Laganowsky A, Russell DH. Development and Evaluation of a Reverse-Entry Ion Source Orbitrap Mass Spectrometer. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:192-198. [PMID: 29796735 PMCID: PMC6251776 DOI: 10.1007/s13361-018-1976-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 04/16/2018] [Accepted: 04/17/2018] [Indexed: 05/08/2023]
Abstract
As a step towards development of a high-resolution ion mobility mass spectrometer using the orbitrap mass analyzer platform, we describe herein a novel reverse-entry ion source (REIS) coupled to the higher-energy C-trap dissociation (HCD) cell of an orbitrap mass spectrometer with extended mass range. Development of the REIS is a first step in the development of a drift tube ion mobility-orbitrap MS. The REIS approach retains the functionality of the commercial instrument ion source which permits the uninterrupted use of the instrument during development as well as performance comparisons between the two ion sources. Ubiquitin (8.5 kDa) and lipid binding to the ammonia transport channel (AmtB, 126 kDa) protein complex were used as model soluble and membrane proteins, respectively, to evaluate the performance of the REIS instrument. Mass resolution obtained with the REIS is comparable to that obtained using the commercial ion source. The charge state distributions for ubiquitin and AmtB obtained on the REIS are in agreement with previous studies which suggests that the REIS-orbitrap EMR retains native structure in the gas phase. Graphical Abstract ᅟ.
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Affiliation(s)
- Michael L Poltash
- Department of Chemistry, Texas A&M University, College Station, TX, 77843, USA
| | - Jacob W McCabe
- Department of Chemistry, Texas A&M University, College Station, TX, 77843, USA
| | - John W Patrick
- 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.
| | - David H Russell
- Department of Chemistry, Texas A&M University, College Station, TX, 77843, USA.
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54
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Vonderach M, Byrne DP, Barran PE, Eyers PA, Eyers CE. DNA Binding and Phosphorylation Regulate the Core Structure of the NF-κB p50 Transcription Factor. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:128-138. [PMID: 29873020 PMCID: PMC6318249 DOI: 10.1007/s13361-018-1984-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 04/26/2018] [Accepted: 04/30/2018] [Indexed: 05/07/2023]
Abstract
The NF-κB transcription factors are known to be extensively phosphorylated, with dynamic site-specific modification regulating their ability to dimerize and interact with DNA. p50, the proteolytic product of p105 (NF-κB1), forms homodimers that bind DNA but lack intrinsic transactivation function, functioning as repressors of transcription from κB promoters. Here, we examine the roles of specific phosphorylation events catalysed by either protein kinase A (PKAc) or Chk1, in regulating the functions of p50 homodimers. LC-MS/MS analysis of proteolysed p50 following in vitro phosphorylation allows us to define Ser328 and Ser337 as PKAc- and Chk1-mediated modifications, and pinpoint an additional four Chk1 phosphosites: Ser65, Thr152, Ser242 and Ser248. Native mass spectrometry (MS) reveals Chk1- and PKAc-regulated disruption of p50 homodimer formation through Ser337. Additionally, we characterise the Chk1-mediated phosphosite, Ser242, as a regulator of DNA binding, with a S242D p50 phosphomimetic exhibiting a > 10-fold reduction in DNA binding affinity. Conformational dynamics of phosphomimetic p50 variants, including S242D, are further explored using ion-mobility MS (IM-MS). Finally, comparative theoretical modelling with experimentally observed p50 conformers, in the absence and presence of DNA, reveals that the p50 homodimer undergoes conformational contraction during electrospray ionisation that is stabilised by complex formation with κB DNA. Graphical Abstract ᅟ.
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Affiliation(s)
- Matthias Vonderach
- Centre for Proteome Research, Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
| | - Dominic P Byrne
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
| | - Perdita E Barran
- Michael Barber Centre for Collaborative Mass Spectrometry, Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Patrick A Eyers
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
| | - Claire E Eyers
- Centre for Proteome Research, Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK.
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55
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Hansen K, Lau AM, Giles K, McDonnell JM, Struwe WB, Sutton BJ, Politis A. A Mass-Spectrometry-Based Modelling Workflow for Accurate Prediction of IgG Antibody Conformations in the Gas Phase. Angew Chem Int Ed Engl 2018; 57:17194-17199. [PMID: 30408305 PMCID: PMC6392142 DOI: 10.1002/anie.201812018] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Indexed: 11/09/2022]
Abstract
Immunoglobulins are biomolecules involved in defence against foreign substances. Flexibility is key to their functional properties in relation to antigen binding and receptor interactions. We have developed an integrative strategy combining ion mobility mass spectrometry (IM-MS) with molecular modelling to study the conformational dynamics of human IgG antibodies. Predictive models of all four human IgG subclasses were assembled and their dynamics sampled in the transition from extended to collapsed state during IM-MS. Our data imply that this collapse of IgG antibodies is related to their intrinsic structural features, including Fab arm flexibility, collapse towards the Fc region, and the length of their hinge regions. The workflow presented here provides an accurate structural representation in good agreement with the observed collision cross section for these flexible IgG molecules. These results have implications for studying other nonglobular flexible proteins.
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Affiliation(s)
- Kjetil Hansen
- Department of ChemistryKing's College London7 Trinity StreetLondonSE1 1DBUK
| | - Andy M. Lau
- Department of ChemistryKing's College London7 Trinity StreetLondonSE1 1DBUK
| | | | | | | | - Brian J. Sutton
- Randall Centre for Cell and Molecular BiophysicsKing's College LondonUK
| | - Argyris Politis
- Department of ChemistryKing's College London7 Trinity StreetLondonSE1 1DBUK
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56
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Hansen K, Lau AM, Giles K, McDonnell JM, Struwe WB, Sutton BJ, Politis A. A Mass‐Spectrometry‐Based Modelling Workflow for Accurate Prediction of IgG Antibody Conformations in the Gas Phase. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201812018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Kjetil Hansen
- Department of Chemistry King's College London 7 Trinity Street London SE1 1DB UK
| | - Andy M. Lau
- Department of Chemistry King's College London 7 Trinity Street London SE1 1DB UK
| | - Kevin Giles
- Waters Corp. Stamford Road Wilmslow SK9 4AX UK
| | - James M. McDonnell
- Randall Centre for Cell and Molecular Biophysics King's College London UK
| | | | - Brian J. Sutton
- Randall Centre for Cell and Molecular Biophysics King's College London UK
| | - Argyris Politis
- Department of Chemistry King's College London 7 Trinity Street London SE1 1DB UK
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57
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Corona discharge electrospray ionization of formate-containing solutions enables in-source reduction of disulfide bonds. Anal Bioanal Chem 2018; 411:4729-4737. [PMID: 30397758 DOI: 10.1007/s00216-018-1447-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 10/12/2018] [Accepted: 10/22/2018] [Indexed: 01/05/2023]
Abstract
Disulfide bonds are critical linkages for maintaining protein structure and enzyme activity. These linkages, however, can limit peptide sequencing efforts by mass spectrometry (MS) and often require chemical reduction and alkylation. Under such conditions, information regarding cysteine connectivity is lost. Online partial disulfide reduction within the electrospray (ESI) source has recently been established as a means to identify complex cysteine linkage patterns in a liquid chromatography-MS experiment without the need for sample pre-treatment. Corona discharge (CD) is invoked as the causative factor of this in-source reduction (ISR); however, evidence remains largely circumstantial. In this study, we demonstrate that instrumental factors-nebulizing gas, ESI capillary material, organic solvent content, ESI spray needle-to-MS distance-all modulate the degree of reduction observed for the single disulfide in oxytocin, further implicating CD in ISR. Rigorous analysis of solution conditions, however, reveals that corona discharge alone can induce only minor disulfide reduction. We establish that CD-ESI of peptide solutions containing formic acid or its conjugate base results in a dramatic increase in disulfide reduction. It is also determined that ISR is exacerbated at low pH for complex peptides containing multiple disulfide bonds and possessing higher-order structure, as well as for a small protein. Overall, our results demonstrate that ESI of formate/formic acid-containing solutions under corona discharge conditions facilitates disulfide ISR, likely by a similar reduction pathway measured in γ-radiolysis studies nearly three decades ago.
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58
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Dong S, Wagner ND, Russell DH. Collision-Induced Unfolding of Partially Metalated Metallothionein-2A: Tracking Unfolding Reactions of Gas-Phase Ions. Anal Chem 2018; 90:11856-11862. [PMID: 30221929 DOI: 10.1021/acs.analchem.8b01622] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Metallothioneins (MTs) constitute a group of intrinsically disordered proteins that exhibit extreme diversity in structure, biological functionality, and metal ion specificity. Structures of coordinatively saturated metalated MTs have been extensively studied, but very limited structural information for the partially metalated MTs exists. Here, the conformational preferences from partial metalation of rabbit metallothionein-2A (MT) by Cd2+, Zn2+, and Ag+ are studied using nanoelectrospray ionization ion mobility mass spectrometry. We also employ collision-induced unfolding to probe differences in the gas-phase stabilities of these partially metalated MTs. Our results show that despite their similar ion mobility profiles, Cd4-MT, Zn4-MT, Ag4-MT, and Ag6-MT differ dramatically in their gas-phase stabilities. Furthermore, the sequential addition of each Cd2+ and Zn2+ ion results in the incremental stabilization of unique unfolding intermediates.
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Affiliation(s)
- Shiyu Dong
- Department of Chemistry , Texas A&M University , College Station , Texas 77843 , United States
| | - Nicole D Wagner
- 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
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59
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Poltash ML, McCabe JW, Shirzadeh M, Laganowsky A, Clowers BH, Russell DH. Fourier Transform-Ion Mobility-Orbitrap Mass Spectrometer: A Next-Generation Instrument for Native Mass Spectrometry. Anal Chem 2018; 90:10472-10478. [PMID: 30091588 PMCID: PMC6464636 DOI: 10.1021/acs.analchem.8b02463] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A new instrument configuration for native ion mobility-mass spectrometry (IM-MS) is described. Macromolecule ions are generated by using a static ESI source coupled to an RF ion funnel, and these ions are then mobility and mass analyzed using a periodic focusing drift tube IM analyzer and an Orbitrap mass spectrometer. The instrument design retains the capabilities for first-principles determination of rotationally averaged ion-neutral collision cross sections and high-resolution measurements in both mobility and mass analysis modes for intact protein complexes. Operation in the IM mode utilizes FT-IMS modes (originally described by Knorr ( Knorr , F. J. Anal. Chem . 1985 , 57 ( 2 ), 402 - 406 )), which provides a means to overcome the inherent duty cycle mismatch for drift tube (DT)-IM and Orbitrap mass analysis. The performance of the native ESI-FT-DT-IM-Orbitrap MS instrument was evaluated using the protein complexes Gln K (MW 44 kDa) and streptavidin (MW 53 kDa) bound to small molecules (ADP and biotin, respectively) and transthyretin (MW 56 kDa) bound to thyroxine and zinc.
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Affiliation(s)
- Michael L. Poltash
- 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
| | - Mehdi Shirzadeh
- 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
| | - Brian H. Clowers
- Department of Chemistry, Washington State University, Pullman, Washington 99164, United States
| | - David H. Russell
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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60
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Mehaffey MR, Sanders JD, Holden DD, Nilsson CL, Brodbelt JS. Multistage Ultraviolet Photodissociation Mass Spectrometry To Characterize Single Amino Acid Variants of Human Mitochondrial BCAT2. Anal Chem 2018; 90:9904-9911. [PMID: 30016590 PMCID: PMC6323636 DOI: 10.1021/acs.analchem.8b02099] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Unraveling disease mechanisms requires a comprehensive understanding of how the interplay between higher-order structure and protein-ligand interactions impacts the function of a given protein. Recent advances in native mass spectrometry (MS) involving multimodal or higher-energy activation methods have allowed direct interrogation of intact protein complexes in the gas phase, allowing analysis of both composition and subunit connectivity. We report a multistage approach combining collisional activation and 193 nm ultraviolet photodissociation (UVPD) to characterize single amino acid variants of the human mitochondrial enzyme branched-chain amino acid transferase 2 (BCAT2), a protein implicated in chemotherapeutic resistance in glioblastoma tumors. Native electrospray ionization confirms that both proteins exist as homodimers. Front-end collisional activation disassembles the dimers into monomeric subunits that are further interrogated using UVPD to yield high sequence coverage of the mutated region. Additionally, holo (ligand-bound) fragment ions resulting from photodissociation reveal that the mutation causes destabilization of the interactions with a bound cofactor. This study demonstrates the unique advantages of implementing UVPD in a multistage MS approach for analyzing intact protein assemblies.
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Affiliation(s)
- M. Rachel Mehaffey
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712
| | - James D. Sanders
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712
| | - Dustin D. Holden
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712
| | - Carol L. Nilsson
- Institute of Experimental Medical Sciences, Lund University, SE-221, Lund Sweden
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61
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Gel-based proteomics in disease research: Is it still valuable? BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1867:9-16. [PMID: 30392562 DOI: 10.1016/j.bbapap.2018.08.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 06/30/2018] [Accepted: 08/09/2018] [Indexed: 12/17/2022]
Abstract
Gel electrophoresis had been the primary method in proteomics. In the early era of proteomics, gel electrophoresis was a dominant technique of sample preparation for mass spectrometry analysis. Particularly, two-dimensional electrophoresis provided high-resolution proteome separation, and was regarded as the standard methodology for the separation of wide-range proteomes. However, gel electrophoresis turned downwards due to the progress of other separations including liquid chromatography and ionization techniques, resulting gel-free proteomics finally becoming dominant players at present. There are numerous advantages in gel-free approach in aspects of current trends of disease research. Interestingly, gel-free approaches are still advanced, it seems that gel electrophoresis will not be disappeared. The unique features of gel electrophoresis can be complementary for gel-free and it is suitable for the new wave of top-down functional proteomics.
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62
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Kondalaji SG, Khakinejad M, Valentine SJ. Comprehensive Peptide Ion Structure Studies Using Ion Mobility Techniques: Part 3. Relating Solution-Phase to Gas-Phase Structures. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:1665-1677. [PMID: 29858839 PMCID: PMC6525623 DOI: 10.1007/s13361-018-1996-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 05/02/2018] [Accepted: 05/02/2018] [Indexed: 05/16/2023]
Abstract
Molecular dynamics (MD) simulations have been utilized to study peptide ion conformer establishment during the electrospray process. An explicit water model is used for nanodroplets containing a model peptide and hydronium ions. Simulations are conducted at 300 K for two different peptide ion charge configurations and for droplets containing varying numbers of hydronium ions. For all conditions, modeling has been performed until production of the gas-phase ions and the resultant conformers have been compared to proposed gas-phase structures. The latter species were obtained from previous studies in which in silico candidate structures were filtered according to ion mobility and hydrogen-deuterium exchange (HDX) reactivity matches. Results from the present study present three key findings namely (1) the evidence from ion production modeling supports previous structure refinement studies based on mobility and HDX reactivity matching, (2) the modeling of the electrospray process is significantly improved by utilizing initial droplets existing below but close to the calculated Rayleigh limit, and (3) peptide ions in the nanodroplets sample significantly different conformers than those in the bulk solution due to altered physicochemical properties of the solvent. Graphical Abstract ᅟ.
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Affiliation(s)
- Samaneh Ghassabi Kondalaji
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Mahdiar Khakinejad
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Stephen J Valentine
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA.
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63
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Landreh M, Andersson M, Marklund EG, Jia Q, Meng Q, Johansson J, Robinson CV, Rising A. Mass spectrometry captures structural intermediates in protein fiber self-assembly. Chem Commun (Camb) 2018; 53:3319-3322. [PMID: 28184384 PMCID: PMC5530726 DOI: 10.1039/c7cc00307b] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Integrating ion mobility mass spectrometry and molecular dynamics simulations provides insights into intermediates in spider silk formation. The resulting structural models reveal how soluble spidroin proteins use their terminal domains to assemble into silk fibers.
Self-assembling proteins, the basis for a broad range of biological scaffolds, are challenging to study using most structural biology approaches. Here we show that mass spectrometry (MS) in combination with MD simulations captures structural features of short-lived oligomeric intermediates in spider silk formation, providing direct insights into its complex assembly process.
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Affiliation(s)
- Michael Landreh
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK.
| | - Marlene Andersson
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Erik G Marklund
- Department of Chemistry - BMC, Uppsala University, Box 576, SE-751 23, Uppsala, Sweden
| | - Qiupin Jia
- Institute of Biological Sciences and Biotechnology, Donghua University, Shanghai, 201620, P. R. China
| | - Qing Meng
- Institute of Biological Sciences and Biotechnology, Donghua University, Shanghai, 201620, P. R. China
| | - Jan Johansson
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden and Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society (NVS), Center for Alzheimer Research, Karolinska Institutet, Huddinge, 14157, Stockholm, Sweden.
| | - Carol V Robinson
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK.
| | - Anna Rising
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden and Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society (NVS), Center for Alzheimer Research, Karolinska Institutet, Huddinge, 14157, Stockholm, Sweden.
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64
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How can native mass spectrometry contribute to characterization of biomacromolecular higher-order structure and interactions? Methods 2018; 144:3-13. [PMID: 29704661 DOI: 10.1016/j.ymeth.2018.04.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 04/03/2018] [Accepted: 04/21/2018] [Indexed: 01/16/2023] Open
Abstract
Native mass spectrometry (MS) is an emerging approach for characterizing biomacromolecular structure and interactions under physiologically relevant conditions. In native MS measurement, intact macromolecules or macromolecular complexes are directly ionized from a non-denaturing solvent, and key noncovalent interactions that hold the complexes together can be preserved for MS analysis in the gas phase. This technique provides unique multi-level structural information such as conformational changes, stoichiometry, topology and dynamics, complementing conventional biophysical techniques. Despite the maturation of native MS and greatly expanded range of applications in recent decades, further dissemination is needed to make the community aware of such a technique. In this review, we attempt to provide an overview of the current body of knowledge regarding major aspects of native MS and explain how such technique contributes to the characterization of biomacromolecular higher-order structure and interactions.
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65
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Gadkari VV, Harvey SR, Raper AT, Chu WT, Wang J, Wysocki VH, Suo Z. Investigation of sliding DNA clamp dynamics by single-molecule fluorescence, mass spectrometry and structure-based modeling. Nucleic Acids Res 2018; 46:3103-3118. [PMID: 29529283 PMCID: PMC5888646 DOI: 10.1093/nar/gky125] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 01/23/2018] [Accepted: 02/12/2018] [Indexed: 12/20/2022] Open
Abstract
Proliferating cell nuclear antigen (PCNA) is a trimeric ring-shaped clamp protein that encircles DNA and interacts with many proteins involved in DNA replication and repair. Despite extensive structural work to characterize the monomeric, dimeric, and trimeric forms of PCNA alone and in complex with interacting proteins, no structure of PCNA in a ring-open conformation has been published. Here, we use a multidisciplinary approach, including single-molecule Förster resonance energy transfer (smFRET), native ion mobility-mass spectrometry (IM-MS), and structure-based computational modeling, to explore the conformational dynamics of a model PCNA from Sulfolobus solfataricus (Sso), an archaeon. We found that Sso PCNA samples ring-open and ring-closed conformations even in the absence of its clamp loader complex, replication factor C, and transition to the ring-open conformation is modulated by the ionic strength of the solution. The IM-MS results corroborate the smFRET findings suggesting that PCNA dynamics are maintained in the gas phase and further establishing IM-MS as a reliable strategy to investigate macromolecular motions. Our molecular dynamic simulations agree with the experimental data and reveal that ring-open PCNA often adopts an out-of-plane left-hand geometry. Collectively, these results implore future studies to define the roles of PCNA dynamics in DNA loading and other PCNA-mediated interactions.
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Affiliation(s)
- Varun V Gadkari
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Sophie R Harvey
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
- School of Chemistry, Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK
| | - Austin T Raper
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Wen-Ting Chu
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P.R. China
| | - Jin Wang
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P.R. China
- Department of Chemistry and Physics, State University of New York at Stony Brook, Stony Brook, NY 11794-3400, USA
| | - Vicki H Wysocki
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Zucai Suo
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
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66
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Politis A, Schmidt C. Structural characterisation of medically relevant protein assemblies by integrating mass spectrometry with computational modelling. J Proteomics 2018; 175:34-41. [DOI: 10.1016/j.jprot.2017.04.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 04/13/2017] [Accepted: 04/18/2017] [Indexed: 01/14/2023]
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67
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Brahim B, Tabet JC, Alves S. Positive and negative ion mode comparison for the determination of DNA/peptide noncovalent binding sites through the formation of "three-body" noncovalent fragment ions. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2018; 24:168-177. [PMID: 29232990 DOI: 10.1177/1469066717735672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Gas-phase fragmentation of single strand DNA-peptide noncovalent complexes is investigated in positive and negative electrospray ionization modes.Collision-induced dissociation experiments, performed on the positively charged noncovalent complex precursor ions, have confirmed the trend previously observed in negative ion mode, i.e. a high stability of noncovalent complexes containing very basic peptidic residues (i.e. R > K) and acidic nucleotide units (i.e. Thy units), certainly incoming from the existence of salt bridge interactions. Independent of the ion polarity, stable noncovalent complex precursor ions were found to dissociate preferentially through covalent bond cleavages of the partners without disrupting noncovalent interactions. The resulting DNA fragment ions were found to be still noncovalently linked to the peptides. Additionally, the losses of an internal nucleic fragment producing "three-body" noncovalent fragment ions were also observed in both ion polarities, demonstrating the spectacular salt bridge interaction stability. The identical fragmentation patterns (regardless of the relative fragment ion abundances) observed in both polarities have shown a common location of salt bridge interaction certainly preserved from solution. Nonetheless, most abundant noncovalent fragment ions (and particularly three-body ones) are observed from positively charged noncovalent complexes. Therefore, we assume that, independent of the preexisting salt bridge interaction and zwitterion structures, multiple covalent bond cleavages from single-stranded DNA/peptide complexes rely on an excess of positive charges in both electrospray ionization ion polarities.
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Affiliation(s)
- Bessem Brahim
- Sorbonne Universités - UPMC Paris 06, Institut Parisien de Chimie Moléculaire (IPCM) University, Paris, France
| | - Jean-Claude Tabet
- Sorbonne Universités - UPMC Paris 06, Institut Parisien de Chimie Moléculaire (IPCM) University, Paris, France
| | - Sandra Alves
- Sorbonne Universités - UPMC Paris 06, Institut Parisien de Chimie Moléculaire (IPCM) University, Paris, France
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68
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Ion mobility in the pharmaceutical industry: an established biophysical technique or still niche? Curr Opin Chem Biol 2018; 42:147-159. [DOI: 10.1016/j.cbpa.2017.11.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 11/10/2017] [Accepted: 11/15/2017] [Indexed: 01/01/2023]
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69
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70
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Mehaffey MR, Cammarata MB, Brodbelt JS. Tracking the Catalytic Cycle of Adenylate Kinase by Ultraviolet Photodissociation Mass Spectrometry. Anal Chem 2018; 90:839-846. [PMID: 29188992 PMCID: PMC5750083 DOI: 10.1021/acs.analchem.7b03591] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The complex interplay of dynamic protein plasticity and specific side-chain interactions with substrate molecules that allows enzymes to catalyze reactions has yet to be fully unraveled. Top-down ultraviolet photodissociation (UVPD) mass spectrometry is used to track snapshots of conformational fluctuations in the phosphotransferase adenylate kinase (AK) throughout its active reaction cycle by characterization of complexes containing AK and each of four different adenosine phosphate ligands. Variations in efficiencies of UVPD backbone cleavages were consistently observed for three α-helices and the adenosine binding regions for AK complexes representing different steps of the catalytic cycle, implying that these stretches of the protein sample various structural microstates as the enzyme undergoes global open-to-closed transitions. Focusing on the conformational impact of recruiting or releasing the Mg2+ cofactor highlights two loop regions for which fragmentation increases upon UVPD, signaling an increase in loop flexibility as the metal cation disrupts the loop interactions with the substrate ligands. Additionally, the observation of holo ions and variations in UVPD backbone cleavage efficiency at R138 implicate this conserved active site residue in stabilizing the donor phosphoryl group during catalysis. This study showcases the utility of UVPD-MS to provide insight into conformational fluctuations of single residues for active enzymes.
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Affiliation(s)
- M. Rachel Mehaffey
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712
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71
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Campuzano IDG, Netirojjanakul C, Nshanian M, Lippens JL, Kilgour DPA, Van Orden S, Loo JA. Native-MS Analysis of Monoclonal Antibody Conjugates by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry. Anal Chem 2017; 90:745-751. [DOI: 10.1021/acs.analchem.7b03021] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
| | | | - Michael Nshanian
- Department
of Chemistry and Biochemistry, and Department of Biological Chemistry, University of California−Los Angeles, Los Angeles, California 90095, United States
| | | | - David P. A. Kilgour
- Department
of Chemistry and Forensics, Nottingham Trent University, Nottingham NG11 8NS, United Kingdom
| | - Steve Van Orden
- Bruker Daltonics Inc., Billerica, Massachusetts 01821, United States
| | - Joseph A. Loo
- Department
of Chemistry and Biochemistry, and Department of Biological Chemistry, University of California−Los Angeles, Los Angeles, California 90095, United States
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72
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Yefremova Y, Danquah BD, Opuni KF, El-Kased R, Koy C, Glocker MO. Mass spectrometric characterization of protein structures and protein complexes in condensed and gas phase. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2017; 23:445-459. [PMID: 29183193 DOI: 10.1177/1469066717722256] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Proteins are essential for almost all physiological processes of life. They serve a myriad of functions which are as varied as their unique amino acid sequences and their corresponding three-dimensional structures. To fulfill their tasks, most proteins depend on stable physical associations, in the form of protein complexes that evolved between themselves and other proteins. In solution (condensed phase), proteins and/or protein complexes are in constant energy exchange with the surrounding solvent. Albeit methods to describe in-solution thermodynamic properties of proteins and of protein complexes are well established and broadly applied, they do not provide a broad enough access to life-science experimentalists to study all their proteins' properties at leisure. This leaves great desire to add novel methods to the analytical biochemist's toolbox. The development of electrospray ionization created the opportunity to characterize protein higher order structures and protein complexes rather elegantly by simultaneously lessening the need of sophisticated sample preparation steps. Electrospray mass spectrometry enabled us to translate proteins and protein complexes very efficiently into the gas phase under mild conditions, retaining both, intact protein complexes, and gross protein structures upon phase transition. Moreover, in the environment of the mass spectrometer (gas phase, in vacuo), analyte molecules are free of interactions with surrounding solvent molecules and, therefore, the energy of inter- and intramolecular forces can be studied independently from interference of the solvating environment. Provided that gas phase methods can give information which is relevant for understanding in-solution processes, gas phase protein structure studies and/or investigations on the characterization of protein complexes has rapidly gained more and more attention from the bioanalytical scientific community. Recent reports have shown that electrospray mass spectrometry provides direct access to six prime protein complex properties: stabilities, compositions, binding surfaces (epitopes), disassembly processes, stoichiometries, and thermodynamic parameters.
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Affiliation(s)
- Yelena Yefremova
- 1 Proteome Center Rostock, University of Rostock, Rostock, Germany
| | - Bright D Danquah
- 1 Proteome Center Rostock, University of Rostock, Rostock, Germany
| | | | - Reham El-Kased
- 3 Microbiology and Immunology, Faculty of Pharmacy, The British University in Egypt, Cairo, Egypt
| | - Cornelia Koy
- 1 Proteome Center Rostock, University of Rostock, Rostock, Germany
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73
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Haupt C, Hofmann T, Wittig S, Kostmann S, Politis A, Schmidt C. Combining Chemical Cross-linking and Mass Spectrometry of Intact Protein Complexes to Study the Architecture of Multi-subunit Protein Assemblies. J Vis Exp 2017. [PMID: 29286378 PMCID: PMC5755487 DOI: 10.3791/56747] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Proteins interact with their ligands to form active and dynamic assemblies which carry out various cellular functions. Elucidating these interactions is therefore fundamental for the understanding of cellular processes. However, many protein complexes are dynamic assemblies and are not accessible by conventional structural techniques. Mass spectrometry contributes to the structural investigation of these assemblies, and particularly the combination of various mass spectrometric techniques delivers valuable insights into their structural arrangement. In this article, we describe the application and combination of two complementary mass spectrometric techniques, namely chemical cross-linking coupled with mass spectrometry and native mass spectrometry. Chemical cross-linking involves the covalent linkage of amino acids in close proximity by using chemical reagents. After digestion with proteases, cross-linked di-peptides are identified by mass spectrometry and protein interactions sites are uncovered. Native mass spectrometry on the other hand is the analysis of intact protein assemblies in the gas phase of a mass spectrometer. It reveals protein stoichiometries as well as protein and ligand interactions. Both techniques therefore deliver complementary information on the structure of protein-ligand assemblies and their combination proved powerful in previous studies.
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Affiliation(s)
- Caroline Haupt
- Interdisciplinary research center HALOmem, Martin Luther University Halle-Wittenberg
| | - Tommy Hofmann
- Interdisciplinary research center HALOmem, Martin Luther University Halle-Wittenberg
| | - Sabine Wittig
- Interdisciplinary research center HALOmem, Martin Luther University Halle-Wittenberg
| | - Susann Kostmann
- Interdisciplinary research center HALOmem, Martin Luther University Halle-Wittenberg
| | | | - Carla Schmidt
- Interdisciplinary research center HALOmem, Martin Luther University Halle-Wittenberg;
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74
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Huang Y, Salinas ND, Chen E, Tolia NH, Gross ML. Native Mass Spectrometry, Ion mobility, and Collision-Induced Unfolding Categorize Malaria Antigen/Antibody Binding. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:2515-2518. [PMID: 28875466 PMCID: PMC5647250 DOI: 10.1007/s13361-017-1782-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 08/09/2017] [Accepted: 08/10/2017] [Indexed: 05/22/2023]
Abstract
Plasmodium vivax Duffy Binding Protein (PvDBP) is a promising vaccine candidate for P. vivax malaria. Recently, we reported the epitopes on PvDBP region II (PvDBP-II) for three inhibitory monoclonal antibodies (2D10, 2H2, and 2C6). In this communication, we describe the combination of native mass spectrometry and ion mobility (IM) with collision induced unfolding (CIU) to study the conformation and stabilities of three malarial antigen-antibody complexes. These complexes, when collisionally activated, undergo conformational changes that depend on the location of the epitope. CIU patterns for PvDBP-II in complex with antibody 2D10 and 2H2 are highly similar, indicating comparable binding topology and stability. A different CIU fingerprint is observed for PvDBP-II/2C6, indicating that 2C6 binds to PvDBP-II on an epitope different from 2D10 and 2H2. This work supports the use of CIU as a means of classifying antigen-antibody complexes by their epitope maps in a high throughput screening workflow. Graphical Abstract ᅟ.
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Affiliation(s)
- Yining Huang
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Nichole D Salinas
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Edwin Chen
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Niraj H Tolia
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
- Department of Biochemistry and Biophysics, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Michael L Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO, 63130, USA.
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75
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Ishii K, Zhou M, Uchiyama S. Native mass spectrometry for understanding dynamic protein complex. Biochim Biophys Acta Gen Subj 2017; 1862:275-286. [PMID: 28965879 DOI: 10.1016/j.bbagen.2017.09.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 09/17/2017] [Accepted: 09/19/2017] [Indexed: 12/13/2022]
Abstract
Biomolecules have evolved to perform specific and sophisticated activities in a highly coordinated manner organizing into multi-component complexes consisting of proteins, nucleic acids, cofactors or ligands. Understanding such complexes represents a task in earnest for modern bioscience. Traditional structural techniques when extrapolating to macromolecules of ever increasing sizes are confronted with limitations posed by the difficulty in enrichment, solubility, stability as well as lack of homogeneity of these complexes. Alternative approaches are therefore prompted to bridge the gap, one of which is native mass spectrometry. Here we demonstrate the strength of native mass spectrometry, used alone or in combination with other biophysical methods such as analytical ultracentrifugation, small-angle neutron scattering, and small-angle X-ray scattering etc., in addressing dynamic aspects of protein complexes including structural reorganization, subunit exchange, as well as the assembly/disassembly processes in solution that are dictated by transient non-covalent interactions. We review recent studies from our laboratories and others applying native mass spectrometry to both soluble and membrane-embedded assemblies. This article is part of a Special Issue entitled "Biophysical Exploration of Dynamical Ordering of Biomolecular Systems" edited by Dr. Koichi Kato.
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Affiliation(s)
- Kentaro Ishii
- Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Min Zhou
- Institute of Bio-analytical Chemistry, School of Chemical Engineering, Nanjing University of Science and Technology, No. 200 Xiaolingwei Street, Nanjing 210094, China.
| | - Susumu Uchiyama
- Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan; Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
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76
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Haverland NA, Skinner OS, Fellers RT, Tariq AA, Early BP, LeDuc RD, Fornelli L, Compton PD, Kelleher NL. Defining Gas-Phase Fragmentation Propensities of Intact Proteins During Native Top-Down Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:1203-1215. [PMID: 28374312 PMCID: PMC5452613 DOI: 10.1007/s13361-017-1635-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 02/17/2017] [Accepted: 02/20/2017] [Indexed: 05/03/2023]
Abstract
Fragmentation of intact proteins in the gas phase is influenced by amino acid composition, the mass and charge of precursor ions, higher order structure, and the dissociation technique used. The likelihood of fragmentation occurring between a pair of residues is referred to as the fragmentation propensity and is calculated by dividing the total number of assigned fragmentation events by the total number of possible fragmentation events for each residue pair. Here, we describe general fragmentation propensities when performing top-down mass spectrometry (TDMS) using denaturing or native electrospray ionization. A total of 5311 matched fragmentation sites were collected for 131 proteoforms that were analyzed over 165 experiments using native top-down mass spectrometry (nTDMS). These data were used to determine the fragmentation propensities for 399 residue pairs. In comparison to denatured top-down mass spectrometry (dTDMS), the fragmentation pathways occurring either N-terminal to proline or C-terminal to aspartic acid were even more enhanced in nTDMS compared with other residues. More generally, 257/399 (64%) of the fragmentation propensities were significantly altered (P ≤ 0.05) when using nTDMS compared with dTDMS, and of these, 123 were altered by 2-fold or greater. The most notable enhancements of fragmentation propensities for TDMS in native versus denatured mode occurred (1) C-terminal to aspartic acid, (2) between phenylalanine and tryptophan (F|W), and (3) between tryptophan and alanine (W|A). The fragmentation propensities presented here will be of high value in the development of tailored scoring systems used in nTDMS of both intact proteins and protein complexes. Graphical Abstract ᅟ.
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Affiliation(s)
- Nicole A Haverland
- Department of Chemistry and Molecular Biosciences and the Proteomics Center of Excellence, Northwestern University, 2170 Campus Drive, Evanston, IL, 60208, USA
| | - Owen S Skinner
- Department of Chemistry and Molecular Biosciences and the Proteomics Center of Excellence, Northwestern University, 2170 Campus Drive, Evanston, IL, 60208, USA
| | - Ryan T Fellers
- Department of Chemistry and Molecular Biosciences and the Proteomics Center of Excellence, Northwestern University, 2170 Campus Drive, Evanston, IL, 60208, USA
| | - Areeba A Tariq
- Department of Chemistry and Molecular Biosciences and the Proteomics Center of Excellence, Northwestern University, 2170 Campus Drive, Evanston, IL, 60208, USA
| | - Bryan P Early
- Department of Chemistry and Molecular Biosciences and the Proteomics Center of Excellence, Northwestern University, 2170 Campus Drive, Evanston, IL, 60208, USA
| | - Richard D LeDuc
- Department of Chemistry and Molecular Biosciences and the Proteomics Center of Excellence, Northwestern University, 2170 Campus Drive, Evanston, IL, 60208, USA
| | - Luca Fornelli
- Department of Chemistry and Molecular Biosciences and the Proteomics Center of Excellence, Northwestern University, 2170 Campus Drive, Evanston, IL, 60208, USA
| | - Philip D Compton
- Department of Chemistry and Molecular Biosciences and the Proteomics Center of Excellence, Northwestern University, 2170 Campus Drive, Evanston, IL, 60208, USA
| | - Neil L Kelleher
- Department of Chemistry and Molecular Biosciences and the Proteomics Center of Excellence, Northwestern University, 2170 Campus Drive, Evanston, IL, 60208, USA.
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77
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Lu Y, Liu H, Saer R, Li VL, Zhang H, Shi L, Goodson C, Gross ML, Blankenship RE. A Molecular Mechanism for Nonphotochemical Quenching in Cyanobacteria. Biochemistry 2017; 56:2812-2823. [PMID: 28513152 DOI: 10.1021/acs.biochem.7b00202] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The cyanobacterial orange carotenoid protein (OCP) protects photosynthetic cyanobacteria from photodamage by dissipating excess excitation energy collected by phycobilisomes (PBS) as heat. Dissociation of the PBS-OCP complex in vivo is facilitated by another protein known as the fluorescence recovery protein (FRP), which primarily exists as a dimeric complex. We used various mass spectrometry (MS)-based techniques to investigate the molecular mechanism of this FRP-mediated process. FRP in the dimeric state (dFRP) retains its high affinity for the C-terminal domain (CTD) of OCP in the red state (OCPr). Site-directed mutagenesis and native MS suggest the head region on FRP is a candidate to bind OCP. After attachment to the CTD, the conformational changes of dFRP allow it to bridge the two domains, facilitating the reversion of OCPr into the orange state (OCPo) accompanied by a structural rearrangement of dFRP. Interestingly, we found a mutual response between FRP and OCP; that is, FRP and OCPr destabilize each other, whereas FRP and OCPo stabilize each other. A detailed mechanism of FRP function is proposed on the basis of the experimental results.
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Affiliation(s)
- Yue Lu
- Department of Chemistry, Washington University in St. Louis , St. Louis, Missouri 63130, United States.,Photosynthetic Antenna Research Center, Washington University in St. Louis , St. Louis, Missouri 63130, United States
| | - Haijun Liu
- Photosynthetic Antenna Research Center, Washington University in St. Louis , St. Louis, Missouri 63130, United States.,Department of Biology, Washington University in St. Louis , St. Louis, Missouri 63130, United States
| | - Rafael Saer
- Photosynthetic Antenna Research Center, Washington University in St. Louis , St. Louis, Missouri 63130, United States.,Department of Biology, Washington University in St. Louis , St. Louis, Missouri 63130, United States
| | - Veronica L Li
- Department of Chemistry, Washington University in St. Louis , St. Louis, Missouri 63130, United States.,Photosynthetic Antenna Research Center, Washington University in St. Louis , St. Louis, Missouri 63130, United States
| | - Hao Zhang
- Department of Chemistry, Washington University in St. Louis , St. Louis, Missouri 63130, United States.,Photosynthetic Antenna Research Center, Washington University in St. Louis , St. Louis, Missouri 63130, United States
| | - Liuqing Shi
- Department of Chemistry, Washington University in St. Louis , St. Louis, Missouri 63130, United States
| | - Carrie Goodson
- Photosynthetic Antenna Research Center, Washington University in St. Louis , St. Louis, Missouri 63130, United States.,Department of Biology, Washington University in St. Louis , St. Louis, Missouri 63130, United States
| | - Michael L Gross
- Department of Chemistry, Washington University in St. Louis , St. Louis, Missouri 63130, United States.,Photosynthetic Antenna Research Center, Washington University in St. Louis , St. Louis, Missouri 63130, United States
| | - Robert E Blankenship
- Department of Chemistry, Washington University in St. Louis , St. Louis, Missouri 63130, United States.,Photosynthetic Antenna Research Center, Washington University in St. Louis , St. Louis, Missouri 63130, United States.,Department of Biology, Washington University in St. Louis , St. Louis, Missouri 63130, United States
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78
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Ruggeri F, Zosel F, Mutter N, Różycka M, Wojtas M, Ożyhar A, Schuler B, Krishnan M. Single-molecule electrometry. NATURE NANOTECHNOLOGY 2017; 12:488-495. [PMID: 28288117 DOI: 10.1038/nnano.2017.26] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 01/31/2017] [Indexed: 05/22/2023]
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79
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Li J, Lyu W, Rossetti G, Konijnenberg A, Natalello A, Ippoliti E, Orozco M, Sobott F, Grandori R, Carloni P. Proton Dynamics in Protein Mass Spectrometry. J Phys Chem Lett 2017; 8:1105-1112. [PMID: 28207277 DOI: 10.1021/acs.jpclett.7b00127] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Native electrospray ionization/ion mobility-mass spectrometry (ESI/IM-MS) allows an accurate determination of low-resolution structural features of proteins. Yet, the presence of proton dynamics, observed already by us for DNA in the gas phase, and its impact on protein structural determinants, have not been investigated so far. Here, we address this issue by a multistep simulation strategy on a pharmacologically relevant peptide, the N-terminal residues of amyloid-β peptide (Aβ(1-16)). Our calculations reproduce the experimental maximum charge state from ESI-MS and are also in fair agreement with collision cross section (CCS) data measured here by ESI/IM-MS. Although the main structural features are preserved, subtle conformational changes do take place in the first ∼0.1 ms of dynamics. In addition, intramolecular proton dynamics processes occur on the picosecond-time scale in the gas phase as emerging from quantum mechanics/molecular mechanics (QM/MM) simulations at the B3LYP level of theory. We conclude that proton transfer phenomena do occur frequently during fly time in ESI-MS experiments (typically on the millisecond time scale). However, the structural changes associated with the process do not significantly affect the structural determinants.
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Affiliation(s)
- Jinyu Li
- College of Chemistry, Fuzhou University , 350002 Fuzhou, China
| | - Wenping Lyu
- Computational Biomedicine, Institute for Advanced Simulation IAS-5 and Institute of Neuroscience and Medicine INM-9, Forschungszentrum Jülich , 52425 Jülich, Germany
- Faculty of Mathematics, Computer Science and Natural Sciences, RWTH-Aachen University , 52056 Aachen, Germany
- Computation-Based Science and Technology Research Center, Cyprus Institute , 2121 Aglantzia, Nicosia, Cyprus
| | - Giulia Rossetti
- Computational Biomedicine, Institute for Advanced Simulation IAS-5 and Institute of Neuroscience and Medicine INM-9, Forschungszentrum Jülich , 52425 Jülich, Germany
- Department of Hematology, Oncology, Hemostaseology, and Stem Cell Transplantation, Faculty of Medicine, RWTH Aachen University , 52062 Aachen, Germany
- Jülich Supercomputing Centre (JSC), Forschungszentrum Jülich , D-52425 Jülich, Germany
| | - Albert Konijnenberg
- Biomolecular & Analytical Mass Spectrometry group, Department of Chemistry, University of Antwerp , 2000 Antwerpen, Belgium
| | - Antonino Natalello
- Department of Biotechnology and Biosciences, University of Milano-Bicocca , Piazza della Scienza 2, 20126 Milan, Italy
| | - Emiliano Ippoliti
- Computational Biomedicine, Institute for Advanced Simulation IAS-5 and Institute of Neuroscience and Medicine INM-9, Forschungszentrum Jülich , 52425 Jülich, Germany
| | - Modesto Orozco
- Joint BSC-IRB Program on Computational Biology, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology , Baldiri Reixac 10, Barcelona 08028, Spain
- Departament de Bioquímica i Biomedicina, Facultat de Biologia, Universitat de Barcelona , Avgda Diagonal 647, Barcelona 08028, Spain
| | - Frank Sobott
- Biomolecular & Analytical Mass Spectrometry group, Department of Chemistry, University of Antwerp , 2000 Antwerpen, Belgium
- Astbury Centre for Structural Molecular Biology, University of Leeds , Leeds LS2 9JT, United Kingdom
- School of Molecular and Cellular Biology, University of Leeds , Leeds LS2 9JT, United Kingdom
| | - Rita Grandori
- Department of Biotechnology and Biosciences, University of Milano-Bicocca , Piazza della Scienza 2, 20126 Milan, Italy
| | - Paolo Carloni
- Computational Biomedicine, Institute for Advanced Simulation IAS-5 and Institute of Neuroscience and Medicine INM-9, Forschungszentrum Jülich , 52425 Jülich, Germany
- JARA-HPC, 52425 Jülich, Germany
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80
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Investigating the structural transitions of proteins during dissolution by mass spectrometry. Talanta 2017; 164:418-426. [DOI: 10.1016/j.talanta.2016.11.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 11/07/2016] [Accepted: 11/09/2016] [Indexed: 11/17/2022]
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81
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Schmidt C, Macpherson JA, Lau AM, Tan KW, Fraternali F, Politis A. Surface Accessibility and Dynamics of Macromolecular Assemblies Probed by Covalent Labeling Mass Spectrometry and Integrative Modeling. Anal Chem 2017; 89:1459-1468. [PMID: 28208298 PMCID: PMC5299547 DOI: 10.1021/acs.analchem.6b02875] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 01/04/2017] [Indexed: 12/22/2022]
Abstract
Mass spectrometry (MS) has become an indispensable tool for investigating the architectures and dynamics of macromolecular assemblies. Here we show that covalent labeling of solvent accessible residues followed by their MS-based identification yields modeling restraints that allow mapping the location and orientation of subunits within protein assemblies. Together with complementary restraints derived from cross-linking and native MS, we built native-like models of four heterocomplexes with known subunit structures and compared them with available X-ray crystal structures. The results demonstrated that covalent labeling followed by MS markedly increased the predictive power of the integrative modeling strategy enabling more accurate protein assembly models. We applied this strategy to the F-type ATP synthase from spinach chloroplasts (cATPase) providing a structural basis for its function as a nanomotor. By subjecting the models generated by our restraint-based strategy to molecular dynamics (MD) simulations, we revealed the conformational states of the peripheral stalk and assigned flexible regions in the enzyme. Our strategy can readily incorporate complementary chemical labeling strategies and we anticipate that it will be applicable to many other systems providing new insights into the structure and function of protein complexes.
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Affiliation(s)
- Carla Schmidt
- Interdisciplinary
Research Center HALOmem, Martin Luther University
Halle-Wittenberg, Kurt-Mothes-Strasse 3, 06120 Halle/Saale, Germany
| | - Jamie A. Macpherson
- Division
of Cell & Molecular Biophysics, King’s
College London, New Hunt’s
House, SE1 1UL, London, United Kingdom
| | - Andy M. Lau
- Department
of Chemistry, King’s College London, 7 Trinity Street, SE1 1DB, London, United Kingdom
| | - Ken Wei Tan
- Department
of Chemistry, King’s College London, 7 Trinity Street, SE1 1DB, London, United Kingdom
| | - Franca Fraternali
- Division
of Cell & Molecular Biophysics, King’s
College London, New Hunt’s
House, SE1 1UL, London, United Kingdom
| | - Argyris Politis
- Department
of Chemistry, King’s College London, 7 Trinity Street, SE1 1DB, London, United Kingdom
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82
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Roman GT, Murphy JP. Improving sensitivity and linear dynamic range of intact protein analysis using a robust and easy to use microfluidic device. Analyst 2017; 142:1073-1083. [DOI: 10.1039/c6an02518h] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We demonstrate an integrated microfluidic LC device coupled to a QTOF capable of improving sensitivity and linearity for intact protein analysis while also tuning the charge state distributions (CSD) of whole antibodies.
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83
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Zhang H, Harrington LB, Lu Y, Prado M, Saer R, Rempel D, Blankenship RE, Gross ML. Native Mass Spectrometry Characterizes the Photosynthetic Reaction Center Complex from the Purple Bacterium Rhodobacter sphaeroides. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:87-95. [PMID: 27506206 PMCID: PMC5613939 DOI: 10.1007/s13361-016-1451-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 07/07/2016] [Accepted: 07/10/2016] [Indexed: 06/06/2023]
Abstract
Native mass spectrometry (MS) is an emerging approach to study protein complexes in their near-native states and to elucidate their stoichiometry and topology. Here, we report a native MS study of the membrane-embedded reaction center (RC) protein complex from the purple photosynthetic bacterium Rhodobacter sphaeroides. The membrane-embedded RC protein complex is stabilized by detergent micelles in aqueous solution, directly introduced into a mass spectrometer by nano-electrospray (nESI), and freed of detergents and dissociated in the gas phase by collisional activation. As the collision energy is increased, the chlorophyll pigments are gradually released from the RC complex, suggesting that native MS introduces a near-native structure that continues to bind pigments. Two bacteriochlorophyll a pigments remain tightly bound to the RC protein at the highest collision energy. The order of pigment release and their resistance to release by gas-phase activation indicates the strength of pigment interaction in the RC complex. This investigation sets the stage for future native MS studies of membrane-embedded photosynthetic pigment-protein and related complexes.Graphical Abstract.
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Affiliation(s)
- Hao Zhang
- Department of Chemistry, Washington University in St. Louis, One Brookings Dr., St. Louis, MO, 63130, USA
- Photosynthetic Antenna Research Center, Washington University in St. Louis, One Brookings Dr., St. Louis, MO, 63130, USA
| | - Lucas B Harrington
- Department of Chemistry, Washington University in St. Louis, One Brookings Dr., St. Louis, MO, 63130, USA
| | - Yue Lu
- Department of Chemistry, Washington University in St. Louis, One Brookings Dr., St. Louis, MO, 63130, USA
- Photosynthetic Antenna Research Center, Washington University in St. Louis, One Brookings Dr., St. Louis, MO, 63130, USA
| | - Mindy Prado
- Department of Biology, Washington University in St. Louis, One Brookings Dr., St. Louis, MO, 63130, USA
- Photosynthetic Antenna Research Center, Washington University in St. Louis, One Brookings Dr., St. Louis, MO, 63130, USA
| | - Rafael Saer
- Department of Biology, Washington University in St. Louis, One Brookings Dr., St. Louis, MO, 63130, USA
- Photosynthetic Antenna Research Center, Washington University in St. Louis, One Brookings Dr., St. Louis, MO, 63130, USA
| | - Don Rempel
- Department of Chemistry, Washington University in St. Louis, One Brookings Dr., St. Louis, MO, 63130, USA
| | - Robert E Blankenship
- Department of Chemistry, Washington University in St. Louis, One Brookings Dr., St. Louis, MO, 63130, USA.
- Department of Biology, Washington University in St. Louis, One Brookings Dr., St. Louis, MO, 63130, USA.
- Photosynthetic Antenna Research Center, Washington University in St. Louis, One Brookings Dr., St. Louis, MO, 63130, USA.
| | - Michael L Gross
- Department of Chemistry, Washington University in St. Louis, One Brookings Dr., St. Louis, MO, 63130, USA.
- Photosynthetic Antenna Research Center, Washington University in St. Louis, One Brookings Dr., St. Louis, MO, 63130, USA.
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84
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Leney AC, Heck AJR. Native Mass Spectrometry: What is in the Name? JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:5-13. [PMID: 27909974 PMCID: PMC5174146 DOI: 10.1007/s13361-016-1545-3] [Citation(s) in RCA: 404] [Impact Index Per Article: 57.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 10/25/2016] [Accepted: 10/28/2016] [Indexed: 05/11/2023]
Abstract
Electrospray ionization mass spectrometry (ESI-MS) is nowadays one of the cornerstones of biomolecular mass spectrometry and proteomics. Advances in sample preparation and mass analyzers have enabled researchers to extract much more information from biological samples than just the molecular weight. In particular, relevant for structural biology, noncovalent protein-protein and protein-ligand complexes can now also be analyzed by MS. For these types of analyses, assemblies need to be retained in their native quaternary state in the gas phase. This initial small niche of biomolecular mass spectrometry, nowadays often referred to as "native MS," has come to maturation over the last two decades, with dozens of laboratories using it to study mostly protein assemblies, but also DNA and RNA-protein assemblies, with the goal to define structure-function relationships. In this perspective, we describe the origins of and (re)define the term native MS, portraying in detail what we meant by "native MS," when the term was coined and also describing what it does (according to us) not entail. Additionally, we describe a few examples highlighting what native MS is, showing its successes to date while illustrating the wide scope this technology has in solving complex biological questions. Graphical Abstract ᅟ.
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Affiliation(s)
- Aneika C Leney
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584CH, Utrecht, The Netherlands
- Netherlands Proteomics Center, Padualaan 8, 3584CH, Utrecht, The Netherlands
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584CH, Utrecht, The Netherlands.
- Netherlands Proteomics Center, Padualaan 8, 3584CH, Utrecht, The Netherlands.
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85
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Native Mass Spectrometry for the Characterization of Structure and Interactions of Membrane Proteins. Methods Mol Biol 2017; 1635:205-232. [PMID: 28755371 DOI: 10.1007/978-1-4939-7151-0_11] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Over the past years, native mass spectrometry and ion mobility have grown into techniques that are widely applicable to the study of aspects of protein structure. More recently, it has become apparent that this approach provides a very promising avenue for the investigation of integral membrane proteins in lipid or detergent environments.In this chapter, we discuss applications of native mass spectrometry and ion mobility in membrane protein research-what is important to take into consideration when working with membrane proteins, and what the requirements are for sample preparation for native mass spectrometry. Furthermore, we will discuss the types of information provided by the measurements, including the oligomeric state, subunit composition and stoichiometry, interactions with detergents or lipids, conformational transitions, and the binding and structural effect of ligands and drugs.
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86
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Campuzano IDG, Li H, Bagal D, Lippens JL, Svitel J, Kurzeja RJM, Xu H, Schnier PD, Loo JA. Native MS Analysis of Bacteriorhodopsin and an Empty Nanodisc by Orthogonal Acceleration Time-of-Flight, Orbitrap and Ion Cyclotron Resonance. Anal Chem 2016; 88:12427-12436. [PMID: 28193065 PMCID: PMC5505737 DOI: 10.1021/acs.analchem.6b03762] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Over the past two decades, orthogonal acceleration time-of-flight has been the de facto analyzer for solution and membrane-soluble protein native mass spectrometry (MS) studies; this however is gradually changing. Three MS instruments are compared, the Q-ToF, Orbitrap, and the FT-ICR, to analyze, under native instrument and buffer conditions, the seven-transmembrane helical protein bacteriorhodopsin-octylglucoside micelle and the empty nanodisc (MSP1D1-Nd) using both MS and tandem-MS modes of operation. Bacteriorhodopsin can be released from the octylglucoside-micelle efficiently on all three instruments (MS-mode), producing a narrow charge state distribution (z = 8+ to 10+) by either increasing the source lens or collision cell (or HCD) voltages. A lower center-of-mass collision energy (0.20-0.41 eV) is required for optimal bacteriorhodopsin liberation on the FT-ICR, in comparison to the Q-ToF and Orbitrap instruments (0.29-2.47 eV). The empty MSP1D1-Nd can be measured with relative ease on all three instruments, resulting in a highly complex spectrum of overlapping, polydisperse charge states. There is a measurable difference in MSP1D1-Nd charge state distribution (z = 15+ to 26+), average molecular weight (141.7 to 169.6 kDa), and phospholipid incorporation number (143 to 184) under low activation conditions. Utilizing tandem-MS, bacteriorhodopsin can be effectively liberated from the octylglucoside-micelle by collisional (Q-ToF and FT-ICR) or continuous IRMPD activation (FT-ICR). MSP1D1-Nd spectral complexity can also be significantly reduced by tandem-MS (Q-ToF and FT-ICR) followed by mild collisional or continuous IRMPD activation, resulting in a spectrum in which the charge state and phospholipid incorporation levels can easily be determined.
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Affiliation(s)
| | - Huilin Li
- UCLA Department of Chemistry and Biochemistry, Los Angeles, CA, 90095
| | - Dhanashri Bagal
- Discovery Analytical Sciences, Amgen, South San Francisco, CA, 94080, USA
| | | | - Juraj Svitel
- Department of Process Development, Amgen, Thousand Oaks, CA, 91320, USA
| | | | - Han Xu
- Department of Discovery Technologies, Amgen, Thousand Oaks, CA, 91320, USA
| | - Paul D. Schnier
- Discovery Analytical Sciences, Amgen, South San Francisco, CA, 94080, USA
| | - Joseph A. Loo
- UCLA Department of Chemistry and Biochemistry, Los Angeles, CA, 90095
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87
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Abstract
Protein complexes form the critical foundation for a wide range of biological process, however understanding the intricate details of their activities is often challenging. In this review we describe how mass spectrometry plays a key role in the analysis of protein assemblies and the cellular pathways which they are involved in. Specifically, we discuss how the versatility of mass spectrometric approaches provides unprecedented information on multiple levels. We demonstrate this on the ubiquitin-proteasome proteolytic pathway, a process that is responsible for protein turnover. We follow the various steps of this degradation route and illustrate the different mass spectrometry workflows that were applied for elucidating molecular information. Overall, this review aims to stimulate the integrated use of multiple mass spectrometry approaches for analyzing complex biological systems.
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88
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Sinz A. Divide and conquer: cleavable cross-linkers to study protein conformation and protein–protein interactions. Anal Bioanal Chem 2016; 409:33-44. [DOI: 10.1007/s00216-016-9941-x] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 08/25/2016] [Accepted: 09/09/2016] [Indexed: 01/28/2023]
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89
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Cammarata MB, Schardon CL, Mehaffey MR, Rosenberg J, Singleton J, Fast W, Brodbelt JS. Impact of G12 Mutations on the Structure of K-Ras Probed by Ultraviolet Photodissociation Mass Spectrometry. J Am Chem Soc 2016; 138:13187-13196. [DOI: 10.1021/jacs.6b04474] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Michael B. Cammarata
- Department of Chemistry, ‡Graduate Program in Biochemistry, and §Division of Chemical Biology and
Medicinal Chemistry, College of Pharmacy, University of Texas, Austin, Texas 78712, United States
| | - Christopher L. Schardon
- Department of Chemistry, ‡Graduate Program in Biochemistry, and §Division of Chemical Biology and
Medicinal Chemistry, College of Pharmacy, University of Texas, Austin, Texas 78712, United States
| | - M. Rachel Mehaffey
- Department of Chemistry, ‡Graduate Program in Biochemistry, and §Division of Chemical Biology and
Medicinal Chemistry, College of Pharmacy, University of Texas, Austin, Texas 78712, United States
| | - Jake Rosenberg
- Department of Chemistry, ‡Graduate Program in Biochemistry, and §Division of Chemical Biology and
Medicinal Chemistry, College of Pharmacy, University of Texas, Austin, Texas 78712, United States
| | - Jonathan Singleton
- Department of Chemistry, ‡Graduate Program in Biochemistry, and §Division of Chemical Biology and
Medicinal Chemistry, College of Pharmacy, University of Texas, Austin, Texas 78712, United States
| | - Walter Fast
- Department of Chemistry, ‡Graduate Program in Biochemistry, and §Division of Chemical Biology and
Medicinal Chemistry, College of Pharmacy, University of Texas, Austin, Texas 78712, United States
| | - Jennifer S. Brodbelt
- Department of Chemistry, ‡Graduate Program in Biochemistry, and §Division of Chemical Biology and
Medicinal Chemistry, College of Pharmacy, University of Texas, Austin, Texas 78712, United States
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90
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Palamini M, Canciani A, Forneris F. Identifying and Visualizing Macromolecular Flexibility in Structural Biology. Front Mol Biosci 2016; 3:47. [PMID: 27668215 PMCID: PMC5016524 DOI: 10.3389/fmolb.2016.00047] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 08/22/2016] [Indexed: 12/29/2022] Open
Abstract
Structural biology comprises a variety of tools to obtain atomic resolution data for the investigation of macromolecules. Conventional structural methodologies including crystallography, NMR and electron microscopy often do not provide sufficient details concerning flexibility and dynamics, even though these aspects are critical for the physiological functions of the systems under investigation. However, the increasing complexity of the molecules studied by structural biology (including large macromolecular assemblies, integral membrane proteins, intrinsically disordered systems, and folding intermediates) continuously demands in-depth analyses of the roles of flexibility and conformational specificity involved in interactions with ligands and inhibitors. The intrinsic difficulties in capturing often subtle but critical molecular motions in biological systems have restrained the investigation of flexible molecules into a small niche of structural biology. Introduction of massive technological developments over the recent years, which include time-resolved studies, solution X-ray scattering, and new detectors for cryo-electron microscopy, have pushed the limits of structural investigation of flexible systems far beyond traditional approaches of NMR analysis. By integrating these modern methods with powerful biophysical and computational approaches such as generation of ensembles of molecular models and selective particle picking in electron microscopy, more feasible investigations of dynamic systems are now possible. Using some prominent examples from recent literature, we review how current structural biology methods can contribute useful data to accurately visualize flexibility in macromolecular structures and understand its important roles in regulation of biological processes.
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Affiliation(s)
| | | | - Federico Forneris
- The Armenise-Harvard Laboratory of Structural Biology, Department of Biology and Biotechnology, University of PaviaPavia, Italy
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91
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Beveridge R, Migas LG, Payne KAP, Scrutton NS, Leys D, Barran PE. Mass spectrometry locates local and allosteric conformational changes that occur on cofactor binding. Nat Commun 2016; 7:12163. [PMID: 27418477 PMCID: PMC4947166 DOI: 10.1038/ncomms12163] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 06/08/2016] [Indexed: 11/09/2022] Open
Abstract
Fdc1 is a decarboxylase enzyme that requires the novel prenylated FMN cofactor for activity. Here, we use it as an exemplar system to show how native top-down and bottom-up mass spectrometry can measure the structural effect of cofactor binding by a protein. For Fdc1(Ubix), the cofactor confers structural stability to the enzyme. IM-MS shows the holo protein to exist in four closely related conformational families, the populations of which differ in the apo form; the two smaller families are more populated in the presence of the cofactor and depopulated in its absence. These findings, supported by MD simulations, indicate a more open structure for the apo form. HDX-MS reveals that while the dominant structural changes occur proximal to the cofactor-binding site, rearrangements on cofactor binding are evident throughout the protein, predominantly attributable to allosteric conformational tightening, consistent with IM-MS data.
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Affiliation(s)
- Rebecca Beveridge
- Michael Barber Centre for Collaborative Mass Spectrometry, School of Chemistry, Centre for Synthetic Biology of Fine and Speciality Chemicals, Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Lukasz G Migas
- Michael Barber Centre for Collaborative Mass Spectrometry, School of Chemistry, Centre for Synthetic Biology of Fine and Speciality Chemicals, Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Karl A P Payne
- Michael Barber Centre for Collaborative Mass Spectrometry, School of Chemistry, Centre for Synthetic Biology of Fine and Speciality Chemicals, Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Nigel S Scrutton
- Michael Barber Centre for Collaborative Mass Spectrometry, School of Chemistry, Centre for Synthetic Biology of Fine and Speciality Chemicals, Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - David Leys
- Michael Barber Centre for Collaborative Mass Spectrometry, School of Chemistry, Centre for Synthetic Biology of Fine and Speciality Chemicals, Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Perdita E Barran
- Michael Barber Centre for Collaborative Mass Spectrometry, School of Chemistry, Centre for Synthetic Biology of Fine and Speciality Chemicals, Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
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92
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The lipidome associated with the γ-secretase complex is required for its integrity and activity. Biochem J 2016; 473:321-34. [PMID: 26811537 DOI: 10.1042/bj20150448] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
γ-Secretase is a multi-subunit membrane protease complex that catalyses the final intramembrane cleavage of the β-amyloid precursor protein (APP) during the neuronal production of amyloid-β peptides (Aβ), which are implicated as the causative agents of Alzheimer's disease (AD). In the present study, we report the reconstitution of a highly purified, active γ-secretase complex into proteoliposomes without exogenous lipids and provide the first direct evidence for the existence of a microenvironment of 53 molecular species from 11 major lipid classes specifically associated with the γ-secretase complex, including phosphatidylcholine and cholesterol. Importantly, we demonstrate that the pharmacological modulation of certain phospholipids abolishes both the integrity and the enzymatic activity of the intramembrane protease. Together, our findings highlight the importance of a specific lipid microenvironment for the structure and function of γ-secretase.
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93
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Cleary SP, Thompson AM, Prell JS. Fourier Analysis Method for Analyzing Highly Congested Mass Spectra of Ion Populations with Repeated Subunits. Anal Chem 2016; 88:6205-13. [DOI: 10.1021/acs.analchem.6b01088] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Sean P. Cleary
- Department
of Chemistry and
Biochemistry, University of Oregon, Eugene, Oregon 97403-1253, United States
| | - Avery M. Thompson
- Department
of Chemistry and
Biochemistry, University of Oregon, Eugene, Oregon 97403-1253, United States
| | - James S. Prell
- Department
of Chemistry and
Biochemistry, University of Oregon, Eugene, Oregon 97403-1253, United States
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94
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Berezovskaya Y, Porrini M, Nortcliffe C, Barran PE. The use of ion mobility mass spectrometry to assist protein design: a case study on zinc finger fold versus coiled coil interactions. Analyst 2016; 140:2847-56. [PMID: 25734188 DOI: 10.1039/c4an00427b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The dramatic conformational change in zinc fingers on binding metal ions for DNA recognition makes their structure-function behaviour an attractive target to mimic in de novo designed peptides. Mass spectrometry, with its high throughput and low sample consumption provides insight into how primary amino acid sequence can encode stable tertiary fold. We present here the use of ion mobility mass spectrometry (IM-MS) coupled with molecular dynamics (MD) simulations as a rapid analytical platform to inform de novo design efforts for peptide-metal and peptide-peptide interactions. A dual peptide-based synthetic system, ZiCop based on a zinc finger peptide motif, and a coiled coil partner peptide Pp, have been investigated. Titration mass spectrometry determines the relative binding affinities of different divalent metal ions as Zn(2+) > Co(2+) ≫ Ca(2+). With collision induced dissociation (CID), we probe complex stability, and establish that peptide-metal interactions are stronger and more 'specific' than those of peptide-peptide complexes, and the anticipated hetero-dimeric complex is more stable than the two homo-dimers. Collision cross-sections (CCS) measurements by IM-MS reveal increased stability with respect to unfolding of the metal-bound peptide over its apo-form, and further, larger collision cross sections for the hetero-dimeric forms suggest that dimeric species formed in the absence of metal are coiled coil like. MD supports these structural assignments, backed up by data from visible light absorbance measurements.
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95
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Loo RRO, Loo JA. Salt Bridge Rearrangement (SaBRe) Explains the Dissociation Behavior of Noncovalent Complexes. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:975-90. [PMID: 27052739 PMCID: PMC4865452 DOI: 10.1007/s13361-016-1375-3] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Revised: 02/28/2016] [Accepted: 03/01/2016] [Indexed: 05/11/2023]
Abstract
Native electrospray ionization-mass spectrometry, with gas-phase activation and solution compositions that partially release subcomplexes, can elucidate topologies of macromolecular assemblies. That so much complexity can be preserved in gas-phase assemblies is remarkable, although a long-standing conundrum has been the differences between their gas- and solution-phase decompositions. Collision-induced dissociation of multimeric noncovalent complexes typically distributes products asymmetrically (i.e., by ejecting a single subunit bearing a large percentage of the excess charge). That unexpected behavior has been rationalized as one subunit "unfolding" to depart with more charge. We present an alternative explanation based on heterolytic ion-pair scission and rearrangement, a mechanism that inherently partitions charge asymmetrically. Excessive barriers to dissociation are circumvented in this manner, when local charge rearrangements access a lower-barrier surface. An implication of this ion pair consideration is that stability differences between high- and low-charge state ions usually attributed to Coulomb repulsion may, alternatively, be conveyed by attractive forces from ion pairs (salt bridges) stabilizing low-charge state ions. Should the number of ion pairs be roughly inversely related to charge, symmetric dissociations would be favored from highly charged complexes, as observed. Correlations between a gas-phase protein's size and charge reflect the quantity of restraining ion pairs. Collisionally-facilitated salt bridge rearrangement (SaBRe) may explain unusual size "contractions" seen for some activated, low charge state complexes. That some low-charged multimers preferentially cleave covalent bonds or shed small ions to disrupting noncovalent associations is also explained by greater ion pairing in low charge state complexes. Graphical Abstract ᅟ.
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Affiliation(s)
- Rachel R Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, 90095, USA.
| | - Joseph A Loo
- Department of Biological Chemistry, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, 90095, USA.
- UCLA/DOE Institute for Genomics and Proteomics, University of California-Los Angeles, Los Angeles, CA, 90095, USA.
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA, 90095, USA.
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96
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The joining of the Hsp90 and Hsp70 chaperone cycles yields transient interactions and stable intermediates: insights from mass spectrometry. Oncotarget 2016; 6:18276-81. [PMID: 26286954 PMCID: PMC4621890 DOI: 10.18632/oncotarget.4954] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 06/30/2015] [Indexed: 11/25/2022] Open
Abstract
The Hsp70/Hsp90 chaperone cycles depend on the coordinated interplay of several co-chaperones including Hsp40, Hop and peptidyl-prolyl isomerases such as FKBP52. Because of the many proteins involved in these interactions it is often difficult to delineate all possible combinations of subunits in the complexes formed. We employed mass spectrometry to monitor the assembly and to determine the favoured pathways within these chaperone cycles. Combining the subunit composition with chemical cross-linking and proteomics allowed us to define interaction interfaces, protein dynamics and new intermediates.
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97
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Guo R, Gaffney K, Yang Z, Kim M, Sungsuwan S, Huang X, Hubbell WL, Hong H. Steric trapping reveals a cooperativity network in the intramembrane protease GlpG. Nat Chem Biol 2016; 12:353-360. [PMID: 26999782 PMCID: PMC4837050 DOI: 10.1038/nchembio.2048] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Accepted: 01/22/2016] [Indexed: 12/21/2022]
Abstract
Membrane proteins are assembled through balanced interactions among protein, lipids and water. Studying their folding while maintaining the native lipid environment is necessary but challenging. Here we present methods for analyzing key elements in membrane protein folding including thermodynamic stability, compactness of the unfolded state and folding cooperativity under native conditions. The methods are based on steric trapping which couples unfolding of a doubly-biotinylated protein to binding of monovalent streptavidin (mSA). We further advanced this technology for general application by developing versatile biotin probes possessing spectroscopic reporters that are sensitized by mSA binding or protein unfolding. By applying these methods to an intramembrane protease GlpG of Escherichia coli, we elucidated a widely unraveled unfolded state, subglobal unfolding of the region encompassing the active site, and a network of cooperative and localized interactions to maintain the stability. These findings provide crucial insights into the folding energy landscape of membrane proteins.
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Affiliation(s)
- Ruiqiong Guo
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Kristen Gaffney
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Zhongyu Yang
- Jules Stein Eye Institute and Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Miyeon Kim
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Suttipun Sungsuwan
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Xuefei Huang
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Wayne L Hubbell
- Jules Stein Eye Institute and Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Heedeok Hong
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA.,Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
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98
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Fatunmbi O, Abzalimov RR, Savinov SN, Gershenson A, Kaltashov IA. Interactions of Haptoglobin with Monomeric Globin Species: Insights from Molecular Modeling and Native Electrospray Ionization Mass Spectrometry. Biochemistry 2016; 55:1918-28. [DOI: 10.1021/acs.biochem.5b00807] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ololade Fatunmbi
- Department of Chemistry and ‡Department of
Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Rinat R. Abzalimov
- Department of Chemistry and ‡Department of
Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Sergey N. Savinov
- Department of Chemistry and ‡Department of
Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Anne Gershenson
- Department of Chemistry and ‡Department of
Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Igor A. Kaltashov
- Department of Chemistry and ‡Department of
Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
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99
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Bhattacharyya M, Stratton MM, Going CC, McSpadden ED, Huang Y, Susa AC, Elleman A, Cao YM, Pappireddi N, Burkhardt P, Gee CL, Barros T, Schulman H, Williams ER, Kuriyan J. Molecular mechanism of activation-triggered subunit exchange in Ca(2+)/calmodulin-dependent protein kinase II. eLife 2016; 5. [PMID: 26949248 PMCID: PMC4859805 DOI: 10.7554/elife.13405] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/03/2016] [Indexed: 12/04/2022] Open
Abstract
Activation triggers the exchange of subunits in Ca2+/calmodulin-dependent protein kinase II (CaMKII), an oligomeric enzyme that is critical for learning, memory, and cardiac function. The mechanism by which subunit exchange occurs remains elusive. We show that the human CaMKII holoenzyme exists in dodecameric and tetradecameric forms, and that the calmodulin (CaM)-binding element of CaMKII can bind to the hub of the holoenzyme and destabilize it to release dimers. The structures of CaMKII from two distantly diverged organisms suggest that the CaM-binding element of activated CaMKII acts as a wedge by docking at intersubunit interfaces in the hub. This converts the hub into a spiral form that can release or gain CaMKII dimers. Our data reveal a three-way competition for the CaM-binding element, whereby phosphorylation biases it towards the hub interface, away from the kinase domain and calmodulin, thus unlocking the ability of activated CaMKII holoenzymes to exchange dimers with unactivated ones. DOI:http://dx.doi.org/10.7554/eLife.13405.001 How does memory outlast the lifetime of the molecules that encode it? One enzyme that is found in neurons and has been suggested to help long-term memories to form is called CaMKII. Each CaMKII assembly is typically composed of 12 to 14 protein subunits associated in a ring and can exist in either an “unactivated” or “activated” state. In 2014, researchers showed that CaMKII assemblies can exchange subunits with each other. Importantly, an active CaMKII can mix with an unactivated CaMKII and share its activation state. CaMKII may use this mechanism to spread information to the next generation of proteins – thereby allowing activation to outlast the lifespan of the initially activated proteins. However the molecular mechanism that underlies this process was not clear. Now, Bhattacharyya et al. – including some of the researchers involved in the 2014 work – address two questions about this mechanism. How do subunits exchange between CaMKII assemblies? And how does the activation of CaMKII initiate subunit exchange? A closed-ring hub ties the subunits of CaMKII together, similar to the organization of the segments in an orange. To undergo subunit exchange, the hub must open up to release and accept subunits. Bhattacharyya et al. have now uncovered an intrinsic flexibility in the hub that is triggered by a short peptide segment in CaMKII. This segment, which is exposed in activated CaMKII but not in the unactivated form, can crack open the hub ring by binding between the hub subunits, like a finger separating the segments of an orange. This allows the hub to flex and expand, and once open, the hub’s flexibility allows room for subunits to be released or accepted. Although this subunit exchange mechanism could be a powerful means for spreading the activated state throughout signaling pathways, the biological relevance of this phenomenon has not been clarified. However, the mechanistic framework provided by Bhattacharyya et al. may allow new experiments to be performed that test the consequences of subunit exchange in live cells and organisms. It could also enable investigations into the importance of subunit exchange in long-term memory. DOI:http://dx.doi.org/10.7554/eLife.13405.002
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Affiliation(s)
- Moitrayee Bhattacharyya
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
| | - Margaret M Stratton
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
| | - Catherine C Going
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
| | - Ethan D McSpadden
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
| | - Yongjian Huang
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States.,Biophysics Graduate Group, University of California, Berkeley, Berkeley, United States
| | - Anna C Susa
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
| | - Anna Elleman
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
| | - Yumeng Melody Cao
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
| | - Nishant Pappireddi
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
| | - Pawel Burkhardt
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
| | - Christine L Gee
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
| | - Tiago Barros
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
| | | | - Evan R Williams
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
| | - John Kuriyan
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States.,Biophysics Graduate Group, University of California, Berkeley, Berkeley, United States.,Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, United States
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100
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Khakinejad M, Kondalaji SG, Donohoe GC, Valentine SJ. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 3. Estimating Surface Area Exposure by Deuterium Uptake. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:462-73. [PMID: 26620531 PMCID: PMC4872623 DOI: 10.1007/s13361-015-1305-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/28/2015] [Accepted: 11/02/2015] [Indexed: 05/17/2023]
Abstract
Gas-phase hydrogen deuterium exchange (HDX), collision cross section (CCS) measurement, and molecular dynamics simulation (MDS) techniques were utilized to develop and compare three methods for estimating the relative surface area exposure of separate peptide chains within bovine insulin ions. Electrosprayed [M - 3H](3-) and [M - 5H](5-) insulin ions produced a single conformer type with respective collision cross sections of 528 ± 5 Å(2) and 808 ± 2 Å(2). [M - 4H](4-) ions were comprised of more compact (Ω = 676 ± 3 Å(2)) and diffuse (i.e., more elongated, Ω = 779 ± 3 Å(2)) ion conformer types. Ions were subjected to HDX in the drift tube using D2O as the reagent gas. Collision-induced dissociation was used to fragment mobility-selected, isotopically labeled [M - 4H](4-) and [M - 5H](5-) ions into the protein subchains. Deuterium uptake levels of each chain can be explained by limited inter-chain isotopic scrambling upon collisional activation. Using nominal ion structures from MDS and a hydrogen accessibility model, the deuterium uptake for each chain was correlated to its exposed surface area. In separate experiments, the per-residue deuterium content for the protonated and deprotonated ions of the synthetic peptide KKDDDDDIIKIIK were compared. The differences in deuterium content indicated the regional HDX accessibility for cations versus anions. Using ions of similar conformational type, this comparison highlights the complementary nature of HDX data obtained from positive- and negative-ion analysis.
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Affiliation(s)
- Mahdiar Khakinejad
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | | | - Gregory C Donohoe
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Stephen J Valentine
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA.
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