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Schwenzer AK, Kruse L, Jooß K, Neusüß C. Capillary electrophoresis-mass spectrometry for protein analyses under native conditions: Current progress and perspectives. Proteomics 2024; 24:e2300135. [PMID: 37312401 DOI: 10.1002/pmic.202300135] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/16/2023] [Accepted: 05/23/2023] [Indexed: 06/15/2023]
Abstract
Native mass spectrometry is a rapidly emerging technique for fast and sensitive structural analysis of protein constructs, maintaining the protein higher order structure. The coupling with electromigration separation techniques under native conditions enables the characterization of proteoforms and highly complex protein mixtures. In this review, we present an overview of current native CE-MS technology. First, the status of native separation conditions is described for capillary zone electrophoresis (CZE), affinity capillary electrophoresis (ACE), and capillary isoelectric focusing (CIEF), as well as their chip-based formats, including essential parameters such as electrolyte composition and capillary coatings. Further, conditions required for native ESI-MS of (large) protein constructs, including instrumental parameters of QTOF and Orbitrap systems, as well as requirements for native CE-MS interfacing are presented. On this basis, methods and applications of the different modes of native CE-MS are summarized and discussed in the context of biological, medical, and biopharmaceutical questions. Finally, key achievements are highlighted and concluded, while remaining challenges are pointed out.
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Affiliation(s)
| | - Lena Kruse
- Department of Chemistry, Aalen University, Aalen, Germany
| | - Kevin Jooß
- Department of Chemistry and Molecular Biosciences, the Chemistry of Life Processes Institute, and the Proteomics Center of Excellence, Northwestern University, Evanston, Illinois, USA
- Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Centre for Analytical Sciences Amsterdam (CASA), Amsterdam, The Netherlands
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2
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Javanshad R, Panth R, Venter AR. Effects of Amino Acid Additives on Protein Stability during Electrothermal Supercharging in ESI-MS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:151-157. [PMID: 38078777 DOI: 10.1021/jasms.3c00377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
The surprising formation of highly charged protein ions from aqueous ammonium bicarbonate solution is a fascinating phenomenon referred to as electrothermal supercharging (ETS). Although the precise mechanism involved is not clearly understood, previous studies predominantly suggest that ETS is due to native protein destabilization in the presence of bicarbonate anion inside the electrospray ionization droplets under high temperatures and spray voltages. To evaluate existing hypotheses surrounding the underlying mechanism of ETS, the effects of several additives on protein charging under ETS conditions were investigated. The changes in the protein charge state distributions were compared by measuring the ratios between the intensities of highest intensity charge states of native and unfolded protein envelopes and shifts in the lowest and highest observed charge states. This study demonstrated that source temperature plays a more important role in ETS compared to spray voltage, especially when using a nebulized microelectrospray ionization source. Moreover, the effect of amino acids on ETS were generally in good agreement with the extensive literature available on the stabilization or destabilization of proteins by these additives in bulk solution. Among the natural amino acids, protein supercharging was significantly reduced by proline and glycine; however, imidazole provided the highest degree of noncovalent complex stabilization against ETS, outperforming the amino acids. Overall, our study shows that the simple addition of stabilizing reagents such as proline and imidazole can reduce the extent of apparent protein unfolding and supercharging in ammonium bicarbonate solution and provide evidence against the roles of charge depletion and thermal unfolding during ETS.
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Affiliation(s)
- Roshan Javanshad
- Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008-5413, United States
| | - Rajendra Panth
- Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008-5413, United States
| | - Andre R Venter
- Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008-5413, United States
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3
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Chen CJ, Williams ER. Variable Mixing with Theta Emitter Mass Spectrometry: Changing Solution Flow Rates with Emitter Position. Anal Chem 2023; 95:14777-14786. [PMID: 37729435 DOI: 10.1021/acs.analchem.3c02980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Two solutions can be rapidly mixed using theta glass emitters, with products measured using electrospray ionization mass spectrometry. The relative flow rates of the two emitter channels can be measured using different calibration compounds in each channel, or the flow rates are often assumed to be the same. The relative flow rates of each channel can be essentially the same when the emitters are positioned directly in front of the capillary entrance of a mass spectrometer, but the relative flow rates can be varied by up to 3 orders of magnitude by moving the position of the emitter tip ±1 cm in a direction that is perpendicular to the inner divider. Results of the emitter position on the different concentrations of reagents in the initially formed electrospray droplets are demonstrated through protein denaturation using a supercharging reagent as well as two different bimolecular reactions. The average charge state of myoglobin changed from +7.8 to +13.8 when 2.5% sulfolane was mixed with a 200 mM ammonium acetate solution containing the protein when the position of the emitter was scanned in front of the mass spectrometer inlet. The conversion ratio of a bimolecular reaction was changed from 0.98 to 0.04 with varying emitter positions. These results show that the relative flow rates must be carefully monitored because the droplet composition depends strongly on the position of the theta glass emitters. This method can be used to measure the dependence of reaction kinetics on different solution concentrations by using a single emitter and only two solutions.
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Affiliation(s)
- Casey J Chen
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Evan R Williams
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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4
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Javanshad R, Taylor CJ, Delavari N, Barkman TJ, Stull F, Venter AR. Analysis of histidine-tagged recombinant proteins from nickel and copper coated surfaces by direct electrospray ionization and desorption electrospray ionization mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2023; 37 Suppl 1:e9516. [PMID: 37013403 DOI: 10.1002/rcm.9516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 02/28/2023] [Accepted: 03/31/2023] [Indexed: 06/19/2023]
Abstract
RATIONALE Purification of recombinant proteins is a necessary step for functional or structural studies and other applications. Immobilized metal affinity chromatography is a common recombinant protein purification method. Mass spectrometry (MS) allows for confirmation of identity of expressed proteins and unambiguous detection of enzymatic substrates and reaction products. We demonstrate the detection of enzymes purified on immobilized metal affinity surfaces by direct or ambient ionization MS, and follow their enzymatic reactions by direct electrospray ionization (ESI) or desorption electrospray ionization (DESI). METHODS A protein standard, His-Ubq, and two recombinant proteins, His-SHAN and His-CS, expressed in Escherichia coli were immobilized on two immobilized metal affinity systems, Cu-nitriloacetic acid (Cu-NTA) and Ni-NTA. The proteins were purified on surface, and released in the ESI spray solvent for direct infusion, when using the 96-well plate form factor, or analyzed directly from immobilized metal affinity-coated microscope slides by DESI-MS. Enzyme activity was followed by incubating the substrates in wells or by depositing substrate on immobilized protein on coated slides for analysis. RESULTS Small proteins (His-Ubq) and medium proteins (His-SAHN) could readily be detected from 96-well plates by direct infusion ESI, or from microscope slides by DESI-MS after purification on surface from clarified E. coli cell lysate. Protein oxidation was observed for immobilized proteins on both Cu-NTA and Ni-NTA; however, this did not hamper the enzymatic reactions of these proteins. Both the nucleosidase reaction products for His-SAHN and the methylation product of His-CS (theobromine to caffeine) were detected. CONCLUSIONS The immobilization, purification, release and detection of His-tagged recombinant proteins using immobilized metal affinity surfaces for direct infusion ESI-MS or ambient DESI-MS analyses were successfully demonstrated. Recombinant proteins were purified to allow identification directly out of clarified cell lysate. Biological activities of the recombinant proteins were preserved allowing the investigation of enzymatic activity via MS.
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Affiliation(s)
- Roshan Javanshad
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
| | | | - Niusha Delavari
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
| | - Todd J Barkman
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, USA
| | - Frederick Stull
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
| | - Andre R Venter
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
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5
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Mass spectrometry in materials synthesis. Trends Analyt Chem 2023. [DOI: 10.1016/j.trac.2023.117010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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6
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Goranov AI, Tadini AM, Martin-Neto L, Bernardi ACC, Oliveira PPA, Pezzopane JRM, Milori DMBP, Mounier S, Hatcher PG. Comparison of Sample Preparation Techniques for the (-)ESI-FT-ICR-MS Analysis of Humic and Fulvic Acids. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:12688-12701. [PMID: 35969691 DOI: 10.1021/acs.est.2c01125] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Soil organic matter (SOM) plays a key role in the global carbon and nitrogen cycles. Soil biogeochemistry is regularly studied by extracting the base-soluble fractions of SOM: acid-insoluble humic acid (HA) and acid-soluble fulvic acid (FA). Electrospray ionization-Fourier transform-ion cyclotron resonance-mass spectrometry (ESI-FT-ICR-MS) is commonly utilized for molecularly characterizing these fractions. Different sample preparation techniques exist for the analysis of HA and FA though questions remain regarding data comparability following different preparations. Comparisons of different sample preparation techniques here revealed that the negative-mode ESI-FT-ICR-MS analytical window can be skewed to detect different groups of molecules, with primary differences in oxygenation, aromaticity, and molecular weight. It was also observed that HA and FA from soils versus an aquatic matrix behaved very differently. Thus, we conclude that sample preparation techniques determined to be "most optimal" in our study are in no way universal. We recommend that future studies of HA and FA involve similar comparative studies for determining the most suitable sample preparation technique for their particular type of HA or FA matrices. This will enhance data comparability among different studies and environmental systems and ultimately allow us to better understand the complex composition of environmental matrices.
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Affiliation(s)
- Aleksandar I Goranov
- Department of Chemistry and Biochemistry, Old Dominion University, 4501 Elkhorn Avenue, Norfolk, Virginia 23529, United States
| | - Amanda M Tadini
- Department of Chemistry and Biochemistry, Old Dominion University, 4501 Elkhorn Avenue, Norfolk, Virginia 23529, United States
- Embrapa Instrumentação, Brazilian Agricultural Research Corporation - Embrapa, Street XV de Novembro, 1452, São Carlos, São Paulo 13560-970, Brazil
| | - Ladislau Martin-Neto
- Embrapa Instrumentação, Brazilian Agricultural Research Corporation - Embrapa, Street XV de Novembro, 1452, São Carlos, São Paulo 13560-970, Brazil
| | - Alberto C C Bernardi
- Embrapa Pecuária Sudeste, Brazilian Agricultural Research Corporation - Embrapa, Rodovia Washington Luiz, Km 234 s/n°, Fazenda Canchim São Carlos, São Paulo 13560-970, Brazil
| | - Patricia P A Oliveira
- Embrapa Pecuária Sudeste, Brazilian Agricultural Research Corporation - Embrapa, Rodovia Washington Luiz, Km 234 s/n°, Fazenda Canchim São Carlos, São Paulo 13560-970, Brazil
| | - José R M Pezzopane
- Embrapa Pecuária Sudeste, Brazilian Agricultural Research Corporation - Embrapa, Rodovia Washington Luiz, Km 234 s/n°, Fazenda Canchim São Carlos, São Paulo 13560-970, Brazil
| | - Débora M B P Milori
- Embrapa Instrumentação, Brazilian Agricultural Research Corporation - Embrapa, Street XV de Novembro, 1452, São Carlos, São Paulo 13560-970, Brazil
| | - Stéphane Mounier
- Unité mixte 110, Mediterranean Institute of Oceanography (MIO), Université de Toulon, Avenue de l'Université - Bat. R, Toulon 83041, France
- Unité mixte 110, MIO, Aix Marseille Université, 163 Avenue de Luminy, Marseille 13288, France
- Unité mixte 110, MIO, Institut de la Recherche et du Développement, 163 Avenue de Luminy, Marseille 13288, France
- Unité mixte 110, MIO, Institut des Sciences de l'Univers, Centre National de la Recherche Scientifique, 163 Avenue de Luminy, Marseille 13288, France
| | - Patrick G Hatcher
- Department of Chemistry and Biochemistry, Old Dominion University, 4501 Elkhorn Avenue, Norfolk, Virginia 23529, United States
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7
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Bennett JL, Nguyen GTH, Donald WA. Protein-Small Molecule Interactions in Native Mass Spectrometry. Chem Rev 2021; 122:7327-7385. [PMID: 34449207 DOI: 10.1021/acs.chemrev.1c00293] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Small molecule drug discovery has been propelled by the continual development of novel scientific methodologies to occasion therapeutic advances. Although established biophysical methods can be used to obtain information regarding the molecular mechanisms underlying drug action, these approaches are often inefficient, low throughput, and ineffective in the analysis of heterogeneous systems including dynamic oligomeric assemblies and proteins that have undergone extensive post-translational modification. Native mass spectrometry can be used to probe protein-small molecule interactions with unprecedented speed and sensitivity, providing unique insights into polydisperse biomolecular systems that are commonly encountered during the drug discovery process. In this review, we describe potential and proven applications of native MS in the study of interactions between small, drug-like molecules and proteins, including large multiprotein complexes and membrane proteins. Approaches to quantify the thermodynamic and kinetic properties of ligand binding are discussed, alongside a summary of gas-phase ion activation techniques that have been used to interrogate the structure of protein-small molecule complexes. We additionally highlight some of the key areas in modern drug design for which native mass spectrometry has elicited significant advances. Future developments and applications of native mass spectrometry in drug discovery workflows are identified, including potential pathways toward studying protein-small molecule interactions on a whole-proteome scale.
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Affiliation(s)
- Jack L Bennett
- School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Giang T H Nguyen
- School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - William A Donald
- School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia
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8
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Raab SA, El-Baba TJ, Laganowsky A, Russell DH, Valentine SJ, Clemmer DE. Protons Are Fast and Smart; Proteins Are Slow and Dumb: On the Relationship of Electrospray Ionization Charge States and Conformations. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:1553-1561. [PMID: 34151568 PMCID: PMC9003666 DOI: 10.1021/jasms.1c00100] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present simple considerations of how differences in time scales of motions of protons, the lightest and fastest chemical moiety, and the much longer time scales associated with the dynamics of proteins, among the heaviest and slowest analytes, may allow many protein conformations from solution to be kinetically trapped during the process of electrospraying protein solutions into the gas phase. In solution, the quantum nature of protons leads them to change locations by tunneling, an instantaneous process; moreover, the Grotthuss mechanism suggests that these small particles can respond nearly instantaneously to the dynamic motions of proteins that occur on much longer time scales. A conformational change is accompanied by favorable or unfavorable variations in the free energy of the system, providing the impetus for solvent ↔ protein proton exchange. Thus, as thermal distributions of protein conformations interconvert, protonation states rapidly respond, as specific acidic and basic sites are exposed or protected. In the vacuum of the mass spectrometer, protons become immobilized in locations that are specific to the protein conformations from which they were incorporated. In this way, conformational states from solution are preserved upon electrospraying them into the gas phase. These ideas are consistent with the exquisite sensitivity of electrospray mass spectra to small changes of the local environment that alter protein structure in solution. We might remember this approximation for the protonation of proteins in solution with the colloquial expression-protons are fast and smart; proteins are slow and dumb.
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Affiliation(s)
- Shannon A Raab
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Tarick J El-Baba
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Arthur Laganowsky
- 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
| | - Stephen J Valentine
- Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - David E Clemmer
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
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9
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Becher S, Wang H, Leeming MG, Donald WA, Heiles S. Influence of protein ion charge state on 213 nm top-down UVPD. Analyst 2021; 146:3977-3987. [PMID: 34009215 DOI: 10.1039/d1an00571e] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ultraviolet photodissociation (UVPD) is a powerful and rapidly developing method in top-down proteomics. Sequence coverages can exceed those obtained with collision- and electron-induced fragmentation methods. Because of the recent interest in UVPD, factors that influence protein fragmentation and sequence coverage are actively debated in the literature. Here, we performed top-down 213 nm UVPD experiments on a 7 T Fourier-transform ion cyclotron resonance mass spectrometer (FT-ICR MS) for the model proteins ubiquitin, myoglobin and cytochrome c that were electrosprayed from native, denaturing and supercharging solutions in order to investigate the effect of protein charge states on UVPD fragments. By performing UVPD in ultrahigh vacuum, factors associated with collisional cooling and any ion activation during transfer between mass analyzers can be largely eliminated. Sequence coverage increased from <10% for low charge states to >60% for high charge states for all three proteins. This trend is influenced by the overall charge state, i.e., charges per number of amino acid residues, and to a lesser degree by associated structural changes of protein ions of different charge states based on comparisons to published collision-cross section measurements. To rationalize this finding, and correlate sequence ion formation and identity with the number and location of protons, UVPD results were compared to protonation sites predicted based on electrostatic modelling. Assuming confined protonation sites, these results indicate the presence of two general fragmentation types; i.e., charge remote and charge directed. For moderately high protein charge states, fragment ions mostly originate in regions between likely protonation sites (charge remote), whereas sequence ions of highly charge protein ions occur either near backbone amide protonation sites at low-basicity residues (charge directed) or at charge remote sites (i.e., high-basicity residues). Overall, our results suggest that top-down 213 UVPD performance in the zero-pressure limit depends strongly on protein charge states and protonation sites can influence the location of backbone cleavages.
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Affiliation(s)
- Simon Becher
- Institute of Inorganic and Analytical Chemistry, Justus Liebig University Giessen, 35392 Giessen, Germany.
| | - Huixin Wang
- Mark Wainwright Analytical Centre, University of New South Wales, New South Wales, Australia
| | - Michael G Leeming
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - William A Donald
- School of Chemistry, University of New South Wales, Sydney, New South Wales, Australia
| | - Sven Heiles
- Institute of Inorganic and Analytical Chemistry, Justus Liebig University Giessen, 35392 Giessen, Germany.
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10
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Brandis JEP, Zalesak SM, Kane MA, Michel SLJ. Cadmium Exchange with Zinc in the Non-Classical Zinc Finger Protein Tristetraprolin. Inorg Chem 2021; 60:7697-7707. [PMID: 33999622 PMCID: PMC8501473 DOI: 10.1021/acs.inorgchem.0c03808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Tristetraprolin (TTP) is a nonclassical CCCH zinc finger protein that regulates inflammation. TTP targets AU-rich RNA sequences of cytokine mRNAs forming a TTP/mRNA complex. This complex is then degraded, switching off the inflammatory response. Cadmium, a known carcinogen, triggers proinflammatory effects, and there is evidence that Cd increases TTP expression in cells, suggesting that Zn-TTP may be a target for cadmium toxicity. We sought to determine whether Cd exchanges with Zn in the TTP active site and measure the effect of RNA binding on this exchange. A construct of TTP that contains the two CCCH domains (TTP-2D) was employed to investigate these interactions. A spin-filter ICP-MS experiment to quantify the metal that is bound to the ZF after metal exchange was performed, and it was determined that Cd exchanges with Zn in Zn2-TTP-2D and that Zn exchanges with Cd in Cd2-TTP-2D. A native ESI-MS experiment to identify the metal-ZF complexes formed after metal exchange was performed, and M-TTP-2D complexes with singular and double metal exchange were observed. Metal exchange was measured in both the absence and presence of TTP's partner RNA, with retention of RNA binding. These data show that Cd can exchange with Zn in TTP without affecting function.
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Affiliation(s)
- Joel E P Brandis
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland 21201, United States
| | - Stephanie M Zalesak
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland 21201, United States
| | - Maureen A Kane
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland 21201, United States
| | - Sarah L J Michel
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland 21201, United States
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11
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Shelor CP, Yoshikawa K, Dasgupta PK. Automated Programmable Generation of Broad pH Range Volatile Ionic Eluents for Liquid Chromatography. Anal Chem 2021; 93:5442-5450. [PMID: 33759496 DOI: 10.1021/acs.analchem.0c05089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Many of the universal detectors in liquid chromatography, including mass spectrometry, must completely volatilize the chromatographic eluent first before further processing and detection of the analytes. A basic requirement is that the eluent does not contain a nonvolatile dissolved component. However, separation of biomolecules must be conducted in mostly aqueous media of compatible pH and ionic strength if their biological activity must survive the separation process. Combinations of ammonia with acetic and formic acids are commonly used as eluent for this purpose but generally maximum concentrations that can be tolerated are relatively low. Further, buffering is good only over a limited pH range. We describe a system where the eluent is generated in an automated pressure-programmed manner from high-purity gaseous NH3 and CO2 through gas-permeable membrane devices. This can be aided by the prior presence of formic/acetic acids in the mobile phase to extend the attainable low pH limit. We outline the fundamental pH, ionic strength, and buffer intensity considerations and demonstrate the application of such eluents in the separation of amino acids, proteins, and monoclonal antibodies. We also demonstrate the use of dissolved CO2 as an ion-pairing agent in the separation of chiral amines.
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Affiliation(s)
- Charles Phillip Shelor
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Kenji Yoshikawa
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Purnendu K Dasgupta
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019-0065, United States
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12
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Sarrigiannidis S, Moussa H, Dobre O, Dalby MJ, Tamimi F, Salmeron-Sanchez M. Chiral Tartaric Acid Improves Fracture Toughness of Bioactive Brushite-Collagen Bone Cements. ACS APPLIED BIO MATERIALS 2020; 3:5056-5066. [PMID: 32904797 PMCID: PMC7461128 DOI: 10.1021/acsabm.0c00555] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 07/06/2020] [Indexed: 01/08/2023]
Abstract
Brushite cements are promising bone regeneration materials with limited biological and mechanical properties. Here, we engineer a mechanically improved brushite-collagen type I cement with enhanced biological properties by use of chiral chemistry; d- and l-tartaric acid were used to limit crystal growth and increase the mechanical properties of brushite-collagen cements. The impact of the chiral molecules on the cements was examined with Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). A 3-point bend test was utilized to study the fracture toughness, and cell attachment and morphology studies were carried out to demonstrate biocompatibility. XRD and SEM analyses showed that l-, but not d-tartaric acid, significantly restrained brushite crystal growth by binding to the {010} plane of the mineral and increased brushite crystal packing and the collagen interaction area. l-Tartaric acid significantly improved fracture toughness compared to traditional brushite by 30%. Collagen significantly enhanced cell morphology and focal adhesion expression on l-tartaric acid-treated brushite cements.
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Affiliation(s)
- Stylianos
O. Sarrigiannidis
- Centre
for the Cellular Microenvironment, University
of Glasgow, Rankine Building, 79−85 Oakfield Ave, Glasgow G12 8LT, United
Kingdom
| | - Hanan Moussa
- Faculty
of Dentistry, McGill University, Strathcona Building, 3640 University
Street, Montreal, Quebec H3A 2B2, Canada
- Faculty
of Dentistry, Benghazi University, Benghazi 9504, Libya
| | - Oana Dobre
- Centre
for the Cellular Microenvironment, University
of Glasgow, Rankine Building, 79−85 Oakfield Ave, Glasgow G12 8LT, United
Kingdom
| | - Matthew J. Dalby
- Centre
for the Cellular Microenvironment, University
of Glasgow, Joseph Black Building, University Pl, Glasgow G12 8QQ, United Kingdom
| | - Faleh Tamimi
- Faculty
of Dentistry, McGill University, Strathcona Building, 3640 University
Street, Montreal, Quebec H3A 2B2, Canada
- College
of Dental Medicine, Qatar University, Doha, Qatar
| | - Manuel Salmeron-Sanchez
- Centre
for the Cellular Microenvironment, University
of Glasgow, Rankine Building, 79−85 Oakfield Ave, Glasgow G12 8LT, United
Kingdom
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13
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Farsang E, Guillarme D, Veuthey JL, Beck A, Lauber M, Schmudlach A, Fekete S. Coupling non-denaturing chromatography to mass spectrometry for the characterization of monoclonal antibodies and related products. J Pharm Biomed Anal 2020; 185:113207. [DOI: 10.1016/j.jpba.2020.113207] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/21/2020] [Accepted: 02/22/2020] [Indexed: 01/31/2023]
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14
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Feng L, Gong X, Song J, Zhai R, Huang Z, Jiang Y, Fang X, Dai X. Strong Acid Anions Significantly Increasing the Charge State of Proteins during Electrospray Ionization. Anal Chem 2020; 92:1770-1779. [PMID: 31769658 DOI: 10.1021/acs.analchem.9b03416] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Regulation of protein's charge state in electrospray is of great importance to the analysis of proteins. Different methods have been developed so far to increase the charge state of proteins. In this work, we investigated the influence of different anions on the charge state of proteins. Both strong acid anions and weak acid anions were taken into consideration. The results showed that the presence of 5 mM strong acid anions in acidic solutions could significantly increase the charge state of proteins. In comparison, weak acid anions with the same concentration in solution had little impact on the charge state of proteins. The species of the cations in the samples had very limited influence on the charge state. The presence of a certain amount of acid in sample solution was critical to the effect of strong acid anions. Almost no increase of the charge state was observed when no acid was added to the samples. However, remarkable increase of the charge state of myoglobin (Mb) was observed when 0.001% (v/v) acetic acid (HAc) was added to the sample together with 5 mM sodium chloride (NaCl). A higher concentration of acid in samples would further enhance the effect of strong acid anions on the increase of the charge state. Further investigations into the mechanism revealed that the effect of the strong acid anions on the charge state of proteins was based on the unfolding of the protein molecules during electrospray ionization (ESI). The interactions among H+, anions, and protein molecules were so strong that it caused the unfolding of protein molecules and resulted in the increasing of proteins' charge states. The key factor that made strong acid anions and weak acid anions different in the results was the hydrolysis of the weak acid anions in acidic solutions. The present work furthers our understanding about electrospray, as well as the regulation of protein charge state. The presence of strong acid anions in acidic solutions can significantly influence the charge state of proteins in electrospray. Attention should be paid to this when regulating the charge state of proteins.
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Affiliation(s)
- Lulu Feng
- Mass Spectrometry Engineering Technology Research Center, Center for Advanced Measurement Science , National Institute of Metrology , Beijing 100029 , People's Republic of China
| | - Xiaoyun Gong
- Mass Spectrometry Engineering Technology Research Center, Center for Advanced Measurement Science , National Institute of Metrology , Beijing 100029 , People's Republic of China
| | - Jiafeng Song
- Mass Spectrometry Engineering Technology Research Center, Center for Advanced Measurement Science , National Institute of Metrology , Beijing 100029 , People's Republic of China
| | - Rui Zhai
- Mass Spectrometry Engineering Technology Research Center, Center for Advanced Measurement Science , National Institute of Metrology , Beijing 100029 , People's Republic of China
| | - Zejian Huang
- Mass Spectrometry Engineering Technology Research Center, Center for Advanced Measurement Science , National Institute of Metrology , Beijing 100029 , People's Republic of China
| | - You Jiang
- Mass Spectrometry Engineering Technology Research Center, Center for Advanced Measurement Science , National Institute of Metrology , Beijing 100029 , People's Republic of China
| | - Xiang Fang
- Mass Spectrometry Engineering Technology Research Center, Center for Advanced Measurement Science , National Institute of Metrology , Beijing 100029 , People's Republic of China
| | - Xinhua Dai
- Mass Spectrometry Engineering Technology Research Center, Center for Advanced Measurement Science , National Institute of Metrology , Beijing 100029 , People's Republic of China
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15
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Ok K, Li W, Neu HM, Batelu S, Stemmler TL, Kane MA, Michel SLJ. Role of Gold in Inflammation and Tristetraprolin Activity. Chemistry 2020; 26:1535-1547. [DOI: 10.1002/chem.201904837] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Indexed: 12/30/2022]
Affiliation(s)
- Kiwon Ok
- Department of Pharmaceutical Sciences University of Maryland School of Pharmacy 20 Penn St. Baltimore MD 21201 USA
| | - Wenjing Li
- Department of Pharmaceutical Sciences University of Maryland School of Pharmacy 20 Penn St. Baltimore MD 21201 USA
| | - Heather M. Neu
- Department of Pharmaceutical Sciences University of Maryland School of Pharmacy 20 Penn St. Baltimore MD 21201 USA
| | - Sharon Batelu
- Department of Pharmaceutical Sciences Wayne State University 259 Mack Avenue Detroit MI 48201 USA
| | - Timothy L. Stemmler
- Department of Pharmaceutical Sciences Wayne State University 259 Mack Avenue Detroit MI 48201 USA
| | - Maureen A. Kane
- Department of Pharmaceutical Sciences University of Maryland School of Pharmacy 20 Penn St. Baltimore MD 21201 USA
| | - Sarah L. J. Michel
- Department of Pharmaceutical Sciences University of Maryland School of Pharmacy 20 Penn St. Baltimore MD 21201 USA
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16
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Huang T, Rabus JM, Bythell BJ, Edwards JL. Fragmentation of Multi-charged Derivatized Lysine Using Nanospray CID Tandem Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:1158-1162. [PMID: 30993635 DOI: 10.1007/s13361-019-02154-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Revised: 02/01/2019] [Accepted: 02/11/2019] [Indexed: 06/09/2023]
Abstract
We demonstrate increasing the charge state of small molecules using derivatized lysine as our model system. Lysine is chemically tagged with three tertiary amines which enables efficient production of highly charged analytes. A +3 charge state is obtained from direct infusion nanoelectrospray conditions. Collisional activation of the +3 derivatized lysine yielded structurally informative product ions corresponding to cleavages across the analyte backbone and within the proton affinity tags. This suggests a role for multi-charging of metabolites in both targeted MRM analyses and untargeted analyses to help identify novel metabolites. Density functional calculations aid peak assignment and rationalization of structure-property relationships. Graphical Abstract.
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Affiliation(s)
- Tianjiao Huang
- Department of Chemistry and Biochemistry, Saint Louis University, 3501 Laclede Ave, St Louis, MO, 63102, USA
| | - Jordan M Rabus
- Department of Chemistry and Biochemistry, University of Missouri St Louis, 1 University Blvd., 421 Benton Hall, St Louis, MO, 63121, USA
| | - Benjamin J Bythell
- Department of Chemistry and Biochemistry, University of Missouri St Louis, 1 University Blvd., 421 Benton Hall, St Louis, MO, 63121, USA
| | - James L Edwards
- Department of Chemistry and Biochemistry, Saint Louis University, 3501 Laclede Ave, St Louis, MO, 63102, USA.
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17
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Mansour A, Abu-Nada L, Al-Waeli H, Mezour MA, Abdallah MN, Kinsella JM, Kort-Mascort J, Henderson JE, Ramirez-Garcialuna JL, Tran SD, Elkashty OA, Mousa A, El-Hadad AA, Taqi D, Al-Hamad F, Alageel O, Kaartinen MT, Tamimi F. Bone extracts immunomodulate and enhance the regenerative performance of dicalcium phosphates bioceramics. Acta Biomater 2019; 89:343-358. [PMID: 30853609 DOI: 10.1016/j.actbio.2019.03.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 02/28/2019] [Accepted: 03/06/2019] [Indexed: 12/27/2022]
Abstract
Immunomodulation strategies are believed to improve the integration and clinical performance of synthetic bone substitutes. One potential approach is the modification of biomaterial surface chemistry to mimic bone extracellular matrix (ECM). In this sense, we hypothesized that coating synthetic dicalcium phosphate (DCP) bioceramics with bone ECM proteins would modulate the host immune reactions and improve their regenerative performance. To test this, we evaluated the in vitro proteomic surface interactions and the in vivo performance of ECM-coated bioceramic scaffolds. Our results demonstrated that coating DCP scaffolds with bone extracts, specifically those containing calcium-binding proteins, dramatically modulated their interaction with plasma proteins in vitro, especially those relating to the innate immune response. In vivo, we observed an attenuated inflammatory response against the bioceramic scaffolds and enhanced peri-scaffold new bone formation supported by the increased osteoblastogenesis and reduced osteoclastogenesis. Furthermore, the bone extract rich in calcium-binding proteins can be 3D-printed to produce customized hydrogels with improved regeneration capabilities. In summary, bone extracts containing calcium-binding proteins can enhance the integration of synthetic biomaterials and improve their ability to regenerate bone probably by modulating the host immune reaction. This finding helps understand how bone allografts regenerate bone and opens the door for new advances in tissue engineering and bone regeneration. STATEMENT OF SIGNIFICANCE: Foreign-body reaction is an important determinant of in vivo biomaterial integration, as an undesired host immune response can compromise the performance of an implanted biomaterial. For this reason, applying immunomodulation strategies to enhance biomaterial engraftment is of great interest in the field of regenerative medicine. In this article, we illustrated that coating dicalcium phosphate bioceramic scaffolds with bone-ECM extracts, especially those rich in calcium-binding proteins, is a promising approach to improve their surface proteomic interactions and modulate the immune responses towards such biomaterials in a way that improves their bone regeneration performance. Collectively, the results of this study may provide a conceivable explanation for the mechanisms involved in presenting the excellent regenerative efficacy of natural bone grafts.
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Affiliation(s)
- Alaa Mansour
- Faculty of Dentistry, McGill University, Montreal, QC, Canada.
| | - Lina Abu-Nada
- Faculty of Dentistry, McGill University, Montreal, QC, Canada.
| | - Haider Al-Waeli
- Faculty of Dentistry, McGill University, Montreal, QC, Canada.
| | | | | | - Joseph M Kinsella
- Department of Bioengineering, Faculty of Engineering, McGill University, Montreal, QC, Canada.
| | - Jacqueline Kort-Mascort
- Department of Bioengineering, Faculty of Engineering, McGill University, Montreal, QC, Canada.
| | - Janet E Henderson
- Faculty of Medicine, McGill University, Montreal, QC, Canada; The Bone Engineering Labs, Research Institute McGill University Health Center, Montreal, QC, Canada.
| | - Jose Luis Ramirez-Garcialuna
- Faculty of Medicine, McGill University, Montreal, QC, Canada; The Bone Engineering Labs, Research Institute McGill University Health Center, Montreal, QC, Canada.
| | - Simon D Tran
- Faculty of Dentistry, McGill University, Montreal, QC, Canada.
| | - Osama A Elkashty
- Faculty of Medicine, McGill University, Montreal, QC, Canada; Faculty of Dentistry, Mansoura University, Mansoura, Egypt.
| | - Aisha Mousa
- Faculty of Dentistry, McGill University, Montreal, QC, Canada.
| | - Amir A El-Hadad
- Faculty of Dentistry, McGill University, Montreal, QC, Canada.
| | - Doaa Taqi
- Faculty of Dentistry, McGill University, Montreal, QC, Canada.
| | - Faez Al-Hamad
- Faculty of Dentistry, McGill University, Montreal, QC, Canada.
| | - Omar Alageel
- Faculty of Dentistry, McGill University, Montreal, QC, Canada; College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
| | | | - Faleh Tamimi
- Faculty of Dentistry, McGill University, Montreal, QC, Canada.
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18
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Gong X, Li C, Zhai R, Xie J, Jiang Y, Fang X. Supercharging of Proteins by Salts during Polarity Reversed Nano-Electrospray Ionization. Anal Chem 2019; 91:1826-1837. [PMID: 30620564 DOI: 10.1021/acs.analchem.8b02759] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Supercharging is beneficial in many ways to the analysis of proteins by mass spectrometry (MS). In this work, a novel supercharging method was developed. It made use of our previously developed ionization technique: namely, polarity reversed nanoelectrospray ionization (PR-nESI) for the ionization of proteins. Supercharging of proteins was achieved by just adding 1-10 mM of a salt to the sample, such as sodium chloride (NaCl). The charge state of proteins obtained by our method was significantly higher than that by nano-ESI with 1% (v/v) acetic acid (HAc). Different kinds of salts were investigated. Salts with strong acid anions were capable of supercharging proteins, including chlorides, bromides, iodides, and nitrates. The signal intensity and signal to noise ratio ( S/ N) of proteins were increased at the same time. Phosphates were also found to have a supercharging effect, due to the fact that phosphoric acid was a medium-strong acid. In comparison, salts with weak acid anions had no supercharging effect, such as carbonates, sulfides, acetates, and formates. The species of the salt anion was critical to the supercharging effect, while the species of the salt cation showed little influence on the supercharging effect. Investigations were made into the mechanism of our method. The supercharging effect was caused by interactions between protein molecules and salt anions, as well as the influence of protons. The present work offered us an alternative way for the supercharging of proteins. The use of common salts for supercharging made the procedure more convenient. The concentration of salts needed for supercharging was much lower than those conventionally used for supercharging reagents. Taking into consideration the fact that many biological samples are buffered with phosphates and chlorides, these samples could be directly supercharged by our method without any additional additives. Furthermore, as many salts are nontoxic and can easily be found in a chemical laboratory, the use of salts for supercharging would be a much more practical and economical choice. In addition, the present work also furthered our understandings about the mechanism of supercharging, as well as electrospray.
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Affiliation(s)
- Xiaoyun Gong
- Mass Spectrometry Engineering Technology Research Center, Center for Advanced Measurement Science , National Institute of Metrology , Beijing 100029 , People's Republic of China
| | - Chang Li
- Mass Spectrometry Engineering Technology Research Center, Center for Advanced Measurement Science , National Institute of Metrology , Beijing 100029 , People's Republic of China
| | - Rui Zhai
- Mass Spectrometry Engineering Technology Research Center, Center for Advanced Measurement Science , National Institute of Metrology , Beijing 100029 , People's Republic of China
| | - Jie Xie
- Mass Spectrometry Engineering Technology Research Center, Center for Advanced Measurement Science , National Institute of Metrology , Beijing 100029 , People's Republic of China
| | - You Jiang
- Mass Spectrometry Engineering Technology Research Center, Center for Advanced Measurement Science , National Institute of Metrology , Beijing 100029 , People's Republic of China
| | - Xiang Fang
- Mass Spectrometry Engineering Technology Research Center, Center for Advanced Measurement Science , National Institute of Metrology , Beijing 100029 , People's Republic of China
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19
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Xia Z, Williams ER. Effect of droplet lifetime on where ions are formed in electrospray ionization. Analyst 2019; 144:237-248. [DOI: 10.1039/c8an01824c] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The location of gaseous ion formation in electrospray ionization under native mass spectrometry conditions was investigated using theta emitters with tip diameters between 317 nm and 4.4 μm to produce droplets with lifetimes between 1 and 50 μs.
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Affiliation(s)
- Zijie Xia
- Department of Chemistry
- University of California
- Berkeley
- USA
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20
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Enami S, Colussi AJ. OH-Radical Oxidation of Lung Surfactant Protein B on Aqueous Surfaces. Mass Spectrom (Tokyo) 2018; 7:S0077. [PMID: 30533342 PMCID: PMC6245955 DOI: 10.5702/massspectrometry.s0077] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/11/2018] [Indexed: 11/23/2022] Open
Abstract
Air pollutants generate reactive oxygen species on lung surfaces. Here we report how hydroxyl radicals (·OH) injected on the surface of water react with SP-B1-25, a 25-residue polypeptide surrogate of human lung surfactant protein B. Our experiments consist of intersecting microjets of aqueous SP-B1-25 solutions with O3/O2/H2O/N2(g) gas streams that are photolyzed into ·OH(g) in situ by 266 nm laser nanosecond pulses. Surface-sensitive mass spectrometry enables us to monitor the prompt (<10 μs) and simultaneous formation of primary O n -containing products/intermediates (n≤5) triggered by the reaction of ·OH with interfacial SP-B1-25. We found that O-atoms from both O3 and ·OH are incorporated into the reactive cysteine Cys8 and Cys11 and tryptophan Trp9 components of the hydrophobic N-terminus of SP-B1-25 that lies at the topmost layers of the air-liquid interface. Remarkably, these processes are initiated by ·OH additions rather than by H-atom abstractions from S-H, C-H, or N-H groups. By increasing the hydrophilicity of the N-terminus region of SP-B1-25, these transformations will impair its role as a surfactant.
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Affiliation(s)
| | - Agustín J Colussi
- Linde Center for Global Environmental Science, California Institute of Technology
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21
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Huang T, Armbruster MR, Coulton JB, Edwards JL. Chemical Tagging in Mass Spectrometry for Systems Biology. Anal Chem 2018; 91:109-125. [DOI: 10.1021/acs.analchem.8b04951] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Tianjiao Huang
- Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, St. Louis, Missouri 63103, United States
| | - Michael R. Armbruster
- Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, St. Louis, Missouri 63103, United States
| | - John B. Coulton
- Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, St. Louis, Missouri 63103, United States
| | - James L. Edwards
- Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, St. Louis, Missouri 63103, United States
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22
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Calabrese AN, Radford SE. Mass spectrometry-enabled structural biology of membrane proteins. Methods 2018; 147:187-205. [DOI: 10.1016/j.ymeth.2018.02.020] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 01/30/2018] [Accepted: 02/21/2018] [Indexed: 01/01/2023] Open
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23
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Rahman MM, Chen LC. Analytical characteristics of nano-electrospray operated under super-atmospheric pressure. Anal Chim Acta 2018; 1021:78-84. [DOI: 10.1016/j.aca.2018.03.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 03/08/2018] [Accepted: 03/10/2018] [Indexed: 10/17/2022]
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24
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Time-resolved method to distinguish protein/peptide oxidation during electrospray ionization mass spectrometry. Anal Chim Acta 2018; 1011:59-67. [PMID: 29475486 DOI: 10.1016/j.aca.2018.01.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 01/05/2018] [Accepted: 01/08/2018] [Indexed: 11/21/2022]
Abstract
Electrospray ionization mass spectrometry (ESI-MS) is one of the most prevalent techniques used to monitor protein/peptide oxidation induced by reactive oxygen species (ROSs). However, both corona discharge (CD) and electrochemistry (EC) can also lead to protein/peptide oxidation during ESI. Because the two types of oxidation occur almost simultaneously, determining the extent to which the two pathways contribute to protein/peptide oxidation is difficult. Herein, a time-resolved method was introduced to identify and differentiate CD- and EC-induced oxidation. Using this approach, we separated the instantaneous CD-induced oxidation from the hysteretic EC-induced oxidation, and the effects of the spray voltage and flow rate of the ESI source on both oxidation types were investigated with a homemade ESI source. For angiotensin II analogue (b-DRVYVHPF-y), the dehydrogenation and oxygenation species were the detected EC-induced oxidation products, while the oxygenation species were the major CD-induced oxidation products. This time-resolved approach was also applicable to a commercial HESI source, in which both CD and EC were responsible for hemoglobin and cytochrome c oxidation with upstream grounding while CD dominated the oxidation without upstream grounding.
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25
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Wang H, Yong G, Brown SL, Lee HE, Zenaidee MA, Supuran CT, Donald WA. Supercharging protein ions in native mass spectrometry using theta capillary nanoelectrospray ionization mass spectrometry and cyclic alkylcarbonates. Anal Chim Acta 2018; 1003:1-9. [DOI: 10.1016/j.aca.2017.11.075] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 11/22/2017] [Accepted: 11/25/2017] [Indexed: 12/27/2022]
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26
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Affiliation(s)
- Nicholas
M. Riley
- Department
of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Genome
Center of Wisconsin, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Joshua J. Coon
- Department
of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Genome
Center of Wisconsin, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Department
of Biomolecular Chemistry, University of
Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Morgridge
Institute for Research, Madison, Wisconsin 53715, United States
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27
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Polfer NC. Hoch geladende Proteine: Wie viele Ladungen kann ein Protein tragen? Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201704527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Nicolas C. Polfer
- Department of Chemistry University of Florida P.O. Box 117200 Gainesville FL 32611 USA
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28
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Polfer NC. Supercharging Proteins: How Many Charges Can a Protein Carry? Angew Chem Int Ed Engl 2017; 56:8335-8337. [DOI: 10.1002/anie.201704527] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Nicolas C. Polfer
- Department of Chemistry University of Florida P.O. Box 117200 Gainesville FL 32611 USA
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29
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Honarvar E, Venter AR. Ammonium Bicarbonate Addition Improves the Detection of Proteins by Desorption Electrospray Ionization Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:1109-1117. [PMID: 28315234 DOI: 10.1007/s13361-017-1628-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 01/26/2017] [Accepted: 02/09/2017] [Indexed: 05/11/2023]
Abstract
The analysis of protein by desorption electrospray ionization mass spectrometry (DESI-MS) is considered impractical due to a mass-dependent loss in sensitivity with increase in protein molecular weights. With the addition of ammonium bicarbonate to the DESI-MS analysis the sensitivity towards proteins by DESI was improved. The signal to noise ratio (S/N) improvement for a variety of proteins increased between 2- to 3-fold relative to solvent systems containing formic acid and more than seven times relative to aqueous methanol spray solvents. Three methods for ammonium bicarbonate addition during DESI-MS were investigated. The additive delivered improvements in S/N whether it was mixed with the analyte prior to sample deposition, applied over pre-prepared samples, or simply added to the desorption spray solvent. The improvement correlated well with protein pI but not with protein size. Other ammonium or bicarbonate salts did not produce similar improvements in S/N, nor was this improvement in S/N observed for ESI of the same samples. As was previously described for ESI, DESI also caused extensive protein unfolding upon the addition of ammonium bicarbonate. Graphical Abstract ᅟ.
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Affiliation(s)
- Elahe Honarvar
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, 49008-5413, USA
| | - Andre R Venter
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, 49008-5413, USA.
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30
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Susa AC, Xia Z, Tang HYH, Tainer JA, Williams ER. Charging of Proteins in Native Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:332-340. [PMID: 27734326 PMCID: PMC5283922 DOI: 10.1007/s13361-016-1517-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 09/22/2016] [Accepted: 09/27/2016] [Indexed: 05/19/2023]
Abstract
Factors that influence the charging of protein ions formed by electrospray ionization from aqueous solutions in which proteins have native structures and function were investigated. Protein ions ranging in molecular weight from 12.3 to 79.7 kDa and pI values from 5.4 to 9.6 were formed from different solutions and reacted with volatile bases of gas-phase basicities higher than that of ammonia in the cell of a Fourier-transform ion cyclotron resonance mass spectrometer. The charge-state distribution of cytochrome c ions formed from aqueous ammonium or potassium acetate is the same. Moreover, ions formed from these two solutions do not undergo proton transfer to 2-fluoropyridine, which is 8 kcal/mol more basic than ammonia. These results provide compelling evidence that proton transfer between ammonia and protein ions does not limit protein ion charge in native electrospray ionization. Both circular dichroism and ion mobility measurements indicate that there are differences in conformations of proteins in pure water and aqueous ammonium acetate, and these differences can account for the difference in the extent of charging and proton-transfer reactivities of protein ions formed from these solutions. The extent of proton transfer of the protein ions with higher gas-phase basicity bases trends with how closely the protein ions are charged to the value predicted by the Rayleigh limit for spherical water droplets approximately the same size as the proteins. These results indicate that droplet charge limits protein ion charge in native mass spectrometry and are consistent with these ions being formed by the charged residue mechanism. Graphical Abstract ᅟ.
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Affiliation(s)
- Anna C Susa
- Department of Chemistry, University of California, Berkeley, CA, 94720-1460, USA
| | - Zijie Xia
- Department of Chemistry, University of California, Berkeley, CA, 94720-1460, USA
| | - Henry Y H Tang
- Department of Chemistry, University of California, Berkeley, CA, 94720-1460, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - John A Tainer
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, 77030, USA
| | - Evan R Williams
- Department of Chemistry, University of California, Berkeley, CA, 94720-1460, USA.
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31
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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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32
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Mortensen DN, Williams ER. Electrothermal supercharging of proteins in native MS: effects of protein isoelectric point, buffer, and nanoESI-emitter tip size. Analyst 2016; 141:5598-606. [PMID: 27441318 PMCID: PMC5239670 DOI: 10.1039/c6an01380e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The extent of charging resulting from electrothermal supercharging for protein ions formed from various buffered aqueous solutions using nanoESI emitters with tip diameters between ∼1.5 μm and ∼310 nm is compared. Charging increases with decreasing tip size for proteins that are positively charged in solution but not for proteins that are negatively charged in solution. These results suggest that Coulombic attraction between positively charged protein molecules and the negatively charged glass surfaces in the tips of the emitters causes destabilization and even unfolding of proteins prior to nanoESI. Coulombic attraction to the negatively charged glass surfaces does not occur for negatively charged proteins and the extent of charging with electrothermal supercharging decreases with decreasing tip size. Smaller droplets are formed with smaller tips, and these droplets have shorter lifetimes for protein unfolding with electrothermal supercharging to occur prior to gaseous ion formation. Results from this study demonstrate simple principles to consider in order to optimize the extent of charging obtained with electrothermal supercharging, which should be useful for obtaining more structural information in tandem mass spectrometry.
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Affiliation(s)
- Daniel N Mortensen
- Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
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33
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Going CC, Xia Z, Williams ER. Real-time HD Exchange Kinetics of Proteins from Buffered Aqueous Solution with Electrothermal Supercharging and Top-Down Tandem Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:1019-1027. [PMID: 26919868 PMCID: PMC4865425 DOI: 10.1007/s13361-016-1350-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 01/21/2016] [Accepted: 01/22/2016] [Indexed: 06/05/2023]
Abstract
Electrothermal supercharging (ETS) with electrospray ionization produces highly charged protein ions from buffered aqueous solutions in which proteins have native folded structures. ETS increases the charge of ribonuclease A by 34%, whereas only a 6% increase in charge occurs for a reduced-alkylated form of this protein, which is unfolded and its structure is ~66% random coil in this solution. These results indicate that protein denaturation that occurs in the ESI droplets is the primary mechanism for ETS. ETS does not affect the extent of solution-phase hydrogen-deuterium exchange (HDX) that occurs for four proteins that have significantly different structures in solution, consistent with a droplet lifetime that is considerably shorter than observable rates of HDX. Rate constants for HDX of ubiquitin are obtained with a spatial resolution of ~1.3 residues with ETS and electron transfer dissociation of the 10+ charge-state using a single capillary containing a few μL of protein solution in which HDX continuously occurs. HDX protection at individual residues with ETS HDX is similar to that with reagent supercharging HDX and with solution-phase NMR, indicating that the high spray potentials required to induce ETS do not lead to HD scrambling. Graphical Abstract ᅟ.
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Affiliation(s)
- Catherine C Going
- Department of Chemistry, University of California, Berkeley, CA, 94720-1460, USA
| | - Zijie Xia
- Department of Chemistry, University of California, Berkeley, CA, 94720-1460, USA
| | - Evan R Williams
- Department of Chemistry, University of California, Berkeley, CA, 94720-1460, USA.
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34
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Stipetic LH, Dalby MJ, Davies RL, Morton FR, Ramage G, Burgess KEV. A novel metabolomic approach used for the comparison of Staphylococcus aureus planktonic cells and biofilm samples. Metabolomics 2016; 12:75. [PMID: 27013931 PMCID: PMC4783440 DOI: 10.1007/s11306-016-1002-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 01/16/2016] [Indexed: 10/25/2022]
Abstract
INTRODUCTION Bacterial cell characteristics change significantly during differentiation between planktonic and biofilm states. While established methods exist to detect and identify transcriptional and proteomic changes, metabolic fluctuations that distinguish these developmental stages have been less amenable to investigation. OBJECTIVES The objectives of the study were to develop a robust reproducible sample preparation methodology for high throughput biofilm analysis and to determine differences between Staphylococcus aureus in planktonic and biofilm states. METHODS The method uses bead beating in a chloroform/methanol/water extraction solvent to both disrupt cells and quench metabolism. Verification of the method was performed using liquid-chromatography-mass spectrometry. Raw mass-spectrometry data was analysed using an in-house bioinformatics pipe-line incorporating XCMS, MzMatch and in-house R-scripts, with identifications matched to internal standards and metabolite data-base entries. RESULTS We have demonstrated a novel mechanical bead beating method that has been optimised for the extraction of the metabolome from cells of a clinical Staphylococcus aureus strain existing in a planktonic or biofilm state. This high-throughput method is fast and reproducible, allowing for direct comparison between different bacterial growth states. Significant changes in arginine biosynthesis were identified between the two cell populations. CONCLUSIONS The method described herein represents a valuable tool in studying microbial biochemistry at a molecular level. While the methodology is generally applicable to the lysis and extraction of metabolites from Gram positive bacteria, it is particularly applicable to biofilms. Bacteria that exist as a biofilm are shown to be highly distinct metabolically from their 'free living' counterparts, thus highlighting the need to study microbes in different growth states. Metabolomics can successfully distinguish between a planktonic and biofilm growth state. Importantly, this study design, incorporating metabolomics, could be optimised for studying the effects of antimicrobials and drug modes of action, potentially providing explanations and mechanisms of antibiotic resistance and to help devise new antimicrobials.
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Affiliation(s)
- Laurence H. Stipetic
- />Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, The University of Glasgow, Glasgow, UK
- />Glasgow Polyomics, Wolfson Wohl Cancer Research Centre, The University of Glasgow, Garscube Estate, Bearsden, Scotland G61 1QH UK
| | - Matthew J. Dalby
- />Institute of Molecular Cell and Systems Biology, The University of Glasgow, Glasgow, UK
| | - Robert L. Davies
- />Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, The University of Glasgow, Glasgow, UK
| | - Fraser R. Morton
- />Glasgow Polyomics, Wolfson Wohl Cancer Research Centre, The University of Glasgow, Garscube Estate, Bearsden, Scotland G61 1QH UK
| | - Gordon Ramage
- />Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, The University of Glasgow, Glasgow, UK
| | - Karl E. V. Burgess
- />Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, The University of Glasgow, Glasgow, UK
- />Glasgow Polyomics, Wolfson Wohl Cancer Research Centre, The University of Glasgow, Garscube Estate, Bearsden, Scotland G61 1QH UK
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35
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Liu F, Lu W, Yin X, Liu J. Mechanistic and Kinetic Study of Singlet O2 Oxidation of Methionine by On-Line Electrospray Ionization Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:59-72. [PMID: 26306590 DOI: 10.1007/s13361-015-1237-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 07/24/2015] [Indexed: 06/04/2023]
Abstract
We report a reaction apparatus developed to monitor singlet oxygen ((1)O2) reactions in solution using on-line ESI mass spectrometry and spectroscopy measurements. (1)O2 was generated in the gas phase by the reaction of H2O2 with Cl2, detected by its emission at 1270 nm, and bubbled into aqueous solution continuously. (1)O2 concentrations in solution were linearly related to the emission intensities of airborne (1)O2, and their absolute scales were established based on a calibration using 9,10-anthracene dipropionate dianion as an (1)O2 trapping agent. Products from (1)O2 oxidation were monitored by UV-Vis absorption and positive/negative ESI mass spectra, and product structures were elucidated using collision-induced dissociation-tandem mass spectrometry. To suppress electrical discharge in negative ESI of aqueous solution, methanol was added to electrospray via in-spray solution mixing using theta-glass ESI emitters. Capitalizing on this apparatus, the reaction of (1)O2 with methionine was investigated. We have identified methionine oxidation intermediates and products at different pH, and measured reaction rate constants. (1)O2 oxidation of methionine is mediated by persulfoxide in both acidic and basic solutions. Persulfoxide continues to react with another methionine, yielding methionine sulfoxide as end-product albeit with a much lower reaction rate in basic solution. Density functional theory was used to explore reaction potential energy surfaces and establish kinetic models, with solvation effects simulated using the polarized continuum model. Combined with our previous study of gas-phase methionine ions with (1)O2, evolution of methionine oxidation pathways at different ionization states and in different media is described.
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Affiliation(s)
- Fangwei Liu
- Department of Chemistry and Biochemistry, Queens College and the Graduate Center of the City University of New York, Queens, NY, 11367, USA
| | - Wenchao Lu
- Department of Chemistry and Biochemistry, Queens College and the Graduate Center of the City University of New York, Queens, NY, 11367, USA
| | - Xunlong Yin
- Department of Chemistry and Biochemistry, Queens College and the Graduate Center of the City University of New York, Queens, NY, 11367, USA
| | - Jianbo Liu
- Department of Chemistry and Biochemistry, Queens College and the Graduate Center of the City University of New York, Queens, NY, 11367, USA.
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36
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Going CC, Xia Z, Williams ER. New supercharging reagents produce highly charged protein ions in native mass spectrometry. Analyst 2015; 140:7184-94. [PMID: 26421324 PMCID: PMC4617834 DOI: 10.1039/c5an01710f] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effectiveness of two new supercharging reagents for producing highly charged ions by electrospray ionization (ESI) from aqueous solutions in which proteins have native structures and reactivities were investigated. In aqueous solution, 2-thiophenone and 4-hydroxymethyl-1,3-dioxolan-2-one (HD) at a concentration of 2% by volume can increase the average charge of cytochrome c and myoglobin by up to 163%, resulting in even higher charge states than those that are produced from water/methanol/acid solutions in which these proteins are denatured. The greatest extent of supercharging occurs in pure water, but these supercharging reagents are also highly effective in aqueous solutions containing 200 mM ammonium acetate buffer commonly used in native mass spectrometry (MS). These reagents are less effective supercharging reagents than m-nitrobenzyl alcohol (m-NBA) and propylene carbonate (PC) when ions are formed from water/methanol/acid. The extent to which loss of the heme group from myoglobin occurs is related to the extent of supercharging. Results from guanidine melts of cytochrome c monitored with tryptophan fluorescence show that the supercharging reagents PC, sulfolane and HD are effective chemical denaturants in solution. These results provide additional evidence for the role of protein structural changes in the electrospray droplet as the primary mechanism for supercharging with these reagents in native MS. These results also demonstrate that for at least some proteins, the formation of highly charged ions from native MS is no longer a significant barrier for obtaining structural information using conventional tandem MS methods.
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Affiliation(s)
- Catherine C Going
- Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
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37
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Shi F, Flanigan PM, Archer JJ, Levis RJ. Direct analysis of intact biological macromolecules by low-energy, fiber-based femtosecond laser vaporization at 1042 nm wavelength with nanospray postionization mass spectrometry. Anal Chem 2015; 87:3187-94. [PMID: 25688836 DOI: 10.1021/ac502563c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
A fiber-based laser with a pulse duration of 435 fs and a wavelength of 1042 nm was used to vaporize biological macromolecules intact from the condensed phase into the gas phase for nanospray postionization and mass analysis. Laser vaporization of dried standard protein samples from a glass substrate by 10 Hz bursts of 20 pulses having 10 μs pulse separation and <50 μJ pulse energy resulted in signal comparable to a metal substrate. The protein signal observed from an aqueous droplet on a glass substrate was negligible compared to either a droplet on metal or a thin film on glass. The mass spectra generated from dried and aqueous protein samples by the low-energy, fiber laser were similar to the results from high-energy (500 μJ), 45-fs, 800-nm Ti:sapphire-based femtosecond laser electrospray mass spectrometry (LEMS) experiments, suggesting that the fiber-based femtosecond laser desorption mechanism involves a nonresonant, multiphoton process, rather than thermal- or photoacoustic-induced desorption. Direct analysis of whole blood performed without any pretreatment resulted in features corresponding to hemoglobin subunit-heme complex ions. The observation of intact molecular ions with low charge states from protein, and the tentatively assigned hemoglobin α subunit-heme complex from blood suggests that fiber-based femtosecond laser vaporization is a "soft" desorption source at a laser intensity of 2.39 × 10(12) W/cm(2). The low-energy, turnkey fiber laser demonstrates the potential of a more robust and affordable laser for femtosecond laser vaporization to deliver biological macromolecules into the gas phase for mass analysis.
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Affiliation(s)
- Fengjian Shi
- †Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States.,‡Center for Advanced Photonics Research, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States
| | - Paul M Flanigan
- †Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States.,‡Center for Advanced Photonics Research, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States
| | - Jieutonne J Archer
- †Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States.,‡Center for Advanced Photonics Research, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States
| | - Robert J Levis
- †Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States.,‡Center for Advanced Photonics Research, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States
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38
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Going CC, Williams ER. Supercharging with m-Nitrobenzyl Alcohol and Propylene Carbonate: Forming Highly Charged Ions with Extended, Near-Linear Conformations. Anal Chem 2015; 87:3973-80. [DOI: 10.1021/acs.analchem.5b00071] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Catherine C. Going
- Department
of Chemistry, University of California, Berkeley, Berkeley, California 94720-1460, United States
| | - Evan R. Williams
- Department
of Chemistry, University of California, Berkeley, Berkeley, California 94720-1460, United States
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39
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Feng C, Commodore JJ, Cassady CJ. The use of chromium(III) to supercharge peptides by protonation at low basicity sites. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:347-58. [PMID: 25395012 PMCID: PMC4323856 DOI: 10.1007/s13361-014-1020-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 10/09/2014] [Accepted: 10/13/2014] [Indexed: 05/16/2023]
Abstract
The addition of chromium(III) nitrate to solutions of peptides with seven or more residues greatly increases the formation of doubly protonated peptides, [M + 2H](2+), by electrospray ionization. The test compound heptaalanine has only one highly basic site (the N-terminal amino group) and undergoes almost exclusive single protonation using standard solvents. When Cr(III) is added to the solution, abundant [M + 2H](2+) forms, which involves protonation of the peptide backbone or the C-terminus. Salts of Al(III), Mn(II), Fe(III), Fe(II), Cu(II), Zn (II), Rh(III), La(III), Ce(IV), and Eu(III) were also studied. Although several metal ions slightly enhance protonation, Cr(III) has by far the greatest ability to generate [M + 2H](2+). Cr(III) does not supercharge peptide methyl esters, which suggests that the mechanism involves interaction of Cr(III) with a carboxylic acid group. Other factors may include the high acidity of hexa-aquochromium(III) and the resistance of Cr(III) to reduction. Nitrate salts enhance protonation more than chloride salts and a molar ratio of 10:1 Cr(III):peptide produces the most intense [M + 2H](2+). Cr(III) also supercharges numerous other small peptides, including highly acidic species. For basic peptides, Cr(III) increases the charge state (2+ versus 1+) and causes the number of peptide molecules being protonated to double or triple. Chromium(III) does not supercharge the proteins cytochrome c and myoglobin. The ability of Cr(III) to enhance [M + 2H](2+) intensity may prove useful in tandem mass spectrometry because of the resulting overall increase in signal-to-noise ratio, the fact that [M + 2H](2+) generally dissociate more readily than [M + H](+), and the ability to produce [M + 2H](2+) precursors for electron-based dissociation techniques.
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Affiliation(s)
- Changgeng Feng
- Department of Chemistry, The University of Alabama, Tuscaloosa, AL, 35487, USA
| | | | - Carolyn J. Cassady
- Department of Chemistry, The University of Alabama, Tuscaloosa, AL, 35487, USA
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40
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Mortensen DN, Williams ER. Investigating protein folding and unfolding in electrospray nanodrops upon rapid mixing using theta-glass emitters. Anal Chem 2014; 87:1281-7. [PMID: 25525976 PMCID: PMC4303338 DOI: 10.1021/ac503981c] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
Theta-glass emitters are used to
rapidly mix two solutions to induce
either protein folding or unfolding during nanoelectrospray (nanoESI).
Mixing acid-denatured myoglobin with an aqueous ammonium acetate solution
to increase solution pH results in protein folding during nanoESI.
A reaction time and upper limit to the droplet lifetime of 9 ±
2 μs is obtained from the relative abundance of the folded conformer
in these rapid mixing experiments compared to that obtained from solutions
at equilibrium and a folding time constant of 7 μs. Heme reincorporation
does not occur, consistent with the short droplet lifetime and the
much longer time constant for this process. Similar mixing experiments
with acid-denatured cytochrome c and the resulting
folding during nanoESI indicate a reaction time of between 7 and 25
μs depending on the solution composition. The extent of unfolding
of holo-myoglobin upon rapid mixing with theta-glass emitters is less
than that reported previously (Fisher
et al. Anal. Chem.2014, 86, 4581−458824702054), a result
that is attributed to the much smaller, ∼1.5 μm, average
o.d. tips used here. These results indicate that the time frame during
which protein folding or unfolding can occur during nanoESI depends
both on the initial droplet size, which can be varied by changing
the emitter tip diameter, and on the solution composition. This study
demonstrates that protein folding or unfolding processes that occur
on the ∼10 μs time scale can be readily investigated
using rapid mixing with theta-glass emitters combined with mass spectrometry.
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Affiliation(s)
- Daniel N Mortensen
- Department of Chemistry, University of California , Berkeley, California 94720-1460, United States
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41
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Rinke G, Rauschenbach S, Harnau L, Albarghash A, Pauly M, Kern K. Active conformation control of unfolded proteins by hyperthermal collision with a metal surface. NANO LETTERS 2014; 14:5609-5615. [PMID: 25198655 DOI: 10.1021/nl502122j] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The physical and chemical properties of macromolecules like proteins are strongly dependent on their conformation. The degrees of freedom of their chemical bonds generate a huge conformational space, of which, however, only a small fraction is accessible in thermal equilibrium. Here we show that soft-landing electrospray ion beam deposition (ES-IBD) of unfolded proteins allows to control their conformation. The dynamics and result of the deposition process can be actively steered by selecting the molecular ion beam's charge state or tuning the incident energy. Using these parameters, protein conformations ranging from fully extended to completely compact can be prepared selectively on a surface, as evidenced on the subnanometer/amino acid resolution level by scanning tunneling microscopy (STM). Supported by molecular dynamics (MD) simulations, our results demonstrate that the final conformation on the surface is reached through a mechanical deformation during the hyperthermal ion surface collision. Our experimental results independently confirm the findings of ion mobility spectrometry (IMS) studies of protein gas phase conformations. Moreover, we establish a new route for the processing of macromolecular materials, with the potential to reach conformations that would be inaccessible otherwise.
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Affiliation(s)
- Gordon Rinke
- Max-Planck-Institute for Solid State Research , 70569 Stuttgart, Germany
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42
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Rahman MM, Mandal MK, Hiraoka K, Chen LC. High pressure nanoelectrospray ionization mass spectrometry for analysis of aqueous solutions. Analyst 2014; 138:6316-22. [PMID: 23979728 DOI: 10.1039/c3an00699a] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nanoelectrospray ionization (nanoESI) with a very fine emitter and nanoliter solution flow rate is known to be suitable for aqueous solutions. However, under atmospheric pressure, its stability with aqueous solutions is not always guaranteed particularly in the negative ion mode where corona and arc discharge tend to occur more easily. Electrical discharge can be quenched to a certain extent by adding electron scavenging gases like SF6 or CO2 to the ion source. The onset potential that is required to induce the discharge also increases with an increase of gas pressure. Recently, we have reported on a series of high pressure electrospray ion sources that were stable in both positive and negative ion modes using air or N2 as the working gas. In this paper, we compare the performance of nanoelectrospray under atmospheric pressure and super-atmospheric pressure for the analysis of samples in aqueous solution. The comparative study was performed using the same ion source chamber that could be pressurized up to 6 bar. The pressure in the first pumping stage of the mass spectrometer was kept constant when the ion source pressure was changed by using an additional pump with variable pumping speed. High pressure nanoESI optimized at 2-3 bar demonstrated a 3-5 times improvement in ion signal intensity compared to atmospheric pressure nanoESI, and the signal stability was significantly improved particularly in the negative mode.
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Affiliation(s)
- Md Matiur Rahman
- Clean Energy Research Center, University of Yamanashi, 4-3-11, Takeda, Kofu, Yamanashi, 400-8511 Japan
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43
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Susa AC, Mortensen DN, Williams ER. Effects of cations on protein and peptide charging in electrospray ionization from aqueous solutions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:918-27. [PMID: 24729190 PMCID: PMC4051497 DOI: 10.1007/s13361-014-0864-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 02/12/2014] [Accepted: 02/18/2014] [Indexed: 05/11/2023]
Abstract
The effects of eight different cations with ionic radii between 69 and 337 pm on the charging of peptides and proteins with electrospray ionization from aqueous acetate salt solutions are reported. Significant adduction occurs for all cations except NH4(+), and the average protein charge is lower when formed from solutions containing salts compared with solutions without salts added. Circular dichroism and ion mobility results show the protein conformations are different in pure water compared with salt solutions, which likely affects the extent of charging. The average charge of protein and peptide ions formed from solutions with Li(+) and Cs(+), which have Gibbs solvation free energies (GSFEs) that differ by 225 kJ/mol, is similar. Lower charge states are typically formed from solutions with tetramethylammonium and tetraethylammonium that have lower GSFE values. Loss of the larger cations that have the lowest GSFEs is facile when adducted protein ions are collisionally activated, resulting in the formation of lower analyte charge states. This reaction pathway provides a route to produce abundant singly protonated protein ions under native mass spectrometry conditions. The average protein and peptide charge with NH4(+) is nearly the same as that with Rb(+) and K(+), cations with similar GSFE and ionic radii. This indicates that proton transfer from NH4(+) to proteins plays an insignificant role in the extent of protein charging in native mass spectrometry.
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Affiliation(s)
| | | | - Evan R. Williams
- Address correspondence to Prof. Evan R. Williams: Department of Chemistry, University of California, Berkeley, B42 Hildebrand Hall Berkeley, CA 94720, Phone: (510) 643-7161,
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44
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Chingin K, Xu N, Chen H. Soft supercharging of biomolecular ions in electrospray ionization mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:928-934. [PMID: 24733276 DOI: 10.1007/s13361-014-0887-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 03/08/2014] [Accepted: 03/17/2014] [Indexed: 06/03/2023]
Abstract
The charge states of biomolecular ions in ESI-MS can be significantly increased by the addition of low-vapor supercharging (SC) reagents into the spraying solution. Despite the considerable interest from the community, the mechanistic aspects of SC are not well understood and are hotly debated. Arguments that denaturation accounts for the increased charging observed in proteins sprayed from aqueous solutions containing SC reagent have been published widely, but often with incomplete or ambiguous supporting data. In this work, we explored ESI MS charging and SC behavior of several biopolymers including proteins and DNA oligonucleotides. Analytes were ionized from 100 mM ammonium acetate (NH4Ac) aqueous buffer in both positive (ESI+) and negative (ESI-) ion modes. SC was induced either with m-NBA or by the elevated temperature of ESI capillary. For all the analytes studied we, found striking differences in the ESI MS response to these two modes of activation. The data suggest that activation with m-NBA results in more extensive analyte charging with lower degree of denaturation. When working solution with m-NBA was analyzed at elevated temperatures, the SC effect from m-NBA was neutralized. Instead, the net SC effect was similar to the SC effect achieved by thermal activation only. Overall, our observations indicate that SC reagents enhance ESI charging of biomolecules via distinctly different mechanism compared with the traditional approaches based on analyte denaturation. Instead, the data support the hypothesis that the SC phenomenon involves a direct interaction between a biopolymer and SC reagent occurring in evaporating ESI droplets.
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Affiliation(s)
- Konstantin Chingin
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China Institute of Technology, Nanchang, Jiangxi Province, 330013, China,
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45
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Cassou CA, Williams ER. Anions in electrothermal supercharging of proteins with electrospray ionization follow a reverse Hofmeister series. Anal Chem 2014; 86:1640-7. [PMID: 24410546 PMCID: PMC3983018 DOI: 10.1021/ac403398j] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
![]()
The
effects of different anions on the extent of electrothermal
supercharging of proteins from aqueous ammonium and sodium salt solutions
were investigated. Sulfate and hydrogen phosphate are the most effective
anions at producing high charge state protein ions from buffered aqueous
solution, whereas iodide and perchlorate are ineffective with electrothermal
supercharging. The propensity for these anions to produce high charge
state protein ions follows the following trend: sulfate > hydrogen
phosphate > thiocyanate > bicarbonate > chloride > formate
≈
bromide > acetate > iodide > perchlorate. This trend correlates
with
the reverse Hofmeister series over a wide range of salt concentrations
(1 mM to 2 M) and with several physical properties, including solvent
surface tension, anion viscosity B-coefficient, and anion surface/bulk
partitioning coefficient, all of which are related to the Hofmeister
series. The effectiveness of electrothermal supercharging does not
depend on bubble formation, either from thermal degradation of the
buffer or from coalescence of dissolved gas. These results provide
evidence that the effect of different ions in the formation of high
charge state ions by electrothermal supercharging is largely a result
of Hofmeister effects on protein stability leading to protein unfolding
in the heated ESI droplet.
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Affiliation(s)
- Catherine A Cassou
- Department of Chemistry, University of California , Berkeley, California 94720-1460, United States
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46
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Rahman MM, Hiraoka K, Chen LC. Realizing nano electrospray ionization using disposable pipette tips under super atmospheric pressure. Analyst 2014; 139:610-7. [DOI: 10.1039/c3an01635h] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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47
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Konermann L, Vahidi S, Sowole MA. Mass Spectrometry Methods for Studying Structure and Dynamics of Biological Macromolecules. Anal Chem 2013; 86:213-32. [DOI: 10.1021/ac4039306] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7 Canada
| | - Siavash Vahidi
- Department of Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7 Canada
| | - Modupeola A. Sowole
- Department of Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7 Canada
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48
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Abstract
American Society for Mass Spectrometry Sanibel meeting on top-down mass spectrometry St Pete Beach, FL, USA, 24-27 January 2013 Top-down mass spectrometry involves analysis of intact proteins, typically using electrospray ionization, as multiple charging enhances dissociation and thus identification by comparison of precursor and product ion masses with protein sequence databases. Traditionally a low-throughput, precision technology performed on high-resolution Fourier-transform ion cyclotron resonance mass analyzers, top-down proteomics aims to increase throughput for whole proteome analysis while preserving the inherent value of an intact protein mass measurement. This years' American Society for Mass Spectrometry Sanibel meeting brought together established scientists who have demonstrated the viability of the top-down approach and its applicability to virtually all segments of the proteome, mixing them with researchers from diverse areas and with the common interest of advancing top-down into the high-throughput proteomics mainstream. Advances in instrumentation including the orbitrap analyzer, ionization mechanisms, dissociation strategies and informatics, as well as a wide variety of applications, were discussed in depth, leading to the inescapable conclusion that the future for top-down is bright.
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Affiliation(s)
- Julian Whitelegge
- The Pasarow Mass Spectrometry Laboratory, UCLA, Jane and Terry Semel Institute for Neuroscience and Human Behavior, Los Angeles, CA 90095, USA.
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49
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Hedges JB, Vahidi S, Yue X, Konermann L. Effects of Ammonium Bicarbonate on the Electrospray Mass Spectra of Proteins: Evidence for Bubble-Induced Unfolding. Anal Chem 2013; 85:6469-76. [DOI: 10.1021/ac401020s] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Jason B. Hedges
- Department of Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7, Canada
| | - Siavash Vahidi
- Department of Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7, Canada
| | - Xuanfeng Yue
- Department of Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7, Canada
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50
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Testa L, Brocca S, Santambrogio C, D'Urzo A, Habchi J, Longhi S, Uversky VN, Grandori R. Extracting structural information from charge-state distributions of intrinsically disordered proteins by non-denaturing electrospray-ionization mass spectrometry. INTRINSICALLY DISORDERED PROTEINS 2013; 1:e25068. [PMID: 28516012 PMCID: PMC5424789 DOI: 10.4161/idp.25068] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 05/02/2013] [Accepted: 05/16/2013] [Indexed: 11/23/2022]
Abstract
Intrinsically disordered proteins (IDPs) exert key biological functions but tend to escape identification and characterization due to their high structural dynamics and heterogeneity. The possibility to dissect conformational ensembles by electrospray-ionization mass spectrometry (ESI-MS) offers an attracting possibility to develop a signature for this class of proteins based on their peculiar ionization behavior. This review summarizes available data on charge-state distributions (CSDs) obtained for IDPs by non-denaturing ESI-MS, with reference to globular or chemically denatured proteins. The results illustrate the contributions that direct ESI-MS analysis can give to the identification of new putative IDPs and to their conformational investigation.
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Affiliation(s)
- Lorenzo Testa
- Department of Biotechnology and Biosciences; University of Milano-Bicocca; Milan, Italy
| | - Stefania Brocca
- Department of Biotechnology and Biosciences; University of Milano-Bicocca; Milan, Italy
| | - Carlo Santambrogio
- Department of Biotechnology and Biosciences; University of Milano-Bicocca; Milan, Italy
| | - Annalisa D'Urzo
- Department of Biotechnology and Biosciences; University of Milano-Bicocca; Milan, Italy
| | - Johnny Habchi
- Aix-Marseille Université; CNRS, Architecture et Fonction des Macromolécules Biologiques (AFMB); Marseille, France
| | - Sonia Longhi
- Aix-Marseille Université; CNRS, Architecture et Fonction des Macromolécules Biologiques (AFMB); Marseille, France
| | - Vladimir N Uversky
- Department of Molecular Medicine; College of Medicine; University of South Florida; Tampa, FL USA.,Institute for Biological Instrumentation; Russian Academy of Sciences; Pushchino, Moscow Region, Russia
| | - Rita Grandori
- Department of Biotechnology and Biosciences; University of Milano-Bicocca; Milan, Italy
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