1
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Liu J, Zheng Z, Wang N, Li G. Plasma-Droplet Fusion-Mass Spectrometry Reveals Sub-Millisecond Protein Unfolding Dynamics Induced by Reactive Oxygen Species. Anal Chem 2024; 96:2292-2296. [PMID: 38295309 DOI: 10.1021/acs.analchem.3c03419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
Investigating the connection between reactive oxygen species (ROS) and oxidative protein unfolding is critical to reveal the mechanisms underlying disease involving elevated ROS and protein misfolding. This could inform the development of therapeutics targeting cells based on their redox status. In this study, we developed a plasma-droplet fusion-mass spectrometry platform to rapidly assess protein resilience to ROS. This home-built system fuses ROS generated from the microplasma source with protein microdroplets from a tunable nanospray source. At the droplet-plasma intersection, ROS interact with proteins before entering the mass spectrometer for mass identification and structural characterization. Benefiting from the small-sized microdroplet with adjustable traveling velocity, the platform enables the first sub-millisecond kinetic study of ROS-induced protein unfolding, with a rate constant of approximately 1.81 ms-1. Capturing ROS-induced protein unfolding intermediates and the resultant ligand release dynamics can be extended to many more protein systems. We foresee broad applications for establishing previously undetected protein unfolding events when biologically impactful ROS are enriched in time and space with functional proteins and complexes.
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Affiliation(s)
- Jun Liu
- Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Science, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Zhen Zheng
- School of Pharmacy, Tianjin Medical University, Tianjin 300070, China
| | - Ning Wang
- Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Science, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Gongyu Li
- Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Science, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, China
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2
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Ying Y, Li H. Native top-down mass spectrometry for monitoring the rapid chymotrypsin catalyzed hydrolysis reaction. Anal Chim Acta 2024; 1285:341971. [PMID: 38057065 DOI: 10.1016/j.aca.2023.341971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 10/13/2023] [Accepted: 10/26/2023] [Indexed: 12/08/2023]
Abstract
Enzymes play crucial roles in life sciences, pharmaceuticals and industries as biological catalysts that speed up biochemical reactions in living organisms. New catalytic reactions are continuously developed by enzymatic engineering to meet industrial needs, which thereby drives the development of analytical approaches for real-time reaction monitoring to reveal catalytic processes. Here, taking the hydrolase- chymotrypsin as a model system, we proposed a convenient method for monitoring catalytic processes through native top-down mass spectrometry (native TDMS). The chymotrypsin sample heterogeneity was first explored. By altering sample introduction modes and pHs, covalent and noncovalent enzymatic complexes, substrates and products can be monitored during the catalysis and further confirmed by tandem MS. Our results demonstrated that native TDMS based catalysis monitoring has distinctive strength on real-time inspection and continuous observation, making it a promising tool for characterizing more biocatalysts.
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Affiliation(s)
- Yujia Ying
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, 510006, China.
| | - Huilin Li
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, 510006, China; Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, 510006, China.
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3
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Wang T, Li Z, Gao H, Hu J, Chen HY, Xu JJ. Ultrafast C-C and C-N bond formation reactions in water microdroplets facilitated by the spontaneous generation of carbocations. Chem Sci 2023; 14:11515-11520. [PMID: 37886101 PMCID: PMC10599473 DOI: 10.1039/d3sc03870j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 09/24/2023] [Indexed: 10/28/2023] Open
Abstract
Carbocations are important electrophilic intermediates in organic chemistry, but their formation typically requires harsh conditions such as extremely low pH, elevated temperature, strong oxidants and/or expensive noble-metal catalysts. Herein, we report the spontaneous generation of highly reactive carbocations in water microdroplets by simply spraying a diarylmethanol aqueous solution. The formation of transient carbocations as well as their ultrafast in-droplet transformations through carbocation-involved C-C and C-N bond formation reactions are directly characterized by mass spectrometry. The intriguing formation and stabilization of carbocations are attributed to the super acidity of the positively charged water microdroplets as well as the high electric fields at the water-air interfaces. Without the utilization of external acids as catalysts, we believe that these microdroplet reactions would pose a new and sustainable way for the construction of aryl-substituted compounds.
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Affiliation(s)
- Ting Wang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 P. R. China
| | - Zheng Li
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 P. R. China
| | - Hang Gao
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 P. R. China
| | - Jun Hu
- School of Life Sciences and Health Engineering, Jiangnan University Wuxi 214122 China
| | - Hong-Yuan Chen
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 P. R. China
| | - Jing-Juan Xu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 P. R. China
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4
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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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5
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Hatvany JB, Gallagher ES. Hydrogen/deuterium exchange for the analysis of carbohydrates. Carbohydr Res 2023; 530:108859. [PMID: 37290371 DOI: 10.1016/j.carres.2023.108859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/26/2023] [Accepted: 05/30/2023] [Indexed: 06/10/2023]
Abstract
Carbohydrates and glycans are integral to many biological processes, including cell-cell recognition and energy storage. However, carbohydrates are often difficult to analyze due to the high degree of isomerism present. One method being developed to distinguish these isomeric species is hydrogen/deuterium exchange-mass spectrometry (HDX-MS). In HDX-MS, carbohydrates are exposed to a deuterated reagent and the functional groups with labile hydrogen atoms, including hydroxyls and amides, exchange with the 1 amu heavier isotope, deuterium. These labels can then be detected by MS, which monitors the mass increase with the addition of D-labels. The observed rate of exchange is dependent on the exchanging functional group, the accessibility of the exchanging functional group, and the presence of hydrogen bonds. Herein, we discuss how HDX has been applied in the solution-phase, gas-phase, and during MS ionization to label carbohydrates and glycans. Additionally, we compare differences in the conformations that are labeled, the labeling timeframes, and applications of each of these methods. Finally, we comment on future opportunities for development and use of HDX-MS to analyze glycans and glycoconjugates.
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Affiliation(s)
- Jacob B Hatvany
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, TX, 76798, USA
| | - Elyssia S Gallagher
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, TX, 76798, USA.
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6
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Chen CJ, Williams ER. The role of analyte concentration in accelerated reaction rates in evaporating droplets. Chem Sci 2023; 14:4704-4713. [PMID: 37181782 PMCID: PMC10171075 DOI: 10.1039/d3sc00259d] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 04/04/2023] [Indexed: 05/16/2023] Open
Abstract
Accelerated reactions in microdroplets have been reported for a wide range of reactions with some microdroplet reactions occurring over a million times faster than the same reaction in bulk solution. Unique chemistry at the air-water interface has been implicated as a primary factor for accelerated reaction rates, but the role of analyte concentration in evaporating droplets has not been as well studied. Here, theta-glass electrospray emitters and mass spectrometry are used to rapidly mix two solutions on the low to sub-microsecond time scale and produce aqueous nanodrops with different sizes and lifetimes. We demonstrate that for a simple bimolecular reaction where surface chemistry does not appear to play a role, reaction rate acceleration factors are between 102 and 107 for different initial solution concentrations, and these values do not depend on nanodrop size. A rate acceleration factor of 107 is among the highest reported and can be attributed to concentration of analyte molecules, initially far apart in dilute solution, but brought into close proximity in the nanodrop through evaporation of solvent from the nanodrops prior to ion formation. These data indicate that analyte concentration phenomenon is a significant factor in reaction acceleration where droplet volume throughout the experiment is not carefully controlled.
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Affiliation(s)
- Casey J Chen
- Department of Chemistry, University of California Berkeley CA 94720 USA
| | - Evan R Williams
- Department of Chemistry, University of California Berkeley CA 94720 USA
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7
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Aerts JT, Andrén PE, Jansson ET. Electrochemically Etched Tapered-Tip Stainless-Steel Electrospray-Ionization Emitters for Capillary Electrophoresis-Mass Spectrometry. J Proteome Res 2023; 22:1377-1380. [PMID: 36866861 PMCID: PMC10088039 DOI: 10.1021/acs.jproteome.3c00076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
We have used household consumables to facilitate electrochemical etching of stainless-steel hypodermic tubing to produce tapered-tip emitters suitable for electrospray ionization for use in mass spectrometry. The process involves the use of 1% oxalic acid and a 5 W USB power adapter, commonly known as a phone charger. Further, our method avoids the otherwise commonly used strong acids that entail chemical hazards: concentrated HNO3 for etching stainless steel, or concentrated HF for etching fused silica. Hence, we here provide a convenient and self-inhibiting procedure with minimal chemical hazards to manufacture tapered-tip stainless-steel emitters. We show its performance in metabolomic analysis with CE-MS of a tissue homogenate where the metabolites acetylcarnitine, arginine, carnitine, creatine, homocarnosine, and valerylcarnitine were identified, all with basepeak separated electropherograms, within <6 min of separation. The mass spectrometry data are freely available through the MetaboLight public data repository via access number MTBLS7230.
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Affiliation(s)
- Jordan T Aerts
- Department of Pharmaceutical Biosciences, Uppsala University, SE-751 24 Uppsala, Sweden
| | - Per E Andrén
- Department of Pharmaceutical Biosciences, Uppsala University, SE-751 24 Uppsala, Sweden.,Science for Life Laboratory, Spatial Mass Spectrometry, Uppsala University, SE-751 24 Uppsala, Sweden
| | - Erik T Jansson
- Department of Pharmaceutical Biosciences, Uppsala University, SE-751 24 Uppsala, Sweden
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8
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Jordan JS, Williams ER. Laser Heating Nanoelectrospray Emitters for Fast Protein Melting Measurements with Mass Spectrometry. Anal Chem 2022; 94:16894-16900. [DOI: 10.1021/acs.analchem.2c04204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Jacob S. Jordan
- 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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9
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Brown SL, Zenaidee MA, Loo JA, Loo RRO, Donald WA. On the Mechanism of Theta Capillary Nanoelectrospray Ionization for the Formation of Highly Charged Protein Ions Directly from Native Solutions. Anal Chem 2022; 94:13010-13018. [DOI: 10.1021/acs.analchem.2c01654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Susannah L. Brown
- School of Chemistry, University of New South Wales, Sydney 2052, Australia
| | - Muhammad A. Zenaidee
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States of America
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States of America
| | - Rachel R. Ogorzalek Loo
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States of America
| | - William A. Donald
- School of Chemistry, University of New South Wales, Sydney 2052, Australia
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10
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Gao XF, Cheng JC, Ye CL, Xiao S, Qiu ZM, Zhang X. Water promoted 9-fluorenylmethyloxycarbonyl detachment from amino acids in charged microdroplets. Org Biomol Chem 2022; 20:7001-7005. [PMID: 36000329 DOI: 10.1039/d2ob01438f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aqueous microdroplets exhibit unique properties and can trigger reactions that do not occur in bulk solution. Herein, we have demonstrated that water, in microdroplets, can reduce the energy barrier for the lone H transfer of 9-fluorenylmethyloxycarbonyl and promote its detachment from the amino group. This strategy works on various amino acids and opens opportunities of aqueous microdroplets in triggering organic reactions.
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Affiliation(s)
- Xiao-Fei Gao
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China University of Technology, Nanchang 330013, China.
| | - Jin-Cai Cheng
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China University of Technology, Nanchang 330013, China.
| | - Chun-Lian Ye
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China University of Technology, Nanchang 330013, China.
| | - Shan Xiao
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China University of Technology, Nanchang 330013, China.
| | - Zai-Ming Qiu
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China University of Technology, Nanchang 330013, China.
| | - Xinglei Zhang
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China University of Technology, Nanchang 330013, China.
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11
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Chen M, Shang Y, Bai H, Ma Q. Electromembrane Extraction and Dual-Channel Nanoelectrospray Ionization Coupled with a Miniature Mass Spectrometer: Incorporation of a Dicationic Ionic Liquid-Induced Charge Inversion Strategy. Anal Chem 2022; 94:9472-9480. [PMID: 35737371 DOI: 10.1021/acs.analchem.2c01921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Green analytical chemistry aims at developing analytical methods with minimum use and generation of hazardous substances for the protection of human health and the environment. To address this need, a green analytical protocol has been developed for the analysis of anionic compounds integrating electromembrane extraction (EME), dual-channel nanoelectrospray ionization (nanoESI), and a miniature mass spectrometer. Haloacetic acids (HAAs) have attracted considerable public concern due to their adverse effects on human health and were selected as model analytes for method development. A flat membrane EME device was developed and assembled in-house. Optimization of fundamental operational parameters was performed using single-factor test and response surface methodology. Both the EME acceptor phase and an imidazolium-based dicationic ionic liquid (DIL), 1,1-bis(3-methylimidazolium-1-yl) butylene difluoride (C4(MIM)2F2), were subjected to dual-channel nanoESI and miniature mass spectrometry analysis based on a charge inversion strategy, where positively charged complexes were formed. Enhancement in signal intensity by as much as 2 magnitudes was achieved in the positive-ion mode compared to the negative-ion mode in the absence of the dicationic ion-pairing agent. The developed protocol was validated, obtaining good recoveries ranging from 82.7 to 109.9% and satisfactory sensitivity with limits of detection (LODs) and quantitation (LOQs) in the ranges of 1-5 and 2-10 μg/L, respectively. The greenness of the analytical procedure was assessed with a calculated score of 0.71, indicating a high degree of greenness. The developed method was applied to the analysis of real environmental or municipal water samples (n = 16), exhibiting appealing potential for outside-the-laboratory applications.
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Affiliation(s)
- Meng Chen
- Key Laboratory of Consumer Product Quality Safety Inspection and Risk Assessment for State Market Regulation, Chinese Academy of Inspection and Quarantine, Beijing 100176, China
| | - Yuhan Shang
- Key Laboratory of Consumer Product Quality Safety Inspection and Risk Assessment for State Market Regulation, Chinese Academy of Inspection and Quarantine, Beijing 100176, China
| | - Hua Bai
- Key Laboratory of Consumer Product Quality Safety Inspection and Risk Assessment for State Market Regulation, Chinese Academy of Inspection and Quarantine, Beijing 100176, China
| | - Qiang Ma
- Key Laboratory of Consumer Product Quality Safety Inspection and Risk Assessment for State Market Regulation, Chinese Academy of Inspection and Quarantine, Beijing 100176, China
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12
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Kostelic MM, Hsieh CC, Sanders HM, Zak CK, Ryan JP, Baker ES, Aspinwall CA, Marty MT. Surface Modified Nano-Electrospray Needles Improve Sensitivity for Native Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:1031-1037. [PMID: 35588532 DOI: 10.1021/jasms.2c00087] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Native mass spectrometry (MS) and charge detection-mass spectrometry (CD-MS) have become versatile tools for characterizing a wide range of proteins and macromolecular complexes. Both commonly use nanoelectrospray ionization (nESI) from pulled borosilicate needles, but some analytes are known to nonspecifically adsorb to the glass, which may lower sensitivity and limit the quality of the data. To improve the sensitivity of native MS and CD-MS, we modified the surface of nESI needles with inert surface modifiers, including polyethylene-glycol. We found that the surface modification improved the signal intensity for native MS of proteins and for CD-MS of adeno-associated viral capsids. Based on mechanistic comparisons, we hypothesize that the improvement is more likely due to an increased flow rate with coated ESI needles rather than less nonspecific adsorption. In any case, these surface-modified needles provide a simple and inexpensive method for improving the sensitivity of challenging analytes.
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Affiliation(s)
- Marius M Kostelic
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Chih-Chieh Hsieh
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Henry M Sanders
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Ciara K Zak
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Jack P Ryan
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27659, United States
| | - Erin S Baker
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27659, United States
| | - Craig A Aspinwall
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
- Bio5 Institute, University of Arizona, Tucson, Arizona 85721, United States
| | - Michael T Marty
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
- Bio5 Institute, University of Arizona, Tucson, Arizona 85721, United States
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13
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Jordan JS, Xia Z, Williams ER. Tips on Making Tiny Tips: Secrets to Submicron Nanoelectrospray Emitters. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:607-611. [PMID: 35157433 DOI: 10.1021/jasms.1c00372] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Nanoelectrospray ionization emitters with submicron tip diameters have significant advantages for use in native mass spectrometry, including the ability to produce resolved charge-state distributions for proteins and macromolecular complexes from standard biochemical buffers that contain high concentrations of nonvolatile salts and to prevent nonspecific aggregation that can occur during droplet evaporation. We report on various factors affecting the tip morphology and provide suggestions for producing and using emitters with submicron tips. Effects of pulling parameters for a Sutter Instrument P-87 tip puller on the resulting tip diameter and morphology are shown. The "Pull" parameter has the largest effect on tip diameter, followed by "Velocity", "Pressure", and "Heat", whereas the "Time" parameter has minimal effect beyond a lower threshold. High "Pull" values generate emitters with multiple tapers, whereas high "Velocity" values generate a tip with only a single tapered region. A protocol for producing reproducible emitters in the submicron size range, as well as guidelines and tips for using these emitters with standard biochemical buffers that contain high concentrations of nonvolatile salts, is presented with the aim of expanding their use within the native mass spectrometry community.
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Affiliation(s)
- Jacob S Jordan
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Zijie Xia
- 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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14
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Bai Y, Luan P, Bai Y, Zare RN, Ge J. Enzyme-photo-coupled catalysis in gas-sprayed microdroplets. Chem Sci 2022; 13:8341-8348. [PMID: 35919726 PMCID: PMC9297532 DOI: 10.1039/d2sc02791g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 06/22/2022] [Indexed: 11/21/2022] Open
Abstract
Enzyme-photo-coupled catalysis produces fine chemicals by combining the high selectivity of an enzyme with the green energy input of sunlight. Operating a large-scale system, however, remains challenging because of the...
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Affiliation(s)
- Yunxiu Bai
- Key Lab for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University Beijing 100084 P. R. China
| | - Pengqian Luan
- Institute of Biomedical Health Technology and Engineering, Shenzhen Bay Laboratory Shenzhen 518107 P. R. China
| | - Yunpeng Bai
- State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing, East China University of Science and Technology (ECUST) Shanghai 200237 P. R. China
| | - Richard N Zare
- Department of Chemistry, Stanford University Stanford California 94305-5080 USA
| | - Jun Ge
- Key Lab for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University Beijing 100084 P. R. China
- Institute of Biomedical Health Technology and Engineering, Shenzhen Bay Laboratory Shenzhen 518107 P. R. China
- Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School Shenzhen 518055 P. R. China
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15
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Sun J, Yin Y, Li W, Jin O, Na N. CHEMICAL REACTION MONITORING BY AMBIENT MASS SPECTROMETRY. MASS SPECTROMETRY REVIEWS 2022; 41:70-99. [PMID: 33259644 DOI: 10.1002/mas.21668] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/16/2020] [Accepted: 10/22/2020] [Indexed: 06/12/2023]
Abstract
Chemical reactions conducted in different media (liquid phase, gas phase, or surface) drive developments of versatile techniques for the detection of intermediates and prediction of reasonable reaction pathways. Without sample pretreatment, ambient mass spectrometry (AMS) has been applied to obtain structural information of reactive molecules that differ in polarity and molecular weight. Commercial ion sources (e.g., electrospray ionization, atmospheric pressure chemical ionization, and direct analysis in real-time) have been reported to monitor substrates and products by offline reaction examination. While the interception or characterization of reactive intermediates with short lifetime are still limited by the offline modes. Notably, online ionization technologies, with high tolerance to salt, buffer, and pH, can achieve direct sampling and ionization of on-going reactions conducted in different media (e.g., liquid phase, gas phase, or surface). Therefore, short-lived intermediates could be captured at unprecedented timescales, and the reaction dynamics could be studied for mechanism examinations without sample pretreatments. In this review, via various AMS methods, chemical reaction monitoring and mechanism elucidation for different classifications of reactions have been reviewed. The developments and advances of common ionization methods for offline reaction monitoring will also be highlighted.
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Affiliation(s)
- Jianghui Sun
- Key Laboratory of Radiopharmaceuticals Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China
| | - Yiyan Yin
- Key Laboratory of Radiopharmaceuticals Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China
| | - Weixiang Li
- Key Laboratory of Radiopharmaceuticals Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China
| | - Ouyang Jin
- Key Laboratory of Radiopharmaceuticals Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China
| | - Na Na
- Key Laboratory of Radiopharmaceuticals Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China
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16
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Hu J, Wang T, Zhang WJ, Hao H, Yu Q, Gao H, Zhang N, Chen Y, Xia XH, Chen HY, Xu JJ. Dissecting the Flash Chemistry of Electrogenerated Reactive Intermediates by Microdroplet Fusion Mass Spectrometry. Angew Chem Int Ed Engl 2021; 60:18494-18498. [PMID: 34129259 DOI: 10.1002/anie.202106945] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Indexed: 11/06/2022]
Abstract
A novel mass spectrometric method for probing the flash chemistry of electrogenerated reactive intermediates was developed based on rapid collision mixing of electrosprayed microdroplets by using a theta-glass capillary. The two individual microchannels of the theta-glass capillary are asymmetrically or symmetrically fabricated with a carbon bipolar electrode to produce intermediates in situ. Microdroplets containing the newly formed intermediates collide with those of the invoked reactants at sub-10 microsecond level, making it a powerful tool for exploring their ultrafast initial transformations. As a proof-of-concept, we present the identification of the key radical cation intermediate in the oxidative dimerization of 8-methyl-1,2,3,4-tetrahydroquinoline and also the first disclosure of previously hidden nitrenium ion involved reaction pathway in the C-H/N-H cross-coupling between N,N'-dimethylaniline and phenothiazine.
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Affiliation(s)
- Jun Hu
- State Key Laboratory of Reproductive Medicine and Key Laboratory of Cardiovascular & Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, China
| | - Ting Wang
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Wen-Jun Zhang
- State Key Laboratory of Reproductive Medicine and Key Laboratory of Cardiovascular & Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, China
| | - Han Hao
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada
| | - Qiao Yu
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Hang Gao
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Nan Zhang
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Yun Chen
- State Key Laboratory of Reproductive Medicine and Key Laboratory of Cardiovascular & Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, China
| | - Xing-Hua Xia
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Hong-Yuan Chen
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Jing-Juan Xu
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
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17
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Hu J, Wang T, Zhang W, Hao H, Yu Q, Gao H, Zhang N, Chen Y, Xia X, Chen H, Xu J. Dissecting the Flash Chemistry of Electrogenerated Reactive Intermediates by Microdroplet Fusion Mass Spectrometry. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202106945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jun Hu
- State Key Laboratory of Reproductive Medicine and Key Laboratory of Cardiovascular & Cerebrovascular Medicine School of Pharmacy Nanjing Medical University Nanjing 211166 China
| | - Ting Wang
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences School of Chemistry and Chemical Engineering Nanjing University Nanjing 210023 China
| | - Wen‐Jun Zhang
- State Key Laboratory of Reproductive Medicine and Key Laboratory of Cardiovascular & Cerebrovascular Medicine School of Pharmacy Nanjing Medical University Nanjing 211166 China
| | - Han Hao
- Department of Chemistry University of Toronto 80 St. George Street Toronto ON M5S 3H6 Canada
| | - Qiao Yu
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences School of Chemistry and Chemical Engineering Nanjing University Nanjing 210023 China
| | - Hang Gao
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences School of Chemistry and Chemical Engineering Nanjing University Nanjing 210023 China
| | - Nan Zhang
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences School of Chemistry and Chemical Engineering Nanjing University Nanjing 210023 China
| | - Yun Chen
- State Key Laboratory of Reproductive Medicine and Key Laboratory of Cardiovascular & Cerebrovascular Medicine School of Pharmacy Nanjing Medical University Nanjing 211166 China
| | - Xing‐Hua Xia
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences School of Chemistry and Chemical Engineering Nanjing University Nanjing 210023 China
| | - Hong‐Yuan Chen
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences School of Chemistry and Chemical Engineering Nanjing University Nanjing 210023 China
| | - Jing‐Juan Xu
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences School of Chemistry and Chemical Engineering Nanjing University Nanjing 210023 China
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18
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Li YL, Zhou BW, Cao YQ, Zhang J, Zhang L, Guo YL. Chiral Analysis of Lactate during Direct Contact Coculture by Single-Cell On-Probe Enzymatic Dehydrogenation Derivatization: Unraveling Metabolic Changes Caused by d-Lactate. Anal Chem 2021; 93:4576-4583. [PMID: 33656332 DOI: 10.1021/acs.analchem.0c05015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In vitro noncontact cell-based coculture models are frequently employed to study cell-to-cell communication. However, these models cannot accurately represent the complexity of in vivo signaling. d-Lactate is an unusual metabolite produced and released by cancer cells. The characterization of d-lactate is challenging as it shares the same mass but has much lower amounts compared with l-lactate. Herein, d-α-hydroxy acids were specifically recognized and dehydrogenated by d-α-hydroxy acid dehydrogenase. The dehydrogenation products were rapidly quaternized for enhancement of mass signals. An on-probe enzymatic dehydrogenation-derivatization method was proposed for chiral analysis of α-hydroxy acids at the single-cell level. It is a promising amplification methodology and affords over 3 orders of magnitude signal enhancement. Furthermore, direct contact coculture models were used to precisely mimic the tumor microenvironment and explore the communication between cancer and normal cells. Single-cell mass spectrometry (SCMS) was further applied to easily sample cell extracts and study the differences of the aspects of small molecule metabolism in cocultured cells. On the basis of direct contact coculture SCMS, several differential small molecule metabolites and differences of oxidative stress between cocultured and monocultured normal cells were successfully detected. Additionally, d-lactate was discovered as a valuable differential metabolite with application of the two developed methods. It may account for the cancer-associated metabolic behavior of normal cells. These changes could be relieved after d-lactate metabolism-related drug treatment. This discovery may promote the investigation of d-lactate metabolism, which may provide a novel direction for cancer therapy.
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Affiliation(s)
- Yu-Ling Li
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Bo-Wen Zhou
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yu-Qi Cao
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jing Zhang
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Li Zhang
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yin-Long Guo
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China
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19
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Freitas D, Chen X, Cheng H, Davis A, Fallon B, Yan X. Recent Advances of In-Source Electrochemical Mass Spectrometry. Chempluschem 2021; 86:434-445. [PMID: 33689239 DOI: 10.1002/cplu.202100030] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 03/03/2021] [Indexed: 12/16/2022]
Abstract
Hyphenation of electrochemistry (EC) and mass spectrometry has become a powerful tool to study redox processes. Approaches that can achieve this hyphenation include integrating chromatography/electrophoresis between electroinduced redox reactions and detection of products, coupling an EC flow cell to a mass spectrometer, and performing electrochemical reactions inside the ion source of a mass spectrometer. The first two approaches have been well reviewed elsewhere. This Minireview highlights the inherent electrochemical properties of many mass spectrometry ion sources and their roles in the coupling of electrochemistry and mass spectrometric analysis. Development of modified ion sources that allow the compatibility of electrochemistry with ionization processes is also surveyed. Applications of different in-source electrochemical devices are provided including intermediate capturing, bioanalytical studies, nanoparticle formation, electrosynthesis, and electrode imaging.
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Affiliation(s)
- Dallas Freitas
- Department of Chemistry, Texas A&M University, 580 Ross St., College Station, TX 77843, USA
| | - Xi Chen
- Department of Chemistry, Texas A&M University, 580 Ross St., College Station, TX 77843, USA
| | - Heyong Cheng
- Department of Chemistry, Texas A&M University, 580 Ross St., College Station, TX 77843, USA
| | - Austin Davis
- Department of Chemistry, Texas A&M University, 580 Ross St., College Station, TX 77843, USA
| | - Blake Fallon
- Department of Chemistry, Texas A&M University, 580 Ross St., College Station, TX 77843, USA
| | - Xin Yan
- Department of Chemistry, Texas A&M University, 580 Ross St., College Station, TX 77843, USA
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20
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Báez Bolivar EG, Bui DT, Kitova EN, Han L, Zheng RB, Luber EJ, Sayed SY, Mahal LK, Klassen JS. Submicron Emitters Enable Reliable Quantification of Weak Protein-Glycan Interactions by ESI-MS. Anal Chem 2021; 93:4231-4239. [PMID: 33630563 DOI: 10.1021/acs.analchem.0c05003] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Interactions between carbohydrates (glycans) and glycan-binding proteins (GBPs) regulate a wide variety of important biological processes. However, the affinities of most monovalent glycan-GBP complexes are typically weak (dissociation constant (Kd) > μM) and difficult to reliably measure with conventional assays; consequently, the glycan specificities of most GBPs are not well established. Here, we demonstrate how electrospray ionization mass spectrometry (ESI-MS), implemented with nanoflow ESI emitters with inner diameters of ∼50 nm, allows for the facile quantification of low-affinity glycan-GBP interactions. The small size of the droplets produced from these submicron emitters effectively eliminates the formation of nonspecific glycan-GBP binding (false positives) during the ESI process up to ∼mM glycan concentrations. Thus, interactions with affinities as low as ∼5 mM can be measured directly from the mass spectrum. The general suppression of nonspecific adducts (including nonvolatile buffers and salts) achieved with these tips enables ESI-MS glycan affinity measurements to be performed on C-type lectins, a class of GBPs that bind glycans in a calcium-dependent manner and are important regulators of immune response. At physiologically relevant calcium ion concentrations (2-3 mM), the extent of Ca2+ nonspecific adduct formation observed using the submicron emitters is dramatically suppressed, allowing glycan affinities, and the influence of Ca2+ thereon, to be measured. Finally, we show how the use of submicron emitters and suppression of nonspecific binding enable the quantification of labile (prone to in-source dissociation) glycan-GBP interactions.
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Affiliation(s)
- Erick G Báez Bolivar
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
| | - Duong T Bui
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
| | - Elena N Kitova
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
| | - Ling Han
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
| | - Ruixiang B Zheng
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
| | - Erik J Luber
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
| | - Sayed Youssef Sayed
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
| | - Lara K Mahal
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
| | - John S Klassen
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
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21
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Tiwari P, Czar MF, Zenobi R. Fluorescence-Based Detection of the Desolvation Process of Protein Ions Generated in an Aqueous Electrospray Plume. Anal Chem 2021; 93:3635-3642. [PMID: 33557519 DOI: 10.1021/acs.analchem.0c05396] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new experimental setup to study laser-induced fluorescence from analytes at different locations in an electrospray plume has been developed. The high fluorescence collection efficiency (∼2%) of the setup, along with a sensitive charge coupled device (CCD) detector, enabled the study of low ion concentrations (down to ∼fM) in the plume. The use of small electrospray tip inner diameters (<1 μm) facilitated the fast desolvation of gaseous protein ions in an aqueous electrospray plume. Fluorescence spectra were acquired from specific locations along the plume axis in different aqueous electrospray plumes with three different analytes: a rhodamine dye and two proteins (ubiquitin and apomyoglobin) labeled with rhodamine dyes. To confirm the presence of gaseous ions, pure gas-phase fluorescence spectra were acquired in the vacuum of a modified ion trap mass spectrometer. These spectra were used to fit to confirm the presence of gaseous species in the corresponding spectra obtained from the electrospray plume. This study shows that with small inner diameter spray capillaries, gaseous protein ions generated at atmospheric pressure in an electrospray plume can be detected with fluorescence-based techniques. Fluorescence measurements can be used to study their structure in the electrospray plume, and the dynamics as they transition from solution to the gas phase and in the early stages after desolvation from charged droplets. Other techniques can also be applied to further study gaseous biomolecular structures under ambient conditions immediately after desolvation.
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Affiliation(s)
- Prince Tiwari
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093Zürich, Switzerland
| | - Martin F Czar
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093Zürich, Switzerland
| | - Renato Zenobi
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093Zürich, Switzerland
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22
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Jordan JS, Williams ER. Effects of Electrospray Droplet Size on Analyte Aggregation: Evidence for Serine Octamer in Solution. Anal Chem 2021; 93:1725-1731. [PMID: 33369386 DOI: 10.1021/acs.analchem.0c04343] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Spraying solutions of serine under a wide variety of conditions results in unusually abundant gaseous octamer clusters that exhibit significant homochiral specificity, but the extent to which these clusters exist in solution or are formed by clustering during droplet evaporation has been debated. Electrospray ionization emitters with tip sizes between 210 nm and 9.2 μm were used to constrain the number of serine molecules that droplets initially contain. Protonated octamer was observed for all tip sizes with 10 mM serine solution, but the abundance decreases from 10% of the serine population at the largest tip size to ∼5.6% for the two smallest tip sizes. At 100 μM, the population abundance of the protonated serine octamer decreases from 1% to 0.6% from the largest to the smallest tip size, respectively. At 100 μM, fewer than 10% of the initial droplets should contain even a single analyte molecule with 210 nm emitter tips. These results indicate that the majority of protonated octamer observed in mass spectra under previous conditions is formed by clustering inside the electrospray droplet, but ≤5.6% and ∼0.6% of serine exists as an octamer complex in 10 mM and 100 μM solutions, respectively. These results show that aggregation occurs in large droplets, but this aggregation can be eliminated using emitters with sufficiently small tips. Use of these emitters with small tips is advantageous for clearly distinguishing between species that exist in solution and species formed by clustering inside droplets as solvent evaporation occurs.
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Affiliation(s)
- Jacob S Jordan
- 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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23
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Woodall DW, Henderson LW, Raab SA, Honma K, Clemmer DE. Understanding the Thermal Denaturation of Myoglobin with IMS-MS: Evidence for Multiple Stable Structures and Trapped Pre-equilibrium States. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:64-72. [PMID: 32539412 PMCID: PMC7790998 DOI: 10.1021/jasms.0c00075] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Thermal denaturation of holomyoglobin (hMb) in solution (10 mM ammonium acetate at pH = 4.5, 6.8, and 9.0) was monitored by ion mobility spectrometry (IMS) and mass spectrometry (MS) techniques to characterize the stability and investigate structural changes involved in unfolding. We utilize two experimental approaches to induce thermal denaturation: a variable-temperature electrospray ionization (vT-ESI) source that heats the bulk solution in the ESI emitter, and a variable-power 10.6 μm CO2 laser that rapidly heats nanodroplets produced by ESI. These two approaches sample different time scales of the denaturation process; long time scales (seconds to minutes) where the system is at equilibrium using the vT-ESI approach and shorter time scales (μs) by rapid droplet heating in which the system is in a pre-equilibrium state. Increasing the solution temperature (from 28 to 95 °C in the vT-ESI experiments) shifts the charge state distribution from low charge states ([M + 7H]7+ to [M + 9H]9+) to more highly charged species. This is accompanied by loss of the heme group to yield the apomyoglobin (aMb) species, indicating that the protein has unfolded. Monitoring the formation of aMb and the shift in average charge states of aMb and hMb with solution temperature allows for relative quantitation of their individual stabilities, highlighting the stabilizing effects of heme binding. We compare the degree of unfolding induced by heating the bulk solution (using vT-ESI) to the laser droplet heating approach and find that the rapid nature of the laser heating approach allows for transient pre-equilibrium states to be sampled.
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Affiliation(s)
- Daniel W Woodall
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Lucas W Henderson
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Shannon A Raab
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Kenji Honma
- Graduate School of Material Science, University of Hyogo, 3-2-1 Kohto, Kamigori, Hyogo 678-1297, Japan
| | - David E Clemmer
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
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24
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Yu Y, Liu H, Yu Z, Witkowska HE, Cheng Y. Stoichiometry of Nucleotide Binding to Proteasome AAA+ ATPase Hexamer Established by Native Mass Spectrometry. Mol Cell Proteomics 2020; 19:1997-2015. [PMID: 32883800 PMCID: PMC7710143 DOI: 10.1074/mcp.ra120.002067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 08/04/2020] [Indexed: 11/06/2022] Open
Abstract
AAA+ ATPases constitute a large family of proteins that are involved in a plethora of cellular processes including DNA disassembly, protein degradation and protein complex disassembly. They typically form a hexametric ring-shaped structure with six subunits in a (pseudo) 6-fold symmetry. In a subset of AAA+ ATPases that facilitate protein unfolding and degradation, six subunits cooperate to translocate protein substrates through a central pore in the ring. The number and type of nucleotides in an AAA+ ATPase hexamer is inherently linked to the mechanism that underlies cooperation among subunits and couples ATP hydrolysis with substrate translocation. We conducted a native MS study of a monodispersed form of PAN, an archaeal proteasome AAA+ ATPase, to determine the number of nucleotides bound to each hexamer of the WT protein. We utilized ADP and its analogs (TNP-ADP and mant-ADP), and a nonhydrolyzable ATP analog (AMP-PNP) to study nucleotide site occupancy within the PAN hexamer in ADP- and ATP-binding states, respectively. Throughout all experiments we used a Walker A mutant (PANK217A) that is impaired in nucleotide binding as an internal standard to mitigate the effects of residual solvation on mass measurement accuracy and to serve as a reference protein to control for nonspecific nucleotide binding. This approach led to the unambiguous finding that a WT PAN hexamer carried - from expression host - six tightly bound ADP molecules that could be exchanged for ADP and ATP analogs. Although the Walker A mutant did not bind ADP analogs, it did bind AMP-PNP, albeit at multiple stoichiometries. We observed variable levels of hexamer dissociation and an appearance of multimeric species with the over-charged molecular ion distributions across repeated experiments. We posit that these phenomena originated during ESI process at the final stages of ESI droplet evolution.
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Affiliation(s)
- Yadong Yu
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA
| | - Haichuan Liu
- Department of OBGYN & Reproductive Sci, Sandler-Moore MS Core Facility, University of California San Francisco, San Francisco, California, USA
| | - Zanlin Yu
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA
| | - H Ewa Witkowska
- Department of OBGYN & Reproductive Sci, Sandler-Moore MS Core Facility, University of California San Francisco, San Francisco, California, USA.
| | - Yifan Cheng
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA; Howard Hughes Medical Institute, University of California San Francisco, San Francisco, California, USA.
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25
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Rovelli G, Jacobs MI, Willis MD, Rapf RJ, Prophet AM, Wilson KR. A critical analysis of electrospray techniques for the determination of accelerated rates and mechanisms of chemical reactions in droplets. Chem Sci 2020; 11:13026-13043. [PMID: 34094487 PMCID: PMC8163298 DOI: 10.1039/d0sc04611f] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 10/25/2020] [Indexed: 12/14/2022] Open
Abstract
Electrospray and Electrosonic Spray Ionization Mass Spectrometry (ESI-MS and ESSI-MS) have been widely used to report evidence that many chemical reactions in micro- and nano-droplets are dramatically accelerated by factors of ∼102 to 106 relative to macroscale bulk solutions. Despite electrospray's relative simplicity to both generate and detect reaction products in charged droplets using mass spectrometry, substantial complexity exists in how the electrospray process itself impacts the interpretation of the mechanism of these observed accelerated rates. ESI and ESSI are both coupled multi-phase processes, in which analytes in small charged droplets are transferred and detected as gas-phase ions with a mass spectrometer. As such, quantitative examination is needed to evaluate the impact of multiple experimental factors on the magnitude and mechanisms of reaction acceleration. These include: (1) evaporative concentration of reactants as a function of droplet size and initial concentration, (2) competition from gas-phase chemistry and reactions on experimental surfaces, (3) differences in ionization efficiency and ion transmission and (4) droplet charge. We examine (1-4) using numerical models, new ESI/ESSI-MS experimental data, and prior literature to assess the limitations of these approaches and the experimental best practices required to robustly interpret acceleration factors in micro- and nano-droplets produced by ESI and ESSI.
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Affiliation(s)
- Grazia Rovelli
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
| | - Michael I Jacobs
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
- Department of Chemistry, University of California Berkeley 94720 CA USA
| | - Megan D Willis
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
| | - Rebecca J Rapf
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
| | - Alexander M Prophet
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
- Department of Chemistry, University of California Berkeley 94720 CA USA
| | - Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
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26
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Wei Z, Li Y, Cooks RG, Yan X. Accelerated Reaction Kinetics in Microdroplets: Overview and Recent Developments. Annu Rev Phys Chem 2020; 71:31-51. [PMID: 32312193 DOI: 10.1146/annurev-physchem-121319-110654] [Citation(s) in RCA: 193] [Impact Index Per Article: 48.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Various organic reactions, including important synthetic reactions involving C-C, C-N, and C-O bond formation as well as reactions of biomolecules, are accelerated when the reagents are present in sprayed or levitated microdroplets or in thin films. The reaction rates increase by orders of magnitude with decreasing droplet size or film thickness. The effect is associated with reactions at the solution-air interface. A key factor is partial solvation of the reagents at the interface, which reduces the critical energy for reaction. This phenomenon is of intrinsic interest and potentially of practical value as a simple, rapid method of performing small-scale synthesis.
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Affiliation(s)
- Zhenwei Wei
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA;
| | - Yangjie Li
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA;
| | - R Graham Cooks
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA;
| | - Xin Yan
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, USA;
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27
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Pal S, Banerjee S, Prabhakaran EN. Helix-Coil Transition at a Glycine Following a Nascent α-Helix: A Synergetic Guidance Mechanism for Helix Growth. J Phys Chem A 2020; 124:7478-7490. [PMID: 32877193 DOI: 10.1021/acs.jpca.0c05489] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A detailed understanding of forces guiding the rapid folding of a polypeptide from an apparently random coil state to an ordered α-helical structure following the rate-limiting preorganization of the initial three residue backbones into helical conformation is imperative to comprehending and regulating protein folding and for the rational design of biological mimetics. However, several details of this process are still unknown. First, although the helix-coil transition was proposed to originate at the residue level (J. Chem. Phys. 1959, 31, 526-535; J. Chem. Phys. 1961, 34, 1963-1974), all helix-folding studies have only established it between time-averaged bulk states of a long-lived helix and several transiently populated random coils, along the whole helix model sequence. Second, the predominant thermodynamic forces driving either this two-state transition or the faster helix growth following helix nucleation are still unclear. Third, the conformational space of the random coil state is not well-defined unlike its corresponding α-helix. Here we investigate the restrictions placed on the conformational space of a Gly residue backbone, as a result of it immediately succeeding a nascent α-helical turn. Analyses of the temperature-dependent 1D-, 2D-NMR, FT-IR, and CD spectra and GROMACS MD simulation trajectory of a Gly residue backbone following a model α-helical turn, which is artificially rigidified by a covalent hydrogen bond surrogate, reveal that: (i) the α-helical turn guides the ϕ torsion of the Gly exclusively into either a predominantly populated entropically favored α-helical (α-ϕ) state or a scarcely populated random coil (RC-ϕ) state; (ii) the α-ϕ state of Gly in turn favors the stability of the preceding α-helical turn, while the RC-ϕ state disrupts it, revealing an entropy-driven synergetic guidance for helix growth in the residue following helix nucleation. The applicability of a current synergetic guidance mechanism to explain rapid helix growth in folded and unfolded states of proteins and helical peptides is discussed.
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Affiliation(s)
- Sunit Pal
- Department of Chemistry, Indian Institute of Science, Bangalore, Karnataka-560012, India
| | - Shreya Banerjee
- Department of Chemistry, Indian Institute of Science, Bangalore, Karnataka-560012, India
| | - Erode N Prabhakaran
- Department of Chemistry, Indian Institute of Science, Bangalore, Karnataka-560012, India
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28
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Li Y, Meng L, Wang G, Zhou X, Ouyang Z, Nie Z. A Gas-Phase Reaction Accelerator Using Vortex Flows. Anal Chem 2020; 92:12049-12054. [PMID: 32867491 DOI: 10.1021/acs.analchem.0c02672] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Gas-phase microdroplets have been increasingly used for reaction acceleration. Here, we report the development of a vortex tube as a reaction accelerator. Three types of reactions, viz., aromatization, amination isomerization, and acid-induced cytochrome c unfolding were used to characterize the performance of the vortex tube. During ion transfer from a nanoelectrospray ionization (nanoESI) source to the mass spectrometry (MS) inlet, the generated vortex flows helped droplet desolvation and ion confinement and thus improved the MS intensity by 2-3 orders of magnitude compared with that when the vortex tube was not applied. Like the stirring effect in the bulk phase, the reactants were more sufficiently mixed and reacted in vortices. Therefore, with the same reaction distance, a 2-3-fold improvement of conversion ratios was observed by using the vortices. Notably, the vortex tube enabled the use of flow rate to control the reaction time for ∼60 μs, which was useful for precise control of reaction progress. As a demonstration, the intermediates of the amination isomerization were tracked and the equilibrium constant and rate constant of the cytochrome c unfolding were determined.
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Affiliation(s)
- Yuze Li
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 10084, China.,Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lingwei Meng
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guanghui Wang
- National Center for Mass Spectrometry in Beijing, Beijing 100190, China
| | - Xiaoyu Zhou
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 10084, China
| | - Zheng Ouyang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 10084, China
| | - Zongxiu Nie
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China.,National Center for Mass Spectrometry in Beijing, Beijing 100190, China
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29
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Narendra N, Chen X, Wang J, Charles J, Cooks RG, Kubis T. Quantum Mechanical Modeling of Reaction Rate Acceleration in Microdroplets. J Phys Chem A 2020; 124:4984-4989. [PMID: 32453564 DOI: 10.1021/acs.jpca.0c03225] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Organic reactions in microdroplets can be orders of magnitude faster than their bulk counterparts. We hypothesize that solvation energy differences between bulk and interface play a key role in the intrinsic rate constant increase and test the hypothesis with explicit solvent calculations. We demonstrate for both the protonated phenylhydrazine reagent and the hydrazone transition state (TSB) that molecular orientations which place the charge sites at the surface confer high energy. A pathway in which this high-energy form transforms into a fully solvated TSB has a lower activation energy than bulk by some 59 kJ/mol, a result that is consistent with experimental rate acceleration studies.
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Affiliation(s)
- Namita Narendra
- Network for Computational Nanotechnology, Purdue University, West Lafayette, Indiana 47906, United States
| | - Xingshuo Chen
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, United States
| | - Jinying Wang
- Network for Computational Nanotechnology, Purdue University, West Lafayette, Indiana 47906, United States
| | - James Charles
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47906, United States
| | - R Graham Cooks
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, United States
| | - Tillmann Kubis
- Network for Computational Nanotechnology, Purdue University, West Lafayette, Indiana 47906, United States.,School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47906, United States.,Center for Predictive Materials and Devices, Purdue University, West Lafayette, Indiana 47906, United States.,Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, Indiana 47906, United States
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30
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Liu XR, Zhang MM, Gross ML. Mass Spectrometry-Based Protein Footprinting for Higher-Order Structure Analysis: Fundamentals and Applications. Chem Rev 2020; 120:4355-4454. [PMID: 32319757 PMCID: PMC7531764 DOI: 10.1021/acs.chemrev.9b00815] [Citation(s) in RCA: 122] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Proteins adopt different higher-order structures (HOS) to enable their unique biological functions. Understanding the complexities of protein higher-order structures and dynamics requires integrated approaches, where mass spectrometry (MS) is now positioned to play a key role. One of those approaches is protein footprinting. Although the initial demonstration of footprinting was for the HOS determination of protein/nucleic acid binding, the concept was later adapted to MS-based protein HOS analysis, through which different covalent labeling approaches "mark" the solvent accessible surface area (SASA) of proteins to reflect protein HOS. Hydrogen-deuterium exchange (HDX), where deuterium in D2O replaces hydrogen of the backbone amides, is the most common example of footprinting. Its advantage is that the footprint reflects SASA and hydrogen bonding, whereas one drawback is the labeling is reversible. Another example of footprinting is slow irreversible labeling of functional groups on amino acid side chains by targeted reagents with high specificity, probing structural changes at selected sites. A third footprinting approach is by reactions with fast, irreversible labeling species that are highly reactive and footprint broadly several amino acid residue side chains on the time scale of submilliseconds. All of these covalent labeling approaches combine to constitute a problem-solving toolbox that enables mass spectrometry as a valuable tool for HOS elucidation. As there has been a growing need for MS-based protein footprinting in both academia and industry owing to its high throughput capability, prompt availability, and high spatial resolution, we present a summary of the history, descriptions, principles, mechanisms, and applications of these covalent labeling approaches. Moreover, their applications are highlighted according to the biological questions they can answer. This review is intended as a tutorial for MS-based protein HOS elucidation and as a reference for investigators seeking a MS-based tool to address structural questions in protein science.
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Affiliation(s)
| | | | - Michael L. Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO, USA, 63130
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31
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Poltash ML, McCabe JW, Shirzadeh M, Laganowsky A, Russell DH. Native IM-Orbitrap MS: Resolving What Was Hidden. Trends Analyt Chem 2020; 124:115533. [PMID: 32189816 PMCID: PMC7079669 DOI: 10.1016/j.trac.2019.05.035] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Native ion mobility-mass spectrometry (IM-MS) is an emerging biophysical approach to probe the intricate details of protein structure and function. The instrument design enables measurements of accurate first-principle determinations of rotationally-averaged ion-neutral collision cross sections coupled with high-mass, high-resolution mass measurement capabilities of Orbitrap MS. The inherent duty-cycle mismatch between drift tube IM and Orbitrap MS is alleviated by operating the drift tube in a frequency modulated mode while continuously acquiring mass spectra with the Orbitrap MS. Fourier transform of the resulting time-domain signal, i.e., ion abundances as a function of the modulation frequency, yields a frequency domain spectrum that is then converted (s-1 to s) to IM drift time. This multiplexed approach allows for a duty-cycle of 25% compared to <1% for traditional "pulse-and-wait" IM-ToF-MS. Improvements in mobility and mass resolution of the IM-Orbitrap allows for accurate analysis of intact protein complexes and the possibility of capturing protein dynamics.
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Affiliation(s)
- Michael L. Poltash
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843
| | - Jacob W. McCabe
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843
| | - Mehdi Shirzadeh
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843
| | - David H. Russell
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, Texas 77843
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32
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Nie H, Wei Z, Qiu L, Chen X, Holden DT, Cooks RG. High-yield gram-scale organic synthesis using accelerated microdroplet/thin film reactions with solvent recycling. Chem Sci 2020; 11:2356-2361. [PMID: 34084396 PMCID: PMC8157326 DOI: 10.1039/c9sc06265c] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
A closed system has been designed to perform microdroplet/thin film reactions with solvent recycling capabilities for gram-scale chemical synthesis. Claisen-Schmidt, Schiff base, Katritzky and Suzuki coupling reactions show acceleration factors relative to bulk of 15 to 7700 times in this droplet spray system. These values are much larger than those reported previously for the same reactions in microdroplet/thin film reaction systems. The solvent recycling mode of the new system significantly improves the reaction yield, especially for reactions with smaller reaction acceleration factors. The microdroplet/thin film reaction yield improved on recycling from 33% to 86% and from 32% to 72% for the Katritzky and Suzuki coupling reactions, respectively. The Claisen-Schmidt reaction was chosen to test the capability of this system in gram scale syntheses and rates of 3.18 g per h and an isolated yield of 87% were achieved.
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Affiliation(s)
- Honggang Nie
- Aston Labs, Department of Chemistry, Purdue University 560 Oval Drive West Lafayette IN 47906-1393 USA .,Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University Beijing 100871 P. R. China
| | - Zhenwei Wei
- Aston Labs, Department of Chemistry, Purdue University 560 Oval Drive West Lafayette IN 47906-1393 USA
| | - Lingqi Qiu
- Aston Labs, Department of Chemistry, Purdue University 560 Oval Drive West Lafayette IN 47906-1393 USA
| | - Xingshuo Chen
- Aston Labs, Department of Chemistry, Purdue University 560 Oval Drive West Lafayette IN 47906-1393 USA
| | - Dylan T Holden
- Aston Labs, Department of Chemistry, Purdue University 560 Oval Drive West Lafayette IN 47906-1393 USA
| | - R Graham Cooks
- Aston Labs, Department of Chemistry, Purdue University 560 Oval Drive West Lafayette IN 47906-1393 USA
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33
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Kim HJ, Gallagher ES. Achieving multiple hydrogen/deuterium exchange timepoints of carbohydrate hydroxyls using theta-electrospray emitters. Analyst 2020; 145:3056-3063. [DOI: 10.1039/d0an00135j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Microsecond reaction times for in-droplet hydrogen/deuterium exchange of carbohydrate hydroxyls have been varied by changing the opening sizes of theta-electrospray emitters.
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Affiliation(s)
- H. Jamie Kim
- Department of Chemistry and Biochemistry
- Baylor University
- Waco
- USA
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34
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Liu C, Li Y, Liu BF. Micromixers and their applications in kinetic analysis of biochemical reactions. Talanta 2019; 205:120136. [DOI: 10.1016/j.talanta.2019.120136] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/03/2019] [Accepted: 07/08/2019] [Indexed: 01/11/2023]
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35
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Sahraeian T, Kulyk DS, Badu-Tawiah AK. Droplet Imbibition Enables Nonequilibrium Interfacial Reactions in Charged Microdroplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:14451-14457. [PMID: 31622104 DOI: 10.1021/acs.langmuir.9b02439] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A droplet imbibition experiment is proposed to study interfacial effects, which appears to be the main factor influencing reaction acceleration in charged microdroplets produced by electrospray ionization (ESI). One reagent is deposited onto the surface of rapidly moving microdroplets containing the second reagent to be reacted. In this manner, reactions are hindered from reaching equilibrium and monitored in real time by mass spectrometry. We demonstrated this phenomenon using Katritzky chemistry, which is known to proceed either by the solvent-stabilized 2H-pyran intermediate or via the surface-active pseudobase intermediate. Comparisons with reactions performed using ESI show obvious surface effects in favor of the droplet imbibition experiment. By keeping reactant mole ratio constant, it was demonstrated that similar interfacial effects observed in the droplet imbibition experiment can be reached by allowing ESI microdroplets containing premixed reagents to traverse a distance >16 mm. At such spray distance, molecular diffusion and droplet lifetime become comparable allowing reactants to be enriched at droplet surface. Reactions were also conducted in rapid mixing, theta capillary-based droplets, which showed markedly reduced yields compared with the interfacial droplet imbibition experiment.
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Affiliation(s)
- Taghi Sahraeian
- Department of Chemistry and Biochemistry , The Ohio State University , Columbus , Ohio 43210 , United States
| | - Dmytro S Kulyk
- Department of Chemistry and Biochemistry , The Ohio State University , Columbus , Ohio 43210 , United States
| | - Abraham K Badu-Tawiah
- Department of Chemistry and Biochemistry , The Ohio State University , Columbus , Ohio 43210 , United States
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36
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Lawal RO, Donnarumma F, Murray KK. Electrospray Photochemical Oxidation of Proteins. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:2196-2199. [PMID: 31489562 PMCID: PMC6832858 DOI: 10.1007/s13361-019-02313-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/18/2019] [Accepted: 08/10/2019] [Indexed: 06/10/2023]
Abstract
Photooxidation of peptides and proteins by pulsed ultraviolet laser irradiation of an electrospray in the ion source of a mass spectrometer was demonstrated. A 193-nm excimer laser at 1.5-mJ pulse energy was focused with a cylindrical lens at the exit of a nanoelectrospray capillary and ions were sampled into a quadrupole time-of-flight mass spectrometer. A solution containing a peptide or protein and hydrogen peroxide was infused into the spray at a flow rate of 1 μL/min using a syringe pump. The laser creates OH radicals directly in the spray which modify biomolecules within the spray droplet. These results indicate that photochemical oxidation of proteins can be initiated directly within electrospray droplets and detected by mass spectrometry.
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Affiliation(s)
- Remilekun O Lawal
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Fabrizio Donnarumma
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Kermit K Murray
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, USA.
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37
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Liu C, Li J, Chen H, Zare RN. Scale-up of microdroplet reactions by heated ultrasonic nebulization. Chem Sci 2019; 10:9367-9373. [PMID: 32110301 PMCID: PMC7017870 DOI: 10.1039/c9sc03701b] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 08/19/2019] [Indexed: 12/24/2022] Open
Abstract
Dramatically higher rates for a variety of chemical reactions have been reported in microdroplets compared with those in the liquid bulk phase. However, the scale-up of microdroplet chemical synthesis has remained a major challenge to the practical application of microdroplet chemistry. Heated ultrasonic nebulization (HUN) was found as a new way for scaling up chemical synthesis in microdroplets. Four reactions were examined, a base-catalyzed Claisen-Schmidt condensation, an oximation reaction from a ketone, a two-phase oxidation reaction without the use of a phase-transfer-catalyst, and an Eschenmoser coupling reaction. These reactions show acceleration of one to three orders of magnitude (122, 23, 6536, and 62) in HUN microdroplets compared to the same reactions in bulk solution. Then, using the present method, the scale-up of the reactions was achieved at an isolated rate of 19 mg min-1 for the product of the Claisen-Schmidt condensation, 21 mg min-1 for the synthesis of benzophenone oxime from benzophenone, 31 mg min-1 for the synthesis of 4-methoxybenzaldehyde from 4-methoxybenzyl alcohol, and 40 mg min-1 for the enaminone product of the Eschenmoser coupling reaction.
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Affiliation(s)
- Chengyuan Liu
- Department of Chemistry , Fudan University , Shanghai 200438 , China .
| | - Jia Li
- Department of Chemistry , Fudan University , Shanghai 200438 , China .
| | - Hao Chen
- Department of Chemistry & Environmental Science , New Jersey Institute of Technology , Newark , NJ 07102 , USA
| | - Richard N Zare
- Department of Chemistry , Fudan University , Shanghai 200438 , China .
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38
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Hu J, Lei W, Wang J, Chen HY, Xu JJ. Preservation of Protein Zwitterionic States in the Transition from Solution to Gas Phase Revealed by Sodium Adduction Mass Spectrometry. Anal Chem 2019; 91:7858-7863. [PMID: 31134800 DOI: 10.1021/acs.analchem.9b01602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The structural characterization of proteins and their interaction network mapping in the gas phase highlights the need to preserve their most nativelike conformers in the transition from the solution to gas phase. Zwitterionic interactions in a protein are weak bonds between oppositely charged residues, which make an important contribution to protein stability. However, it is still not clear whether the native zwitterionic states of proteins can be retained or not when it is transferred from the solution to gas phase. Using the nonspecific Na+ adduction as a novel signature, here we show that the zwitterionic states of proteins can be preserved when a moderated droplet desolvation condition (temperature <30 °C) is used in native electrospray ionization mass spectrometry. The very low-level nonspecific metal adduction to proteins under such conditions also enables rapid and direct determination of the binding states of metal-binding proteins and sensitive detection of proteins from solutions containing highly concentrated involatile salts (e.g., 50 mM NaCl). We believe that our findings can be instructive for performing mass spectrometric analysis of proteins and useful for protein ions desalting which simply involves altering the temperature and flow rate of drying gas in the desolvation region.
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Affiliation(s)
- Jun Hu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , P. R. China
| | - Wen Lei
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , P. R. China
| | - Jiang Wang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , P. R. China
| | - Hong-Yuan Chen
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , P. R. China
| | - Jing-Juan Xu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , P. R. China
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39
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Sahota N, AbuSalim DI, Wang ML, Brown CJ, Zhang Z, El-Baba TJ, Cook SP, Clemmer DE. A microdroplet-accelerated Biginelli reaction: mechanisms and separation of isomers using IMS-MS. Chem Sci 2019; 10:4822-4827. [PMID: 31160956 PMCID: PMC6509997 DOI: 10.1039/c9sc00704k] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Accepted: 03/28/2019] [Indexed: 01/17/2023] Open
Abstract
Electrospray ionization (ESI) combined with ion mobility spectrometry (IMS) and mass spectrometry (MS) techniques is used to examine the Biginelli reaction in an ensemble of ions generated from droplets.
Electrospray ionization (ESI) combined with ion mobility spectrometry (IMS) and mass spectrometry (MS) techniques is used to examine the Biginelli reaction in an ensemble of ions generated from droplets. We find evidence for rapid dihydropyrimidinone formation from condensation of ethyl acetoacetate, benzaldehyde, and urea on the very short timescales associated with the electrospray process (∼10 μs to ∼1.0 ms). Control bulk-solution reactions show no product formation even after several days. This implies that the in-droplet reaction rate is enhanced by an astonishing factor. Examination of the reaction conditions and characterization of the intermediates en route to product shows evidence for variations in the reaction mechanism. IMS separation shows that the Knoevenagel condensation intermediate from benzaldehyde and ethyl acetoacetate exists as both the cis- and trans-isomer, in a ∼5 to 1 ratio. We suggest that the dramatic acceleration arises because of increased reagent confinement as electrosprayed droplets shrink. The ability of IMS-MS to resolve intermediates (including isomers) provides a new means of understanding reaction pathways.
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Affiliation(s)
- Navneet Sahota
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , IN 47405-7102 , USA . ;
| | - Deyaa I AbuSalim
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , IN 47405-7102 , USA . ;
| | - Melinda L Wang
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , IN 47405-7102 , USA . ;
| | - Christopher J Brown
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , IN 47405-7102 , USA . ;
| | - Zhicaho Zhang
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , IN 47405-7102 , USA . ;
| | - Tarick J El-Baba
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , IN 47405-7102 , USA . ;
| | - Silas P Cook
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , IN 47405-7102 , USA . ;
| | - David E Clemmer
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , IN 47405-7102 , USA . ;
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40
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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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41
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Gallo A, Farinha ASF, Dinis M, Emwas AH, Santana A, Nielsen RJ, Goddard WA, Mishra H. The chemical reactions in electrosprays of water do not always correspond to those at the pristine air-water interface. Chem Sci 2018; 10:2566-2577. [PMID: 30996971 PMCID: PMC6422012 DOI: 10.1039/c8sc05538f] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 12/21/2018] [Indexed: 12/11/2022] Open
Abstract
The recent application of electrosprays to characterize the air-water interface, along with the reports on dramatically accelerated chemical reactions in aqueous electrosprays, have sparked a broad interest. Herein, we report on complementary laboratory and in silico experiments tracking the oligomerization of isoprene, an important biogenic gas, in electrosprays and isoprene-water emulsions to differentiate the contributions of interfacial effects from those of high voltages leading to charge-separation and concentration of reactants in the electrosprays. To this end, we employed electrospray ionization mass spectrometry, proton nuclear magnetic resonance, ab initio calculations and molecular dynamics simulations. We found that the oligomerization of isoprene in aqueous electrosprays involved minimally hydrated and highly reactive hydronium ions. Those conditions, however, are non-existent at pristine air-water interfaces and oil-water emulsions under normal temperature and pressure. Thus, electrosprays should be complemented with surface-specific platforms and theoretical methods to reliably investigate chemistries at the pristine air-water interface.
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Affiliation(s)
- Adair Gallo
- King Abdullah University of Science and Technology (KAUST) , Saudi Arabia . .,Water Desalination and Reuse Center (WDRC) , Saudi Arabia.,Division of Biological and Environmental Sciences (BESE) , Saudi Arabia
| | - Andreia S F Farinha
- King Abdullah University of Science and Technology (KAUST) , Saudi Arabia . .,Water Desalination and Reuse Center (WDRC) , Saudi Arabia.,Division of Biological and Environmental Sciences (BESE) , Saudi Arabia
| | - Miguel Dinis
- King Abdullah University of Science and Technology (KAUST) , Saudi Arabia . .,KAUST Catalysis Center (KCC) , Saudi Arabia
| | - Abdul-Hamid Emwas
- King Abdullah University of Science and Technology (KAUST) , Saudi Arabia . .,Imaging and Characterization Core Laboratory , Thuwal 23955-6900 , Saudi Arabia
| | - Adriano Santana
- King Abdullah University of Science and Technology (KAUST) , Saudi Arabia . .,Water Desalination and Reuse Center (WDRC) , Saudi Arabia.,Division of Biological and Environmental Sciences (BESE) , Saudi Arabia
| | - Robert J Nielsen
- Materials and Process Simulation Center , California Institute of Technology , Pasadena , CA 91125 , USA
| | - William A Goddard
- Materials and Process Simulation Center , California Institute of Technology , Pasadena , CA 91125 , USA
| | - Himanshu Mishra
- King Abdullah University of Science and Technology (KAUST) , Saudi Arabia . .,Water Desalination and Reuse Center (WDRC) , Saudi Arabia.,Division of Biological and Environmental Sciences (BESE) , Saudi Arabia
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42
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van Geenen FAG, Franssen MCR, Zuilhof H, Nielen MWF. Reactive Laser Ablation Electrospray Ionization Time-Resolved Mass Spectrometry of Click Reactions. Anal Chem 2018; 90:10409-10416. [PMID: 30063331 PMCID: PMC6127799 DOI: 10.1021/acs.analchem.8b02290] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 07/31/2018] [Indexed: 11/30/2022]
Abstract
Reactions in confined compartments like charged microdroplets are of increasing interest, notably because of their substantially increased reaction rates. When combined with ambient ionization mass spectrometry (MS), reactions in charged microdroplets can be used to improve the detection of analytes or to study the molecular details of the reactions in real time. Here, we introduce a reactive laser ablation electrospray ionization (reactive LAESI) time-resolved mass spectrometry (TRMS) method to perform and study reactions in charged microdroplets. We demonstrate this approach with a class of reactions new to reactive ambient ionization MS: so-called click chemistry reactions. Click reactions are high-yielding reactions with a high atom efficiency, and are currently drawing significant attention from fields ranging from bioconjugation to polymer modification. Although click reactions are typically at least moderately fast (time scale of minutes to a few hours), in a reactive LAESI approach a substantial increase of reaction time is required for these reactions to occur. This increase was achieved using microdroplet chemistry and followed by MS using the insertion of a reaction tube-up to 1 m in length-between the LAESI source and the MS inlet, leading to near complete conversions due to significantly extended microdroplet lifetime. This novel approach allowed for the collection of kinetic data for a model (strain-promoted) click reaction between a substituted tetrazine and a strained alkyne and showed in addition excellent instrument stability, improved sensitivity, and applicability to other click reactions. Finally, the methodology was also demonstrated in a mass spectrometry imaging setting to show its feasibility in future imaging experiments.
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Affiliation(s)
- Fred A.
M. G. van Geenen
- Laboratory of Organic
Chemistry, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
- TI-COAST, Science Park
904, 1098 XH Amsterdam, The Netherlands
| | - Maurice C. R. Franssen
- Laboratory of Organic
Chemistry, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Han Zuilhof
- Laboratory of Organic
Chemistry, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
- School of Pharmaceutical Sciences and Technology, Tianjin University, 92 Weijin Road, Tianjin 300072, People’s Republic of China
| | - Michel W. F. Nielen
- Laboratory of Organic
Chemistry, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
- RIKILT, Wageningen University & Research, P.O. Box 230, 6700 AE Wageningen, The Netherlands
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Falcone CE, Jaman Z, Wleklinski M, Koswara A, Thompson DH, Cooks RG. Reaction screening and optimization of continuous-flow atropine synthesis by preparative electrospray mass spectrometry. Analyst 2018; 142:2836-2845. [PMID: 28703239 DOI: 10.1039/c7an00622e] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Preparative electrospray (ES) exploits the acceleration of reactions in charged microdroplets to perform a small scale chemical synthesis. In combination with on-line mass spectrometric (MS) analysis, it constitutes a rapid screening tool to select reagents to generate specific products. A successful reaction in preparative ES triggers a refined microfluidic reaction screening procedure which includes the optimization for stoichiometry, temperature and residence time. We apply this combined approach for refining a flow synthesis of atropine. A successful preparative ES pathway for the synthesis of the phenylacetyl ester intermediate, using tropine/HCl/phenylacetyl chloride, was optimized for solvent in both the preparative ES and microfluidics flow systems and a base screening was conducted by both methods to increase atropine yield, increase percentage conversion and reduce byproducts. In preparative ES, the first step yielded 55% conversion (judged using MS) to intermediate and the second step yielded 47% conversion to atropine. When combined in two discrete steps in continuous-flow microfluidics, a 44% conversion of the starting material and a 30% actual yield of atropine were achieved. When the reactions were continuously telescoped in a new form of preparative reactive extractive electrospray (EES), atropine was synthesized with a 24% conversion. The corresponding continuous-flow microfluidics experiment gave a 55% conversion with an average of 34% yield in 8 min residence time. This is the first in depth study to utilize telescoped preparative ES and the first use of dual ESI emitters for multistep synthesis.
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Affiliation(s)
- Caitlin E Falcone
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA.
| | - Zinia Jaman
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA.
| | - Michael Wleklinski
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA.
| | - Andy Koswara
- Chemical Engineering, Purdue University, 480 W Stadium Ave., West Lafayette, IN 47907, USA
| | - David H Thompson
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA.
| | - R Graham Cooks
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA.
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Li H, Vertes A. Solvent gradient electrospray for laser ablation electrospray ionization mass spectrometry. Analyst 2018; 142:2921-2927. [PMID: 28718844 DOI: 10.1039/c7an00819h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Most electrospray based ambient ionization techniques, e.g., laser ablation electrospray ionization (LAESI), utilize a fixed spray solution composition. Complex samples often contain compounds of different polarity that exhibit a wide range of solubilities in the electrospray solvent. Thus, the fixed spray solution composition limits the molecular coverage of these approaches. Two-barrel theta glass capillaries have been used for the rapid mixing of two solutions for manipulating fast reactions including protein folding, unfolding, and charge state distributions. Here, we present a new variant of LAESI mass spectrometry (MS) by scanning the high voltages applied to the two barrels of a theta glass capillary containing two different solvents. In the resulting gradient LAESI (g-LAESI), the composition of the spray solution is ramped between the two solvents in the barrels to facilitate the detection of compounds of diverse polarity and solubility. Dynamic ranges and limits of detection achieved for g-LAESI-MS were comparable to conventional LAESI-MS. We have demonstrated simultaneous detection of different types of chemical standards, and polar and less polar compounds from Escherichia coli cell pellets using g-LAESI-MS. Varying the spray solution composition in a gradient electrospray can benefit from the enhanced solubilities of different analytes in polar and less polar solvents, ultimately improving the molecular coverage in the direct analysis of biological samples.
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Affiliation(s)
- Hang Li
- Department of Chemistry, W. M. Keck Institute for Proteomics Technology and Applications, The George Washington University, Washington, DC 20052, USA.
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45
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Banerjee S, Gnanamani E, Yan X, Zare RN. Can all bulk-phase reactions be accelerated in microdroplets? Analyst 2018; 142:1399-1402. [PMID: 28332662 DOI: 10.1039/c6an02225a] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Recent studies have shown that microdroplet reactions are markedly accelerated compared to the corresponding bulk-phase reactions. This raises the question whether all reactions can be sped up by this means. We present a counter example, and we show that the reaction mechanism in microdroplets can differ sharply from that in bulk, especially because of the distinct microdroplet surface environment. This analysis helps to guide us how to choose and control reactions in microdroplets and provides a possible perspective on utilizing microdroplet chemistry to scale up synthesis.
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Affiliation(s)
- Shibdas Banerjee
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
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46
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Saha-Shah A, Karty JA, Baker LA. Local collection, reaction and analysis with theta pipette emitters. Analyst 2018; 142:1512-1518. [PMID: 28361146 DOI: 10.1039/c7an00109f] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A mobile nanofluidic device based on theta pipettes was developed for "collect-react-analyze" measurements of small volumes of a sample collected locally from biological samples. Specifically, we demonstrate execution of local reactions inside single cells and on Pseudomonas aeruginosa biofilms for targeted analysis of metabolites. Nanoliter volumes of the sample, post-reaction, were delivered to a mass spectrometer via electrospray ionization (ESI) for chemical analysis. A new strategy was developed where the additional barrel of a theta pipette was utilized both to enable chemical manipulations after sample collection and to electrospray the nanoliter sample volumes collected directly from the pipette tip. This strategy proved a robust method for ESI from nanometer sized tips without clogging or degradation of the emitter and obviated the need to coat glass pipettes with a conductive metal coating. Chemical reactions investigated include acid catalyzed degradation of oligosaccharides inside the pipette tip to increase the detection sensitivity of minor metabolites found in Allium cepa cells. Additionally, phenylboronic acid complexation of carbohydrates from single cells and liposaccharides from biofilms was also performed inside the pipette tip for selective detection of carbohydrates and liposaccharides with cis-diols.
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Affiliation(s)
- Anumita Saha-Shah
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405, USA.
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Lai YH, Sathyamoorthi S, Bain RM, Zare RN. Microdroplets Accelerate Ring Opening of Epoxides. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:1036-1043. [PMID: 29569167 DOI: 10.1007/s13361-018-1908-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/18/2018] [Accepted: 01/29/2018] [Indexed: 06/08/2023]
Abstract
The nucleophilic opening of an epoxide is a classic organic reaction that has widespread utility in both academic and industrial applications. We have studied the reaction of limonene oxide with morpholine to form 1-methyl-2-morpholino-4-(prop-1-en-2-yl) cyclohexan-1-ol in bulk solution and in electrosprayed microdroplets with a 1:1 v/v water/methanol solvent system. We find that even after 90 min at room temperature, there is no product detected by nuclear magnetic resonance spectroscopy in bulk solution whereas in room-temperature microdroplets (2-3 μm in diameter), the yield is already 0.5% in a flight time of 1 ms as observed by mass spectrometry. This constitutes a rate acceleration of ~ 105 in the microdroplet environment, if we assume that as much as 5% of product is formed in bulk after 90 min of reaction time. We examine how the reaction rate depends on droplet size, solvent composition, sheath gas pressure, and applied voltage. These factors profoundly influence the extent of reaction. This dramatic acceleration is not limited to just one system. We have also found that the nucleophilic opening of cis-stilbene oxide by morpholine is similarly accelerated. Such large acceleration factors in reaction rates suggest the use of microdroplets for ring opening of epoxides in other systems, which may have practical significance if such a procedure could be scaled. Graphical Abstract This graphical image is distorted. It is too extended in the vertical direction. Please fix.ᅟ.
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Affiliation(s)
- Yin-Hung Lai
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | | | - Ryan M Bain
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Richard N Zare
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA.
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El-Baba TJ, Fuller DR, Woodall DW, Raab SA, Conant CR, Dilger JM, Toker Y, Williams ER, Russell DH, Clemmer DE. Melting proteins confined in nanodroplets with 10.6 μm light provides clues about early steps of denaturation. Chem Commun (Camb) 2018; 54:3270-3273. [PMID: 29536995 PMCID: PMC5871606 DOI: 10.1039/c7cc09829d] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Ubiquitin confined within nanodroplets was irradiated with a variable-power CO2 laser. Mass spectrometry analysis shows evidence for a protein "melting"-like transition within droplets prior to solvent evaporation and ion formation. Ion mobility spectrometry reveals that structures associated with early steps of denaturation are trapped because of short droplet lifetimes.
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Affiliation(s)
- Tarick J El-Baba
- Department of Chemistry, Indiana University, 800 Kirkwood Avenue, Bloomington, Indiana, 47401, USA.
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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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50
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Mortensen DN, Williams ER. Microsecond and nanosecond polyproline II helix formation in aqueous nanodrops measured by mass spectrometry. Chem Commun (Camb) 2018; 52:12218-12221. [PMID: 27711437 DOI: 10.1039/c6cc06423j] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The 1.5 μs and <400 ns time constants for the formation of polyproline II helix structures in 21 and 16 residue peptides, respectively, are measured using rapid mixing from theta-glass emitters coupled with mass spectrometry. Results from these studies should serve as useful benchmarks for comparison with computational simulation results.
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Affiliation(s)
- Daniel N Mortensen
- Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
| | - Evan R Williams
- Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
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