1
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Ramos-Bermúdez PE, Pousa S, Carvalho P, Brant RSC, Batista M, Hojo H, Garay HE, Roscoe A, Mallón AR, Besada V, Takao T, González LJ. A hydrolyzed N-propionylthiosuccinimide linker is cleaved by metastable fragmentation, increasing reliability of conjugation site identification in conjugate vaccines. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2024; 38:e9859. [PMID: 39034666 DOI: 10.1002/rcm.9859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 06/05/2024] [Accepted: 06/09/2024] [Indexed: 07/23/2024]
Abstract
RATIONALE Conjugation sites are a quality attribute of conjugate vaccines. Proteolysis of bioconjugates synthesized by maleimide-thiol chemistry generates type 2 peptides with a hydrolyzed thiosuccinimide linker containing information on the conjugation sites. A mass spectrometry (MS)-cleavable linker could make the identification of conjugation sites by MS more reliable. METHODS Four synthetic type 2 peptides with a hydrolyzed thiosuccinimide linker were analyzed by matrix-assisted laser desorption ionization (MALDI) MS/MS with and without collision gas. These peptides were also partially labeled with 18O in the linker to confirm the proposed fragmentation mechanism. A conjugate vaccine with the hydrolyzed thiosuccinimide linker was reduced and S-alkylated, digested with trypsin and analyzed by liquid chromatography-MS/MS using collision-induced dissociation (CID) and higher-energy collisional dissociation (HCD) fragmentation methods at a normalized collision energy of 30. RESULTS A metastable fragmentation preferentially cleaves the newly formed pseudopeptide bond within the hydrolyzed thiosuccinimide linker of type 2 peptides to yield P + 71 and C + 98 ions. These ions make the assignment of conjugation sites more reliable. Partial 18O-labeling and MS/MS analysis confirmed the proposed structures. CID produces these ions as the two most intense signals more favorably than HCD. The latter also yields these ions, guarantees better sequence coverage and promotes other fragmentations in the linker. CONCLUSIONS Hydrolyzed thiosuccinimide linker is cleavable in MALDI and electrospray ionization MS/MS analysis by a gas-phase metastable fragmentation. The resulting fragment ions (P + 71 and C + 98) make the identification of conjugation sites more reliable. These results could be extended to self-hydrolyzing maleimides, which efficiently stabilize the thiosuccinimide linker upon hydrolysis, in antibody-drug conjugates.
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Affiliation(s)
| | - Satomy Pousa
- Center for Genetic Engineering and Biotechnology, Havana, Cuba
| | - Paulo Carvalho
- Carlos Chagas Institute/FioCruz Rua Professor Algacyr Munhoz Mader, Curitiba, Brazil
| | | | - Michel Batista
- Carlos Chagas Institute/FioCruz Rua Professor Algacyr Munhoz Mader, Curitiba, Brazil
| | - Hironobu Hojo
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Hilda E Garay
- Center for Genetic Engineering and Biotechnology, Havana, Cuba
| | - Abel Roscoe
- Center for Genetic Engineering and Biotechnology, Havana, Cuba
| | | | - Vladimir Besada
- Center for Genetic Engineering and Biotechnology, Havana, Cuba
| | - Toshifumi Takao
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Luis Javier González
- Carlos Chagas Institute/FioCruz Rua Professor Algacyr Munhoz Mader, Curitiba, Brazil
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2
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Hellinger J, Brodbelt JS. Impact of Charge State on Characterization of Large Middle-Down Sized Peptides by Tandem Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024. [PMID: 39013103 DOI: 10.1021/jasms.3c00405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
Fragmentation trends of large peptides were characterized by five activation methods, including HCD, ETD, EThcD, 213 nm UVPD, and 193 nm UVPD. Sequence coverages and scores were assessed based on charge site, peptide sequence, and peptide size. The effect of charge state and peptide size on sequence coverage was explored for a Glu-C digest of E. coli ribosomal proteins, and linear regression analysis of the collection of peptides indicated that HCD, ETD, and EThcD have a higher dependence charge state than 193 and 213 nm UV. Four model peptides, neuromedin, glucagon, galanin, and amyloid β, were characterized in greater detail based on charge site analysis and showed a charge state dependence on sequence coverage for collision and electron-based activation methods.
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Affiliation(s)
- Jessica Hellinger
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Jennifer S Brodbelt
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
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3
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Khawaja N, Hortal Sánchez L, O'Sullivan TR, Bloema J, Napoleoni M, Klenner F, Beinlich A, Hillier J, John T, Postberg F. Laboratory characterization of hydrothermally processed oligopeptides in ice grains emitted by Enceladus and Europa. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2024; 382:20230201. [PMID: 38736335 DOI: 10.1098/rsta.2023.0201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Accepted: 01/30/2024] [Indexed: 05/14/2024]
Abstract
The Cassini mission provided evidence for a global subsurface ocean and ongoing hydrothermal activity on Enceladus, based on results from Cassini's mass spectrometers. Laboratory simulations of hydrothermal conditions on icy moons are needed to further constrain the composition of ejected ice grains containing hydrothermally altered organic material. Here, we present results from our newly established facility to simulate the processing of ocean material within the temperature range 80-150°C and the pressure range 80-130 bar, representing conditions suggested for the water-rock interface on Enceladus. With this new facility, we investigate the hydrothermal processing of triglycine (GGG) peptide and, for the first time, analyse the extracted samples using laser-induced liquid beam ion desorption (LILBID) mass spectrometry, a laboratory analogue for impact ionization mass spectrometry of ice grains in space. We outline an approach to elucidate hydrothermally processed GGG in ice grains ejected from icy moons based on characteristic differences between GGG anion and cation mass spectra. These differences are linked to hydrothermal processing and thus provide a fingerprint of hydrothermal activity on extraterrestrial bodies. These results will serve as important guidelines for biosignatures potentially obtained by a future Enceladus mission and the SUrface Dust Analyzer (SUDA) instrument onboard Europa Clipper. This article is part of the theme issue 'Dust in the Solar System and beyond'.
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Affiliation(s)
- Nozair Khawaja
- Department of Planetary Sciences and Remote Sensing, Institut für Geologische Wissenschaften, Freie Universität Berlin , Malteserstraße, Berlin 12249, Germany
- Institute of Space Systems, University of Stuttgart , Stuttgart 70569, Germany
| | - Lucía Hortal Sánchez
- Department of Planetary Sciences and Remote Sensing, Institut für Geologische Wissenschaften, Freie Universität Berlin , Malteserstraße, Berlin 12249, Germany
| | - Thomas R O'Sullivan
- Department of Planetary Sciences and Remote Sensing, Institut für Geologische Wissenschaften, Freie Universität Berlin , Malteserstraße, Berlin 12249, Germany
| | - Judith Bloema
- Department of Planetary Sciences and Remote Sensing, Institut für Geologische Wissenschaften, Freie Universität Berlin , Malteserstraße, Berlin 12249, Germany
| | - Maryse Napoleoni
- Department of Planetary Sciences and Remote Sensing, Institut für Geologische Wissenschaften, Freie Universität Berlin , Malteserstraße, Berlin 12249, Germany
| | - Fabian Klenner
- Department of Earth and Space Sciences, University of Washington , Seattle, WA 98195, USA
| | - Andreas Beinlich
- Department of Mineralogy and Petrology, Institut für Geologische Wissenschaften, Freie Universität Berlin , Malteserstraße, Berlin 12249, Germany
| | - Jon Hillier
- Department of Planetary Sciences and Remote Sensing, Institut für Geologische Wissenschaften, Freie Universität Berlin , Malteserstraße, Berlin 12249, Germany
| | - Timm John
- Department of Mineralogy and Petrology, Institut für Geologische Wissenschaften, Freie Universität Berlin , Malteserstraße, Berlin 12249, Germany
| | - Frank Postberg
- Department of Planetary Sciences and Remote Sensing, Institut für Geologische Wissenschaften, Freie Universität Berlin , Malteserstraße, Berlin 12249, Germany
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4
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Martínez-Fernández L, Ranković ML, Canon F, Nahon L, Giuliani A, Milosavljević AR, Martin-Somer A. Photodissociation of leucine-enkephalin protonated peptide: an experimental and theoretical perspective. RSC Adv 2024; 14:16809-16820. [PMID: 38784408 PMCID: PMC11112675 DOI: 10.1039/d4ra01690d] [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: 03/04/2024] [Accepted: 05/14/2024] [Indexed: 05/25/2024] Open
Abstract
Understanding the competing processes that govern far ultraviolet photodissociation (FUV-PD) of biopolymers such as proteins is a challenge. Here, we report a combined experimental and theoretical investigation of FUV-PD of protonated leucine-enkephalin pentapeptide ([YGGFL + H]+) in the gas-phase. Time-dependent density functional theory (TD-DFT) calculations in combination with experiments and previous results for amino acids and shorter peptides help in rationalizing the evolution of the excited states. The results confirm that fragmentation of [YGGFL + H]+ results mainly from vibrationally excited species in the ground electronic state, populated after internal conversion. We also propose fragmentation mechanisms for specific photo-fragments such as tyrosine side chain loss (with an extra hydrogen) or hydrogen loss. In general, we observe the same mechanisms as for smaller peptides or protonated Tyr and Phe, that are not quenched by the presence of other amino acids. Nevertheless, we also found some differences, as for H loss, in part due to the fact that the charge is solvated by the peptide chain and not only by the COOH terminal group.
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Affiliation(s)
- Lara Martínez-Fernández
- Departamento de Química Física de Materiales, Instituto de Química Física de Materiales, Instituto de Química Física Blas Cabrera, CSIC 28006 Madrid Spain
| | - Miloš Lj Ranković
- Institute of Physics Belgrade, University of Belgrade Pregrevica 118 11080 Belgrade Serbia
| | - Francis Canon
- SOLEIL l'Orme des Merisiers, St Aubin, BP48, F-91192 Gif sur Yvette Cedex France
| | - Laurent Nahon
- SOLEIL l'Orme des Merisiers, St Aubin, BP48, F-91192 Gif sur Yvette Cedex France
| | - Alexandre Giuliani
- SOLEIL l'Orme des Merisiers, St Aubin, BP48, F-91192 Gif sur Yvette Cedex France
- INRAE, Dpet. Transform UAR1008, Rue de la Géraudière, BP 71627 F-44316 Nantes France
| | | | - Ana Martin-Somer
- Departamento de Química Física Aplicada, Universidad Autónoma de Madrid Módulo 14 28049 Spain
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5
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Maroto A, Dit Fouque DJ, Lartia R, Memboeuf A. Removal of isobaric interference using pseudo-multiple reaction monitoring and energy-resolved mass spectrometry for the isotope dilution quantification of a tryptic peptide. JOURNAL OF MASS SPECTROMETRY : JMS 2024; 59:e5025. [PMID: 38607249 DOI: 10.1002/jms.5025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 02/22/2024] [Accepted: 03/11/2024] [Indexed: 04/13/2024]
Abstract
Energy-resolved mass spectrometry (ERMS) and an isotopically labelled internal standard were successfully combined to accurately quantify a tryptic peptide despite the presence of an isobaric interference. For this purpose, electrospray ionisation tandem mass spectrometry (ESI-MS/MS) experiments were conducted into an ion trap instrument using an unconventional 8 m/z broadband isolation window, which encompassed both the tryptic peptide and its internal standard. Interference removal was assessed by determining an excitation voltage that was high enough to maintain a constant value for the analyte/internal standard peaks intensity ratio, thus ensuring accurate quantification even in the presence of isobaric contamination. Pseudo-multiple reaction monitoring (MRM) was employed above this excitation voltage to quantify the trypic peptide. The internal standard calibration model showed no lack of fit and exhibited a linear dynamic range from 0.5 μM up to 2.5 μM. The detection limit was 0.08 μM. The accuracy of the method was evaluated by quantifying the tryptic peptide of three reference samples intentionally contaminated with the isobaric interference. All the reference samples were accurately quantified with ∼1% deviation despite the isobaric contamination. Furthermore, we have demonstrated that this methodology can also be applied to quantify the isobaric peptide by standard additions down to 0.2 μM. Finally, liquid chromatography ERMS (LC ERMS) experiments yielded similar results, suggesting the potential of the proposed methodology for analysing complex samples.
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6
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Palstrøm NB, Campbell AJ, Lindegaard CA, Cakar S, Matthiesen R, Beck HC. Spectral library search for improved TMTpro labelled peptide assignment in human plasma proteomics. Proteomics 2024; 24:e2300236. [PMID: 37706597 DOI: 10.1002/pmic.202300236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 06/21/2023] [Accepted: 06/22/2023] [Indexed: 09/15/2023]
Abstract
Clinical biomarker discovery is often based on the analysis of human plasma samples. However, the high dynamic range and complexity of plasma pose significant challenges to mass spectrometry-based proteomics. Current methods for improving protein identifications require laborious pre-analytical sample preparation. In this study, we developed and evaluated a TMTpro-specific spectral library for improved protein identification in human plasma proteomics. The library was constructed by LC-MS/MS analysis of highly fractionated TMTpro-tagged human plasma, human cell lysates, and relevant arterial tissues. The library was curated using several quality filters to ensure reliable peptide identifications. Our results show that spectral library searching using the TMTpro spectral library improves the identification of proteins in plasma samples compared to conventional sequence database searching. Protein identifications made by the spectral library search engine demonstrated a high degree of complementarity with the sequence database search engine, indicating the feasibility of increasing the number of protein identifications without additional pre-analytical sample preparation. The TMTpro-specific spectral library provides a resource for future plasma proteomics research and optimization of search algorithms for greater accuracy and speed in protein identifications in human plasma proteomics, and is made publicly available to the research community via ProteomeXchange with identifier PXD042546.
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Affiliation(s)
- Nicolai B Palstrøm
- Department of Clinical Biochemistry, Odense University Hospital, Odense, Denmark
| | - Amanda J Campbell
- Department of Clinical Biochemistry, Odense University Hospital, Odense, Denmark
| | | | - Samir Cakar
- Department of Clinical Biochemistry, Odense University Hospital, Odense, Denmark
| | - Rune Matthiesen
- Computational and Experimental Biology Group, CEDOC, Chronic Diseases Research Centre, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Hans C Beck
- Department of Clinical Biochemistry, Odense University Hospital, Odense, Denmark
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7
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Nakamura T, Hongo Y, Harada KI. Mobilize a Proton to Transform the Collision-Induced Dissociation Spectral Pattern of a Cyclic Peptide. Mass Spectrom (Tokyo) 2024; 13:A0144. [PMID: 38435076 PMCID: PMC10904930 DOI: 10.5702/massspectrometry.a0144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 02/05/2024] [Indexed: 03/05/2024] Open
Abstract
The collision-induced dissociation (CID) behaviors of protonated molecules of anabaenopeptins, a group of cyanobacterial cyclic peptides, were investigated in detail using liquid chromatography-tandem mass spectrometry. Although anabaenopeptin A and B share a macrocyclic peptide structure, they give strikingly different fragmentation patterns; the former gives a variety of product ions including cleavages in the cyclic peptide structure, which is useful for structural analysis; whereas the latter gives far fewer product ions and no fragmentation in the cyclic moiety. Energy-resolved CID experiments clarified the mechanism behind the striking difference attributable to the difference in exocyclic amino acid residues, Tyr or Arg. The guanidino group in Arg-containing analogue, anabaenopeptin B, should be by far the most preferred protonation site; the proton would be sequestered at the guanidino group in the protonated molecule, with the lack of proton mobility prohibiting opening of the charge-directed fragmentation channels in the cyclic moiety. Enzymatic hydrolysis of the guanidino group to give citrullinated-anabaenopeptin B restored proton mobility. The fragmentation pattern of the citrullinated peptide became almost identical to that of anabaenopeptin A. The observed fragmentation behaviors of these cyclic peptides were consistent with those of linear peptides, which have been well understood based on the mobile proton model.
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Affiliation(s)
- Takemichi Nakamura
- Molecular Structure Characterization Unit, RIKEN Center for Sustainable Resource Science, 2–1 Hirosawa, Wako, Saitama 351–0198, Japan
| | - Yayoi Hongo
- Molecular Structure Characterization Unit, RIKEN Center for Sustainable Resource Science, 2–1 Hirosawa, Wako, Saitama 351–0198, Japan
| | - Ken-ichi Harada
- Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku, Nagoya 468–8503, Japan
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8
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Habeck T, Maciel EVS, Kretschmer K, Lermyte F. Charge site manipulation to enhance top-down fragmentation efficiency. Proteomics 2024; 24:e2300082. [PMID: 37043727 DOI: 10.1002/pmic.202300082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/05/2023] [Accepted: 04/06/2023] [Indexed: 04/14/2023]
Abstract
In recent years, top-down mass spectrometry has become a widely used approach to study proteoforms; however, improving sequence coverage remains an important goal. Here, two different proteins, α-synuclein and bovine carbonic anhydrase, were subjected to top-down collision-induced dissociation (CID) after electrospray ionisation. Two high-boiling solvents, DMSO and propylene carbonate, were added to the protein solution in low concentration (2%) and the effects on the top-down fragmentation patterns of the proteins were systematically investigated. Each sample was measured in triplicate, which revealed highly reproducible differences in the top-down CID fragmentation patterns in the presence of a solution additive, even if the same precursor charge state was isolated in the quadrupole of the instrument. Further investigation supports the solution condition-dependent selective formation of different protonation site isomers as the underlying cause of these differences. Higher sequence coverage was often observed in the presence of additives, and the benefits of this approach became even more evident when datasets from different solution conditions were combined, as increases up to 35% in cleavage coverage were obtained. Overall, this approach therefore represents a promising opportunity to increase top-down fragmentation efficiency.
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Affiliation(s)
- Tanja Habeck
- Department of Chemistry, Clemens-Schöpf-Institute of Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Hessen, Germany
| | - Edvaldo Vasconcelos Soares Maciel
- Department of Chemistry, Clemens-Schöpf-Institute of Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Hessen, Germany
| | - Kevin Kretschmer
- Department of Chemistry, Clemens-Schöpf-Institute of Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Hessen, Germany
| | - Frederik Lermyte
- Department of Chemistry, Clemens-Schöpf-Institute of Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Hessen, Germany
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9
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Gorshkov V, Kjeldsen F. Exploiting Charge State Distribution To Probe Intramolecular Interactions in Gas-Phase Phosphopeptides and Enhance Proteomics Analyses. Anal Chem 2024; 96:1167-1177. [PMID: 38183295 DOI: 10.1021/acs.analchem.3c04270] [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: 01/08/2024]
Abstract
Charging of analytes is a prerequisite for performing mass spectrometry analysis. In proteomics, electrospray ionization is the dominant technique for this process. Although the observation of differences in the peptide charge state distribution (CSD) is well-known among experimentalists, its analytical value remains underexplored. To investigate the utility of this dimension, we analyzed several public data sets, comprising over 250,000 peptide CSD profiles from the human proteome. We found that the dimensions of the CSD demonstrate high reproducibility across multiple laboratories, mass analyzers, and extensive time intervals. The general observation was that the CSD enabled effective partitioning of the peptide property space, resulting in enhanced discrimination between sequence and constitutional peptide isomers. Next, by evaluating the CSD values of phosphorylated peptides, we were able to differentiate between phosphopeptides that indicate the formation of intramolecular structures in the gas phase and those that do not. The reproducibility of the CSD values (mean cosine similarity above 0.97 for most of the experiments) qualified CSD data suitable to train a deep-learning model capable of accurately predicting CSD values (mean cosine similarity - 0.98). When we applied the CSD dimension to MS1- and MS2-based proteomics experiments, we consistently observed around a 5% increase in protein and peptide identification rate. Even though the CSD dimension is not as effective a discriminator as the widely used retention time dimension, it still holds the potential for application in direct infusion proteomics.
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Affiliation(s)
- Vladimir Gorshkov
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Frank Kjeldsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
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10
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Code C, Qiu D, Solov’yov IA, Lee JG, Shin HC, Roland C, Sagui C, Houde D, Rand KD, Jørgensen TJD. Conformationally Restricted Glycopeptide Backbone Inhibits Gas-Phase H/D Scrambling between Glycan and Peptide Moieties. J Am Chem Soc 2023; 145:23925-23938. [PMID: 37883679 PMCID: PMC10636759 DOI: 10.1021/jacs.3c04068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 10/28/2023]
Abstract
Protein glycosylation is a common post-translational modification on extracellular proteins. The conformational dynamics of several glycoproteins have been characterized by hydrogen/deuterium exchange mass spectrometry (HDX-MS). However, it is, in most cases, not possible to extract information about glycan conformation and dynamics due to the general difficulty of separating the deuterium content of the glycan from that of the peptide (in particular, for O-linked glycans). Here, we investigate whether the fragmentation of protonated glycopeptides by collision-induced dissociation (CID) can be used to determine the solution-specific deuterium content of the glycan. Central to this concept is that glycopeptides can undergo a facile loss of glycans upon CID, thereby allowing for the determination of their masses. However, an essential prerequisite is that hydrogen and deuterium (H/D) scrambling can be kept in check. Therefore, we have measured the degree of scrambling upon glycosidic bond cleavage in glycopeptides that differ in the conformational flexibility of their backbone and glycosylation pattern. Our results show that complete scrambling precedes the glycosidic bond cleavage in normal glycopeptides derived from a glycoprotein; i.e., all labile hydrogens have undergone positional randomization prior to loss of the glycan. In contrast, the glycosidic bond cleavage occurs without any scrambling in the glycopeptide antibiotic vancomycin, reflecting that the glycan cannot interact with the peptide moiety due to a conformationally restricted backbone as revealed by molecular dynamics simulations. Scrambling is also inhibited, albeit to a lesser degree, in the conformationally restricted glycopeptides ristocetin and its pseudoaglycone, demonstrating that scrambling depends on an intricate interplay between the flexibility and proximity of the glycan and the peptide backbone.
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Affiliation(s)
- Christian Code
- Department
of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
- Department
of Physics, Chemistry and Pharmacy, University
of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Danwen Qiu
- Department
of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Ilia A. Solov’yov
- Department
of Physics, Chemistry and Pharmacy, University
of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
- Department
of Physics, Carl von Ossietzky University
Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
- Research
Centre for Neurosensory Science, Carl von
Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
- Center
for Nanoscale Dynamics (CENAD), Carl von
Ossietzky Universität Oldenburg Institut für Physik, Ammerländer Heerstr. 114-118, 26129 Oldenburg, Germany
| | - Jung-Goo Lee
- Center for
Molecular Intelligence, The State University
of New York (SUNY), Korea,
119 Songdo Munwha-ro, Yeonsu-gu, 21985 Incheon, Korea
| | - Hyeon-Cheol Shin
- Center for
Molecular Intelligence, The State University
of New York (SUNY), Korea,
119 Songdo Munwha-ro, Yeonsu-gu, 21985 Incheon, Korea
| | - Christopher Roland
- Department
of Physics, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Celeste Sagui
- Department
of Physics, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Damian Houde
- Department
of Protein Pharmaceutical Development, Biogen, Cambridge, Massachusetts 02142, United States
| | - Kasper D. Rand
- Department
of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Thomas J. D. Jørgensen
- Department
of Biochemistry and Molecular Biology, University
of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark
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11
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Gass DT, Cordes MS, Alberti SN, Kim HJ, Gallagher ES. Evidence of H/D Exchange within Metal-Adducted Carbohydrates after Ion/Ion-Dissociation Reactions. J Am Chem Soc 2023; 145:23972-23985. [PMID: 37874934 DOI: 10.1021/jacs.3c05793] [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: 10/26/2023]
Abstract
Tandem mass spectrometry (MS/MS) using fragmentation has become one of the most effective methods for gaining sequence and structural information on biomolecules. Ion/ion reactions are competitive reactions, where either proton transfer (PT) or electron transfer (ET) can occur from interactions between multiply charged cations and singly charged anions. Utilizing ion/ion reactions with fluoranthene has offered a unique method of fragment formation for the structural elucidation of biomolecules. Fluoranthene is considered an ideal anion reagent because it selectively causes electron-transfer dissociation (ETD) and minimizes PT when interacting with peptides. However, limited investigations have sought to understand how fluoranthene─the primary, commercially available anion reagent─interacts with other biomolecules. Here, we apply deuterium labeling to investigate ion/ion reaction mechanisms between fluoranthene and divalent, metal-adducted carbohydrates (Ca2+, Mg2+, Co2+, and Ni2+). Deuterium labeling of carbohydrates allowed us to observe evidence of hydrogen/deuterium exchange (HDX) occurring after ion/ion dissociation reactions. The extent of deuterium loss is dependent on several factors, including the physical properties of the metal ion and the fragment structure. Based on the deuterium labeling data, we have proposed ETD, PTD, and intermolecular PT─also described as HDX─mechanisms. This research provides a fundamental perspective of ion/ion and ion/molecule reaction mechanisms and illustrates properties that impact ion/ion and ion/molecule reactions for carbohydrates. Together, this could improve the capability to distinguish complex and heterogeneous biomolecules, such as carbohydrates.
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Affiliation(s)
- Darren T Gass
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
| | - Michael S Cordes
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
| | - Sebastian N Alberti
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
| | - H Jamie Kim
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
| | - Elyssia S Gallagher
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
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12
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Mane SS, Ghaste M, Dearden DV. Mass spectrometry-based gas phase intramolecular benzyl migration in sparsentan, a novel endothelin and angiotensin II receptor antagonist. JOURNAL OF MASS SPECTROMETRY : JMS 2023; 58:e4980. [PMID: 37903508 DOI: 10.1002/jms.4980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 09/19/2023] [Accepted: 10/05/2023] [Indexed: 11/01/2023]
Abstract
We report a collision-induced dissociation (CID) based gas phase rearrangement study using quadrupole time-of-flight mass spectrometry coupled with liquid chromatography on a novel endothelin and angiotensin II receptor antagonist, sparsentan. We performed tandem mass spectrometry to identify precursor and fragment ion relationships and assigned structures for major fragment ions. We propose a benzyl migration mechanism based on bond length measurements in density functional theory (B3LYP/6-31+G*) optimized geometries of protonated sparsentan and its m/z 547 fragment. Protonated sparsentan undergoes loss of ethanol, which yields a resonance-stabilized benzylic cation with m/z 547, which further fragments into m/z 353 via benzyl migration, where the benzylic cation migrates to one of the nucleophilic nitrogen atoms followed by proton transfer from the sulfonamide nitrogen to a carbonyl oxygen, resulting in a neutral loss of mass 194. Further fragmentation of m/z 353 results in m/z 258, which undergoes radical and neutral loss to yield m/z 193 and 194, respectively. The proposed mechanism of generation of m/z 353 was confirmed by CID of deuterated sparsentan. Considering the importance of gas phase rearrangements of organic molecules in structural identifications as well as the novelty of the molecule, these findings will be helpful for future studies to predict gas phase benzyl migration in sparsentan analogs and for degradation product and metabolite identification of sparsentan and its analogs using LC-MS.
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Affiliation(s)
- Sudam S Mane
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah, 84602-1030, USA
| | - Manoj Ghaste
- Analytical Chemistry Department, Nelson Laboratories, 6280 S. Redwood Road, Salt Lake City, Utah, 84123, USA
| | - David V Dearden
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah, 84602-1030, USA
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13
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Schramm HM, Tamadate T, Hogan CJ, Clowers BH. Evaluation of Hydrogen-Deuterium Exchange during Transient Vapor Binding of MeOD with Model Peptide Systems Angiotensin II and Bradykinin. J Phys Chem A 2023; 127:8849-8861. [PMID: 37827113 DOI: 10.1021/acs.jpca.3c04608] [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: 10/14/2023]
Abstract
The advancement of hybrid mass spectrometric tools as an indirect probe of molecular structure and dynamics relies heavily upon a clear understanding between gas-phase ion reactivity and ion structural characteristics. This work provides new insights into gas-phase ion-neutral reactions of the model peptides (i.e., angiotensin II and bradykinin) on a per-residue basis by integrating hydrogen/deuterium exchange, ion mobility, tandem mass spectrometry, selective vapor binding, and molecular dynamics simulations. By comparing fragmentation patterns with simulated probabilities of vapor uptake, a clear link between gas-phase hydrogen/deuterium exchange and the probabilities of localized vapor association is established. The observed molecular dynamics trends related to the sites and duration of vapor binding track closely with experimental observation. Additionally, the influence of additional charges and structural characteristics on exchange kinetics and ion-neutral cluster formation is examined. These data provide a foundation for the analysis of solvation dynamics of larger, native-like conformations of proteins in the gas phase.
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Affiliation(s)
- Haley M Schramm
- Department of Chemistry, Washington State University, Pullman, Washington 99163, United States
| | - Tomoya Tamadate
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Christopher J Hogan
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Brian H Clowers
- Department of Chemistry, Washington State University, Pullman, Washington 99163, United States
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14
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Révész Á, Hevér H, Steckel A, Schlosser G, Szabó D, Vékey K, Drahos L. Collision energies: Optimization strategies for bottom-up proteomics. MASS SPECTROMETRY REVIEWS 2023; 42:1261-1299. [PMID: 34859467 DOI: 10.1002/mas.21763] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 11/17/2021] [Accepted: 11/17/2021] [Indexed: 06/07/2023]
Abstract
Mass-spectrometry coupled to liquid chromatography is an indispensable tool in the field of proteomics. In the last decades, more and more complex and diverse biochemical and biomedical questions have arisen. Problems to be solved involve protein identification, quantitative analysis, screening of low abundance modifications, handling matrix effect, and concentrations differing by orders of magnitude. This led the development of more tailored protocols and problem centered proteomics workflows, including advanced choice of experimental parameters. In the most widespread bottom-up approach, the choice of collision energy in tandem mass spectrometric experiments has outstanding role. This review presents the collision energy optimization strategies in the field of proteomics which can help fully exploit the potential of MS based proteomics techniques. A systematic collection of use case studies is then presented to serve as a starting point for related further scientific work. Finally, this article discusses the issue of comparing results from different studies or obtained on different instruments, and it gives some hints on methodology transfer between laboratories based on measurement of reference species.
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Affiliation(s)
- Ágnes Révész
- MS Proteomics Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Budapest, Hungary
| | - Helga Hevér
- Chemical Works of Gedeon Richter Plc, Budapest, Hungary
| | - Arnold Steckel
- Department of Analytical Chemistry, MTA-ELTE Lendület Ion Mobility Mass Spectrometry Research Group, Institute of Chemistry, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Gitta Schlosser
- Department of Analytical Chemistry, MTA-ELTE Lendület Ion Mobility Mass Spectrometry Research Group, Institute of Chemistry, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Dániel Szabó
- MS Proteomics Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Budapest, Hungary
| | - Károly Vékey
- MS Proteomics Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Budapest, Hungary
| | - László Drahos
- MS Proteomics Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Budapest, Hungary
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15
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Armentrout PB. Energetics and mechanisms for decomposition of cationized amino acids and peptides explored using guided ion beam tandem mass spectrometry. MASS SPECTROMETRY REVIEWS 2023; 42:928-953. [PMID: 34392555 DOI: 10.1002/mas.21723] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/22/2021] [Accepted: 07/23/2021] [Indexed: 06/13/2023]
Abstract
Fragmentation studies of cationized amino acids and small peptides as studied using guided ion beam tandem mass spectrometry (GIBMS) are reviewed. After a brief examination of the key attributes of the GIBMS approach, results for a variety of systems are examined, compared, and contrasted. Cationization of amino acids, diglycine, and triglycine with alkali cations generally leads to dissociations in which the intact biomolecule is lost. Exceptions include most lithiated species as well as a few examples for sodiated and one example for potassiated species. Like the lithiated species, cationization by protons leads to numerous dissociation channels. Results for protonated glycine, cysteine, asparagine, diglycine, and a series of tripeptides are reviewed, along with the thermodynamic consequences that can be gleaned. Finally, the important physiological process of the deamidation of asparagine (Asn) residues is explored by the comparison of five dipeptides in which the C-terminal partner (AsnXxx) is altered. The GIBMS thermochemistry is shown to correlate well with kinetic results from solution phase studies.
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Affiliation(s)
- P B Armentrout
- Department of Chemistry, University of Utah, Salt Lake City, Utah, USA
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16
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Moore CC, Staroverov VN, Konermann L. Using Density Functional Theory for Testing the Robustness of Mobile-Proton Molecular Dynamics Simulations on Electrosprayed Ions: Structural Implications for Gaseous Proteins. J Phys Chem B 2023; 127:4061-4071. [PMID: 37116098 DOI: 10.1021/acs.jpcb.3c01581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
Current experiments only provide low-resolution information on gaseous protein ions generated by electrospray ionization (ESI). Molecular dynamics (MD) simulations can yield complementary insights. Unfortunately, conventional MD does not capture the mobile nature of protons in gaseous proteins. Mobile-proton MD (MPMD) overcomes this limitation. Earlier MPMD data at 300 K indicated that protein ions generated by "native" ESI retain solution-like structures with a hydrophobic core and zwitterionic exterior [Bakhtiari, M.; Konermann, L. J. Phys. Chem. B 2019, 123, 1784-1796]. MPMD redistributes protons using electrostatic and proton affinity calculations. The robustness of this approach has never been scrutinized. Here, we close this gap by benchmarking MPMD against density functional theory (DFT) at the B3LYP/6-31G* level, which is well suited for predicting proton affinities. The computational cost of DFT necessitated the use of small peptides. The MPMD energetic ranking of proton configurations was found to be consistent with DFT single-point energies, implying that MPMD can reliably identify favorable protonation sites. Peptide MPMD runs converged to DFT-optimized structures only when applying 300-500 K temperature cycling, which was necessary to prevent trapping in local minima. Temperature cycling MPMD was then applied to gaseous protein ions. Native ubiquitin converted to slightly expanded structures with a zwitterionic core and a nonpolar exterior. Our data suggest that such inside-out protein structures are intrinsically preferred in the gas phase, and that they form in ESI experiments after moderate collisional excitation. This is in contrast to native ESI (with minimal collisional excitation, simulated by MPMD at 300 K), where kinetic trapping promotes the survival of solution-like structures. In summary, this work validates the MPMD approach for simulations on gaseous peptides and proteins.
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Affiliation(s)
- Conrad C Moore
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Viktor N Staroverov
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
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17
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Nacsa AB, Kígyósi M, Czakó G. Protonation of serine: conformers, proton affinities and gas-phase basicities at the "gold standard" and beyond. Phys Chem Chem Phys 2023; 25:8891-8902. [PMID: 36916632 DOI: 10.1039/d3cp00612c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
The potential energy surfaces (PESs) of serine and its protonated counterparts are investigated to determine the structures of the minima. A total of 95 neutral serine, 15 N-(amino-) and 46 O-(carbonyl-)protonated serine conformers are found. Their relative energies, geometries and harmonic vibrational frequencies are determined at the MP2/aug-cc-pVDZ level of theory. To obtain highly accurate thermodynamic values, further computations are performed: the ten conformers with the lowest relative energies from each molecule type (neutral, N- and O-protonated) are further optimized using the explicitly correlated CCSD(T)-F12a/cc-pVDZ-F12 method (for neutral serine, harmonic vibrational frequencies were also computed). In addition, auxiliary corrections were determined: basis-set effects up to CCSD(T)-F12b/cc-pVQZ-F12, electron correlation effects up to CCSDT(Q), core correlation and second-order Douglas-Kroll relativistic effects along with zero-point energy contributions. Two important thermodynamic parameters (at 298.15 K), proton affinity (PA)/gas-phase basicity (GB) are calculated considering the two different protonation sites: 218.05 ± 0.2/209.86 ± 0.6 kcal mol-1 and 205.87 ± 0.2/196.36 ± 0.3 kcal mol-1 for the amino and carbonyl sites, respectively. The uncertainty of the determined values was approximated based on various sources including auxiliary corrections, basis-set effects, harmonic vibrational frequencies.
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Affiliation(s)
- András B Nacsa
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
| | - Máté Kígyósi
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
| | - Gábor Czakó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
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18
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Tian X, Permentier HP, Bischoff R. Chemical isotope labeling for quantitative proteomics. MASS SPECTROMETRY REVIEWS 2023; 42:546-576. [PMID: 34091937 PMCID: PMC10078755 DOI: 10.1002/mas.21709] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/22/2021] [Accepted: 05/17/2021] [Indexed: 05/05/2023]
Abstract
Advancements in liquid chromatography and mass spectrometry over the last decades have led to a significant development in mass spectrometry-based proteome quantification approaches. An increasingly attractive strategy is multiplex isotope labeling, which significantly improves the accuracy, precision and throughput of quantitative proteomics in the data-dependent acquisition mode. Isotope labeling-based approaches can be classified into MS1-based and MS2-based quantification. In this review, we give an overview of approaches based on chemical isotope labeling and discuss their principles, benefits, and limitations with the goal to give insights into fundamental questions and provide a useful reference for choosing a method for quantitative proteomics. As a perspective, we discuss the current possibilities and limitations of multiplex, isotope labeling approaches for the data-independent acquisition mode, which is increasing in popularity.
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Affiliation(s)
- Xiaobo Tian
- Department of Analytical Biochemistry and Interfaculty Mass Spectrometry Center, Groningen Research Institute of PharmacyUniversity of GroningenGroningenThe Netherlands
| | - Hjalmar P. Permentier
- Department of Analytical Biochemistry and Interfaculty Mass Spectrometry Center, Groningen Research Institute of PharmacyUniversity of GroningenGroningenThe Netherlands
| | - Rainer Bischoff
- Department of Analytical Biochemistry and Interfaculty Mass Spectrometry Center, Groningen Research Institute of PharmacyUniversity of GroningenGroningenThe Netherlands
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19
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Fu D, Habtegabir SG, Wang H, Feng S, Han Y. Understanding of protomers/deprotomers by combining mass spectrometry and computation. Anal Bioanal Chem 2023:10.1007/s00216-023-04574-1. [PMID: 36737499 DOI: 10.1007/s00216-023-04574-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 01/19/2023] [Accepted: 01/27/2023] [Indexed: 02/05/2023]
Abstract
Multifunctional compounds may form different prototropic isomers under different conditions, which are known as protomers/deprotomers. In biological systems, these protomer/deprotomer isomers affect the interaction modes and conformational landscape between compounds and enzymes and thus present different biological activities. Study on protomers/deprotomers is essentially the study on the acidity/basicity of each intramolecular functional group and its effect on molecular structure. In recent years, the combination of mass spectrometry (MS) and computational chemistry has been proven to be a powerful and effective means to study prototropic isomers. MS-based technologies are developed to discriminate and characterize protomers/deprotomers to provide structural information and monitor transformations, showing great superiority than other experimental methods. Computational chemistry is used to predict the thermodynamic stability of protomers/deprotomers, provide the simulated MS/MS spectra, infrared spectra, and calculate collision cross-section values. By comparing the theoretical data with the corresponding experimental results, the researchers can not only determine the protomer/deprotomer structure, but also investigate the structure-activity relationship in a given system. This review covers various MS methods and theoretical calculations and their devotion to isomer discrimination, structure identification, conformational transformation, and phase transition investigation of protomers/deprotomers.
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Affiliation(s)
- Dali Fu
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing, 102249, People's Republic of China
| | - Sara Girmay Habtegabir
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing, 102249, People's Republic of China
| | - Haodong Wang
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing, 102249, People's Republic of China
| | - Shijie Feng
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing, 102249, People's Republic of China
| | - Yehua Han
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing, 102249, People's Republic of China.
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20
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Juetten KJ, Brodbelt JS. MS-TAFI: A Tool for the Analysis of Fragment Ions Generated from Intact Proteins. J Proteome Res 2023; 22:546-550. [PMID: 36516971 DOI: 10.1021/acs.jproteome.2c00594] [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: 12/23/2022]
Abstract
Tandem mass spectrometry (MS/MS) spectra of intact proteins can be difficult to interpret owing to the variety of fragment ion types and abundances. This information is crucial for maximizing the information derived from top-down mass spectrometry of proteins and protein complexes. MS-TAFI (Mass Spectrometry Tool for the Analysis of Fragment Ions) is a free Python-based program which offers a streamlined approach to the data analysis and visualization of deconvoluted MS/MS data of intact proteins. The application also contains tools for native mass spectrometry experiments with the ability to search for fragment ions that retain ligands (holo ions) as well as visualize the location of charge sites obtained from 193 nm ultraviolet photodissociation data. The source code and complete application for MS-TAFI is available for download at https://github.com/kylejuetten.
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Affiliation(s)
- Kyle J Juetten
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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21
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Burris BJ, Walsh LC, Badu-Tawiah AK. Online Cross-Linking of Peptides and Proteins during Contained-Electrospray Ionization Mass Spectrometry. Anal Chem 2023; 95:1085-1094. [PMID: 36534015 DOI: 10.1021/acs.analchem.2c03791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Recent advancements in mass spectrometry (MS) now enable all levels of protein structures to be characterized, including primary protein sequence, post-translational modifications, and three-dimensional protein conformations. However, protein conformational studies by MS require the use of many separate techniques that are performed independently of each other. Herein, we described a contained-electrospray (ES) experiment that has potential to integrate peptide/protein cross-linking with the general MS workflow. In our experiment, cross-linking of protein/peptide occurs simultaneously with ionization after analytes, and cross-linkers are sprayed from two separate ES emitters. The online cross-linking process occurring in the charged microdroplet environment was optimized using trilysine peptide and bis(sulfosuccinimidyl)suberate cross-linker. We detected the electrostatic complex between analyte and cross-linker, the mono-linked intermediate, and the fully cross-linked product, allowing us to correctly predict the sequence of reaction events in the cross-linking process. Importantly, we observed that the terminal fully cross-linked product is composed of two distinct conformations. In one form, the product involved cross-linking between two ε-NH2 amines in lysine residues, while the other conformer was formed by a reaction between one ε-NH2 amine and the N-terminus. The experimental conditions for selecting one cross-linked species over others during the online ES ionization-MS analysis have been detailed. Appropriate parameters enabled the reaction between α-lactalbumin proteins and cross-linkers using a non-denaturing spray condition. These results establish a framework for a future development in high-throughput structural MS method, where all levels of protein information can be gathered in a single experiment.
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Affiliation(s)
- Benjamin J Burris
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio43210, United States
| | - Leah C Walsh
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio43210, United States
| | - Abraham K Badu-Tawiah
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio43210, United States
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22
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Kashina AS, Yates Iii JR. Identification of Arginylated Proteins by Mass Spectrometry. Methods Mol Biol 2023; 2620:139-152. [PMID: 37010760 DOI: 10.1007/978-1-0716-2942-0_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
Abstract
Here, we describe the method for the identification of arginylated proteins by mass spectrometry. This method has been originally applied to the identification of N-terminally added Arg on proteins and peptides and then expanded to the side chain modification which has been recently described by our groups. The key steps in this method include the use of the mass spectrometry instruments that can identify peptides with very high pass accuracy (Orbitrap) and apply stringent mass cutoffs during automated data analysis, followed by manual validation of the identified spectra. These methods can be used with both complex and purified protein samples and, to date, constitute the only reliable way to confirm arginylation at a particular site on a protein or peptide.
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Affiliation(s)
- Anna S Kashina
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - John R Yates Iii
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
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23
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Nacsa AB, Czakó G. Benchmark Ab Initio Determination of the Conformers, Proton Affinities, and Gas-Phase Basicities of Cysteine. J Phys Chem A 2022; 126:9667-9679. [PMID: 36524999 PMCID: PMC9806835 DOI: 10.1021/acs.jpca.2c07035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A systematic conformational mapping combined with literature data leads to 85 stable neutral cysteine conformers. The implementation of the same mapping process for the protonated counterparts reveals 21 N-(amino-), 64 O-(carbonyl-), and 37 S-(thiol-)protonated cysteine conformers. Their relative energies and harmonic vibrational frequencies are given at the MP2/aug-cc-pVDZ level of theory. Further benchmark ab initio computations are performed for the 10 lowest-lying neutral and protonated amino acid conformers (for each type) such as CCSD(T)-F12a/cc-pVDZ-F12 geometry optimizations (and frequency computations for cysteine) as well as auxiliary correction computations of the basis set effects up to CCSD(T)-F12b/cc-pVQZ-F12, electron correlation effects up to CCSDT(Q), core correlation effects, second-order Douglass-Kroll relativistic effects, and zero-point energy contributions. Boltzmann-averaged 0 (298.15) K proton affinity and [298.15 K gas-phase basicity] values of cysteine are predicted to be 214.96 (216.39) [208.21], 201.83 (203.55) [194.16], and 193.31 (194.74) [186.40] kcal/mol for N-, O-, and S-protonation, respectively, also considering the previously described auxiliary corrections.
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24
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Koopman J, Grimme S. Calculation of Mass Spectra with the QCxMS Method for Negatively and Multiply Charged Molecules. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:2226-2242. [PMID: 36343304 DOI: 10.1021/jasms.2c00209] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Analysis and validation of a mass spectrometry (MS) experiment are usually performed by comparison to reference spectra. However, if references are missing, measured spectra cannot be properly matched. To close this gap, the Quantum Chemical Mass Spectrometry (QCxMS) program has been developed. It enables fully automatic calculations of electron ionization (EI) and positive ion collision-induced dissociation (CID) mass spectra of singly charged molecular ions. In this work, the extension to negative and multiple ion charge for the CID run mode is presented. QCxMS is now capable of calculating structures carrying any charge, without the need for pretabulated fragmentation pathways or machine learning of database spectra. Mass spectra of four single negatively charged and two multiple positively charged organic ions with molecular sizes from 12 to 92 atoms were computed and compared to reference spectra. The underlying Born-Oppenheimer molecular dynamics (MD) calculations were conducted using the semiempirical quantum mechanical GFN2-xTB method, while for some small molecules, ab initio DFT-based MD simulations were performed. Detailed insights into the fragmentation pathways were gained, and the effects of the computed charge assignments on the resulting spectrum are discussed. Especially for the negative ion mode, the influence of the deprotonation site to create the anion was found to be substantial. Doubly charged fragments could successfully be calculated fully automatically for the first time, while higher charged structures introduced severe assignment problems. Overall, this extension of the QCxMS program further enhances its applicability and underlines its value as a sophisticated toolkit for CID-based tandem MS structure elucidation.
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Affiliation(s)
- Jeroen Koopman
- Mulliken Center for Theoretical Chemistry, Institute for Physical and Theoretical Chemistry, University of Bonn, Beringstr. 4, 53115Bonn, Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, Institute for Physical and Theoretical Chemistry, University of Bonn, Beringstr. 4, 53115Bonn, Germany
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25
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Lenčo J, Jadeja S, Naplekov DK, Krokhin OV, Khalikova MA, Chocholouš P, Urban J, Broeckhoven K, Nováková L, Švec F. Reversed-Phase Liquid Chromatography of Peptides for Bottom-Up Proteomics: A Tutorial. J Proteome Res 2022; 21:2846-2892. [PMID: 36355445 DOI: 10.1021/acs.jproteome.2c00407] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The performance of the current bottom-up liquid chromatography hyphenated with mass spectrometry (LC-MS) analyses has undoubtedly been fueled by spectacular progress in mass spectrometry. It is thus not surprising that the MS instrument attracts the most attention during LC-MS method development, whereas optimizing conditions for peptide separation using reversed-phase liquid chromatography (RPLC) remains somewhat in its shadow. Consequently, the wisdom of the fundaments of chromatography is slowly vanishing from some laboratories. However, the full potential of advanced MS instruments cannot be achieved without highly efficient RPLC. This is impossible to attain without understanding fundamental processes in the chromatographic system and the properties of peptides important for their chromatographic behavior. We wrote this tutorial intending to give practitioners an overview of critical aspects of peptide separation using RPLC to facilitate setting the LC parameters so that they can leverage the full capabilities of their MS instruments. After briefly introducing the gradient separation of peptides, we discuss their properties that affect the quality of LC-MS chromatograms the most. Next, we address the in-column and extra-column broadening. The last section is devoted to key parameters of LC-MS methods. We also extracted trends in practice from recent bottom-up proteomics studies and correlated them with the current knowledge on peptide RPLC separation.
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Affiliation(s)
- Juraj Lenčo
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - Siddharth Jadeja
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - Denis K Naplekov
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - Oleg V Krokhin
- Department of Internal Medicine, Manitoba Centre for Proteomics and Systems Biology, University of Manitoba, 799 JBRC, 715 McDermot Avenue, WinnipegR3E 3P4, Manitoba, Canada
| | - Maria A Khalikova
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - Petr Chocholouš
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - Jiří Urban
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00Brno, Czech Republic
| | - Ken Broeckhoven
- Department of Chemical Engineering (CHIS), Faculty of Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050Brussel, Belgium
| | - Lucie Nováková
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - František Švec
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
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26
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Stability and conformational memory of electrosprayed and rehydrated bacteriophage MS2 virus coat proteins. Curr Res Struct Biol 2022; 4:338-348. [PMID: 36440379 PMCID: PMC9685359 DOI: 10.1016/j.crstbi.2022.10.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 09/23/2022] [Accepted: 10/13/2022] [Indexed: 11/06/2022] Open
Abstract
Proteins are innately dynamic, which is important for their functions, but which also poses significant challenges when studying their structures. Gas-phase techniques can utilise separation and a range of sample manipulations to transcend some of the limitations of conventional techniques for structural biology in crystalline or solution phase, and isolate different states for separate interrogation. However, the transfer from solution to the gas phase risks affecting the structures, and it is unclear to what extent different conformations remain distinct in the gas phase, and if resolution in silico can recover the native conformations and their differences. Here, we use extensive molecular dynamics simulations to study the two distinct conformations of dimeric capsid protein of the MS2 bacteriophage. The protein undergoes notable restructuring of its peripheral parts in the gas phase, but subsequent simulation in solvent largely recovers the native structure. Our results suggest that despite some structural loss due to the experimental conditions, gas-phase structural biology techniques provide meaningful data that inform not only about the structures but also conformational dynamics of proteins. Presented extensive molecular dynamics (MD) simulation data investigating protein vacuum exposure and rehydration dynamics. Demonstrated that the majority of the protein structure recovers their initial solution conformation after vacuum exposure. Explored the potential gain for structural biology of using MD simulation to refine gas-phase determined protein structures.
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27
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Estrada P, Bañares-Hidalgo Á, Pérez-Gil J. Disulfide bonds in the SAPA domain of the pulmonary surfactant protein B precursor. J Proteomics 2022; 269:104722. [PMID: 36108905 DOI: 10.1016/j.jprot.2022.104722] [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: 06/21/2022] [Revised: 08/31/2022] [Accepted: 09/06/2022] [Indexed: 10/14/2022]
Abstract
The disulfide bonds formed in the SAPA domain of a recombinant version of the NH2-terminal propeptide (SP-BN) from the precursor of human pulmonary surfactant protein B (SP-B) were identified through sequential digestion of SP-BN with GluC/trypsin or thermolysin/GluC, followed by mass spectrometry (MS) analysis. MS spectra allowed identification of disulfide bonds between Cys32-Cys49 and Cys40-Cys55, and we propose a disulfide connectivity pattern of 1-3 and 2-4 within the SAPA domain, with the Cys residues numbered according to their position from the N-terminus of the propeptide sequence. The peaks with m/z ∼ 2136 and ∼ 1780 in the MS spectrum of the GluC/trypsin digest were assigned to peptides 24AWTTSSLACAQGPE37 and 45QALQCR50 linked by Cys32-Cys49 and 38FWCQSLE44 and 51ALGHCLQE58 linked by Cys40-Cys55 respectively. Tandem mass spectrometry (MS/MS) analysis verified the position of the bonds. The results of the series ions, immonium ions and internal fragment ions were all compatible with the proposed 1-3/2-4 position of the disulfide bonds in the SAPA domain. This X-pattern differs from the kringle-type found in the SAPB domain of the SAPLIP proteins, where the first Cys in the sequence links to the last, the second to the penultimate and the third to the fourth one. Regarding the SAPB domain of the SP-BN propeptide, the MS analysis of both digests identified the bond Cys100-Cys112, numbered 7-8, which is coincident with the bond position in the kringle motif. SIGNIFICANCE: The SAPLIP (saposin-like proteins) family encompasses several proteins with homology to saposins (sphingolipids activator proteins). These are proteins with mainly alpha-helical folds, compact packing including well conserved disulfide bonds and ability to interact with phospholipids and membranes. There are two types of saposin-like domains termed as Saposin A (SAPA) and Saposin B (SAPB) domains. While disulfide connectivity has been well established in several SAPB domains, the position of disulfide bonds in SAPA domains is still unknown. The present study approaches a detailed proteomic study to determine disulfide connectivity in the SAPA domain of the precursor of human pulmonary surfactant-associated protein SP-B. This task has been a challenge requiring the combination of different sequential proteolytic treatments followed by MS analysis including MALDI-TOF and tandem mass MS/MS spectrometry. The determination for first time of the position of disulfide bonds in SAPA domains is an important step to understand the structural determinants defining its biological functions.
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Affiliation(s)
- Pilar Estrada
- Dept. Biochemistry and Molecular Biology, Faculty of Biology, Complutense University, 28040 Madrid, Spain
| | - Ángeles Bañares-Hidalgo
- Dept. Biochemistry and Molecular Biology, Faculty of Biology, Complutense University, 28040 Madrid, Spain
| | - Jesús Pérez-Gil
- Dept. Biochemistry and Molecular Biology, Faculty of Biology, Complutense University, 28040 Madrid, Spain.
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28
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Pauwels J, Fijałkowska D, Eyckerman S, Gevaert K. Mass spectrometry and the cellular surfaceome. MASS SPECTROMETRY REVIEWS 2022; 41:804-841. [PMID: 33655572 DOI: 10.1002/mas.21690] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 02/05/2021] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
The collection of exposed plasma membrane proteins, collectively termed the surfaceome, is involved in multiple vital cellular processes, such as the communication of cells with their surroundings and the regulation of transport across the lipid bilayer. The surfaceome also plays key roles in the immune system by recognizing and presenting antigens, with its possible malfunctioning linked to disease. Surface proteins have long been explored as potential cell markers, disease biomarkers, and therapeutic drug targets. Despite its importance, a detailed study of the surfaceome continues to pose major challenges for mass spectrometry-driven proteomics due to the inherent biophysical characteristics of surface proteins. Their inefficient extraction from hydrophobic membranes to an aqueous medium and their lower abundance compared to intracellular proteins hamper the analysis of surface proteins, which are therefore usually underrepresented in proteomic datasets. To tackle such problems, several innovative analytical methodologies have been developed. This review aims at providing an extensive overview of the different methods for surfaceome analysis, with respective considerations for downstream mass spectrometry-based proteomics.
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Affiliation(s)
- Jarne Pauwels
- VIB Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | | | - Sven Eyckerman
- VIB Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Kris Gevaert
- VIB Center for Medical Biotechnology, VIB, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
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29
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Blevins MS, Juetten KJ, James VK, Butalewicz JP, Escobar EE, Lanzillotti MB, Sanders JD, Fort KL, Brodbelt JS. Nanohydrophobic Interaction Chromatography Coupled to Ultraviolet Photodissociation Mass Spectrometry for the Analysis of Intact Proteins in Low Charge States. J Proteome Res 2022; 21:2493-2503. [PMID: 36043517 DOI: 10.1021/acs.jproteome.2c00450] [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: 11/29/2022]
Abstract
The direct correlation between proteoforms and biological phenotype necessitates the exploration of mass spectrometry (MS)-based methods more suitable for proteoform detection and characterization. Here, we couple nano-hydrophobic interaction chromatography (nano-HIC) to ultraviolet photodissociation MS (UVPD-MS) for separation and characterization of intact proteins and proteoforms. High linearity, sensitivity, and sequence coverage are obtained with this method for a variety of proteins. Investigation of collisional cross sections of intact proteins during nano-HIC indicates semifolded conformations in low charge states, enabling a different dimension of separation in comparison to traditional, fully denaturing reversed-phase separations. This method is demonstrated for a mixture of intact proteins from Escherichia coli ribosomes; high sequence coverage is obtained for a variety of modified and unmodified proteoforms.
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Affiliation(s)
- Molly S Blevins
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Kyle J Juetten
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Virginia K James
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Jamie P Butalewicz
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Edwin E Escobar
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Michael B Lanzillotti
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - James D Sanders
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Kyle L Fort
- Thermo Fisher Scientific, Bremen 28199, Germany
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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30
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Zhang Y, Dreyer B, Govorukhina N, Heberle AM, Končarević S, Krisp C, Opitz CA, Pfänder P, Bischoff R, Schlüter H, Kwiatkowski M, Thedieck K, Horvatovich PL. Comparative Assessment of Quantification Methods for Tumor Tissue Phosphoproteomics. Anal Chem 2022; 94:10893-10906. [PMID: 35880733 PMCID: PMC9366746 DOI: 10.1021/acs.analchem.2c01036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
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With increasing sensitivity and accuracy in mass spectrometry,
the tumor phosphoproteome is getting into reach. However, the selection
of quantitation techniques best-suited to the biomedical question
and diagnostic requirements remains a trial and error decision as
no study has directly compared their performance for tumor tissue
phosphoproteomics. We compared label-free quantification (LFQ), spike-in-SILAC
(stable isotope labeling by amino acids in cell culture), and tandem
mass tag (TMT) isobaric tandem mass tags technology for quantitative
phosphosite profiling in tumor tissue. Compared to the classic SILAC
method, spike-in-SILAC is not limited to cell culture analysis, making
it suitable for quantitative analysis of tumor tissue samples. TMT
offered the lowest accuracy and the highest precision and robustness
toward different phosphosite abundances and matrices. Spike-in-SILAC
offered the best compromise between these features but suffered from
a low phosphosite coverage. LFQ offered the lowest precision but the
highest number of identifications. Both spike-in-SILAC and LFQ presented
susceptibility to matrix effects. Match between run (MBR)-based analysis
enhanced the phosphosite coverage across technical replicates in LFQ
and spike-in-SILAC but further reduced the precision and robustness
of quantification. The choice of quantitative methodology is critical
for both study design such as sample size in sample groups and quantified
phosphosites and comparison of published cancer phosphoproteomes.
Using ovarian cancer tissue as an example, our study builds a resource
for the design and analysis of quantitative phosphoproteomic studies
in cancer research and diagnostics.
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Affiliation(s)
- Yang Zhang
- Department of Analytical Biochemistry, Groningen Research Institute of Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands.,Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria.,Laboratory of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Benjamin Dreyer
- Section/Core Facility Mass Spectrometry and Proteomics, Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246 Hamburg, Germany
| | - Natalia Govorukhina
- Department of Analytical Biochemistry, Groningen Research Institute of Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands
| | - Alexander M Heberle
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria.,Laboratory of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Saša Končarević
- Proteome Sciences R&D GmbH & Co. KG, Altenhöferallee 3, 60438 Frankfurt/Main, Germany
| | - Christoph Krisp
- Section/Core Facility Mass Spectrometry and Proteomics, Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246 Hamburg, Germany
| | - Christiane A Opitz
- Metabolic Crosstalk in Cancer, German Consortium of Translational Cancer Research (DKTK), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany.,Department of Neurology, National Center for Tumor Diseases, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Pauline Pfänder
- Metabolic Crosstalk in Cancer, German Consortium of Translational Cancer Research (DKTK), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany.,Faculty of Bioscience, Heidelberg University, 69117 Heidelberg, Germany
| | - Rainer Bischoff
- Department of Analytical Biochemistry, Groningen Research Institute of Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands
| | - Hartmut Schlüter
- Section/Core Facility Mass Spectrometry and Proteomics, Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246 Hamburg, Germany
| | - Marcel Kwiatkowski
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria.,Department of Molecular Pharmacology, Groningen Research Institute for Pharmacy, University of Groningen, Groningen 9700 AD, The Netherlands.,Groningen Research Institute for Asthma and COPD, University Medical Center Groningen, University of Groningen, Groningen 9700 AD, The Netherlands
| | - Kathrin Thedieck
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria.,Laboratory of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands.,Department of Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26129 Oldenburg, Germany
| | - Peter L Horvatovich
- Department of Analytical Biochemistry, Groningen Research Institute of Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands
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31
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Liu R, Xia S, Li H. Native top-down mass spectrometry for higher-order structural characterization of proteins and complexes. MASS SPECTROMETRY REVIEWS 2022:e21793. [PMID: 35757976 DOI: 10.1002/mas.21793] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
Progress in structural biology research has led to a high demand for powerful and yet complementary analytical tools for structural characterization of proteins and protein complexes. This demand has significantly increased interest in native mass spectrometry (nMS), particularly native top-down mass spectrometry (nTDMS) in the past decade. This review highlights recent advances in nTDMS for structural research of biological assemblies, with a particular focus on the extra multi-layers of information enabled by TDMS. We include a short introduction of sample preparation and ionization to nMS, tandem fragmentation techniques as well as mass analyzers and software/analysis pipelines used for nTDMS. We highlight unique structural information offered by nTDMS and examples of its broad range of applications in proteins, protein-ligand interactions (metal, cofactor/drug, DNA/RNA, and protein), therapeutic antibodies and antigen-antibody complexes, membrane proteins, macromolecular machineries (ribosome, nucleosome, proteosome, and viruses), to endogenous protein complexes. The challenges, potential, along with perspectives of nTDMS methods for the analysis of proteins and protein assemblies in recombinant and biological samples are discussed.
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Affiliation(s)
- Ruijie Liu
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Shujun Xia
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Huilin Li
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
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32
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Asakawa D, Hosokai T, Nakayama Y. Experimental and Theoretical Investigation of MALDI In-Source Decay of Peptides with a Reducing Matrix: What Is the Initial Fragmentation Step? JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:1011-1021. [PMID: 35587880 DOI: 10.1021/jasms.2c00066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Matrix-assisted laser desorption/ionization in-source decay (MALDI-ISD) with a reducing matrix is believed to be initiated by hydrogen transfer from the matrix to the peptide. Several new matrices have recently been developed to achieve more efficient MALDI-ISD. In particular, the use of matrices containing aniline groups facilitates MALDI-ISD to a greater extent than that of matrices containing phenol groups, although the N-H bond in aniline is stronger than the O-H bond in phenol. In this study, photoelectron yield spectroscopy of matrix solids revealed that conversion of the phenol group to the aniline group decreased the ionization energy of the matrix solids. Crucially, the use of a matrix with lower ionization energy has been found to result in efficient cleavage at N-Cα and disulfide bonds by MALDI-ISD. Therefore, electron association with the peptide rather than the fragmentation mechanism involving hydrogen atom attachment is proposed as the initial step of the MALDI-ISD process. In this mechanism, electron transfer from the reducing matrix to the peptide produces a peptide anion radical, which provides either a [cn + H]/[zm]• or [an]•/[ym + H] fragment pair. Fragmentation of the peptide anion radical strongly depends on the gas-phase acidity of the matrix used. Subsequently, the resultant fragments/radicals underwent a reaction in the MALDI plume, producing observable even-electron ions. Consequently, MALDI-ISD fragments are observed as both positive and negative ions, even though MALDI-ISD with a reducing matrix involves fragmentation of peptide anion radicals. The proposed mechanism is suitable for obtaining a better understanding of the MALDI-ISD process.
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Affiliation(s)
- Daiki Asakawa
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Takuya Hosokai
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
- Department of Pure and Applied Chemistry, Tokyo University of Science, Noda, Chiba 278-8510, Japan
| | - Yasuo Nakayama
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
- Department of Pure and Applied Chemistry; Division of Colloid and Interface Science; Research Group for Advanced Energy Conversion, Tokyo University of Science, Noda 278-8510, Japan
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33
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Li Z, Liu K, Xu P, Yang J. Benchmarking Cleavable Biotin Tags for Peptide-Centric Chemoproteomics. J Proteome Res 2022; 21:1349-1358. [PMID: 35467356 DOI: 10.1021/acs.jproteome.2c00174] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Click chemistry─specifically the copper-catalyzed azide-alkyne cycloaddition─has enabled the development of a wide range of chemical probes to analyze subsets of the functional proteome. The "clickable" proteome can be selectively enriched by using diverse cleavable biotin tags, but the direct identification of probe/tag-modified peptides (or peptide-centric analysis) remains challenging. Here, we evaluated the performance of five commercially available cleavable biotin tags in three most common chemoproteomic workflows, resulting in a comparative analysis of 15 methods. An acid-cleavable biotin tag with a dialkoxydiphenylsilane moiety, in combination with the protein "click", peptide "capture" workflow, outperforms all other methods in terms of enrichment efficiency, identification yield, and reproducibility, although its performance may be slightly compromised by the formation of an unwanted formate product revealed by blind search. Despite being inferior, photocleavable, and reduction-cleavable, biotin tags can also find their applicable sceneries, especially when dealing with acid-sensitive probes or probe-derived modifications. Furthermore, the systematic comparison of LC-MS/MS characteristics of tag-modified peptides provides valuable information for the future development of cleavable biotin reagents. Taken together, our data provides a much-needed practical guidance for researchers interested in developing and/or applying an ideal cleavable biotin tag to peptide-centric chemoproteomics.
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Affiliation(s)
- Zongmin Li
- School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China.,State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences Beijing, Beijing Institute of Lifeomics, Beijing 102206, China
| | - Keke Liu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences Beijing, Beijing Institute of Lifeomics, Beijing 102206, China
| | - Ping Xu
- School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China.,State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences Beijing, Beijing Institute of Lifeomics, Beijing 102206, China
| | - Jing Yang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences Beijing, Beijing Institute of Lifeomics, Beijing 102206, China
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34
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Fornelli L, Toby TK. Characterization of large intact protein ions by mass spectrometry: What directions should we follow? BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2022; 1870:140758. [PMID: 35077914 DOI: 10.1016/j.bbapap.2022.140758] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 11/16/2022]
Abstract
Theoretically, the gas-phase interrogation of whole proteoforms via mass spectrometry, known as top-down proteomics, bypasses the protein inference problem that afflicts peptide-centric proteomic approaches. Despite this obvious advantage, the application of top-down proteomics remains rare, mainly due to limited throughput and difficulty of analyzing proteins >30 kDa. Here we will discuss some of the problems encountered during the characterization of large proteoforms, and guided by a combination of theoretical background and experimental evidence we will describe some innovative data acquisition strategies and novel mass spectrometry technologies that can at least partially overcome such limitations.
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Affiliation(s)
- Luca Fornelli
- University of Oklahoma, Department of Biology, 730 Van Vleet oval, Norman, OK 73109, United States of America; University of Oklahoma, Department Chemistry and Biochemistry, 101 Stephenson Parkway, Norman, OK 73109, United States of America.
| | - Timothy K Toby
- DiscernDx, 2478 Embarcadero Way, Palo Alto, CA 94303, United States of America
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35
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Richards AL, Chen KH, Wilburn DB, Stevenson E, Polacco BJ, Searle BC, Swaney DL. Data-Independent Acquisition Protease-Multiplexing Enables Increased Proteome Sequence Coverage Across Multiple Fragmentation Modes. J Proteome Res 2022; 21:1124-1136. [PMID: 35234472 PMCID: PMC9035370 DOI: 10.1021/acs.jproteome.1c00960] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The use of multiple proteases has been shown to increase protein sequence coverage in proteomics experiments; however, due to the additional analysis time required, it has not been widely adopted in routine data-dependent acquisition (DDA) proteomic workflows. Alternatively, data-independent acquisition (DIA) has the potential to analyze multiplexed samples from different protease digests, but has been primarily optimized for fragmenting tryptic peptides. Here we evaluate a DIA multiplexing approach that combines three proteolytic digests (Trypsin, AspN, and GluC) into a single sample. We first optimize data acquisition conditions for each protease individually with both the canonical DIA fragmentation mode (beam type CID), as well as resonance excitation CID, to determine optimal consensus conditions across proteases. Next, we demonstrate that application of these conditions to a protease-multiplexed sample of human peptides results in similar protein identifications and quantitative performance as compared to trypsin alone, but enables up to a 63% increase in peptide detections, and a 45% increase in nonredundant amino acid detections. Nontryptic peptides enabled noncanonical protein isoform determination and resulted in 100% sequence coverage for numerous proteins, suggesting the utility of this approach in applications where sequence coverage is critical, such as protein isoform analysis.
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Affiliation(s)
- Alicia L Richards
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, California 94158, United States.,J. David Gladstone Institutes, San Francisco, California 94158, United States.,Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California 94158, United States
| | - Kuei-Ho Chen
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, California 94158, United States.,J. David Gladstone Institutes, San Francisco, California 94158, United States.,Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California 94158, United States
| | - Damien B Wilburn
- Pelotonia Institute for Immuno-Oncology, The Ohio State University Comprehensive Cancer Center, Columbus, Ohio 43210, United States.,Department of Biomedical Informatics, The Ohio State University, Columbus, Ohio 43210, United States.,Department of Genome Sciences, University of Washington, Seattle, Washington 98195, United States
| | - Erica Stevenson
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, California 94158, United States.,J. David Gladstone Institutes, San Francisco, California 94158, United States.,Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California 94158, United States
| | - Benjamin J Polacco
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, California 94158, United States.,J. David Gladstone Institutes, San Francisco, California 94158, United States.,Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California 94158, United States
| | - Brian C Searle
- Pelotonia Institute for Immuno-Oncology, The Ohio State University Comprehensive Cancer Center, Columbus, Ohio 43210, United States.,Department of Biomedical Informatics, The Ohio State University, Columbus, Ohio 43210, United States
| | - Danielle L Swaney
- Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, California 94158, United States.,J. David Gladstone Institutes, San Francisco, California 94158, United States.,Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California 94158, United States
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36
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Towards understanding the formation of internal fragments generated by collisionally activated dissociation for top-down mass spectrometry. Anal Chim Acta 2022; 1194:339400. [PMID: 35063165 PMCID: PMC9088748 DOI: 10.1016/j.aca.2021.339400] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/30/2021] [Accepted: 12/23/2021] [Indexed: 12/15/2022]
Abstract
Top-down mass spectrometry (TD-MS) generates fragment ions that returns information on the polypeptide amino acid sequence. In addition to terminal fragments, internal fragments that result from multiple cleavage events can also be formed. Traditionally, internal fragments are largely ignored due to a lack of available software to reliably assign them, mainly caused by a poor understanding of their formation mechanism. To accurately assign internal fragments, their formation process needs to be better understood. Here, we applied a statistical method to compare fragmentation patterns of internal and terminal fragments of peptides and proteins generated by collisionally activated dissociation (CAD). Internal fragments share similar fragmentation propensities with terminal fragments (e.g., enhanced cleavages N-terminal to proline and C-terminal to acidic residues), suggesting that their formation follows conventional CAD pathways. Internal fragments should be generated by subsequent cleavages of terminal fragments and their formation can be explained by the well-known mobile proton model. In addition, internal fragments can be coupled with terminal fragments to form complementary product ions that span the entire protein sequence. These enhance our understanding of internal fragment formation and can help improve sequencing algorithms to accurately assign internal fragments, which will ultimately lead to more efficient and comprehensive TD-MS analysis of proteins and proteoforms.
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37
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Affinity Selection from Synthetic Peptide Libraries Enabled by De Novo MS/MS Sequencing. Int J Pept Res Ther 2022. [DOI: 10.1007/s10989-022-10370-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AbstractRecently, de novo MS/MS peptide sequencing has enabled the application of affinity selections to synthetic peptide mixtures that approach the diversity of phage libraries (> 108 random peptides). In conjunction with ‘split-mix’ solid phase synthesis to access equimolar peptide mixtures, this approach provides a straightforward means to examine synthetic peptide libraries of considerably higher diversity than has been feasible historically. Here, we offer a critical perspective on this work, report emerging data, and highlight opportunities for further methods refinement. With continued development, ‘affinity selection–mass spectrometry’ may become a complimentary approach to phage display, in vitro selection, and DNA-encoded libraries for the discovery of synthetic ligands that modulate protein function.
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Ucur B, Maccarone AT, Ellis SR, Blanksby SJ, Trevitt AJ. Solvent-Mediated Proton-Transfer Catalysis of the Gas-Phase Isomerization of Ciprofloxacin Protomers. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:347-354. [PMID: 35014802 DOI: 10.1021/jasms.1c00331] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Understanding how neutral molecules become protonated during positive-ion electrospray ionization (ESI) mass spectrometry is critically important to ensure analytes can be efficiently ionized, detected, and unambiguously identified. The ESI solvent is one of several parameters that can alter the dominant site of protonation in polyfunctional molecules and thus, in turn, can significantly change the collision-induced dissociation (CID) mass spectra relied upon for compound identification. Ciprofloxacin─a common fluoroquinolone antibiotic─is one such example whereby positive-ion ESI can result in gas-phase [M + H]+ ions protonated at either the keto-oxygen or the piperazine-nitrogen. Here, we demonstrate that these protonation isomers (or protomers) of ciprofloxacin can be resolved by differential ion mobility spectrometry and give rise to distinctive CID mass spectra following both charge-directed and charge-remote mechanisms. Interaction of mobility-selected protomers with methanol vapor (added via the throttle gas supply) was found to irreversibly convert the piperazine N-protomer to the keto-O-protomer. This methanol-mediated proton-transport catalysis is driven by the overall exothermicity of the reaction, which is computed to favor the O-protomer by 93 kJ mol-1 (in the gas phase). Conversely, gas phase interactions of mobility-selected ions with acetonitrile vapor selectively depletes the N-protomer ion signal as formation of stable [M + H + CH3CN]+ cluster ions skews the apparent protomer population ratio, as the O-protomer is unaffected. These findings provide a mechanistic basis for tuning protomer populations to ensure faithful characterization of multifunctional molecules by tandem mass spectrometry.
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Affiliation(s)
- Boris Ucur
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Alan T Maccarone
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Shane R Ellis
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, New South Wales 2522, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology, Brisbane 4001, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
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Macias LA, Sipe SN, Santos IC, Bashyal A, Mehaffey MR, Brodbelt JS. Influence of Primary Structure on Fragmentation of Native-Like Proteins by Ultraviolet Photodissociation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:2860-2873. [PMID: 34714071 PMCID: PMC8639798 DOI: 10.1021/jasms.1c00269] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Analysis of native-like protein structures in the gas phase via native mass spectrometry and auxiliary techniques has become a powerful tool for structural biology applications. In combination with ultraviolet photodissociation (UVPD), native top-down mass spectrometry informs backbone flexibility, topology, hydrogen bonding networks, and conformational changes in protein structure. Although it is known that the primary structure affects dissociation of peptides and proteins in the gas phase, its effect on the types and locations of backbone cleavages promoted by UVPD and concomitant influence on structural characterization of native-like proteins is not well understood. Here, trends in the fragmentation of native-like proteins were evaluated by tracking the propensity of 10 fragment types (a, a+1, b, c, x, x+1, y, y-1, Y, and z) in relation to primary structure in a native-top down UVPD data set encompassing >9600 fragment ions. Differing fragmentation trends are reported for the production of distinct fragment types, attributed to a combination of both direct dissociation pathways from excited electronic states and those surmised to involve intramolecular vibrational energy redistribution after internal conversion. The latter pathways were systematically evaluated to evince the role of proton mobility in the generation of "CID-like" fragments through UVPD, providing pertinent insight into the characterization of native-like proteins. Fragmentation trends presented here are envisioned to enhance analysis of the protein higher-order structure or augment scoring algorithms in the high-throughput analysis of intact proteins.
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Affiliation(s)
- Luis A Macias
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Sarah N Sipe
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Inês C Santos
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Aarti Bashyal
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - M Rachel Mehaffey
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Jennifer S Brodbelt
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
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Analysis of Fragmentation Pathways of Peptide Modified with Quaternary Ammonium and Phosphonium Group as Ionization Enhancers. Molecules 2021; 26:molecules26226964. [PMID: 34834054 PMCID: PMC8623324 DOI: 10.3390/molecules26226964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/15/2021] [Accepted: 11/16/2021] [Indexed: 11/17/2022] Open
Abstract
Peptide modification by a quaternary ammonium group containing a permanent positive charge is a promising method of increasing the ionization efficiency of the analyzed compounds, making ultra-sensitive detection even at the attomolar level possible. Charge-derivatized peptides may undergo both charge remote (ChR) and charge-directed (ChD) fragmentation. A series of model peptide conjugates derivatized with N,N,N-triethyloammonium (TEA), 1-azoniabicyclo[2.2.2]octane (ABCO), 2,4,6-triphenylopyridinium (TPP) and tris(2,4,6-trimetoxyphenylo)phosphonium (TMPP) groups were analyzed by their fragmentation pathways both in collision-induced dissociation (CID) and electron-capture dissociation (ECD) mode. The effect of the fixed-charge tag type and peptide sequence on the fragmentation pathways was investigated. We found that the aspartic acid effect plays a crucial role in the CID fragmentation of TPP and TEA peptide conjugates whereas it was not resolved for the peptides derivatized with the phosphonium group. ECD spectra are mostly dominated by cn ions. ECD fragmentation of TMPP-modified peptides results in the formation of intense fragments derived from this fixed-charge tag, which may serve as reporter ion.
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41
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Semkova ME, Hsuan JJ. Mass Spectrometric Identification of a Novel Factor XIIIa Cross-Linking Site in Fibrinogen. Proteomes 2021; 9:proteomes9040043. [PMID: 34842803 PMCID: PMC8628943 DOI: 10.3390/proteomes9040043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/20/2021] [Accepted: 10/28/2021] [Indexed: 11/17/2022] Open
Abstract
Transglutaminases are a class of enzymes that catalyze the formation of a protein:protein cross-link between a lysine and a glutamine residue. These cross-links play important roles in diverse biological processes. Analysis of cross-linking sites in target proteins is required to elucidate their molecular action on target protein function and the molecular specificity of different transglutaminase isozymes. Mass-spectrometry using settings designed for linear peptide analysis and software designed for the analysis of disulfide bridges and chemical cross-links have previously been employed to identify transglutaminase cross-linking sites in proteins. As no control peptide with which to assess and improve the mass spectrometric analysis of TG cross-linked proteins was available, we developed a method for the enzymatic synthesis of a well-defined transglutaminase cross-linked peptide pair that mimics a predicted tryptic digestion product of collagen I. We then used this model peptide to determine optimal score thresholds for correct peptide identification from y- and b-ion series of fragments produced by collision-induced dissociation. We employed these settings in an analysis of fibrinogen cross-linked by the transglutaminase Factor XIIIa. This approach resulted in identification of a novel cross-linked peptide in the gamma subunit. We discuss the difference in behavior of ions derived from different cross-linked peptide sequences and the consequent demand for a more tailored mass spectrometry approach for cross-linked peptide identification compared to that routinely used for linear peptide analysis.
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42
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Perez-Mellor AF, Spezia R. Determination of kinetic properties in unimolecular dissociation of complex systems from graph theory based analysis of an ensemble of reactive trajectories. J Chem Phys 2021; 155:124103. [PMID: 34598552 DOI: 10.1063/5.0058382] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
In this paper, we report how graph theory can be used to analyze an ensemble of independent molecular trajectories, which can react during the simulation time-length, and obtain structural and kinetic information. This method is totally general and here is applied to the prototypical case of gas phase fragmentation of protonated cyclo-di-glycine. This methodology allows us to analyze the whole set of trajectories in an automatic computer-based way without the need of visual inspection but by getting all the needed information. In particular, we not only determine the appearance of different products and intermediates but also characterize the corresponding kinetics. The use of colored graph and canonical labeling allows for the correct characterization of the chemical species involved. In the present case, the simulations consist of an ensemble of unimolecular fragmentation trajectories at constant energy such that from the rate constants at different energies, the threshold energy can also be obtained for both global and specific pathways. This approach allows for the characterization of ion-molecule complexes, likely through a roaming mechanism, by properly taking into account the elusive nature of such species. Finally, it is possible to directly obtain the theoretical mass spectrum of the fragmenting species if the reacting system is an ion as in the specific example.
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Affiliation(s)
- Ariel F Perez-Mellor
- LAMBE UMR8587, Université d'Evry Val d'Essonne, CNRS, CEA, Université Paris-Saclay, Laboratoire Analyse et Modélisation pour la Biologie et l'Environnement, 91025 Evry, France
| | - Riccardo Spezia
- Laboratoire de Chimie Théorique, Sorbonne Université and CNRS, F-75005 Paris, France
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43
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Le MT, Morato NM, Kaerner A, Welch CJ, Cooks RG. Fragmentation of Polyfunctional Compounds Recorded Using Automated High-Throughput Desorption Electrospray Ionization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:2261-2273. [PMID: 34280312 DOI: 10.1021/jasms.1c00176] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Using desorption electrospray ionization (DESI) as part of an automated high-throughput system, tandem mass spectra of the compounds in a pharmaceutical library were recorded in the positive mode under standardized conditions. Quality control filtering yielded an MS/MS library of 16 662 spectra. Fragmentation of subsets of the compounds in the library chosen to contain a single instance of a particular functional group (amide, piperazine, sulfonamide) was predicted by experts, and the results were compared with the experimental data. Expert performance was good to excellent for all the cases evaluated. Substituents on the functional groups were found to exert important secondary control over the fragmentation, with the main effect observed being product ion stabilization by aromatic substitution, which was consistent across the different groups evaluated. These substituent effects are generally explicable in terms of standard physical organic chemistry considerations of product ion stability as controlling fragmentation. A somewhat unexpected feature was the incidence of homolytic cleavages, driven by the stability of substituted amine radical cations. The findings of this study are intended to lay the groundwork for machine learning approaches to performing MS/MS spectrum → structure and structure → MS/MS spectrum operations on the same experimental data set. The effort involved and the success achieved in computer-aided interpretation, now underway, will be compared with the expert performance as described here.
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Affiliation(s)
- MyPhuong T Le
- Department of Chemistry and Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Nicolás M Morato
- Department of Chemistry and Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Andreas Kaerner
- Discovery Chemistry Research and Technologies, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, United States
| | - Christopher J Welch
- Indiana Consortium for Analytical Science and Engineering (ICASE), Indianapolis, Indiana 46202, United States
| | - R Graham Cooks
- Department of Chemistry and Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907, United States
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Abstract
A systematic conformational search reveals three N- (amino) and eight O- (carbonyl) protonated glycine conformers with benchmark equilibrium(adiabatic) relative energies in the 0.00-7.51(0.00-7.37) and 25.91-31.61(24.45-30.28) kcal mol-1 ranges, respectively. Benchmark ab initio structures of the glycine conformers and its protonated species are obtained at the CCSD(T)-F12b/aug-cc-pVTZ level of theory and the relative energy computations consider basis-set effects up to aug-cc-pVQZ with CCSD(T)-F12b, electron correlation up to CCSDT(Q), core correlation corrections, scalar relativistic effects, and zero-point energy contributions. The best predictions for Boltzmann-averaged 0(298.15) K proton affinities and [298.15 K gas-phase basicities] of glycine are 211.00(212.43)[204.75] and 186.38(187.64)[180.21] kcal mol-1 for N- and O-protonation, respectively, in excellent agreement with experiments.
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Affiliation(s)
- András B Nacsa
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
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45
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Koopman J, Grimme S. From QCEIMS to QCxMS: A Tool to Routinely Calculate CID Mass Spectra Using Molecular Dynamics. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:1735-1751. [PMID: 34080847 DOI: 10.1021/jasms.1c00098] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Mass spectrometry (MS) is a powerful tool in chemical research and substance identification. For the computational modeling of electron ionization MS, we have developed the quantum-chemical electron ionization mass spectra (QCEIMS) program. Here, we present an extension of QCEIMS to calculate collision-induced dissociation (CID) spectra. The more general applicability is accounted for by the new name QCxMS, where "x" refers to EI or CID. To this end, fragmentation and rearrangement reactions are computed "on-the-fly" in Born-Oppenheimer molecular dynamics (MD) simulations with the semiempirical GFN2-xTB Hamiltonian, which provides an efficient quantum mechanical description of all elements up to Z = 86 (Rn). Through the explicit modeling of multicollision processes between precursor ions and neutral gas atoms as well as temperature-induced decomposition reactions, QCxMS provides detailed insight into the collision kinetics and fragmentation pathways. In combination with the CREST program to determine the preferential protonation sites, QCxMS becomes the first standalone MD-based program that can predict mass spectra based solely on molecular structures as input. We demonstrate this for six organic molecules with masses ranging from 159 to 296 Da, for which QCxMS yields CID spectra in reasonable agreement with experiments.
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Affiliation(s)
- Jeroen Koopman
- Mulliken Center for Theoretical Chemistry, Institute for Physical and Theoretical Chemistry, University of Bonn, Beringstr. 4, 53115 Bonn, Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, Institute for Physical and Theoretical Chemistry, University of Bonn, Beringstr. 4, 53115 Bonn, Germany
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46
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Konermann L, Aliyari E, Lee JH. Mobile Protons Limit the Stability of Salt Bridges in the Gas Phase: Implications for the Structures of Electrosprayed Protein Ions. J Phys Chem B 2021; 125:3803-3814. [PMID: 33848419 DOI: 10.1021/acs.jpcb.1c00944] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Electrosprayed protein ions can retain native-like conformations. The intramolecular contacts that stabilize these compact gas-phase structures remain poorly understood. Recent work has uncovered abundant salt bridges in electrosprayed proteins. Salt bridges are zwitterionic BH+/A- contacts. The low dielectric constant in the vacuum strengthens electrostatic interactions, suggesting that salt bridges could be a key contributor to the retention of compact protein structures. A problem with this assertion is that H+ are mobile, such that H+ transfer can convert salt bridges into neutral B0/HA0 contacts. This possible salt bridge annihilation puts into question the role of zwitterionic motifs in the gas phase, and it calls for a detailed analysis of BH+/A- versus B0/HA0 interactions. Here, we investigate this issue using molecular dynamics (MD) simulations and electrospray experiments. MD data for short model peptides revealed that salt bridges with static H+ have dissociation energies around 700 kJ mol-1. The corresponding B0/HA0 contacts are 1 order of magnitude weaker. When considering the effects of mobile H+, BH+/A- bond energies were found to be between these two extremes, confirming that H+ migration can significantly weaken salt bridges. Next, we examined the protein ubiquitin under collision-induced unfolding (CIU) conditions. CIU simulations were conducted using three different MD models: (i) Positive-only runs with static H+ did not allow for salt bridge formation and produced highly expanded CIU structures. (ii) Zwitterionic runs with static H+ resulted in abundant salt bridges, culminating in much more compact CIU structures. (iii) Mobile H+ simulations allowed for the dynamic formation/annihilation of salt bridges, generating CIU structures intermediate between scenarios (i) and (ii). Our results uncover that mobile H+ limit the stabilizing effects of salt bridges in the gas phase. Failure to consider the effects of mobile H+ in MD simulations will result in unrealistic outcomes under CIU conditions.
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Affiliation(s)
- Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Elnaz Aliyari
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Justin H Lee
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
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47
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Schmitt ND, Berger JM, Conway JB, Agar JN. Increasing Top-Down Mass Spectrometry Sequence Coverage by an Order of Magnitude through Optimized Internal Fragment Generation and Assignment. Anal Chem 2021; 93:6355-6362. [DOI: 10.1021/acs.analchem.0c04670] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Nicholas D. Schmitt
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
- Barnett Institute for Chemical and Biological Analysis, Northeastern University, Boston, Massachusetts 02115, United States
| | - Joshua M. Berger
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
- Barnett Institute for Chemical and Biological Analysis, Northeastern University, Boston, Massachusetts 02115, United States
| | - Jeremy B. Conway
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
- Barnett Institute for Chemical and Biological Analysis, Northeastern University, Boston, Massachusetts 02115, United States
| | - Jeffrey N. Agar
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
- Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts 02115, United States
- Barnett Institute for Chemical and Biological Analysis, Northeastern University, Boston, Massachusetts 02115, United States
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Guan S, Bythell BJ. Size Dependent Fragmentation Chemistry of Short Doubly Protonated Tryptic Peptides. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:1020-1032. [PMID: 33779179 DOI: 10.1021/jasms.1c00009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Tandem mass spectrometry of electrospray ionized multiply charged peptide ions is commonly used to identify the sequence of peptide(s) and infer the identity of source protein(s). Doubly protonated peptide ions are consistently the most efficiently sequenced ions following collision-induced dissociation of peptides generated by tryptic digestion. While the broad characteristics of longer (N ≥ 8 residue) doubly protonated peptides have been investigated, there is comparatively little data on shorter systems where charge repulsion should exhibit the greatest influence on the dissociation chemistry. To address this gap and further understand the chemistry underlying collisional-dissociation of doubly charged tryptic peptides, two series of analytes ([GxR+2H]2+ and [AxR+2H]2+, x = 2-5) were investigated experimentally and with theory. We find distinct differences in the preference of bond cleavage sites for these peptides as a function of size and to a lesser extent composition. Density functional calculations at two levels of theory predict that the threshold relative energies required for bond cleavages at the same site for peptides of different size are quite similar (for example, b2-yN-2). In isolation, this finding is inconsistent with experiment. However, the predicted extent of entropy change of these reactions is size dependent. Subsequent RRKM rate constant calculations provide a far clearer picture of the kinetics of the competing bond cleavage reactions enabling rationalization of experimental findings. The M06-2X data were substantially more consistent with experiment than were the B3LYP data.
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Affiliation(s)
- Shanshan Guan
- Department of Chemistry and Biochemistry, Ohio University, 307 Chemistry Building, Athens, Ohio 45701, United States
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, 1 University Boulevard, St. Louis, Missouri 63121, United States
| | - Benjamin J Bythell
- Department of Chemistry and Biochemistry, Ohio University, 307 Chemistry Building, Athens, Ohio 45701, United States
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, 1 University Boulevard, St. Louis, Missouri 63121, United States
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49
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Parker K, Weragoda GK, Canty AJ, Ryzhov V, O’Hair RAJ. Modeling Metal-Catalyzed Polyethylene Depolymerization: [(Phen)Pd(X)] + (X = H and CH 3) Catalyze the Decomposition of Hexane into a Mixture of Alkenes via a Complex Reaction Network. Organometallics 2021. [DOI: 10.1021/acs.organomet.0c00782] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Kevin Parker
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, United States
| | - Geethika K. Weragoda
- School of Chemistry, Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Melbourne, Victoria 3010, Australia
- CSIRO Manufacturing, Research Way, Clayton, Victoria 3168, Australia
| | - Allan J. Canty
- School of Natural Sciences-Chemistry, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001, Australia
| | - Victor Ryzhov
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, United States
| | - Richard A. J. O’Hair
- School of Chemistry, Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Melbourne, Victoria 3010, Australia
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50
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Borbély A, Pethő L, Szabó I, Al-Majidi M, Steckel A, Nagy T, Kéki S, Kalló G, Csősz É, Mező G, Schlosser G. Structural Characterization of Daunomycin-Peptide Conjugates by Various Tandem Mass Spectrometric Techniques. Int J Mol Sci 2021; 22:ijms22041648. [PMID: 33562082 PMCID: PMC7914584 DOI: 10.3390/ijms22041648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 02/01/2021] [Accepted: 02/03/2021] [Indexed: 11/16/2022] Open
Abstract
The use of peptide-drug conjugates has generated wide interest as targeted antitumor therapeutics. The anthracycline antibiotic, daunomycin, is a widely used anticancer agent and it is often conjugated to different tumor homing peptides. However, comprehensive analytical characterization of these conjugates via tandem mass spectrometry (MS/MS) is challenging due to the lability of the O-glycosidic bond and the appearance of MS/MS fragment ions with little structural information. Therefore, we aimed to investigate the optimal fragmentation conditions that suppress the prevalent dissociation of the anthracycline drug and provide good sequence coverage. In this study, we comprehensively compared the performance of common fragmentation techniques, such as higher energy collisional dissociation (HCD), electron transfer dissociation (ETD), electron-transfer higher energy collisional dissociation (EThcD) and matrix-assisted laser desorption/ionization–tandem time-of-flight (MALDI-TOF/TOF) activation methods for the structural identification of synthetic daunomycin-peptide conjugates by high-resolution tandem mass spectrometry. Our results showed that peptide backbone fragmentation was inhibited by applying electron-based dissociation methods to conjugates, most possibly due to the “electron predator” effect of the daunomycin. We found that efficient HCD fragmentation was largely influenced by several factors, such as amino acid sequences, charge states and HCD energy. High energy HCD and MALDI-TOF/TOF combined with collision induced dissociation (CID) mode are the methods of choice to unambiguously assign the sequence, localize different conjugation sites and differentiate conjugate isomers.
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Affiliation(s)
- Adina Borbély
- MTA-ELTE Lendület Ion Mobility Mass Spectrometry Research Group and Department of Analytical Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary; (A.B.); (M.A.-M.); (A.S.)
| | - Lilla Pethő
- Eötvös Loránd Research Network, Supported Research Groups, Research Group of Peptide Chemistry, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary; (L.P.); (I.S.); (G.M.)
| | - Ildikó Szabó
- Eötvös Loránd Research Network, Supported Research Groups, Research Group of Peptide Chemistry, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary; (L.P.); (I.S.); (G.M.)
| | - Mohammed Al-Majidi
- MTA-ELTE Lendület Ion Mobility Mass Spectrometry Research Group and Department of Analytical Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary; (A.B.); (M.A.-M.); (A.S.)
- Hevesy György PhD School of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary
| | - Arnold Steckel
- MTA-ELTE Lendület Ion Mobility Mass Spectrometry Research Group and Department of Analytical Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary; (A.B.); (M.A.-M.); (A.S.)
- Hevesy György PhD School of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary
| | - Tibor Nagy
- Department of Applied Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (T.N.); (S.K.)
| | - Sándor Kéki
- Department of Applied Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (T.N.); (S.K.)
| | - Gergő Kalló
- Proteomics Core Facility, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (G.K.); (É.C.)
| | - Éva Csősz
- Proteomics Core Facility, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (G.K.); (É.C.)
| | - Gábor Mező
- Eötvös Loránd Research Network, Supported Research Groups, Research Group of Peptide Chemistry, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary; (L.P.); (I.S.); (G.M.)
- Department of Organic Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary
| | - Gitta Schlosser
- MTA-ELTE Lendület Ion Mobility Mass Spectrometry Research Group and Department of Analytical Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary; (A.B.); (M.A.-M.); (A.S.)
- Correspondence: ; Tel.: +36-1-372-2500
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