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Papanastasiou D, Kounadis D, Lekkas A, Orfanopoulos I, Mpozatzidis A, Smyrnakis A, Panagiotopoulos E, Kosmopoulou M, Reinhardt-Szyba M, Fort K, Makarov A, Zubarev RA. The Omnitrap Platform: A Versatile Segmented Linear Ion Trap for Multidimensional Multiple-Stage Tandem Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:1990-2007. [PMID: 36113052 PMCID: PMC9850925 DOI: 10.1021/jasms.2c00214] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/08/2022] [Accepted: 09/12/2022] [Indexed: 06/15/2023]
Abstract
Multidimensional multiple-stage tandem processing of ions is demonstrated successfully in a novel segmented linear ion trap. The enhanced performance is enabled by incorporating the entire range of ion activation methods into a single platform in a highly dynamic fashion. The ion activation network comprises external injection of reagent ions, radical neutral species, photons, electrons, and collisions with neutrals. Axial segmentation of the two-dimensional trapping field provides access to a unique functionality landscape through a system of purpose-designed regions for processing ions with maximum flexibility. Design aspects of the segmented linear ion trap, termed the Omnitrap platform, are highlighted, and motion of ions trapped by rectangular waveforms is investigated experimentally by mapping the stability diagram, tracing secular frequencies, and exploring different isolation techniques. All fragmentation methods incorporated in the Omnitrap platform involving radical chemistry are shown to provide complete sequence coverage for partially unfolded ubiquitin. Three-stage (MS3) tandem mass spectrometry experiments combining collision-induced dissociation of radical ions produced by electron meta-ionization and further involving two intermediate steps of ion isolation and accumulation are performed with high efficiency, producing information rich spectra with signal-to-noise levels comparable to those obtained in a two-stage (MS2) experiment. The advanced capabilities of the Omnitrap platform to provide in-depth top-down MSn characterization of proteins are portrayed. Performance is further enhanced by connecting the Omnitrap platform to an Orbitrap mass analyzer, while successful integration with time-of-flight analyzers has already been demonstrated.
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Affiliation(s)
- Dimitris Papanastasiou
- Fasmatech
Science & Technology, TESPA Lefkippos, NCSR Demokritos, Agia Paraskevi, 15341 Athens, Greece
| | - Diamantis Kounadis
- Fasmatech
Science & Technology, TESPA Lefkippos, NCSR Demokritos, Agia Paraskevi, 15341 Athens, Greece
| | - Alexandros Lekkas
- Fasmatech
Science & Technology, TESPA Lefkippos, NCSR Demokritos, Agia Paraskevi, 15341 Athens, Greece
| | - Ioannis Orfanopoulos
- Fasmatech
Science & Technology, TESPA Lefkippos, NCSR Demokritos, Agia Paraskevi, 15341 Athens, Greece
| | - Andreas Mpozatzidis
- Fasmatech
Science & Technology, TESPA Lefkippos, NCSR Demokritos, Agia Paraskevi, 15341 Athens, Greece
| | - Athanasios Smyrnakis
- Fasmatech
Science & Technology, TESPA Lefkippos, NCSR Demokritos, Agia Paraskevi, 15341 Athens, Greece
| | - Elias Panagiotopoulos
- Fasmatech
Science & Technology, TESPA Lefkippos, NCSR Demokritos, Agia Paraskevi, 15341 Athens, Greece
| | - Mariangela Kosmopoulou
- Fasmatech
Science & Technology, TESPA Lefkippos, NCSR Demokritos, Agia Paraskevi, 15341 Athens, Greece
| | | | - Kyle Fort
- Thermo
Fisher Scientific, Hanna-Kunath-Straße
11, 28199 Bremen, Germany
| | - Alexander Makarov
- Thermo
Fisher Scientific, Hanna-Kunath-Straße
11, 28199 Bremen, Germany
| | - Roman A. Zubarev
- Department
of Medical Biochemistry and Biophysics, Karolinska Institutet, Solnavägen 9, 17165 Solna, Sweden
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2
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Bonney JR, Prentice BM. Perspective on Emerging Mass Spectrometry Technologies for Comprehensive Lipid Structural Elucidation. Anal Chem 2021; 93:6311-6322. [PMID: 33856206 PMCID: PMC8177724 DOI: 10.1021/acs.analchem.1c00061] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Lipids and metabolites are of interest in many clinical and research settings because it is the metabolome that is increasingly recognized as a more dynamic and sensitive molecular measure of phenotype. The enormous diversity of lipid structures and the importance of biological structure-function relationships in a wide variety of applications makes accurate identification a challenging yet crucial area of research in the lipid community. Indeed, subtle differences in the chemical structures of lipids can have important implications in cellular metabolism and many disease pathologies. The speed, sensitivity, and molecular specificity afforded by modern mass spectrometry has led to its widespread adoption in the field of lipidomics on many different instrument platforms and experimental workflows. However, unambiguous and complete structural identification of lipids by mass spectrometry remains challenging. Increasingly sophisticated tandem mass spectrometry (MS/MS) approaches are now being developed and seamlessly integrated into lipidomics workflows to meet this challenge. These approaches generally either (i) alter the type of ion that is interrogated or (ii) alter the dissociation method in order to improve the structural information obtained from the MS/MS experiment. In this Perspective, we highlight recent advances in both ion type alteration and ion dissociation methods for lipid identification by mass spectrometry. This discussion is aimed to engage investigators involved in fundamental ion chemistry and technology developments as well as practitioners of lipidomics and its many applications. The rapid rate of technology development in recent years has accelerated and strengthened the ties between these two research communities. We identify the common characteristics and practical figures of merit of these emerging approaches and discuss ways these may catalyze future directions of lipid structural elucidation research.
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Affiliation(s)
- Julia R Bonney
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - Boone M Prentice
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
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3
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Bayat P, Lesage D, Cole RB. TUTORIAL: ION ACTIVATION IN TANDEM MASS SPECTROMETRY USING ULTRA-HIGH RESOLUTION INSTRUMENTATION. MASS SPECTROMETRY REVIEWS 2020; 39:680-702. [PMID: 32043643 DOI: 10.1002/mas.21623] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 01/23/2020] [Indexed: 05/16/2023]
Abstract
Tandem mass spectrometry involves isolation of specific precursor ions and their subsequent excitation through collision-, photon-, or electron-mediated activation techniques in order to induce unimolecular dissociation leading to formation of fragment ions. These powerful ion activation techniques, typically used in between mass selection and mass analysis steps for structural elucidation, have not only found a wide variety of analytical applications in chemistry and biology, but they have also been used to study the fundamental properties of ions in the gas phase. In this tutorial paper, a brief overview is presented of the theories that have been used to describe the activation of ions and their subsequent unimolecular dissociation. Acronyms of the presented techniques include CID, PQD, HCD, SORI, SID, BIRD, IRMPD, UVPD, EPD, ECD, EDD, ETD, and EID. The fundamental principles of these techniques are discussed in the context of their implementation on ultra-high resolution tandem mass spectrometers. © 2020 John Wiley & Sons Ltd. Mass Spec Rev.
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Affiliation(s)
- Parisa Bayat
- Faculté des Sciences et Ingénierie, Sorbonne Université, IPCM (UMR 8232), F-75252, Paris, France
| | - Denis Lesage
- Faculté des Sciences et Ingénierie, Sorbonne Université, IPCM (UMR 8232), F-75252, Paris, France
| | - Richard B Cole
- Faculté des Sciences et Ingénierie, Sorbonne Université, IPCM (UMR 8232), F-75252, Paris, France
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4
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Brodbelt JS, Morrison LJ, Santos I. Ultraviolet Photodissociation Mass Spectrometry for Analysis of Biological Molecules. Chem Rev 2020; 120:3328-3380. [PMID: 31851501 PMCID: PMC7145764 DOI: 10.1021/acs.chemrev.9b00440] [Citation(s) in RCA: 139] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The development of new ion-activation/dissociation methods continues to be one of the most active areas of mass spectrometry owing to the broad applications of tandem mass spectrometry in the identification and structural characterization of molecules. This Review will showcase the impact of ultraviolet photodissociation (UVPD) as a frontier strategy for generating informative fragmentation patterns of ions, especially for biological molecules whose complicated structures, subtle modifications, and large sizes often impede molecular characterization. UVPD energizes ions via absorption of high-energy photons, which allows access to new dissociation pathways relative to more conventional ion-activation methods. Applications of UVPD for the analysis of peptides, proteins, lipids, and other classes of biologically relevant molecules are emphasized in this Review.
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Affiliation(s)
- Jennifer S. Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Lindsay J. Morrison
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Inês Santos
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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Brown CJ, Woodall DW, El-Baba TJ, Clemmer DE. Characterizing Thermal Transitions of IgG with Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:2438-2445. [PMID: 31363989 PMCID: PMC6866664 DOI: 10.1007/s13361-019-02292-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/15/2019] [Accepted: 07/16/2019] [Indexed: 06/02/2023]
Abstract
Variable temperature electrospray ionization (ESI) is coupled with mass spectrometry techniques in order to investigate structural transitions of monoclonal antibody immunoglobulin G (IgG) in a 100-mM ammonium acetate (pH 7.0) solution from 26 to 70 °C. At 26 °C, the mass spectrum for intact IgG shows six charge states + 22 to + 26. Upon increasing the solution temperature, the fraction of low-charge states decreases and new, higher-charge state ions are observed. Upon analysis, it appears that heating the solution aids in desolvation of the intact IgG precursor. Above ~ 50 °C, a cleavage event between the light and heavy chains is observed. An analysis of the kinetics for these processes at different temperatures yields transition state thermochemistry of ΔH‡ = 95 ± 10 kJ mol-1, ΔS‡ = 8 ± 1 J mol-1 K-1, and ΔG‡ = 92 ± 11 kJ mol-1. The mechanism for light chain dissociation appears to involve disulfide bond scrambling that ultimately results in a non-native Cys199-Cys217 disulfide bond in the light chain product. Above ~ 70 °C, we are unable to produce a stable ESI signal. The loss of signal is ascribed to aggregation that is primarily associated with the remaining portion of the antibody after having lost the light chain. Graphical Abstract.
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Affiliation(s)
- Christopher J Brown
- Department of Chemistry, Indiana University, 800 Kirkwood Avenue, Bloomington, IN, 47401, USA
| | - Daniel W Woodall
- Department of Chemistry, Indiana University, 800 Kirkwood Avenue, Bloomington, IN, 47401, USA
| | - Tarick J El-Baba
- Department of Chemistry, Indiana University, 800 Kirkwood Avenue, Bloomington, IN, 47401, USA
| | - David E Clemmer
- Department of Chemistry, Indiana University, 800 Kirkwood Avenue, Bloomington, IN, 47401, USA.
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Girod M. Increasing specificity of tandem mass spectrometry by laser-induced dissociation. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2019; 33 Suppl 3:64-71. [PMID: 29689642 DOI: 10.1002/rcm.8148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 04/15/2018] [Indexed: 06/08/2023]
Abstract
Mass spectrometry offers an arsenal of tools for diverse proteomic investigations. This perspective article reviews some of the recent developments in the field of coupling laser-induced dissociation with mass spectrometry (LID-MS). Strategies involving labelling with a chromophore to induce specific photo-absorption properties are considered, with a focus on specific amino acid derivatization. Some of the opportunities and challenges of LID-MS after targeted labelling for increasing specificity in complex sample analysis are discussed.
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Affiliation(s)
- Marion Girod
- Univ Lyon, CNRS, Université Claude Bernard Lyon 1, Ens de Lyon, Institut des Sciences Analytiques, UMR 5280, 5 rue de la Doua, F-69100, Villeurbanne, France
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7
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Talbert LE, Julian RR. Directed-Backbone Dissociation Following Bond-Specific Carbon-Sulfur UVPD at 213 nm. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:1760-1767. [PMID: 29623659 PMCID: PMC6087500 DOI: 10.1007/s13361-018-1934-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 02/16/2018] [Accepted: 02/23/2018] [Indexed: 05/22/2023]
Abstract
Ultraviolet photodissociation or UVPD is an increasingly popular option for tandem-mass spectrometry experiments. UVPD can be carried out at many wavelengths, and it is important to understand how the results will be impacted by this choice. Here, we explore the utility of 213 nm photons for initiating bond-selective fragmentation. It is found that bonds previously determined to be labile at 266 nm, including carbon-iodine and sulfur-sulfur bonds, can also be cleaved with high selectivity at 213 nm. In addition, many carbon-sulfur bonds that are not subject to direct dissociation at 266 nm can be selectively fragmented at 213 nm. This capability can be used to site-specifically create alaninyl radicals that direct backbone dissociation at the radical site, creating diagnostic d-ions. Furthermore, the additional carbon-sulfur bond fragmentation capability leads to signature triplets for fragmentation of disulfide bonds. Absorption of amide bonds can enhance dissociation of nearby labile carbon-sulfur bonds and can be used for stochastic backbone fragmentation typical of UVPD experiments at shorter wavelengths. Several potential applications of the bond-selective fragmentation chemistry observed at 213 nm are discussed. Graphical Abstract ᅟ.
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Affiliation(s)
- Lance E Talbert
- Department of Chemistry, University of California, Riverside, 501 Big Springs Road, Riverside, CA, 92521, USA
| | - Ryan R Julian
- Department of Chemistry, University of California, Riverside, 501 Big Springs Road, Riverside, CA, 92521, USA.
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8
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Herburger A, van der Linde C, Beyer MK. Photodissociation spectroscopy of protonated leucine enkephalin. Phys Chem Chem Phys 2018; 19:10786-10795. [PMID: 28233882 DOI: 10.1039/c6cp08436b] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Protonated leucine enkephalin (YGGFL) was studied by ultraviolet photodissociation (UVPD) from 225 to 300 nm utilizing an optical parametric oscillator tunable wavelength laser system (OPO). Fragments were identified by absolute mass measurement in a 9.4 T Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS). Bond cleavage was preferred in the vicinity of the two aromatic residues, resulting in high ion abundances for a4, a1, b3, y2 and y1 fragments. a, b and y ions dominated the mass spectrum, and full sequence coverage was achieved for those types. Photodissociation was most effective at the short wavelength end of the studied range, which is assigned to the onset of the La π-π* transition of the tyrosine chromophore, but worked well also at the Lb π-π* chromophore absorption maxima in the 35 000-39 000 cm-1 region. Several side-chain and internal fragments were observed. H atom loss is observed only above 41 000 cm-1, consistent with the requirement of a curve crossing to a repulsive 1πσ* state. It is suggested that the photochemically generated mobile H atom plays a role in further backbone cleavages, similar to the mechanism for electron capture dissociation. The b4 fragment is most intense at the Lb chromophore absorptions, undergoing additional fragmentation at higher photon energies. The high resolution of the FT-ICR MS revealed that out of all x and z-type fragments only x3 and x4 were formed, with low intensity. Other previously reported x- and z-fragments were re-assigned to internal fragments, based on exact mass measurement.
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Affiliation(s)
- Andreas Herburger
- Institut für Ionenphysik und Angewandte Physik, Leopold-Franzens-Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria.
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9
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Quick MM, Mehaffey MR, Johns RW, Parker WR, Brodbelt JS. SITS Derivatization of Peptides to Enhance 266 nm Ultraviolet Photodissociation (UVPD). JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:1462-1472. [PMID: 28315237 DOI: 10.1007/s13361-017-1650-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/01/2017] [Accepted: 03/03/2017] [Indexed: 06/06/2023]
Abstract
N-terminal derivatization of peptides with the chromogenic reagent 4-acetamido-4-isothiocyanatostilbene-2,2-disulfonic acid (SITS) is demonstrated to enhance the efficiency of 266 nm ultraviolet photodissociation (UVPD). Attachment of the chromophore results in a mass shift of 454 Da and provides significant gains in the number and abundances of diagnostic fragment ions upon UVPD. Activation of SITS-tagged peptides with 266 nm UVPD leads to many fragment ions akin to the a/b/y ions commonly produced by CID, along with other sequence ions (c, x, and z) typically accessed through higher energy pathways. Extreme bias towards C-terminal fragment ions is observed upon activation of SITS-tagged peptides using multiple 266 nm laser pulses. Due to the high reaction efficiency of the isothiocyanate coupling to the N-terminus of peptides, we demonstrate the ability to adapt this strategy to a high-throughput LC-MS/MS workflow with 266 nm UVPD. Graphical Abstract ᅟ.
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Affiliation(s)
- M Montana Quick
- Department of Chemistry, University of Texas, Austin, TX, 78712, USA
| | - M Rachel Mehaffey
- Department of Chemistry, University of Texas, Austin, TX, 78712, USA
| | - Robert W Johns
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
- McKetta Department of Chemical Engineering, University of Texas, Austin, TX, 78712, USA
| | - W Ryan Parker
- Department of Chemistry, University of Texas, Austin, TX, 78712, USA
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Black DM, Crittenden CM, Brodbelt JS, Whetten RL. Ultraviolet Photodissociation of Selected Gold Clusters: Ultraefficient Unstapling and Ligand Stripping of Au 25(pMBA) 18 and Au 36(pMBA) 24. J Phys Chem Lett 2017; 8:1283-1289. [PMID: 28234006 DOI: 10.1021/acs.jpclett.7b00442] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We report the first results of ultraviolet photodissociation (UVPD) mass spectrometry of trapped monolayer-protected cluster (MPC) ions generated by electrospray ionization. Gold clusters Au25(pMBA)18 and Au36(pMBA)24 (pMBA = para-mercaptobenzoic acid) were analyzed in both the positive and negative modes. Whereas activation methods including collisional- and electron-based methods produced relatively few fragment ions, even a single ultraviolet pulse (at λ = 193 nm) caused extensive fragmentation of the positively charged clusters. Upon photoactivation using a low number of laser pulses, the staple motifs of both clusters were cleaved and stripped of the protecting ligand portions without removal of any contained gold atoms. This striking process involved Au-S and C-S bond cleavages via a pathway made possible by 6.4 eV photon absorption. Monomer evaporation (neutral gold atom loss) occurred upon exposure to multiple pulses, resulting in a size series of bare gold-cluster ions. All tandem mass spectrometric methods produced the singly charged ring tetramer ion, [Au4(pMBA)4 + Na]+, for each cluster.
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Affiliation(s)
- David M Black
- Department of Physics and Astronomy, The University of Texas at San Antonio , San Antonio, Texas 78249, United States
| | | | - Jennifer S Brodbelt
- Department of Chemistry, The University of Texas at Austin , Austin, Texas 78712, United States
| | - Robert L Whetten
- Department of Physics and Astronomy, The University of Texas at San Antonio , San Antonio, Texas 78249, United States
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Robotham SA, Horton AP, Cannon JR, Cotham VC, Marcotte EM, Brodbelt JS. UVnovo: A de Novo Sequencing Algorithm Using Single Series of Fragment Ions via Chromophore Tagging and 351 nm Ultraviolet Photodissociation Mass Spectrometry. Anal Chem 2016; 88:3990-7. [PMID: 26938041 PMCID: PMC4850734 DOI: 10.1021/acs.analchem.6b00261] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
De novo peptide sequencing by mass spectrometry represents an important strategy for characterizing novel peptides and proteins, in which a peptide's amino acid sequence is inferred directly from the precursor peptide mass and tandem mass spectrum (MS/MS or MS(3)) fragment ions, without comparison to a reference proteome. This method is ideal for organisms or samples lacking a complete or well-annotated reference sequence set. One of the major barriers to de novo spectral interpretation arises from confusion of N- and C-terminal ion series due to the symmetry between b and y ion pairs created by collisional activation methods (or c, z ions for electron-based activation methods). This is known as the "antisymmetric path problem" and leads to inverted amino acid subsequences within a de novo reconstruction. Here, we combine several key strategies for de novo peptide sequencing into a single high-throughput pipeline: high-efficiency carbamylation blocks lysine side chains, and subsequent tryptic digestion and N-terminal peptide derivatization with the ultraviolet chromophore AMCA yield peptides susceptible to 351 nm ultraviolet photodissociation (UVPD). UVPD-MS/MS of the AMCA-modified peptides then predominantly produces y ions in the MS/MS spectra, specifically addressing the antisymmetric path problem. Finally, the program UVnovo applies a random forest algorithm to automatically learn from and then interpret UVPD mass spectra, passing results to a hidden Markov model for de novo sequence prediction and scoring. We show this combined strategy provides high-performance de novo peptide sequencing, enabling the de novo sequencing of thousands of peptides from an Escherichia coli lysate at high confidence.
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Affiliation(s)
- Scott A Robotham
- Department of Chemistry, University of Texas , Austin, Texas 78712, United States
| | - Andrew P Horton
- Center for Systems and Synthetic Biology, Department of Molecular Biosciences, University of Texas , Austin, Texas 78712, United States
| | - Joe R Cannon
- Department of Chemistry, University of Texas , Austin, Texas 78712, United States
| | - Victoria C Cotham
- Department of Chemistry, University of Texas , Austin, Texas 78712, United States
| | - Edward M Marcotte
- Center for Systems and Synthetic Biology, Department of Molecular Biosciences, University of Texas , Austin, Texas 78712, United States
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas , Austin, Texas 78712, United States
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Affiliation(s)
- Jennifer S Brodbelt
- Department of Chemistry, University of Texas at Austin , Austin, Texas 78712, United States
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13
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Robotham SA, Brodbelt JS. Comparison of Ultraviolet Photodissociation and Collision Induced Dissociation of Adrenocorticotropic Hormone Peptides. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:1570-9. [PMID: 26122515 DOI: 10.1007/s13361-015-1186-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 04/19/2015] [Accepted: 05/10/2015] [Indexed: 05/16/2023]
Abstract
In an effort to better characterize the fragmentation pathways promoted by ultraviolet photoexcitation in comparison to collision induced dissociation (CID), six adrenocorticotropic hormone (ACTH) peptides in a range of charge states were subjected to 266 nm ultraviolet photodissociation (UVPD), 193 nm UVPD, and CID. Similar fragment ions and distributions were observed for 266 nm UVPD and 193 nm UVPD for all peptides investigated. While both UVPD and CID led to preferential cleavage of the Y-S bond for all ACTH peptides [except ACTH (1-39)], UVPD was far less dependent on charge state and location of basic sites for the production of C-terminal and N-terminal ions. For ACTH (1-16), ACTH (1-17), ACTH (1-24), and ACTH (1-39), changes in the distributions of fragment ion types (a, b, c, x, y, z, and collectively N-terminal ions versus C-terminal ions) showed only minor changes upon UVPD for all charge states. In contrast, CID displayed significant changes in the fragment ion type distributions as a function of charge state, an outcome consistent with the dependence on the number and location of mobile protons that is not prominent for UVPD. Sequence coverages obtained by UVPD showed less dependence on charge state than those determined by CID, with the latter showing a consistent decrease in coverage as charge state increased.
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Affiliation(s)
- Scott A Robotham
- Department of Chemistry, University of Texas, Austin, TX, 78712, USA
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14
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Zhang X, Li H, Moore B, Wongkongkathep P, Ogorzalek Loo RR, Loo JA, Julian RR. Radical-directed dissociation of peptides and proteins by infrared multiphoton dissociation and sustained off-resonance irradiation collision-induced dissociation with Fourier transform ion cyclotron resonance mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2014; 28:2729-34. [PMID: 25380495 PMCID: PMC4237167 DOI: 10.1002/rcm.7068] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 10/01/2014] [Accepted: 10/02/2014] [Indexed: 05/19/2023]
Abstract
RATIONALE Recent experiments utilizing photodissociation in linear ion traps have enabled significant development of Radical-Directed Dissociation (RDD) for the examination of peptides and proteins. The increased mass accuracy and resolution available in Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) should enable further progress in this area. Preliminary experiments with photoactivated radicals are reported herein. METHODS A 266 nm Nd:YAG laser is coupled to a FTICR or linear ion trap mass spectrometer. Radical peptides and proteins are generated by ultraviolet photodissociation (PD) and further activated by collisions or infrared photons. RESULTS A 266 nm UV laser and an IR laser can be simultaneously coupled to a 15 Tesla FTICR mass spectrometer. The ultra-low-pressure environment in FTICR-MS makes collisional cooling less competitive, and thus more secondary fragments are generated by UVPD than in linear ion traps. Activation by sustained off-resonance irradiation collision-induced dissociation (SORI-CID) or infrared multiphoton dissociation (IRMPD) also yields additional secondary fragmentation relative to CID in an ion trap. Accurate identification of RDD fragments is possible in FTICR-MS. CONCLUSIONS Relative to linear ion trap instruments, PD experiments in FTICR-MS are more difficult to execute due to poor ion cloud overlap and the low pressure environment. However, the results can be more easily interpreted due to the increased resolution and mass accuracy.
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Affiliation(s)
- Xing Zhang
- Department of Chemistry, University of California, Riverside, California, 92521, USA
| | - Huilin Li
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California, 90095, USA
| | - Benjamin Moore
- Department of Chemistry, University of California, Riverside, California, 92521, USA
| | - Piriya Wongkongkathep
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, 90095, USA
| | - Rachel R. Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California, 90095, USA
- UCLA/DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California, 90095, USA
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, 90095, USA
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California, 90095, USA
- UCLA/DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California, 90095, USA
- To whom correspondence should be addressed: and
| | - Ryan R. Julian
- Department of Chemistry, University of California, Riverside, California, 92521, USA
- To whom correspondence should be addressed: and
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Aponte JR, Vasicek L, Swaminathan J, Xu H, Koag MC, Lee S, Brodbelt JS. Streamlining bottom-up protein identification based on selective ultraviolet photodissociation (UVPD) of chromophore-tagged histidine- and tyrosine-containing peptides. Anal Chem 2014; 86:6237-44. [PMID: 24897623 DOI: 10.1021/ac403654m] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We report a fast and highly efficient diazonium reaction that couples a nitroazobenzene chromophore to tyrosine and histidine residues, thus endowing peptides with high photoabsorption cross sections at 351 nm in the gas phase. Only the tagged peptides undergo ultraviolet photodissociation (UVPD) at 351 nm, as demonstrated for several Tyr- and His-containing peptides from protein digests. Additional selectivity is achieved by the integration of the UVPD-MS method with an in silico database search restricted to Tyr- and His-containing peptides. A modified MassMatrix algorithm condenses analysis by filtering the input database file to include Tyr/His-containing peptides only, thus reducing the search space and increasing confidence. In summary, derivatization of specific amino acid residues in conjunction with selective activation of the derivatized peptides provides a streamlined approach to shotgun proteomics.
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Affiliation(s)
- Julia R Aponte
- Department of Chemistry, The University of Texas at Austin , 1 University Station A5300, Austin, Texas 78712, United States
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16
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Dang X, Young NL. Ultraviolet photodissociation enhances top-down mass spectrometry as demonstrated on green fluorescent protein variants. Proteomics 2014; 14:1128-9. [PMID: 24723542 DOI: 10.1002/pmic.201400114] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 04/07/2014] [Indexed: 11/07/2022]
Abstract
Ultraviolet photodissociation (UVPD) is a compelling fragmentation technique with great potential to enhance proteomics generally and top-down MS specifically. In this issue, Cannon et al. (Proteomics 2014, 14, XXXX-XXXX) use UVPD to perform top-down MS on several sequence variants of green fluorescent protein and compare the results to CID, higher energy collision induced dissociation, and electron transfer dissociation. As compared to the other techniques UVPD produces a wider variety of fragment ion types that are relatively evenly distributed across the protein sequences. Overall, their results demonstrate enhanced sequence coverage and higher confidence in sequence assignment via UVPD MS. Based on these and other recent results UVPD is certain to become an increasingly widespread and valuable tool for top-down proteomics.
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Affiliation(s)
- Xibei Dang
- Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA; Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, USA
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17
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Brodbelt JS. Photodissociation mass spectrometry: new tools for characterization of biological molecules. Chem Soc Rev 2014; 43:2757-83. [PMID: 24481009 PMCID: PMC3966968 DOI: 10.1039/c3cs60444f] [Citation(s) in RCA: 232] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Photodissociation mass spectrometry combines the ability to activate and fragment ions using photons with the sensitive detection of the resulting product ions by mass spectrometry. This combination affords a versatile tool for characterization of biological molecules. The scope and breadth of photodissociation mass spectrometry have increased substantially over the past decade as new research groups have entered the field and developed a number of innovative applications that illustrate the ability of photodissociation to produce rich fragmentation patterns, to cleave bonds selectively, and to target specific molecules based on incorporation of chromophores. This review focuses on many of the key developments in photodissociation mass spectrometry over the past decade with a particular emphasis on its applications to biological molecules.
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18
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Marshall DL, Hansen CS, Trevitt AJ, Oh HB, Blanksby SJ. Photodissociation of TEMPO-modified peptides: new approaches to radical-directed dissociation of biomolecules. Phys Chem Chem Phys 2014; 16:4871-9. [DOI: 10.1039/c3cp54825b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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19
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Robotham SA, Kluwe C, Cannon JR, Ellington A, Brodbelt JS. De novo sequencing of peptides using selective 351 nm ultraviolet photodissociation mass spectrometry. Anal Chem 2013; 85:9832-8. [PMID: 24050806 DOI: 10.1021/ac402309h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Although in silico database search methods remain more popular for shotgun proteomics methods, de novo sequencing offers the ability to identify peptides derived from proteins lacking sequenced genomes and ones with subtle splice variants or truncations. Ultraviolet photodissociation (UVPD) of peptides derivatized by selective attachment of a chromophore at the N-terminus generates a characteristic series of y ions. The UVPD spectra of the chromophore-labeled peptides are simplified and thus amenable to de novo sequencing. This method resulted in an observed sequence coverage of 79% for cytochrome C (eight peptides), 47% for β-lactoglobulin (five peptides), 25% for carbonic anhydrase (six peptides), and 51% for bovine serum albumin (33 peptides). This strategy also allowed differentiation of proteins with high sequence homology as evidenced by de novo sequencing of two variants of green fluorescent protein.
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Affiliation(s)
- Scott A Robotham
- Department of Chemistry, University of Texas , Austin, Texas 78712, United States
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20
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Fragmentation of deuterated rhodamine B derivates by laser and collisional activation in an FT-ICR mass spectrometer. Anal Bioanal Chem 2013; 405:7061-9. [DOI: 10.1007/s00216-013-7078-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 05/15/2013] [Accepted: 05/17/2013] [Indexed: 11/25/2022]
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21
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Cotham VC, Wine Y, Brodbelt JS. Selective 351 nm photodissociation of cysteine-containing peptides for discrimination of antigen-binding regions of IgG fragments in bottom-up liquid chromatography-tandem mass spectrometry workflows. Anal Chem 2013; 85:5577-85. [PMID: 23641966 DOI: 10.1021/ac400851x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Despite tremendous inroads in the development of more sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) strategies for mass spectrometry-based proteomics, there remains a significant need for enhancing the selectivity of MS/MS-based workflows for streamlined analysis of complex biological mixtures. Here, a novel LC-MS/MS platform based on 351 nm ultraviolet photodissociation (UVPD) is presented for the selective analysis of cysteine-peptide subsets in complex protein digests. Cysteine-selective UVPD is mediated through the site-specific conjugation of reduced cysteine residues with a 351 nm active chromogenic Alexa Fluor 350 (AF350) maleimide tag. Only peptides containing the AF350 chromophore undergo photodissociation into extensive arrays of b- and y-type fragment ions, thus providing a facile means for differentiating cysteine-peptide targets from convoluting peptide backgrounds. With the use of this approach in addition to strategic proteolysis, the selective analysis of diagnostic heavy-chain complementarity determining regions (CDRs) of single-chain antibody (scAb) fragments is demonstrated.
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Affiliation(s)
- Victoria C Cotham
- Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, TX 78712, USA
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22
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Webb IK, Mentinova M, McGee WM, McLuckey SA. Gas-phase intramolecular protein crosslinking via ion/ion reactions: ubiquitin and a homobifunctional sulfo-NHS ester. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2013; 24:733-43. [PMID: 23463545 PMCID: PMC3644013 DOI: 10.1007/s13361-013-0590-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 12/18/2012] [Accepted: 01/18/2013] [Indexed: 05/11/2023]
Abstract
Gas-phase intra-molecular crosslinking of protein ubiquitin cations has been demonstrated via ion/ion reactions with anions of a homobifunctional N-hydroxysulfosuccinimide (sulfo-NHS) ester reagent. The ion/ion reaction between multiply-protonated ubiquitin and crosslinker monoanions produces a stable, charge-reduced complex. Covalent crosslinking is indicated by the consecutive loss of 2 molecules of sulfo-NHS under ion trap collisional activation conditions. Covalent modification is verified by the presence of covalently crosslinked sequence ions produced by ion-trap collision-induced dissociation of the ion generated from the losses of sulfo-NHS. Analysis of the crosslinked sequence fragments allows for the localization of crosslinked primary amines, enabling proximity mapping of the gas-phase 3-D structures. The presence of two unprotonated reactive sites within the distance constraint of the crosslinker is required for successful crosslinking. The ability to covalently crosslink is, therefore, sensitive to protein charge state. As the charge state increases, fewer reactive sites are available and protein structure is more likely to become extended because of intramolecular electrostatic repulsion. At high charge states, the reagent shows little evidence for covalent crosslinking but does show evidence for 'electrostatic crosslinking' in that the binding of the sulfonate groups to the protein is sufficiently strong that backbone cleavages are favored over reagent detachment under ion trap collisional activation conditions.
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23
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Enjalbert Q, Girod M, Simon R, Jeudy J, Chirot F, Salvador A, Antoine R, Dugourd P, Lemoine J. Improved detection specificity for plasma proteins by targeting cysteine-containing peptides with photo-SRM. Anal Bioanal Chem 2013; 405:2321-31. [PMID: 23325399 DOI: 10.1007/s00216-012-6603-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 11/16/2012] [Accepted: 11/23/2012] [Indexed: 01/05/2023]
Abstract
Targeted mass spectrometry using selected reaction monitoring (SRM) has emerged as an alternative to immunoassays for protein quantification owing to faster development time and higher multiplexing capability. However, the SRM strategy is faced with the high complexity of peptide mixtures after trypsin digestion of whole plasma or the cellular proteome that most of the time causes contamination, irremediably, by interfering compounds in the transition channels monitored. This problem becomes increasingly acute when the targeted protein is present at a low concentration. In this work, the merit of laser-induced photo-dissociation in the visible region at 473 nm implemented in an hybrid quadrupole linear ion-trap mass spectrometer (photo-SRM) was evaluated for detection specificity of cysteine-containing peptides in a group of plasma proteins after tagging with a dabcyl chromophore. Compared with conventional SRM, photo-SRM chromatograms have improved detection specificity for most of peptides monitored. Comparison of the signals obtained for the best proteotypic peptides in SRM mode and those recorded by photo-SRM of cysteine-containing peptides for the same proteins reveals either increased (up to 10-fold) or similar signal to photo-SRM detection. Finally, photo-SRM has extended response linearity across a calibration plot obtained by diluting human plasma in rat plasma, down to the lowest concentrations. Hence, photo-SRM may advantageously complement conventional SRM in assay of proteins in complex biological matrices.
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Affiliation(s)
- Quentin Enjalbert
- Université Lyon, 43 Boulevard du 11 Novembre 1918, 69622 Lyon, France
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24
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Facile identification of photocleavable reactive metabolites and oxidative stress biomarkers in proteins via mass spectrometry. Anal Bioanal Chem 2012; 403:2269-77. [DOI: 10.1007/s00216-012-5867-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 02/01/2012] [Accepted: 02/10/2012] [Indexed: 10/28/2022]
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25
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Kalcic CL, Reid GE, Lozovoy VV, Dantus M. Mechanism elucidation for nonstochastic femtosecond laser-induced ionization/dissociation: from amino acids to peptides. J Phys Chem A 2012; 116:2764-74. [PMID: 22141398 DOI: 10.1021/jp208421d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Femtosecond laser-induced ionization/dissociation (fs-LID) has been demonstrated as a novel ion activation method for use in tandem mass spectrometry. The technique opens the door to unique structural information about biomolecular samples that is not easily accessed by traditional means. fs-LID is able to cleave strong bonds while keeping weaker bonds intact. This feature has been found to be particularly useful for the mapping of post-translational modifications such as phosphorylation, which is difficult to achieve by conventional proteomic studies. Here we investigate the laser-ion interaction on a fundamental level through the characterization of fs-LID spectra for the protonated amino acids and two series of derivatized samples. The findings are used to better understand the fs-LID spectra of synthetic peptides. This is accomplished by exploring the effects of several single-residue substitutions.
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Affiliation(s)
- Christine L Kalcic
- Departments of Chemistry, Michigan State University East Lansing, Michigan 48824, USA
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26
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Antoine R, Dugourd P. Visible and ultraviolet spectroscopy of gas phase protein ions. Phys Chem Chem Phys 2011; 13:16494-509. [PMID: 21811728 DOI: 10.1039/c1cp21531k] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Optical spectroscopy has contributed enormously to our knowledge of the structure and dynamics of atoms and molecules and is now emerging as a cornerstone of the gas phase methods available for investigating biomolecular ions. This article focuses on the UV and visible spectroscopy of peptide and protein ions stored in ion traps, with emphasis placed on recent results obtained on protein polyanions, by electron photodetachment experiments. We show that among a large number of possible de-excitation pathways, the relaxation of biomolecular polyanions is mainly achieved by electron emission following photo-excitation in electronically excited states. Electron photodetachment is a fast process that occurs prior to relaxation on vibrational degrees of freedom. Electron photodetachment yield can then be used to record gas phase action spectra for systems as large as entire proteins, without the limitation of system size that would arise from energy redistribution on numerous modes and prevent fragmentation after the absorption of a photon. The optical activity of proteins in the near UV is directly related to the electronic structure and optical absorption of aromatic amino acids (Trp, Phe and Tyr). UV spectra for peptides and proteins containing neutral, deprotonated and radical aromatic amino acids were recorded. They displayed strong bathochromic shifts. In particular, the results outline the privileged role played by open shell ions in molecular spectroscopy which, in the case of biomolecules, is directly related to their reactivity and biological functions. The optical shifts observed are sufficient to provide unambiguous fingerprints of the electronic structure of chromophores without the requirement of theoretical calculations. They constitute benchmarks for calculating the absorption spectra of chromophores embedded in entire proteins and could be used in the future to study biochemical processes in the gas phase involving charge transfer in aromatic amino acids, such as in the mediation of electron transfer or redox reactions. We then addressed the important question of the sensitivity of protein optical spectra to the intrinsic properties of protein ions, including conformation, charge state, etc., and to environmental factors. We report optical spectra for different charge states of insulin, for ubiquitin starting from native and denaturated solutions, and for apo-myoglobin protein. All these spectra are compared critically to spectra recorded in solution, in order to assess solvent effects. We also report the spectra of peptides complexed with metal cations and show that complexation gives rise to new optical transitions related to charge transfer types of excitation. The perspectives of this work include integrative approaches where UV-Vis spectroscopy could, for example, be combined with ion mobility spectrometry and high level calculations for protein structural characterization. It could also be used in spectroscopy to probe biological processes in the gas phase, with different light sources including VUV radiation (to probe different types of excitations) and ultra short pulses with time and phase modulation (to probe and control the dynamics of de-excitation or charge transfer events), and with the derivatization of proteins with chromophores to modulate their optical properties. We also envision that photo-excitation will play an important role in the future to produce intermediates with new chemical and reactive properties. Another promising route is to conduct activated electron photodetachment dissociation experiments.
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27
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Ko BJ, Brodbelt JS. Ultraviolet photodissociation of chromophore-labeled oligosaccharides via reductive amination and hydrazide conjugation. JOURNAL OF MASS SPECTROMETRY : JMS 2011; 46:359-366. [PMID: 21438085 DOI: 10.1002/jms.1901] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The fragmentation patterns of hydrazide-conjugated and reductively aminated oligosaccharides, including lacto-N-fucopentaoses and lacto-N-difucohexaoses, produced on collisionally induced dissociation (CID) and ultraviolet photodissociation (UVPD) in a quadrupole ion trap are presented. The two derivatization methods generate different cross-ring cleavages on UVPD and CID. UVPD of hydrazide-conjugated oligosaccharides yield predominant (2, 4)A-type cross-ring cleavage ions. In contrast, UVPD of aminated oligosaccharides results mainly in (0, 1)A-type ions. Moreover, more extensive dual-cleavage pathways (i.e. internal fragment ions) were observed on UVPD.
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Affiliation(s)
- Byoung Joon Ko
- Department Chemical Engineering, The University of Texas at Austin, 1 University Station A5300, Texas 78712, USA
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28
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Brodbelt JS. Shedding light on the frontier of photodissociation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2011; 22:197-206. [PMID: 21472579 DOI: 10.1007/s13361-010-0023-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 10/11/2010] [Accepted: 10/13/2010] [Indexed: 05/30/2023]
Abstract
The development of new ion activation/dissociation methods is motivated by the need for more versatile ways to characterize structures of ions, especially in the growing arena of biological mass spectrometry in which better tools for determining sequences, modifications, interactions, and conformations of biopolymers are essential. Although most agree that collision-induced dissociation (CID) remains the gold standard for ion activation/dissociation, recent inroads in electron- and photon-based activation methods have cemented their role as outstanding alternatives. This article will focus on the impact of photodissociation, including its strengths and drawbacks as an analytical tool, and its potential for further development in the next decade. Moreover, the discussion will emphasize photodissociation in quadrupole ion traps, because that platform has been used for one of the greatest arrays of new applications over the past decade.
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Affiliation(s)
- Jennifer S Brodbelt
- Department of Chemistry and Biochemistry, University of Texas, Austin, TX 78712, USA.
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29
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Ko BJ, Brodbelt JS. Ultraviolet photodissociation of carboxylate-derivatized peptides in a quadrupole ion trap. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2011; 22:49-56. [PMID: 21472543 DOI: 10.1007/s13361-010-0016-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Accepted: 10/13/2010] [Indexed: 05/30/2023]
Abstract
The fragmentation patterns obtained by ultraviolet photodissociation (UVPD) and collision-induced dissociation (CID) in a quadrupole ion trap mass spectrometer were compared for peptides modified at their C-termini and at acidic amino acids. Attachment of Alexa Fluor 350 or 7-amino-4-methyl-coumarin chromophores at the C-terminal and acidic residues enhances the UV absorptivity of the peptides and all fragment ions that retain the chromophore, such as the y ions that contain the chromophore-modified C-terminus. Whereas CID results in the formation of the typical array of mainly y-type and a/b-type fragment ions, UVPD produces predominantly a/b-type ions with greatly reduced abundances of y ions. Immonium ions, mostly ones from aromatic or basic amino acids, are also observed in the low m/z range upon UVPD. UVPD of peptides containing two chromophore moieties (with one at the C-terminus and another at an acidic residue) results in even more efficient photodissociation at the expense of the annihilation of almost all diagnostic b and y ions containing the chromophore.
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Affiliation(s)
- Byoung Joon Ko
- Department of Chemical Engineering, University of Texas at Austin, 1 University Station A5300, Austin, TX 78712, USA
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30
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Vasicek L, Brodbelt JS. Enhancement of ultraviolet photodissociation efficiencies through attachment of aromatic chromophores. Anal Chem 2010; 82:9441-6. [PMID: 20961088 DOI: 10.1021/ac102126s] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two N-terminal derivatization reagents containing aromatic chromophores, 4-sulfophenyl isothiocyanate (SPITC) and 4-methylphosphonophenyl isothiocyanate (PPITC), were used to increase the dissociation efficiencies of peptides upon ultraviolet photodissociation (UVPD) at 193 nm. The resulting UVPD spectra are dominated by C-terminal ions, including y, z, x, v, and w ions, and immonium ions. The attachment of the PPITC or SPITC groups leads to a reduction in the number and abundances of N-terminal ions because the added phosphonate or sulfonate functionalities result in neutralization of some of the N-terminal species, ones that might normally be singly protonated in the absence of the negatively charged sulfonate or phosphonate groups. In addition, the greater photoabsorptivities of the PPITC- and SPITC-derivatized N-terminal product ions enhanced their secondary photodissociation, leading to formation of immonium ions.
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Affiliation(s)
- Lisa Vasicek
- Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, Texas 78712, United States
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31
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Hao C, Le Blanc JCY, Verkerk UH, Siu KWM, Loboda AV. Ultraviolet photodissociation of protonated pharmaceuticals in a pressurized linear quadrupole ion trap. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2010; 24:2262-2268. [PMID: 20623481 DOI: 10.1002/rcm.4633] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Ultraviolet photodissociation (UVPD) was evaluated as a technique for generating ion fragmentation information that is alternative and/or complementary to the information obtained by collision-induced dissociation (CID). Ions trapped in a pressurized linear ion trap were dissociated using a 355 nm or a 266 nm pulsed laser. Comparisons of UVPD and CID spectra using a set of aromatic chromophore-containing compounds (desmethyl bosentan, haloperidol, nelfinavir) demonstrated distinct characteristic fragmentation patterns resulting from photodissociation. The wavelength of light and the pressure of the buffer gas in the UVPD cell are important parameters that control fragmentation pathways. The wavelength effect is related to the absorption cross section, location of the chromophore and the energy carried by one photon. Thus, UV irradiation wavelength affects fragmentation pathways as well as the fragmentation rate. The pressure effect can be explained by collisional quenching of 'slow' fragmentation pathways. We observed that higher pressure of the buffer gas during UVPD experiments highlights unique fragment ions by suppressing slow fragmentation pathways responsible for CID-like fragmentation patterns.
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Affiliation(s)
- Changtong Hao
- Department of Chemistry and Centre for Research in Mass Spectrometry, York University, 4700 Keele St, Toronto, ON, Canada, M3J 1P3
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32
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Larraillet V, Antoine R, Dugourd P, Lemoine J. Activated-electron photodetachment dissociation for the structural characterization of protein polyanions. Anal Chem 2010; 81:8410-6. [PMID: 19775153 DOI: 10.1021/ac901304d] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Multiply deprotonated anions [M - nH](n-) of large peptide mellitin, ubiquitin, and beta-casein proteins were subjected to laser irradiation at 260 nm in a quadrupole ion trap. For all compounds, the predominant event consecutive to laser irradiation was the detachment of an electron. The subsequent isolation and collisional activation of the oxidized [M - nH]((n-1)-*) resulted in extensive fragmentation of the peptide backbone. For mellitin peptide, nearly a complete series of c(*), z, and a(*), x product ions were observed. Applied to proteins, this technique, coined as activated-electron photodetachment dissociation (activated-EPD), achieved much more extensive sequence coverage than regular collision activated dissociation (CAD) on the even-electron components. Furthermore, the activated-EPD spectrum of beta-casein displayed phosphorylated fragment ions which suggest that the method is able to preserve part of the labile bonds of post-translational modifications. Activated-EPD is, therefore, a promising complementary technique to other dissociation techniques governed by radicals, i.e., electron capture dissociation (ECD), electron transfer dissociation (ETD), and electron detachment dissociation (EDD), for the structural characterization of large peptides and small proteins.
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33
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Kim TY, Schwartz JC, Reilly JP. Development of a Linear Ion Trap/Orthogonal-Time-of-Flight Mass Spectrometer for Time-Dependent Observation of Product Ions by Ultraviolet Photodissociation of Peptide Ions. Anal Chem 2009; 81:8809-17. [DOI: 10.1021/ac9013258] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tae-Young Kim
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, and Thermo Electron, 355 River Oaks Parkway, San Jose, California 95134
| | - Jae C. Schwartz
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, and Thermo Electron, 355 River Oaks Parkway, San Jose, California 95134
| | - James P. Reilly
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, and Thermo Electron, 355 River Oaks Parkway, San Jose, California 95134
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34
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Gardner MW, Smith SI, Ledvina AR, Madsen JA, Coon JJ, Schwartz JC, Stafford GC, Brodbelt JS. Infrared multiphoton dissociation of peptide cations in a dual pressure linear ion trap mass spectrometer. Anal Chem 2009; 81:8109-18. [PMID: 19739654 PMCID: PMC2774747 DOI: 10.1021/ac901313m] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A dual pressure linear ion trap mass spectrometer was modified to permit infrared multiphoton dissociation (IRMPD) in each of the two cells-the first a high pressure cell operated at nominally 5 x 10(-3) Torr and the second a low pressure cell operated at nominally 3 x 10(-4) Torr. When IRMPD was performed in the high pressure cell, most peptide ions did not undergo significant photodissociation; however, in the low pressure cell peptide cations were efficiently dissociated with less than 25 ms of IR irradiation regardless of charge state. IRMPD of peptide cations allowed the detection of low m/z product ions including the y(1) fragments and immonium ions which are not typically observed by ion trap collision induced dissociation (CID). Photodissociation efficiencies of approximately 100% and MS/MS (tandem mass spectrometry) efficiencies of greater than 60% were observed for both multiply and singly protonated peptides. In general, higher sequence coverage of peptides was obtained using IRMPD over CID. Further, greater than 90% of the product ion current in the IRMPD mass spectra of doubly charged peptide ions was composed of singly charged product ions compared to the CID mass spectra in which the abundances of the multiply and singly charged product ions were equally divided. Highly charged primary product ions also underwent efficient photodissociation to yield singly charged secondary product ions, thus simplifying the IRMPD product ion mass spectra.
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Affiliation(s)
- Myles W Gardner
- Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, Texas 78751, USA
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35
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Ly T, Julian R. Ultraviolet Photodissociation: Developments towards Applications for Mass-Spectrometry-Based Proteomics. Angew Chem Int Ed Engl 2009; 48:7130-7. [DOI: 10.1002/anie.200900613] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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36
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Ly T, Julian R. Photodissoziation durch UV-Licht: Anwendungen in der massenspektrometrischen Proteomforschung. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200900613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Gardner MW, Brodbelt JS. Ultraviolet photodissociation mass spectrometry of bis-aryl hydrazone conjugated peptides. Anal Chem 2009; 81:4864-72. [PMID: 19449860 DOI: 10.1021/ac9005233] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ultraviolet photodissociation (UVPD) at 355 nm was used to rapidly identify peptides which had been chemically conjugated through bis-aryl hydrazone (BAH) moieties. The two biomolecules of interest were separately tagged to introduce either an aldehyde or a hydrazine and then conjugated together through these functional groups to from the UV-chromogenic BAH-group. In a mock mixture of peptides, UVPD was used to screen for the BAH-conjugated peptides in direct infusion ESI-UVPD-MS and online LC-UVPD-MS methods by comparing the abundances of the ions with the laser off and with the laser on. Only the BAH-conjugated peptides were observed to photodissociate upon exposure to UV irradiation, thus affording excellent selectivity for the pinpointing the relevant conjugated peptides in a complex mixture of nonconjugated peptides. UVPD analysis of conjugated model peptides indicated that the UVPD efficiencies of these species were charge state dependent. BAH-conjugated peptides that had a mobile proton which could protonate the basic BAH-moiety underwent more efficient photodissociation than the peptide ions with sequestered protons. Ultraviolet photodissociation of BAH-cross-linked peptides also yielded more diagnostic sequence ions than CID to unambiguously locate the site of conjugation.
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Affiliation(s)
- Myles W Gardner
- Department of Chemistry and Biochemistry,The University of Texas at Austin, 1 University Station A5300, Austin, Texas 78712-1167, USA
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Brodbelt JS, Wilson JJ. Infrared multiphoton dissociation in quadrupole ion traps. MASS SPECTROMETRY REVIEWS 2009; 28:390-424. [PMID: 19294735 DOI: 10.1002/mas.20216] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The development of new ion activation techniques continues to be a dynamic area of scientific discovery, in part to complement the tremendous innovations in ionization methods that have allowed the mass spectrometric analysis of an enormous array of molecules. Ion activation/dissociation provides key information about ion structures, binding energies, and differentiation of isomers, as well as affording a primary means of identifying compounds in mixtures. Numerous new activation methods have emerged over the past two decades in an effort to develop alternatives to collisional activated dissociation, the gold standard for providing structurally diagnostic fragmentation patterns. Collisional activated dissociation does not always offer sufficiently high or controllable energy deposition, thus rendering it less useful for certain classes of molecules, such as large proteins or macromolecular complexes. Photodissociation is one of the most promising alternatives and is readily implemented in ion trapping and time-of-flight mass spectrometers. Photodissociation generally entails using a laser to irradiate ions with UV, visible, or IR photons, thus resulting in internal energy deposition based on the number and wavelengths of the photons. The activation process can be extremely rapid and efficient, as well as having the potential for high total energy deposition. This review describes infrared multiphoton dissociation in quadrupole ion trap mass spectrometry. A comparison of photodissociation and collisional activated dissociation is covered, in addition to some of the methods to increase photodissociation efficiency. Numerous applications of IRMPD are discussed as well, including ones related to the analysis of drugs, peptides, nucleic acids, and oligosaccharides.
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Affiliation(s)
- Jennifer S Brodbelt
- Department of Chemistry and Biochemistry, University of Texas, Austin, TX 78712, USA.
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Abstract
Mass spectrometric identification of all types of molecules relies on the observation and interpretation of ion fragmentation patterns. Peptides, proteins, carbohydrates, and nucleic acids that are often found as components of complex biological samples represent particularly important challenges. The most common strategies for fragmenting biomolecular ions include low- and high-energy collisional activation, post-source decay, and electron capture or transfer dissociation. Each of these methods has its own idiosyncrasies and advantages but encounters problems with some types of samples. Novel fragmentation methods that can offer improvements are always desirable. One approach that has been under study for years but is not yet incorporated into a commercial instrument is ultraviolet photofragmentation. This review discusses experimental results on various biological molecules that have been generated by several research groups using different light wavelengths and mass analyzers. Work involving short-wavelength vacuum ultraviolet light is particularly emphasized. The characteristics of photofragmentation are examined and its advantages summarized.
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Affiliation(s)
- James P Reilly
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
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Madsen JA, Brodbelt JS. Simplifying Fragmentation Patterns of Multiply Charged Peptides by N-Terminal Derivatization and Electron Transfer Collision Activated Dissociation. Anal Chem 2009; 81:3645-53. [DOI: 10.1021/ac9000942] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- James A. Madsen
- Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, Texas 78712
| | - Jennifer S. Brodbelt
- Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, Texas 78712
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Kalcic CL, Gunaratne TC, Jones AD, Dantus M, Reid GE. Femtosecond laser-induced ionization/dissociation of protonated peptides. J Am Chem Soc 2009; 131:940-2. [PMID: 19128059 DOI: 10.1021/ja8089119] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Although tandem mass spectrometry has revolutionized the identification and structural characterization of peptides and proteins, future advances in comprehensive proteome analysis will depend on the development of improved methods for ion activation that yield greater sequence information, and with selective control over the fragmentation chemistry. This report presents initial findings that demonstrate the utility of a novel ion activation method using ultrashort (approximately 30 fs) laser pulses as a means to overcome the limitations of current technologies, while opening the door to solving significant challenges in protein and peptide analysis.
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Affiliation(s)
- Christine L Kalcic
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
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Vasicek LA, Wilson JJ, Brodbelt JS. Improved infrared multiphoton dissociation of peptides through N-terminal phosphonite derivatization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2009; 20:377-384. [PMID: 19027323 DOI: 10.1016/j.jasms.2008.10.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 10/24/2008] [Accepted: 10/27/2008] [Indexed: 05/27/2023]
Abstract
A strategy for improving the sequencing of peptides by infrared multiphoton dissociation (IRMPD) in a linear ion trap mass spectrometer is described. We have developed an N-terminal derivatization reagent, 4-methylphosphonophenylisothiocyanate (PPITC), which allows the attachment of an IR-chromogenic phosphonite group to the N-terminus of peptides, thus enhancing their IRMPD efficiencies. After the facile derivatization process, the PPITC-modified peptides require shorter irradiation times for efficient IRMPD and yield extensive series of y ions, including those of low m/z that are not detected upon traditional CID. The resulting IRMPD mass spectra afford more complete sequence coverage for both model peptides and tryptic peptides from cytochrome c. We compare the effectiveness of this derivatization/IRMPD approach to that of a common N-terminal sulfonation reaction that utilizes 4-sulfophenylisothiocyanate (SPITC) in conjunction with CID and IRMPD.
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Affiliation(s)
- Lisa A Vasicek
- Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712, USA
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Sassin NA, Everhart SC, Dangi BB, Ervin KM, Cline JI. Fluorescence and photodissociation of rhodamine 575 cations in a quadrupole ion trap. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2009; 20:96-104. [PMID: 18849170 DOI: 10.1016/j.jasms.2008.09.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 09/05/2008] [Accepted: 09/05/2008] [Indexed: 05/26/2023]
Abstract
The fluorescence and photodissociation of rhodamine 575 cations confined to a quadrupole ion trap are observed during laser irradiation at 488 nm. The kinetics of photodissociation is measured by time-dependent mass spectra and time-dependent fluorescence. The rhodamine ion signal and fluorescence decay are studied as functions of buffer gas pressure, laser fluence, and irradiation time. The decay rates of the ions in the mass spectra agree with decay rates of the fluorescence. Some of the fragment ions also fluoresce and further dissociate. The photodissociation rate is found to depend on the incident laser fluence and buffer gas pressure. The implications of rapid absorption/fluorescence cycling for photodissociation of dye-labeled biomolecular ions under continuous irradiation are discussed.
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Affiliation(s)
- Nicholas A Sassin
- Department of Chemistry and Chemical Physics Program, University of Nevada, Reno, Reno, Nevada, USA
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Devakumar A, Mechref Y, Kang P, Novotny MV, Reilly JP. Identification of isomeric N-glycan structures by mass spectrometry with 157 nm laser-induced photofragmentation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2008; 19:1027-40. [PMID: 18487060 PMCID: PMC2523269 DOI: 10.1016/j.jasms.2008.03.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Revised: 03/07/2008] [Accepted: 03/07/2008] [Indexed: 05/03/2023]
Abstract
Characterization of structural isomers has become increasingly important and extremely challenging in glycobiology. This communication demonstrates the capability of ion-trap mass spectrometry in conjunction with 157 nm photofragmentation to identify different structural isomers of permethylated N-glycans derived from ovalbumin without chromatographic separation. The results are compared with collision-induced dissociation (CID) experiments. Photodissociation generates extensive cross-ring fragment ions as well as diagnostic glycosidic product ions that are not usually observed in CID MS/MS experiments. The detection of these product ions aids in characterizing indigenous glycan isomers. The ion trap facilitates MS(n) experiments on the diagnostic glycosidic fragments and cross-ring product ions generated through photofragmentation, thus allowing unambiguous assignment of all of the isomeric structures associated with the model glycoprotein used in this study. Photofragmentation is demonstrated to be a powerful technique for the structural characterization of glycans.
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Affiliation(s)
| | | | | | | | - James P. Reilly
- * Corresponding Author: James P. Reilly, Department of Chemistry, Indiana University, Bloomington, IN 47405, USA, E-mail:
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Wilson JJ, Brodbelt JS. Ultraviolet photodissociation at 355 nm of fluorescently labeled oligosaccharides. Anal Chem 2008; 80:5186-96. [PMID: 18505268 DOI: 10.1021/ac800315k] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Ultraviolet photodissociation (UVPD) produces complementary fragmentation to collision-induced dissociation (CID) when implemented for activation of fluorescently labeled oligosaccharide and glycan ions. Reductive amination of oligosaccharides with fluorophore reagents results in efficient photon absorption at 355 nm, producing fragment ions from the nonreducing end that do not contain the appended fluorophore. In contrast to the fragment ions observed upon UVPD (A- and C-type ions), CID produces mainly reducing end fragments retaining the fluorophore (Y-type ions). UVPD affords better isomeric differentiation of both the lacto-N-fucopentaoses series and the lacto-N-difucohexaoses series, but in general, the combination of UVPD and CID offers the most diagnostic elucidation of complex branched oligosaccharides. Four fluorophores yielded similar MS/MS results; however, 6-aminoquinoline (6-AQ), 2-amino-9(10 H)-acridone (AMAC) and 7-aminomethylcoumarin (AMC) afforded more efficient photon absorption and subsequent dissociation than 2-aminobenzamide (2-AB). UVPD also was useful for characterization of glycans released from ribonuclease B and derivatized with 6-AQ. Lastly, electron photodetachment dissociation of oligosaccharides derivatized with 7-amino-1,3-naphthalenedisulfonic acid (AGA) yielded unique cross-ring cleavages similar to those obtained by electron detachment dissociation.
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Affiliation(s)
- Jeffrey J Wilson
- Department of Chemistry and Biochemistry, 1 University Station A5300, University of Texas at Austin, Austin, Texas 78712, USA
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Wilson JJ, Kirkovits GJ, Sessler JL, Brodbelt JS. Photodissociation of non-covalent peptide-crown ether complexes. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2008; 19:257-60. [PMID: 18077179 PMCID: PMC2288744 DOI: 10.1016/j.jasms.2007.10.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Revised: 10/29/2007] [Accepted: 10/29/2007] [Indexed: 05/25/2023]
Abstract
Highly chromogenic 18-crown-6-dipyrrolylquinoxaline coordinates primary amines of peptides, forming non-covalent complexes that can be transferred to the gas-phase by electrospray ionization. The appended chromogenic crown ether facilitates efficient energy transfer to the peptide upon ultraviolet irradiation in the gas phase, resulting in diagnostic peptide fragmentation. Collisional-activated dissociation and infrared multiphoton dissociation of these non-covalent complexes result only in their disassembly with the charge retained on either the peptide or crown ether, yielding no sequence ions. Upon UV photon absorption the intermolecular energy transfer is facilitated by the fast activation timescale of ultraviolet photodissociation (<10 ns) and by the collectively strong hydrogen bonding between the crown ether and peptide, thus allowing effective transfer of energy to the peptide moiety before disruption of the intermolecular hydrogen bonds.
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Affiliation(s)
- Jeffrey J Wilson
- Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712, USA
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