51
|
Yang L, Tang X, Weisbrod CR, Munske GR, Eng JK, von Haller PD, Kaiser NK, Bruce JE. A photocleavable and mass spectrometry identifiable cross-linker for protein interaction studies. Anal Chem 2010; 82:3556-66. [PMID: 20373789 DOI: 10.1021/ac902615g] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this paper, we present the results of proof-of-concept experiments using a novel photocleavable and mass spectrometry identifiable cross-linker pcPIR (photocleavable protein interaction reporter). pcPIR can be dissociated under UV irradiation either off- or online before the introduction to the mass spectrometers. Photo dissociation of cross-linkers is different from either the gas phase or the chemical cleavage of cross-linkers. Different types of cross-links can be identified using the pcPIR mass relationships, where the mass of cross-linked precursor equals the sum of the masses of the released products and reporter. Since pcPIR is cleaved prior to the entrance to the mass spectrometer, the released peptides are available to be sequenced with routine collision-induced dissociation (CID) MS/MS experiments and database search algorithms. In this report, the pcPIR strategy of identifying the cross-linked peptides with on- and off-line photocleavage coupled with novel targeted data dependent LC-MS/MS is demonstrated with the use of standard peptides, bovine serum albumin (BSA), and human hemoglobin tetramer protein complex.
Collapse
Affiliation(s)
- Li Yang
- Department of Chemistry, Washington State University, Pullman, Washington 99164, USA
| | | | | | | | | | | | | | | |
Collapse
|
52
|
Fabris D, Yu ET. Elucidating the higher-order structure of biopolymers by structural probing and mass spectrometry: MS3D. JOURNAL OF MASS SPECTROMETRY : JMS 2010; 45:841-60. [PMID: 20648672 PMCID: PMC3432860 DOI: 10.1002/jms.1762] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Chemical probing represents a very versatile alternative for studying the structure and dynamics of substrates that are intractable by established high-resolution techniques. The implementation of MS-based strategies for the characterization of probing products has not only extended the range of applicability to virtually all types of biopolymers but has also paved the way for the introduction of new reagents that would not have been viable with traditional analytical platforms. As the availability of probing data is steadily increasing on the wings of the development of dedicated interpretation aids, powerful computational approaches have been explored to enable the effective utilization of such information to generate valid molecular models. This combination of factors has contributed to making the possibility of obtaining actual 3D structures by MS-based technologies (MS3D) a reality. Although approaches for achieving structure determination of unknown targets or assessing the dynamics of known structures may share similar reagents and development trajectories, they clearly involve distinctive experimental strategies, analytical concerns and interpretation paradigms. This Perspective offers a commentary on methods aimed at obtaining distance constraints for the modeling of full-fledged structures while highlighting common elements, salient distinctions and complementary capabilities exhibited by methods used in dynamics studies. We discuss critical factors to be addressed for completing effective structural determinations and expose possible pitfalls of chemical methods. We survey programs developed for facilitating the interpretation of experimental data and discuss possible computational strategies for translating sparse spatial constraints into all-atom models. Examples are provided to illustrate how the concerted application of very diverse probing techniques can lead to the solution of actual biological systems.
Collapse
Affiliation(s)
- Daniele Fabris
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD, USA.
| | | |
Collapse
|
53
|
Gardner MW, Brodbelt JS. Preferential Cleavage of N−N Hydrazone Bonds for Sequencing Bis-arylhydrazone Conjugated Peptides by Electron Transfer Dissociation. Anal Chem 2010; 82:5751-9. [DOI: 10.1021/ac100788a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Myles W. Gardner
- 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
| |
Collapse
|
54
|
Smith SI, Brodbelt JS. Rapid characterization of cross-links, mono-adducts, and non-covalent binding of psoralens to deoxyoligonucleotides by LC-UV/ESI-MS and IRMPD mass spectrometry. Analyst 2010; 135:943-52. [PMID: 20419242 PMCID: PMC2890229 DOI: 10.1039/b924023c] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Upon UV photoactivation, psoralen analogs form covalent mono-adducts and cross-links with DNA at thymine residues. Electrospray ionization mass spectrometric analysis allowed rapid and efficient determination of the reaction percentages of each psoralen analog with DNA duplexes containing different binding sites after exposure to UV irradiation. The distribution of cross-linked products and mono-adducts was monitored by both LC-UV and IRMPD-MS methods with the highest ratio of cross-linked products to mono-adducts obtained for 8-methoxypsoralen (8-MOP), psoralen (P), and 5-methoxypsoralen (5-MOP). Reactions at 5'-TA sites were favored over 5'-AT sites, and duplexes containing two and three binding sites showed extensive binding by the psoralens. 4'-Aminomethyl-4,5',8-trimethylpsoralen (AMP) bound non-selectively via non-covalent interactions and was the only psoralen analog to show significant binding in the absence of UV irradiation. 8-MOP binding displayed the greatest sequence selectivity among the psoralen analogs. The sites of interstrand cross-linking were determined by fragmentation of the duplex/psoralen complexes by infrared multiphoton dissociation (IRMPD), which produced cross-linked product ions containing an intact single strand, the psoralen analog, and either a w(n) or a(n)-B portion of the complementary strand. IRMPD of DNA/AMP complexes after UV irradiation also produced high abundances of the intact single strands with the AMP ligand attached, products indicative of a significant population of mono-adducts.
Collapse
Affiliation(s)
- Suncerae I Smith
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712, USA
| | | |
Collapse
|
55
|
Gardner MW, Li N, Ellington AD, Brodbelt JS. Infrared multiphoton dissociation of small-interfering RNA anions and cations. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2010; 21:580-91. [PMID: 20129797 PMCID: PMC2847665 DOI: 10.1016/j.jasms.2009.12.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2009] [Revised: 12/21/2009] [Accepted: 12/22/2009] [Indexed: 05/13/2023]
Abstract
Infrared multiphoton dissociation (IRMPD) on a linear ion trap mass spectrometer is applied for the sequencing of small interfering RNA (siRNA). Both single-strand siRNAs and duplex siRNA were characterized by IRMPD, and the results were compared with that obtained by traditional ion trap-based collision induced dissociation (CID). The single-strand siRNA anions were observed to dissociate via cleavage of the 5' P-O bonds yielding c- and y-type product ions as well as undergo neutral base loss. Full sequence coverage of the siRNA anions was obtained by both IRMPD and CID. While the CID mass spectra were dominated by base loss ions, accounting for approximately 25% to 40% of the product ion current, these ions were eliminated through secondary dissociation by increasing the irradiation time in the IRMPD mass spectra to produce higher abundances of informative sequence ions. With longer irradiation times, however, internal ions corresponding to cleavage of two 5' P-O bonds began to populate the product ion mass spectra as well as higher abundances of [a - Base] and w-type ions. IRMPD of siRNA cations predominantly produced c- and y-type ions with minimal contributions of [a - Base] and w-type ions to the product ion current; the presence of only two complementary series of product ions in the IRMPD mass spectra simplified spectral interpretation. In addition, IRMPD produced high abundances of protonated nucleobases, [G + H](+), [A + H](+), and [C + H](+), which were not detected in the CID mass spectra due to the low-mass cut-off associated with conventional CID in ion traps. CID and IRMPD using short irradiation times of duplex siRNA resulted in strand separation, similar to the dissociation trends observed for duplex DNA. With longer irradiation times, however, the individual single-strands underwent secondary dissociation to yield informative sequence ions not obtained by CID.
Collapse
Affiliation(s)
- Myles W Gardner
- Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712-0165, USA
| | | | | | | |
Collapse
|
56
|
Tang X, Bruce JE. A new cross-linking strategy: protein interaction reporter (PIR) technology for protein-protein interaction studies. MOLECULAR BIOSYSTEMS 2010; 6:939-47. [PMID: 20485738 DOI: 10.1039/b920876c] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Chemical cross-linking coupled with mass spectrometry, an emerging approach for protein topology and interaction studies, has gained increasing interest in the past few years. A number of recent proof-of-principle studies on model proteins or protein complex systems with improved cross-linking strategies have shown great promise. However, the heterogeneity and low abundance of the cross-linked products as well as data complexity continue to pose enormous challenges for large-scale application of cross-linking approaches. A novel mass spectrometry-cleavable cross-linking strategy embodied in Protein Interaction Reporter (PIR) technology, first reported in 2005, was recently successfully applied for in vivo identification of protein-protein interactions as well as actual regions of the interacting proteins that share close proximity while present within cells. PIR technology holds great promise for achieving the ultimate goal of mapping protein interaction network at systems level using chemical cross-linking. In this review, we will briefly describe the recent progress in the field of chemical cross-linking development with an emphasis on the PIR concepts, its applications and future directions.
Collapse
Affiliation(s)
- Xiaoting Tang
- Novo Nordisk Inflammation Research Center, Seattle, Washington, USA
| | | |
Collapse
|
57
|
Singh P, Panchaud A, Goodlett DR. Chemical Cross-Linking and Mass Spectrometry As a Low-Resolution Protein Structure Determination Technique. Anal Chem 2010; 82:2636-42. [DOI: 10.1021/ac1000724] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pragya Singh
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195-7610
| | - Alexandre Panchaud
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195-7610
| | - David R. Goodlett
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195-7610
| |
Collapse
|
58
|
Madsen JA, Gardner MW, Smith SI, Ledvina AR, Coon JJ, Schwartz JC, Stafford GC, Brodbelt JS. Top-down protein fragmentation by infrared multiphoton dissociation in a dual pressure linear ion trap. Anal Chem 2010; 81:8677-86. [PMID: 19785447 DOI: 10.1021/ac901554z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Infrared multiphoton dissociation (IRMPD) was implemented in a novel dual pressure linear ion trap for rapid top-down proteomics. The high pressure cell provided improved trapping and isolation efficiencies while the isotopic profiles of 10+ charged ions could be resolved by mass analysis in the low pressure cell that enabled effective top down protein identification. Striking differences between IRMPD in the low pressure cell and CID in the high pressure cell were observed for proteins ranging from 8.6 to 29 kDa. Because of secondary dissociation, IRMPD yielded product ions in significantly lower charge states as compared to CID, thus facilitating more accurate mass identification and streamlining product ion assignment. This outcome was especially useful for database searching of larger proteins (approximately 29 kDa) as IRMPD substantially improved protein identification and scoring confidence. Also, IRMPD showed an increased selectivity toward backbone cleavages N-terminal to proline and C-terminal to acidic residues (especially for the lowest charge states), which could be useful for a priori spectral predictions and enhanced database searching for protein identification.
Collapse
Affiliation(s)
- James A Madsen
- Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, Texas 78712, USA
| | | | | | | | | | | | | | | |
Collapse
|
59
|
Gardner MW, Brodbelt JS. Reduction of chemical noise in electrospray ionization mass spectrometry by supplemental IR activation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2009; 20:2206-2210. [PMID: 19775908 DOI: 10.1016/j.jasms.2009.08.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Revised: 08/08/2009] [Accepted: 08/09/2009] [Indexed: 05/28/2023]
Abstract
Supplemental infrared (IR) activation was applied to reduce background chemical noise and increase analyte ion signal in a linear ion trap mass spectrometer. Peptides, proteins, and small molecules were all introduced by electrospray ionization, and when regions of chemical noise were isolated and subjected to IR irradiation, protonated analyte molecules were observed in the product ion mass spectra. By isolating the entire mass range (e.g., m/z 400-2000) and then irradiating all ions in the trap, supplemental IR activation increased the signal of singly protonated peptides by almost 70% and by 40%-55% for the lower charge states of cytochrome c. This increase in analyte ion signal was less dramatic for the higher charge states of peptides and proteins. The chemical noise present in the mass spectra is attributed to incomplete desolvation of the electrospray, as the abundance of the protonated peptides observed upon supplemental IR activation of the chemical noise decreased with higher inlet capillary temperatures. Collision activation was not as effective for desolvating the ions present in the chemical noise.
Collapse
Affiliation(s)
- Myles W Gardner
- Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712-0165, USA
| | | |
Collapse
|
60
|
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.
Collapse
Affiliation(s)
- Myles W Gardner
- Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, Texas 78751, USA
| | | | | | | | | | | | | | | |
Collapse
|
61
|
Chowdhury SM, Du X, Tolić N, Wu S, Moore RJ, Mayer MU, Smith RD, Adkins JN. Identification of cross-linked peptides after click-based enrichment using sequential collision-induced dissociation and electron transfer dissociation tandem mass spectrometry. Anal Chem 2009; 81:5524-32. [PMID: 19496583 DOI: 10.1021/ac900853k] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chemical cross-linking combined with mass spectrometry can be a powerful approach for the identification of protein-protein interactions and for providing constraints on protein structures. However, enrichment of cross-linked peptides is crucial to reduce sample complexity before mass spectrometric analysis. In addition compact cross-linkers are often preferred to provide short spacer lengths, surface accessibility to the protein complexes, and must have reasonable solubility under conditions where the native complex structure is stable. In this study, we present a novel compact cross-linker that contains two distinct features: (1) an alkyne tag and (2) a small molecule detection tag (NO(2)) to maintain reasonable solubility in water. The alkyne tag enables enrichment of the cross-linked peptides after proteolytic cleavage and coupling of an affinity tag using alkyne-azido click chemistry. Neutral loss of the small NO(2) moiety provides a secondary means of detecting cross-linked peptides in MS/MS analyses, providing additional confidence in peptide identifications. We show the labeling efficiency of this cross-linker, which we termed CLIP (click-enabled linker for interacting proteins) using ubiquitin. The enrichment capability of CLIP is demonstrated for cross-linked ubiquitin in highly complex E. coli cell lysates. Sequential collision-induced dissociation tandem mass spectrometry (CID-MS/MS) and electron transfer dissociation (ETD)-MS/MS of intercross-linked peptides (two peptides connected with a cross-linker) are also demonstrated for improved automated identification of cross-linked peptides.
Collapse
Affiliation(s)
- Saiful M Chowdhury
- Biological Sciences Division and Environmental and Molecular Science Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | | | | | | | | | | | | | | |
Collapse
|
62
|
Lu Y, Tanasova M, Borhan B, Reid GE. Ionic reagent for controlling the gas-phase fragmentation reactions of cross-linked peptides. Anal Chem 2009; 80:9279-87. [PMID: 19551991 DOI: 10.1021/ac801625e] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chemical cross-linking combined with proteolytic digestion and mass spectrometry (MS) is a promising approach to provide inter- and intramolecular distance constraints for the structural characterization of protein topologies and functional multiprotein complexes. Despite the relative straightforwardness of these methodologies, the identification and characterization of cross-linked proteins presents a significant analytical challenge, due to the complexity of the resultant peptide mixtures, as well as the array of inter-, intra-, or "dead-end"-cross-linked peptides that may be generated from a single cross-linking experiment. To address these issues, we describe here the synthesis, characterization, and initial evaluation of a novel "fixed charge" sulfonium ion-containing crosslinking reagent, S-methyl 5,5'-thiodipentanoylhydroxysuc-cinimide. The peptide products obtained by reaction with this reagent are all shown to fragment exclusively via facile cleavage of the C-S bond directly adjacent to the fixed charge during CID-MS/MS, resulting in the formation of characteristic product ions that enable the presence and type (i.e., inter, intra, or dead-end) of the cross-linked products to be readily determined, independently of the "proton mobility" of the precursor ion. Subsequent isolation and dissociation of these products by MS3 provides additional structural information required for identification of the peptide sequences involved in the cross-linking reactions, as well as for characterization of the specific site(s) at which cross-linking has occurred. The specificity of these gas-phase fragmentation reactions, as well as the solubility and stability of the cross-linking reagent under aqueous conditions, suggests that this strategy holds great promise for use in future studies aimed at the structural analysis of large proteins or multiprotein assemblies.
Collapse
Affiliation(s)
- Yali Lu
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | | | | | | |
Collapse
|
63
|
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.
Collapse
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
| | | |
Collapse
|
64
|
Remes PM, Glish GL. Mapping the distribution of ion positions as a function of quadrupole ion trap mass spectrometer operating parameters to optimize infrared multiphoton dissociation. J Phys Chem A 2009; 113:3447-54. [PMID: 19320447 DOI: 10.1021/jp808955w] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Infrared multiphoton dissociation (IRMPD) combined with ion trajectory simulations has been used to obtain probability maps of ion position as a function of different operating parameters in a quadrupole ion trap mass spectrometer. The factors that contribute to the depth of the pseudopotential trapping well are analyzed, and their effects on the efficiency of IRMPD are demonstrated. Ion trajectory simulations are used to substantiate experimental results and demonstrate in greater detail the dynamic nature of the ion population's positional distribution. In particular, it is shown that the so-called "q(z) value" used during photodissociation can be of great consequence, as can the frequency of ac trapping voltage applied to the ring electrode. The results reveal that parameters which increase the pseudopotential well have the effect of decreasing the size of the ion cloud and maximizing overlap between the irradiating laser and the ions. Thus, while the common understanding of IRMPD dictates otherwise, IRMPD fragmentation efficiencies really depend on many ion trap operating parameters, much as collision-induced dissociation does.
Collapse
Affiliation(s)
- Philip M Remes
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA
| | | |
Collapse
|
65
|
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.
Collapse
Affiliation(s)
- Jennifer S Brodbelt
- Department of Chemistry and Biochemistry, University of Texas, Austin, TX 78712, USA.
| | | |
Collapse
|
66
|
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.
Collapse
Affiliation(s)
- Lisa A Vasicek
- Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712, USA
| | | | | |
Collapse
|
67
|
Madsen JA, Brodbelt JS. Comparison of infrared multiphoton dissociation and collision-induced dissociation of supercharged peptides in ion traps. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2009; 20:349-58. [PMID: 19036605 DOI: 10.1016/j.jasms.2008.10.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Revised: 10/20/2008] [Accepted: 10/20/2008] [Indexed: 05/12/2023]
Abstract
The number and types of diagnostic ions obtained by infrared multiphoton dissociation (IRMPD) and collision-induced dissociation (CID) were evaluated for supercharged peptide ions created by electrospray ionization of solutions spiked with m-nitrobenzyl alcohol. IRMPD of supercharged peptide ions increased the sequence coverage compared with that obtained by CID for all charge states investigated. The number of diagnostic ions increased with the charge state for IRMPD; however, this trend was not consistent for CID because the supercharged ions did not always yield the greatest number of diagnostic ions. Significantly different fragmentation pathways were observed for the different charge states upon CID or IRMPD with the latter yielding far more immonium ions and often fewer uninformative ammonia, water, and phosphoric acid neutral losses. Pulsed-Q dissociation resulted in an increase in the number of internal product ions, a decrease in sequence-informative ions, and reduced overall ion abundances. The enhanced sequence coverage afforded by IRMPD of supercharged ions was demonstrated for a variety of model peptides, as well as for a tryptic digest of cytochrome c.
Collapse
Affiliation(s)
- James A Madsen
- Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712-0165, USA
| | | |
Collapse
|
68
|
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.
Collapse
Affiliation(s)
- Nicholas A Sassin
- Department of Chemistry and Chemical Physics Program, University of Nevada, Reno, Reno, Nevada, USA
| | | | | | | | | |
Collapse
|