1
|
Hatvany JB, Liyanage OT, Gallagher ES. Effect of pH on In-Electrospray Hydrogen/Deuterium Exchange of Carbohydrates and Peptides. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:441-448. [PMID: 38323552 DOI: 10.1021/jasms.3c00341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Carbohydrates are critical for cellular functions as well as an important class of metabolites. Characterizing carbohydrate structures is a difficult analytical challenge due to the presence of isomers. In-electrospray hydrogen/deuterium exchange mass spectrometry (in-ESI HDX-MS) is a method of HDX that samples the solvated structure of carbohydrates during the ESI process and requires little to no instrument modification. Traditionally, solution-phase HDX is utilized with proteins to sample conformational differences, and pH is a critical parameter to monitor and control due to the presence of both acid- and base-catalyzed mechanisms of exchange. For In-ESI HDX, the pH surrounding the analyte changes before and during labeling, which has the potential to affect the rate of labeling for analytes. Herein, we alter the pH of spray solutions containing model carbohydrates and peptides, perform in-ESI HDX-MS, and characterize the deuterium uptake trends. Varying pH results in altered D uptake, though the overall trends differ from the expected bulk-solution trends due to the electrospray process. These findings show the utility of varying pH prior to in-ESI HDX-MS for establishing different extents of HDX as well as distinguishing labile functional groups that are present in different analytes.
Collapse
Affiliation(s)
- Jacob B Hatvany
- Department of Chemistry & Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - O Tara Liyanage
- Department of Chemistry & Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - Elyssia S Gallagher
- Department of Chemistry & Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| |
Collapse
|
2
|
Schramm HM, Tamadate T, Hogan CJ, Clowers BH. Evaluation of Hydrogen-Deuterium Exchange during Transient Vapor Binding of MeOD with Model Peptide Systems Angiotensin II and Bradykinin. J Phys Chem A 2023; 127:8849-8861. [PMID: 37827113 DOI: 10.1021/acs.jpca.3c04608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
The advancement of hybrid mass spectrometric tools as an indirect probe of molecular structure and dynamics relies heavily upon a clear understanding between gas-phase ion reactivity and ion structural characteristics. This work provides new insights into gas-phase ion-neutral reactions of the model peptides (i.e., angiotensin II and bradykinin) on a per-residue basis by integrating hydrogen/deuterium exchange, ion mobility, tandem mass spectrometry, selective vapor binding, and molecular dynamics simulations. By comparing fragmentation patterns with simulated probabilities of vapor uptake, a clear link between gas-phase hydrogen/deuterium exchange and the probabilities of localized vapor association is established. The observed molecular dynamics trends related to the sites and duration of vapor binding track closely with experimental observation. Additionally, the influence of additional charges and structural characteristics on exchange kinetics and ion-neutral cluster formation is examined. These data provide a foundation for the analysis of solvation dynamics of larger, native-like conformations of proteins in the gas phase.
Collapse
Affiliation(s)
- Haley M Schramm
- Department of Chemistry, Washington State University, Pullman, Washington 99163, United States
| | - Tomoya Tamadate
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Christopher J Hogan
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Brian H Clowers
- Department of Chemistry, Washington State University, Pullman, Washington 99163, United States
| |
Collapse
|
3
|
Haidar Y, Konermann L. Effects of Hydrogen/Deuterium Exchange on Protein Stability in Solution and in the Gas Phase. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023. [PMID: 37314114 DOI: 10.1021/jasms.3c00130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Mass spectrometry (MS)-based techniques are widely used for probing protein structure and dynamics in solution. H/D exchange (HDX)-MS is one of the most common approaches in this context. HDX is often considered to be a "benign" labeling method, in that it does not perturb protein behavior in solution. However, several studies have reported that D2O pushes unfolding equilibria toward the native state. The origin, and even the existence of this protein stabilization remain controversial. Here we conducted thermal unfolding assays in solution to confirm that deuterated proteins in D2O are more stable, with 2-4 K higher melting temperatures than unlabeled proteins in H2O. Previous studies tentatively attributed this phenomenon to strengthened H-bonds after deuteration, an effect that may arise from the lower zero-point vibrational energy of the deuterated species. Specifically, it was proposed that strengthened water-water bonds (W···W) in D2O lower the solubility of nonpolar side chains. The current work takes a broader view by noting that protein stability in solution also depends on water-protein (W···P) and protein-protein (P···P) H-bonds. To help unravel these contributions, we performed collision-induced unfolding (CIU) experiments on gaseous proteins generated by native electrospray ionization. CIU profiles of deuterated and unlabeled proteins were indistinguishable, implying that P···P contacts are insensitive to deuteration. Thus, protein stabilization in D2O is attributable to solvent effects, rather than alterations of intraprotein H-bonds. Strengthening of W···W contacts represents one possible explanation, but the stabilizing effect of D2O can also originate from weakened W···P bonds. Future work will be required to elucidate which of these two scenarios is correct, or if both contribute to protein stabilization in D2O. In any case, the often-repeated adage that "D-bonds are more stable than H-bonds" does not apply to intramolecular contacts in native proteins.
Collapse
Affiliation(s)
- Yousef Haidar
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
4
|
Developments in rapid hydrogen-deuterium exchange methods. Essays Biochem 2023; 67:165-174. [PMID: 36636941 DOI: 10.1042/ebc20220174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 01/14/2023]
Abstract
Biological macromolecules, such as proteins, nucleic acids, and carbohydrates, contain heteroatom-bonded hydrogens that undergo exchange with solvent hydrogens on timescales ranging from microseconds to hours. In hydrogen-deuterium exchange mass spectrometry (HDX-MS), this exchange process is used to extract information about biomolecular structure and dynamics. This minireview focuses on millisecond timescale HDX-MS measurements, which, while less common than 'conventional' timescale (seconds to hours) HDX-MS, provide a unique window into weakly structured species, weak (or fast cycling) binding interactions, and subtle shifts in conformational dynamics. This includes intrinsically disordered proteins and regions (IDPs/IDRs) that are associated with cancer and amyloidotic neurodegenerative disease. For nucleic acids and carbohydrates, structures such as isomers, stems, and loops, can be elucidated and overall structural rigidity can be assessed. We will provide a brief overview of technical developments in rapid HDX followed by highlights of various applications, emphasising the importance of broadening the HDX timescale to improve throughput and to capture a wider range of function-relevant dynamic and structural shifts.
Collapse
|
5
|
Wu F, Wang Y, Chen Y, Li Z, Ding CF. Alkali metal ion-induced conformation changes of methionine- and leucine enkephalin investigated by gas-phase hydrogen/deuterium exchange combined with theoretical calculations. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
6
|
Hamuro Y. Tutorial: Chemistry of Hydrogen/Deuterium Exchange Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:133-151. [PMID: 33227208 DOI: 10.1021/jasms.0c00260] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Chemistry related to hydrogen/deuterium exchange-mass spectrometry (HDX-MS) for the analysis of proteins is described. First, the HDX rates of various functional groups in proteins are explained by reviewing the observed rates described in the literature, followed by estimating rates of all types of heteroatom hydrogens in proteins using proton transfer theory and the pKa values. The estimated HDX rates match well with the respective observed rates for most functional groups, with the exception of indole and amide groups. The discrepancies between the observed and estimated HDX rates for these groups are explained by the reaction mechanisms. Second, the factors that affect the HDX rates of backbone amide hydrogen, including side chain, N- and C-terminals, pH, temperature, organic solvent, and isotopes, are discussed. These factors are important for the proper design of exchange reactions and downstream process as well as the analysis and interpretation of HDX-MS data.
Collapse
Affiliation(s)
- Yoshitomo Hamuro
- ExSAR Corporation, 11 Deer Park Drive, Suite 103, Monmouth Junction, New Jersey 08852, United States
| |
Collapse
|
7
|
Sanguantrakun N, Chanthamontri C, Gross ML. Top-Down Analysis of In-Source HDX of Native Protein Ions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:1151-1154. [PMID: 32275420 PMCID: PMC7489294 DOI: 10.1021/jasms.9b00149] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Hydrogen/deuterium exchange (HDX) is used in protein biophysics to probe folding dynamics, intermolecular interactions, epitope and other mapping. A typical procedure often involves HDX in buffered D2O solution followed by pepsin digestion, and liquid chromatography/electrospray ionization mass spectrometry analysis. In this work, HDX of protein ions was conducted in the ESI source. Both native electrospray droplets of ubiquitin and denatured myoglobin were exposed to D2O vapor in the source region of a Bruker SolariX 12T FTICR-mass spectrometer. Electron capture dissociation was used to assess deuterium incorporation at the residue level. This in-source HDX, on the millisecond-time scale, exchanges side-chain hydrogens and fast-exchanging amides compared to conventional minutes-to-hours HDX of backbone hydrogens in solution with less sample preparation (i.e., no D2O/protein mixing and incubation, no quenching, protein digestion, or LC separation).
Collapse
Affiliation(s)
- Nawaporn Sanguantrakun
- Department of Basic Sciences, St. Louis College of Pharmacy, St. Louis, MO 63110
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130
| | - Chamnongsak Chanthamontri
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130
- Millipore Sigma, 2909 Laclede Avenue, St. Louis, MO 63103
| | - Michael L. Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130
| |
Collapse
|
8
|
Arndt JR, Chaibva M, Beasley M, Karanji AK, Kondalaji SG, Khakinejad M, Sarver O, Legleiter J, Valentine SJ. Nucleation Inhibition of Huntingtin Protein (htt) by Polyproline PPII Helices: A Potential Interaction with the N-Terminal α-Helical Region of Htt. Biochemistry 2020; 59:436-449. [PMID: 31814404 PMCID: PMC7344267 DOI: 10.1021/acs.biochem.9b00689] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Huntington's disease is a genetic neurodegenerative disorder characterized by the formation of amyloid fibrils of the huntingtin protein (htt). The 17-residue N-terminal region of htt (Nt17) has been implicated in the formation of early phase oligomeric species, which may be neurotoxic. Because tertiary interactions with a downstream (C-terminal) polyproline (polyP) region of htt may disrupt the formation of oligomers, which are precursors to fibrillar species, the effect of co-incubation of a region of htt with a 10-residue polyP peptide on oligomerization and fibrillization has been examined by atomic force microscopy. From multiple, time-course experiments, morphological changes in oligomeric species are observed for the protein/peptide mixture and compared with the protein alone. Additionally, an overall decrease in fibril formation is observed for the heterogeneous mixture. To consider potential sites of interaction between the Nt17 region and polyP, mixtures containing Nt17 and polyP peptides have been examined by ion mobility spectrometry and gas-phase hydrogen-deuterium exchange coupled with mass spectrometry. These data combined with molecular dynamics simulations suggest that the C-terminal region of Nt17 may be a primary point of contact. One interpretation of the results is that polyP may possibly regulate Nt17 by inducing a random coil region in the C-terminal portion of Nt17, thus decreasing the propensity to form the reactive amphipathic α-helix. A separate interpretation is that the residues important for helix-helix interactions are blocked by polyP association.
Collapse
Affiliation(s)
- James R Arndt
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Maxmore Chaibva
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Maryssa Beasley
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Ahmad Kiani Karanji
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Samaneh Ghassabi Kondalaji
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Mahdiar Khakinejad
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Olivia Sarver
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Justin Legleiter
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
- WV Nano Safe Iniative, West Virginia University, Morgantown, West Virginia 26506, United States
- The Center for Neuroscience, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Stephen J Valentine
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| |
Collapse
|
9
|
Wang Q, Borotto NB, Håkansson K. Gas-Phase Hydrogen/Deuterium Scrambling in Negative-Ion Mode Tandem Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:855-863. [PMID: 30805882 PMCID: PMC6680243 DOI: 10.1007/s13361-019-02143-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 01/12/2019] [Accepted: 01/22/2019] [Indexed: 06/07/2023]
Abstract
Hydrogen/deuterium exchange coupled with mass spectrometry (HDX MS) has become a powerful method to characterize protein conformational dynamics. Workflows typically utilize pepsin digestion prior to MS analysis to yield peptide level structural resolution. Tandem mass spectrometry (MS/MS) can potentially facilitate determination of site-specific deuteration to single-residue resolution. However, to be effective, MS/MS activation must minimize the occurrence of gas-phase intramolecular randomization of solution-generated deuterium labels. While significant work has focused on understanding this process in positive-ion mode, little is known about hydrogen/deuterium (H/D) scrambling processes in negative-ion mode. Here, we utilize selectively deuterated model peptides to investigate the extent of intramolecular H/D scrambling upon several negative-ion mode MS/MS techniques, including negative-ion collision-induced dissociation (nCID), electron detachment dissociation (EDD), negative-ion free radical-initiated peptide sequencing (nFRIPS), and negative-ion electron capture dissociation (niECD). H/D scrambling was extensive in deprotonated peptides upon nCID and nFRIPS. In fact, the energetics required to induce dissociation in nCID are sufficient to allow histidine C-2 and Cβ hydrogen atoms to participate in the scrambling process. EDD and niECD demonstrated moderate H/D scrambling with niECD being superior in terms of minimizing hydrogen migration, achieving ~ 30% scrambling levels for small c-type fragment ions. We believe the observed scrambling is likely due to activation during ionization and ion transport rather than during the niECD event itself.
Collapse
Affiliation(s)
- Qingyi Wang
- Department of Chemistry, University of Michigan, 930 N University Avenue, Ann Arbor, MI, 48109-1055, USA
| | - Nicholas B Borotto
- Department of Chemistry, University of Michigan, 930 N University Avenue, Ann Arbor, MI, 48109-1055, USA.
| | - Kristina Håkansson
- Department of Chemistry, University of Michigan, 930 N University Avenue, Ann Arbor, MI, 48109-1055, USA.
| |
Collapse
|
10
|
Straus RN, Jockusch RA. Hydrogen-Deuterium Exchange and Electron Capture Dissociation to Interrogate the Conformation of Gaseous Melittin Ions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:864-875. [PMID: 30834508 DOI: 10.1007/s13361-019-02150-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 02/04/2019] [Accepted: 02/05/2019] [Indexed: 06/09/2023]
Abstract
There is a need in the field of biological mass spectrometry for structural tools which can report on regional, rather than solely global, structure of gaseous protein ions. Site-specific hydrogen-deuterium (H/D) exchange has shown promise in fulfilling this need, but requires additional method development to prove its utility. In this study, we use H/D exchange and electron capture dissociation (ECD) to probe the gaseous structure of two peptides which are α-helical in solution and which differ by a single point mutation. Global H/D exchange levels, ECD fragmentation profiles, and region specific H/D exchange profiles are compared between wild type (WT) melittin, which adopts a hinged helix conformation in solution, and a mutant P14A melittin which folds into a single helix in solution. High protection from H/D exchange by both peptides is consistent with retention of secondary structure in the gas phase (or refolding into some other compact structure). The P14A mutant melittin exhibits lower ECD fragmentation efficiency than WT melittin, suggesting that it contains more secondary structure in the gas phase, which may indicate that these peptides retain some memory of their solution-phase structures. Examination of the isotopic distributions of fragment ions derived from H/D exchange with subsequent ECD reveals that the C-terminus of these peptides adopts multiple conformations. The results reported here offer insight into the stability of alpha helices in the gas phase, and also highlight the value of combining gas-phase H/D exchange with electron capture dissociation to interrogate gaseous peptide conformation.
Collapse
Affiliation(s)
- Rita N Straus
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada
| | - Rebecca A Jockusch
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada.
| |
Collapse
|
11
|
Hamuro Y, Zhang T. High-Resolution HDX-MS of Cytochrome c Using Pepsin/Fungal Protease Type XIII Mixed Bed Column. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:227-234. [PMID: 30374663 DOI: 10.1007/s13361-018-2087-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 10/05/2018] [Accepted: 10/08/2018] [Indexed: 06/08/2023]
Abstract
A pepsin/FPXIII (protease from Aspergillus saitoi, type XIII) mixed bed column significantly improved the resolution of bottom-up hydrogen/deuterium exchange mass spectrometry (HDX-MS) data compared with a pepsin-only column. The HDX-MS method using the mixed bed column determined 65 amide hydrogen exchange rates out of one hundred cytochrome c backbone amide hydrogens. Different cleavage specificities of the two enzymes generated 138 unique high-quality peptic fragments, which allows fine sub-localization of deuterium. The exchange rates determined in this method are consistent within the current study as well as with the previous HDX-NMR study. High-resolution HDX-MS data can determine the exchange rate of each residue not the deuterium buildup curve of a peptic fragment. The exchange rates provide more precise and quantitative measurements of protein dynamics in a more reproducible manner. Graphical Abstract ᅟ.
Collapse
Affiliation(s)
- Yoshitomo Hamuro
- SGS Life North America, 606 Brandywine Parkway, West Chester, PA, 19380, USA.
- Janssen Pharmaceutical, 1400 McKean Road, Spring House, PA, 19477, USA.
| | - Terry Zhang
- Thermo Fisher Scientific, 355 River Oaks Parkway, San Jose, CA, 95134, USA
| |
Collapse
|
12
|
Mistarz UH, Chandler SA, Brown JM, Benesch JLP, Rand KD. Probing the Dissociation of Protein Complexes by Means of Gas-Phase H/D Exchange Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:45-57. [PMID: 30460642 DOI: 10.1007/s13361-018-2064-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 08/29/2018] [Accepted: 08/30/2018] [Indexed: 05/16/2023]
Abstract
Gas-phase hydrogen/deuterium exchange measured by mass spectrometry (gas-phase HDX-MS) is a fast method to probe the conformation of protein ions. The use of gas-phase HDX-MS to investigate the structure and interactions of protein complexes is however mostly unharnessed. Ionizing proteins under conditions that maximize preservation of their native structure (native MS) enables the study of solution-like conformation for milliseconds after electrospray ionization (ESI), which enables the use of ND3-gas inside the mass spectrometer to rapidly deuterate heteroatom-bound non-amide hydrogens. Here, we explored the utility of gas-phase HDX-MS to examine protein-protein complexes and inform on their binding surface and the structural consequences of gas-phase dissociation. Protein complexes ranging from 24 kDa dimers to 395 kDa 24mers were analyzed by gas-phase HDX-MS with subsequent collision-induced dissociation (CID). The number of exchangeable sites involved in complex formation could, therefore, be estimated. For instance, dimers of cytochrome c or α-lactalbumin incorporated less deuterium/subunit than their unbound monomer counterparts, providing a measure of the number of heteroatom-bound side-chain hydrogens involved in complex formation. We furthermore studied if asymmetric charge-partitioning upon dissociation of protein complexes caused intermolecular H/D migration. In larger multimeric protein complexes, the dissociated monomer showed a significant increase in deuterium. This indicates that intermolecular H/D migration occurs as part of the asymmetric partitioning of charge during CID. We discuss several models that may explain this increase deuterium content and find that a model where only deuterium involved in migrating charge can account for most of the deuterium enrichment observed on the ejected monomer. In summary, the deuterium content of the ejected subunit can be used to estimate that of the intact complex with deviations observed for large complexes accounted for by charge migration. Graphical abstract ᅟ.
Collapse
Affiliation(s)
- Ulrik H Mistarz
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark
| | - Shane A Chandler
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK
| | - Jeffery M Brown
- Waters Corporation, Stamford Avenue, Altrincham Road, Wilmslow, SK9 4AX, UK
| | - Justin L P Benesch
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK.
| | - Kasper D Rand
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark.
| |
Collapse
|
13
|
Karanji AK, Khakinejad M, Kondalaji SG, Majuta SN, Attanayake K, Valentine SJ. Comparison of Peptide Ion Conformers Arising from Non-Helical and Helical Peptides Using Ion Mobility Spectrometry and Gas-Phase Hydrogen/Deuterium Exchange. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:2402-2412. [PMID: 30324261 PMCID: PMC6553874 DOI: 10.1007/s13361-018-2053-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 07/17/2018] [Accepted: 08/03/2018] [Indexed: 05/06/2023]
Abstract
The dominant gas-phase conformer of [M+3H]3+ ions of the model peptide acetyl-PSSSSKSSSSKSSSSKSSSSK has been examined with ion mobility spectrometry (IMS), gas-phase hydrogen deuterium exchange (HDX), and mass spectrometry (MS) techniques. The [M+3H]3+ peptide ions are observed predominantly as a relatively compact conformer type. Upon subjecting these ions to electron transfer dissociation (ETD), the level of protection for each amino acid residue in the peptide sequence is assessed. The overall per-residue deuterium uptake is observed to be relatively more efficient for the neutral residues than for the model peptide acetyl-PAAAAKAAAAKAAAAKAAAAK. In comparison, the N-terminal and C-terminal regions of the serine peptide show greater relative protection compared with interior residues. Molecular dynamics (MD) simulations have been used to generate candidate structures for collision cross section and HDX reactivity matching. Hydrogen accessibility scoring (HAS) for select structural candidates from MD simulations has been used to suggest conformer types that could contribute to the observed HDX patterns. The results are discussed with respect to recent studies employing extensive MD simulations of gas-phase structure establishment of a peptide system. Graphical Abstract ᅟ.
Collapse
Affiliation(s)
- Ahmad Kiani Karanji
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Mahdiar Khakinejad
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, 21218, USA
| | | | - Sandra N Majuta
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Kushani Attanayake
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Stephen J Valentine
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA.
| |
Collapse
|
14
|
Mistarz UH, Rand KD. Installation, validation, and application examples of two instrumental setups for gas-phase HDX-MS analysis of peptides and proteins. Methods 2018; 144:113-124. [PMID: 29753788 DOI: 10.1016/j.ymeth.2018.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/17/2018] [Accepted: 05/04/2018] [Indexed: 01/15/2023] Open
Abstract
Gas-phase hydrogen/deuterium exchange measured by mass spectrometry in a millisecond timeframe after ESI (gas-phase HDX-MS) is a fast and sensitive, yet unharnessed method to analyze the primary- and higher-order structure, intramolecular and intermolecular interactions, surface properties, and charge location of peptides and proteins. During a gas-phase HDX-MS experiment, heteroatom-bound non-amide hydrogens are made to exchange with deuterium during a millisecond timespan after electrospray ionization (ESI) by reaction with the highly basic reagent ND3, enabling conformational analysis of protein states that are pertinent to the native solution-phase. Here, we describe two different instrumental approaches to enable gas-phase HDX-MS for analysis of peptides and proteins on high-resolution Q-TOF mass spectrometers. We include a description of the procedure and equipment required for successful installation as well as suggested procedures for testing, validation, and troubleshooting of a gas-phase HDX-MS setup. In the two described approaches, gas-phase HDX-MS are performed either immediately after ESI in the cone exit region by leading N2-gas over a deuterated ND3/D2O solution, or by leading purified ND3-gas into different traveling wave ion guides (TWIG) of the mass spectrometer. We envision that a detailed description of the two gas-phase HDX-MS setups and their practical implementation and validation can pave the way for gas-phase HDX-MS to become a more routinely used MS technique for structural analysis of peptides and proteins.
Collapse
Affiliation(s)
- Ulrik H Mistarz
- Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark
| | - Kasper D Rand
- Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark.
| |
Collapse
|
15
|
Hamuro Y, E SY. Determination of Backbone Amide Hydrogen Exchange Rates of Cytochrome c Using Partially Scrambled Electron Transfer Dissociation Data. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:989-1001. [PMID: 29500740 DOI: 10.1007/s13361-018-1892-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 01/08/2018] [Accepted: 01/08/2018] [Indexed: 06/08/2023]
Abstract
The technological goal of hydrogen/deuterium exchange-mass spectrometry (HDX-MS) is to determine backbone amide hydrogen exchange rates. The most critical challenge to achieve this goal is obtaining the deuterium incorporation in single-amide resolution, and gas-phase fragmentation may provide a universal solution. The gas-phase fragmentation may generate the daughter ions which differ by a single amino acid and the difference in deuterium incorporations in the two analogous ions can yield the deuterium incorporation at the sub-localized site. Following the pioneering works by Jørgensen and Rand, several papers utilized the electron transfer dissociation (ETD) to determine the location of deuterium in single-amide resolution. This paper demonstrates further advancement of the strategy by determining backbone amide hydrogen exchange rates, instead of just determining deuterium incorporation at a single time point, in combination with a wide time window monitoring. A method to evaluate the effects of scrambling and to determine the exchange rates from partially scrambled HDX-ETD-MS data is described. All parent ions for ETD fragmentation were regio-selectively scrambled: The deuterium in some regions of a peptide ion was scrambled while that in the other regions was not scrambled. The method determined 31 backbone amide hydrogen exchange rates of cytochrome c in the non-scrambled regions. Good fragmentation of a parent ion, a low degree of scrambling, and a low number of exchangeable hydrogens in the preceding side chain are the important factors to determine the exchange rate. The exchange rates determined by the HDX-MS are in good agreement with those determined by NMR. Graphical Abstract ᅟ.
Collapse
Affiliation(s)
- Yoshitomo Hamuro
- ExSAR Corporation, 11 Deer Park Drive, Suite 103, Monmouth Junction, NJ, 08852, USA.
- SGS Life North America, 606 Brandywine Parkway, West Chester, PA, 19380, USA.
| | - Sook Yen E
- ExSAR Corporation, 11 Deer Park Drive, Suite 103, Monmouth Junction, NJ, 08852, USA
- Regeneron, 777 Old Saw Mill River Road, Tarrytown, NY, 10591, USA
| |
Collapse
|
16
|
Maleki H, Karanji AK, Majuta S, Maurer MM, Valentine SJ. Ion Mobility Spectrometry-Mass Spectrometry Coupled with Gas-Phase Hydrogen/Deuterium Exchange for Metabolomics Analyses. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:230-241. [PMID: 28956290 PMCID: PMC5942887 DOI: 10.1007/s13361-017-1798-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 08/22/2017] [Accepted: 08/26/2017] [Indexed: 05/11/2023]
Abstract
Ion mobility spectrometry-mass spectrometry (IMS-MS) in combination with gas-phase hydrogen/deuterium exchange (HDX) and collision-induced dissociation (CID) is evaluated as an analytical method for small-molecule standard and mixture characterization. Experiments show that compound ions exhibit unique HDX reactivities that can be used to distinguish different species. Additionally, it is shown that gas-phase HDX kinetics can be exploited to provide even further distinguishing capabilities by using different partial pressures of reagent gas. The relative HDX reactivity of a wide variety of molecules is discussed in light of the various molecular structures. Additionally, hydrogen accessibility scoring (HAS) and HDX kinetics modeling of candidate (in silico) ion structures is utilized to estimate the relative ion conformer populations giving rise to specific HDX behavior. These data interpretation methods are discussed with a focus on developing predictive tools for HDX behavior. Finally, an example is provided in which ion mobility information is supplemented with HDX reactivity data to aid identification efforts of compounds in a metabolite extract. Graphical Abstract ᅟ.
Collapse
Affiliation(s)
- Hossein Maleki
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Ahmad K Karanji
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Sandra Majuta
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Megan M Maurer
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Stephen J Valentine
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA.
| |
Collapse
|
17
|
Chandler SA, Benesch JL. Mass spectrometry beyond the native state. Curr Opin Chem Biol 2017; 42:130-137. [PMID: 29288996 DOI: 10.1016/j.cbpa.2017.11.019] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/27/2017] [Accepted: 11/30/2017] [Indexed: 12/31/2022]
Abstract
Native mass spectrometry allows the study of proteins by probing in vacuum the interactions they form in solution. It is a uniquely useful approach for structural biology and biophysics due to the high resolution of separation it affords, allowing the concomitant interrogation of multiple protein components with high mass accuracy. At its most basic, native mass spectrometry reports the mass of intact proteins and the assemblies they form in solution. However, the opportunities for more detailed characterisation are extensive, enabled by the exquisite control of ion motion that is possible in vacuum. Here we describe recent developments in mass spectrometry approaches to the structural interrogation of proteins both in, and beyond, their native state.
Collapse
Affiliation(s)
- Shane A Chandler
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
| | - Justin Lp Benesch
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK.
| |
Collapse
|
18
|
Khakinejad M, Ghassabi Kondalaji S, Tafreshian A, Valentine SJ. Comprehensive Gas-Phase Peptide Ion Structure Studies Using Ion Mobility Techniques: Part 2. Gas-Phase Hydrogen/Deuterium Exchange for Ion Population Estimation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:960-970. [PMID: 28315238 PMCID: PMC5656063 DOI: 10.1007/s13361-017-1641-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/23/2017] [Accepted: 02/25/2017] [Indexed: 05/09/2023]
Abstract
Gas-phase hydrogen/deuterium exchange (HDX) using D2O reagent and collision cross-section (CCS) measurements are utilized to monitor the ion conformers of the model peptide acetyl-PAAAAKAAAAKAAAAKAAAAK. The measurements are carried out on a home-built ion mobility instrument coupled to a linear ion trap mass spectrometer containing electron transfer dissociation (ETD) capabilities. ETD is utilized to obtain per-residue deuterium uptake data for select ion conformers, and a new algorithm is presented for interpreting the HDX data. Using molecular dynamics (MD) production data and a hydrogen accessibility scoring (HAS)-number of effective collisions (NEC) model, hypothetical HDX behavior is attributed to various in-silico candidate (CCS match) structures. The HAS-NEC model is applied to all candidate structures, and non-negative linear regression is employed to determine structure contributions resulting in the best match to deuterium uptake. The accuracy of the HAS-NEC model is tested with the comparison of predicted and experimental isotopic envelopes for several of the observed c-ions. It is proposed that gas-phase HDX can be utilized effectively as a second criterion (after CCS matching) for filtering suitable MD candidate structures. In this study, the second step of structure elucidation, 13 nominal structures were selected (from a pool of 300 candidate structures) and each with a population contribution proposed for these ions. Graphical Abstract ᅟ.
Collapse
Affiliation(s)
- Mahdiar Khakinejad
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | | | - Amirmahdi Tafreshian
- Department of Statistics, West Virginia University, P.O. Box 6330, Morgantown, WV, 26506, USA
| | - Stephen J Valentine
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA.
| |
Collapse
|
19
|
Straus RN, Jockusch RA. Probing the Gaseous Structure of a β-Hairpin Peptide with H/D Exchange and Electron Capture Dissociation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:358-369. [PMID: 27943124 DOI: 10.1007/s13361-016-1528-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 10/05/2016] [Accepted: 10/10/2016] [Indexed: 06/06/2023]
Abstract
An improved understanding of the extent to which native protein structure is retained upon transfer to the gas phase promises to enhance biological mass spectrometry, potentially streamlining workflows and providing fundamental insights into hydration effects. Here, we investigate the gaseous conformation of a model β-hairpin peptide using gas-phase hydrogen-deuterium (H/D) exchange with subsequent electron capture dissociation (ECD). Global gas-phase H/D exchange levels, and residue-specific exchange levels derived from ECD data, are compared among the wild type 16-residue peptide GB1p and several variants. High protection from H/D exchange observed for GB1p, but not for a truncated version, is consistent with the retention of secondary structure of GB1p in the gas phase or its refolding into some other compact structure. Four alanine mutants that destabilize the hairpin in solution show levels of protection similar to that of GB1p, suggesting collapse or (re)folding of these peptides upon transfer to the gas phase. These results offer a starting point from which to understand how a key secondary structural element, the β-hairpin, is affected by transfer to the gas phase. This work also demonstrates the utility of a much-needed addition to the tool set that is currently available for the investigation of the gaseous conformation of biomolecules, which can be employed in the future to better characterize gaseous proteins and protein complexes. Graphical Abstract ᅟ.
Collapse
Affiliation(s)
- Rita N Straus
- Department of Chemistry, University of Toronto, Toronto, ON, M5S 3H6, Canada
| | - Rebecca A Jockusch
- Department of Chemistry, University of Toronto, Toronto, ON, M5S 3H6, Canada.
| |
Collapse
|
20
|
Mistarz UH, Brown JM, Haselmann KF, Rand KD. Probing the Binding Interfaces of Protein Complexes Using Gas-Phase H/D Exchange Mass Spectrometry. Structure 2015; 24:310-8. [PMID: 26749447 DOI: 10.1016/j.str.2015.11.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 11/16/2015] [Accepted: 11/23/2015] [Indexed: 12/20/2022]
Abstract
Fast gas-phase hydrogen/deuterium exchange mediated by ND3 gas and measured by mass spectrometry (gas-phase HDX-MS) is a largely unharnessed, fast, and sensitive method for probing primary- and higher-order polypeptide structure. Labeling of heteroatom-bound non-amide hydrogens in a sub-millisecond time span after electrospray ionization by ND3 gas can provide structural insights into protein conformers present in solution. Here, we have explored the use of gas-phase HDX-MS for probing the higher-order structure and binding interfaces of protein complexes originating from native solution conditions. Lysozyme ions bound by an oligosaccharide incorporated less deuterium than the unbound ion. Similarly, trypsin ions showed reduced deuterium uptake when bound by the peptide ligand vasopressin. Our results are in good agreement with crystal structures of the native protein complexes, and illustrate that gas-phase HDX-MS can provide a sensitive and simple approach to measure the number of heteroatom-bound non-amide side-chain hydrogens involved in the binding interface of biologically relevant protein complexes.
Collapse
Affiliation(s)
- Ulrik H Mistarz
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, Copenhagen 2100, Denmark
| | - Jeffery M Brown
- Waters MS Technologies Centre, Waters Corporation, Altrincham Road, Wilmslow SK9 4AX, UK
| | - Kim F Haselmann
- Diabetes Protein Engineering, Novo Nordisk A/S, Novo Nordisk Park 1, Måløv 2670, Denmark
| | - Kasper D Rand
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, Copenhagen 2100, Denmark.
| |
Collapse
|
21
|
Schennach M, Breuker K. Probing Protein Structure and Folding in the Gas Phase by Electron Capture Dissociation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:1059-67. [PMID: 25868904 PMCID: PMC4475247 DOI: 10.1007/s13361-015-1088-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 01/19/2015] [Accepted: 01/27/2015] [Indexed: 05/11/2023]
Abstract
The established methods for the study of atom-detailed protein structure in the condensed phases, X-ray crystallography and nuclear magnetic resonance spectroscopy, have recently been complemented by new techniques by which nearly or fully desolvated protein structures are probed in gas-phase experiments. Electron capture dissociation (ECD) is unique among these as it provides residue-specific, although indirect, structural information. In this Critical Insight article, we discuss the development of ECD for the structural probing of gaseous protein ions, its potential, and limitations.
Collapse
Affiliation(s)
- Moritz Schennach
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Kathrin Breuker
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| |
Collapse
|
22
|
Khakinejad M, Kondalaji SG, Tafreshian A, Valentine SJ. Gas-Phase Hydrogen-Deuterium Exchange Labeling of Select Peptide Ion Conformer Types: a Per-Residue Kinetics Analysis. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:1115-1127. [PMID: 25895891 DOI: 10.1007/s13361-015-1127-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 02/26/2015] [Accepted: 03/05/2015] [Indexed: 06/04/2023]
Abstract
The per-residue, gas-phase hydrogen deuterium exchange (HDX) kinetics for individual amino acid residues on selected ion conformer types of the model peptide KKDDDDDIIKIIK have been examined using ion mobility spectrometry (IMS) and HDX-tandem mass spectrometry (MS/MS) techniques. The [M + 4H](4+) ions exhibit two major conformer types with collision cross sections of 418 Å(2) and 446 Å(2); the [M + 3H](3+) ions also yield two different conformer types having collision cross sections of 340 Å(2) and 367 Å(2). Kinetics plots of HDX for individual amino acid residues reveal fast- and slow-exchanging hydrogens. The contributions of each amino acid residue to the overall conformer type rate constant have been estimated. For this peptide, N- and C-terminal K residues exhibit the greatest contributions for all ion conformer types. Interior D and I residues show decreased contributions. Several charge state trends are observed. On average, the D residues of the [M + 3H](3+) ions show faster HDX rate contributions compared with [M + 4H](4+) ions. In contrast the interior I8 and I9 residues show increased accessibility to exchange for the more elongated [M + 4H](4+) ion conformer type. The contribution of each residue to the overall uptake rate showed a good correlation with a residue hydrogen accessibility score model calculated using a distance from charge site and initial incorporation site for nominal structures obtained from molecular dynamic simulations (MDS).
Collapse
Affiliation(s)
- Mahdiar Khakinejad
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | | | | | | |
Collapse
|
23
|
Beeston HS, Ault JR, Pringle SD, Brown JM, Ashcroft AE. Changes in protein structure monitored by use of gas-phase hydrogen/deuterium exchange. Proteomics 2015; 15:2842-50. [PMID: 25603979 PMCID: PMC4973844 DOI: 10.1002/pmic.201400440] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 12/15/2014] [Accepted: 01/15/2015] [Indexed: 12/02/2022]
Abstract
The study of protein conformation by solution‐phase hydrogen/deuterium exchange (HDX) coupled to MS is well documented. This involves monitoring the exchange of backbone amide protons with deuterium and provides details concerning the protein's tertiary structure. However, undesired back‐exchange during post‐HDX analyses can be difficult to control. Here, gas‐phase HDX‐MS, during which labile hydrogens on amino acid side chains are exchanged in sub‐millisecond time scales, has been employed to probe changes within protein structures. Addition of the solvent 2,2,2‐trifluoroethanol to a protein in solution can affect the structure of the protein, resulting in an increase in secondary and/or tertiary structure which is detected using circular dichroism. Using a Synapt G2‐S ESI‐mass spectrometer modified to allow deuterated ammonia into the transfer ion guide (situated between the ion mobility cell and the TOF analyser), gas‐phase HDX‐MS is shown to reflect minor structural changes experienced by the proteins β‐lactoglobulin and ubiquitin, as observed by the reduction in the level of deuterium incorporation. Additionally, the use of gas‐phase HDX‐MS to distinguish between co‐populated proteins conformers within a solution is demonstrated with the disordered protein calmodulin; the gas‐phase HDX‐MS results correspond directly with complementary data obtained by use of ion mobility spectrometry‐MS.
Collapse
Affiliation(s)
- Helen S Beeston
- Astbury Centre for Structural Molecular Biology & Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - James R Ault
- Astbury Centre for Structural Molecular Biology & Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | | | | | - Alison E Ashcroft
- Astbury Centre for Structural Molecular Biology & Faculty of Biological Sciences, University of Leeds, Leeds, UK
| |
Collapse
|
24
|
McMahon TB, Ohanessian G. Probing the mechanisms and dynamics of gas phase hydrogen-deuterium exchange reactions of sodiated polyglycines. Phys Chem Chem Phys 2015; 17:4237-49. [PMID: 25573245 DOI: 10.1039/c4cp03960b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The rate constants for H-D exchange reactions of sodiated polyglycines (GnNa(+), n = 2-8) and polyalanines (AnNa(+), n = 2, 3 and 5) with ND3 have been measured in the cell of an FT-ICR mass spectrometer. All peptides except G2Na(+) are found to undergo three exchange reactions, all of which are consecutive with no sign of multiple exchanges within a single collision event. This information has been used to construct full mechanistic scenarios with the help of detailed quantum chemical calculations of the possible reaction paths for H-D exchange. The first exchange is always located at the C terminus however with different mechanisms depending upon whether the peptide termini can (larger peptides) or cannot (smaller peptides) interact directly without strong energy penalty. The most favourable mechanisms for the second and third exchanges of the N terminus protons, are found to be different from those for the first for all peptide sizes. The peptide distortions that are necessary in order for some of these reactions to occur are made possible by the energy reservoir provided by the favorable interaction of the peptide ion with ND3. Their occurrence and variety preclude any general relationship between H-D exchange kinetics and the most stable ion structures. There is however a break at G7Na(+) in the kinetics trend, with a first exchange rate which is much smaller than for all other peptide sizes. This break can be directly related to a different structural type in which the C terminus is neither free nor close to the N terminus.
Collapse
Affiliation(s)
- T B McMahon
- Laboratoire de Chimie Moléculaire, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex, France.
| | | |
Collapse
|
25
|
Kostyukevich Y, Kononikhin A, Popov I, Spasskiy A, Nikolaev E. In ESI-source H/D exchange under atmospheric pressure for peptides and proteins of different molecular weights from 1 to 66 kDa: the role of the temperature of the desolvating capillary on H/D exchange. JOURNAL OF MASS SPECTROMETRY : JMS 2015; 50:49-55. [PMID: 25601674 DOI: 10.1002/jms.3535] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 10/17/2014] [Accepted: 10/26/2014] [Indexed: 06/04/2023]
Abstract
Transition of proteins from the solution to the gas phase during electrospray ionization remains a challenging problem despite the large amount of attention it has received during the past few decades. One of the major questions relates to the extent to which proteins in the gas phase retain their condensed phase structures. We have used in-electrospray source hydrogen/deuterium exchange to determine the number of deuterium incorporations as a function of protein mass, charge state and temperature of the desolvating capillary where the reaction occurs. All experiments were performed on a Thermo LTQ FT Ultra equipped with a 7-T superconducting magnet. Ions were generated by an IonMax Electrospray ion source operated in the positive ESI mode. Deuterium exchange was performed by introducing a droplet of D2 O beneath the ESI capillary. We systematically investigated gas phase hydrogen/deuterium (H/D) exchange under atmospheric pressure for peptides and proteins of different molecular weights from 1 to 66 kDa. We observed that almost all proteins demonstrate similar exchange rates for all charge states and that these rates increase exponentially with the temperature of the desolvating capillary. We did not observe any clear correlation of the number of H/D exchanges with the value of the cross section for a corresponding charge state. We have demonstrated the possibility of performing in-ESI source H/D exchange of large proteins under atmospheric pressure. The simplicity of the experimental setup makes it a useful experimental technique that can be applied for the investigation of gas phase conformations of proteins.
Collapse
Affiliation(s)
- Yury Kostyukevich
- Institute for Energy Problems of Chemical Physics, Russian Academy of Sciences, Leninskij pr., 38k.2, 119334, Moscow, Russia; Moscow Institute of Physics and Technology, 141700, Dolgoprudnyi, Moscow Region, Russia; Skolkovo Institute of Science and Technology, Novaya St., 100, Skolkovo, 143025, Russian Federation
| | | | | | | | | |
Collapse
|
26
|
Mistarz UH, Brown JM, Haselmann KF, Rand KD. Simple setup for gas-phase H/D exchange mass spectrometry coupled to electron transfer dissociation and ion mobility for analysis of polypeptide structure on a liquid chromatographic time scale. Anal Chem 2014; 86:11868-76. [PMID: 25375223 DOI: 10.1021/ac5035456] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Gas-phase hydrogen/deuterium exchange (HDX) is a fast and sensitive, yet unharnessed analytical approach for providing information on the structural properties of biomolecules, in a complementary manner to mass analysis. Here, we describe a simple setup for ND3-mediated millisecond gas-phase HDX inside a mass spectrometer immediately after ESI (gas-phase HDX-MS) and show utility for studying the primary and higher-order structure of peptides and proteins. HDX was achieved by passing N2-gas through a container filled with aqueous deuterated ammonia reagent (ND3/D2O) and admitting the saturated gas immediately upstream or downstream of the primary skimmer cone. The approach was implemented on three commercially available mass spectrometers and required no or minor fully reversible reconfiguration of gas-inlets of the ion source. Results from gas-phase HDX-MS of peptides using the aqueous ND3/D2O as HDX reagent indicate that labeling is facilitated exclusively through gaseous ND3, yielding similar results to the infusion of purified ND3-gas, while circumventing the complications associated with the use of hazardous purified gases. Comparison of the solution-phase- and gas-phase deuterium uptake of Leu-Enkephalin and Glu-Fibrinopeptide B, confirmed that this gas-phase HDX-MS approach allows for labeling of sites (heteroatom-bound non-amide hydrogens located on side-chains, N-terminus and C-terminus) not accessed by classical solution-phase HDX-MS. The simple setup is compatible with liquid chromatography and a chip-based automated nanoESI interface, allowing for online gas-phase HDX-MS analysis of peptides and proteins separated on a liquid chromatographic time scale at increased throughput. Furthermore, online gas-phase HDX-MS could be performed in tandem with ion mobility separation or electron transfer dissociation, thus enabling multiple orthogonal analyses of the structural properties of peptides and proteins in a single automated LC-MS workflow.
Collapse
Affiliation(s)
- Ulrik H Mistarz
- Department of Pharmacy, University of Copenhagen , Universitetsparken 2, 2100 Copenhagen, Denmark
| | | | | | | |
Collapse
|
27
|
Marciano DP, Dharmarajan V, Griffin PR. HDX-MS guided drug discovery: small molecules and biopharmaceuticals. Curr Opin Struct Biol 2014; 28:105-11. [PMID: 25179005 DOI: 10.1016/j.sbi.2014.08.007] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 07/24/2014] [Accepted: 08/13/2014] [Indexed: 12/24/2022]
Abstract
Hydrogen/deuterium exchange coupled with mass spectrometry (HDX-MS or DXMS) has emerged as an important tool for the development of small molecule therapeutics and biopharmaceuticals. Central to these advances have been improvements to automated HDX-MS platforms and software that allow for the rapid acquisition and processing of experimental data. Correlating the HDX-MS profile of large numbers of ligands with their functional outputs has enabled the development of structure activity relationships (SAR) and delineation of ligand classes based on functional selectivity. HDX-MS has also been applied to address many of the unique challenges posed by the continued emergence of biopharmaceuticals. Here we review the latest applications of HDX-MS to drug discovery, recent advances in technology and software, and provide perspective on future outlook.
Collapse
Affiliation(s)
- David P Marciano
- Molecular Therapeutics Department, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, United States
| | | | - Patrick R Griffin
- Molecular Therapeutics Department, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, United States.
| |
Collapse
|
28
|
Morrison LJ, Chamot-Rooke J, Wysocki VH. IR action spectroscopy shows competitive oxazolone and diketopiperazine formation in peptides depends on peptide length and identity of terminal residue in the departing fragment. Analyst 2014; 139:2137-43. [PMID: 24618890 PMCID: PMC6467643 DOI: 10.1039/c4an00064a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The interplay between the entropically and enthalpically favored products of peptide fragmentation is probed using a combined experimental and theoretical approach. These b2 ion products can take either an oxazolone or diketopiperazine structure. Cleavage after the second amide bond is often a favorable process because the products are small ring structures that are particularly stable. These structures are structurally characterized by action IRMPD spectroscopy and semi-quantified using gas-phase hydrogen-deuterium exchange. The formation of the oxazolone and diketopiperazine has been thought to be largely governed by the identity of the first two residues at the N-terminus of the peptide. We show here that the length of the precursor peptide and identity of the third residue play a significant role in the formation of the diketopiperazine structure in peptides containing an N-terminal asparagine residue. This is additionally the first instance showing an N-terminal residue with an amide side chain can promote formation of the diketopiperazine b2 ion structure.
Collapse
Affiliation(s)
- L J Morrison
- Department of Chemistry and Biochemistry, The Ohio State University, 484 W. 12th Ave, Columbus, OH 43210, USA.
| | | | | |
Collapse
|
29
|
Piatkivskyi A, Pyatkivskyy Y, Ryzhov V. Evaluation of various silicon-and boron-containing compounds for the detection of phosphorylation in peptides via gas-phase ion-molecule reactions. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2014; 20:337-344. [PMID: 25420346 DOI: 10.1255/ejms.1286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Gas-phase ion-molecule reactions [IMR] of various boron- and silicon-containing neutrals were investigated as a potential route for detecting phosphorylation within peptides in the negative ion mode. Trimethyl borate (TMB), triethyl borate (TEB) and N,O- Bis(trimethylsilyl)acetamide (TMSA), unlike diethylmethoxyborane (DEMB), diisopropoxymethylborane [DiPMB] and chlorotrimethylsi- Lane (TMSCIL], reacted differently if a phosphate moiety was present and thus are suitable to detect phosphorylation. During multistage collision-induced dissociation experiments of the reaction products of IMR with TMB and TEB, the [LSsF - 4H + B]- ion formed a modified y2 fragment allowing the phosphorylation site to be assigned, unlike reaction products of DEMB and DiPMB which lost both the phos- phoric acid and the boron-containing moiety.
Collapse
|
30
|
Konermann L, Vahidi S, Sowole MA. Mass Spectrometry Methods for Studying Structure and Dynamics of Biological Macromolecules. Anal Chem 2013; 86:213-32. [DOI: 10.1021/ac4039306] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7 Canada
| | - Siavash Vahidi
- Department of Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7 Canada
| | - Modupeola A. Sowole
- Department of Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7 Canada
| |
Collapse
|
31
|
Protein hydrogen exchange at residue resolution by proteolytic fragmentation mass spectrometry analysis. Proc Natl Acad Sci U S A 2013; 110:16438-43. [PMID: 24019478 DOI: 10.1073/pnas.1315532110] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hydrogen exchange technology provides a uniquely powerful instrument for measuring protein structural and biophysical properties, quantitatively and in a nonperturbing way, and determining how these properties are implemented to produce protein function. A developing hydrogen exchange-mass spectrometry method (HX MS) is able to analyze large biologically important protein systems while requiring only minuscule amounts of experimental material. The major remaining deficiency of the HX MS method is the inability to deconvolve HX results to individual amino acid residue resolution. To pursue this goal we used an iterative optimization program (HDsite) that integrates recent progress in multiple peptide acquisition together with previously unexamined isotopic envelope-shape information and a site-resolved back-exchange correction. To test this approach, residue-resolved HX rates computed from HX MS data were compared with extensive HX NMR measurements, and analogous comparisons were made in simulation trials. These tests found excellent agreement and revealed the important computational determinants.
Collapse
|
32
|
Affiliation(s)
- František Tureček
- Department of Chemistry, Bagley Hall, University of Washington , Seattle, Washington 98195-1700, United States
| | | |
Collapse
|
33
|
Affiliation(s)
- Sandra Osburn
- Department of Chemistry and Biochemistry and Center for Biochemical and Biophysical Studies, Northern Illinois University, DeKalb, Illinois 60115, USA
| | | |
Collapse
|
34
|
Rand KD, Pringle SD, Morris M, Brown JM. Site-Specific Analysis of Gas-Phase Hydrogen/Deuterium Exchange of Peptides and Proteins by Electron Transfer Dissociation. Anal Chem 2012; 84:1931-40. [DOI: 10.1021/ac202918j] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Kasper D. Rand
- The Department of
Pharmaceutics
and Analytical Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Steven D. Pringle
- Waters
MS Technologies Centre, Micromass U.K. Ltd., Floats Rd, Wythenshawe, Manchester
M23 9LZ, U.K
| | - Michael Morris
- Waters
MS Technologies Centre, Micromass U.K. Ltd., Floats Rd, Wythenshawe, Manchester
M23 9LZ, U.K
| | - Jeffery M. Brown
- Waters
MS Technologies Centre, Micromass U.K. Ltd., Floats Rd, Wythenshawe, Manchester
M23 9LZ, U.K
| |
Collapse
|