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Code C, Qiu D, Solov’yov IA, Lee JG, Shin HC, Roland C, Sagui C, Houde D, Rand KD, Jørgensen TJD. Conformationally Restricted Glycopeptide Backbone Inhibits Gas-Phase H/D Scrambling between Glycan and Peptide Moieties. J Am Chem Soc 2023; 145:23925-23938. [PMID: 37883679 PMCID: PMC10636759 DOI: 10.1021/jacs.3c04068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 10/28/2023]
Abstract
Protein glycosylation is a common post-translational modification on extracellular proteins. The conformational dynamics of several glycoproteins have been characterized by hydrogen/deuterium exchange mass spectrometry (HDX-MS). However, it is, in most cases, not possible to extract information about glycan conformation and dynamics due to the general difficulty of separating the deuterium content of the glycan from that of the peptide (in particular, for O-linked glycans). Here, we investigate whether the fragmentation of protonated glycopeptides by collision-induced dissociation (CID) can be used to determine the solution-specific deuterium content of the glycan. Central to this concept is that glycopeptides can undergo a facile loss of glycans upon CID, thereby allowing for the determination of their masses. However, an essential prerequisite is that hydrogen and deuterium (H/D) scrambling can be kept in check. Therefore, we have measured the degree of scrambling upon glycosidic bond cleavage in glycopeptides that differ in the conformational flexibility of their backbone and glycosylation pattern. Our results show that complete scrambling precedes the glycosidic bond cleavage in normal glycopeptides derived from a glycoprotein; i.e., all labile hydrogens have undergone positional randomization prior to loss of the glycan. In contrast, the glycosidic bond cleavage occurs without any scrambling in the glycopeptide antibiotic vancomycin, reflecting that the glycan cannot interact with the peptide moiety due to a conformationally restricted backbone as revealed by molecular dynamics simulations. Scrambling is also inhibited, albeit to a lesser degree, in the conformationally restricted glycopeptides ristocetin and its pseudoaglycone, demonstrating that scrambling depends on an intricate interplay between the flexibility and proximity of the glycan and the peptide backbone.
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Affiliation(s)
- Christian Code
- Department
of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
- Department
of Physics, Chemistry and Pharmacy, University
of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Danwen Qiu
- Department
of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Ilia A. Solov’yov
- Department
of Physics, Chemistry and Pharmacy, University
of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
- Department
of Physics, Carl von Ossietzky University
Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
- Research
Centre for Neurosensory Science, Carl von
Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
- Center
for Nanoscale Dynamics (CENAD), Carl von
Ossietzky Universität Oldenburg Institut für Physik, Ammerländer Heerstr. 114-118, 26129 Oldenburg, Germany
| | - Jung-Goo Lee
- Center for
Molecular Intelligence, The State University
of New York (SUNY), Korea,
119 Songdo Munwha-ro, Yeonsu-gu, 21985 Incheon, Korea
| | - Hyeon-Cheol Shin
- Center for
Molecular Intelligence, The State University
of New York (SUNY), Korea,
119 Songdo Munwha-ro, Yeonsu-gu, 21985 Incheon, Korea
| | - Christopher Roland
- Department
of Physics, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Celeste Sagui
- Department
of Physics, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Damian Houde
- Department
of Protein Pharmaceutical Development, Biogen, Cambridge, Massachusetts 02142, United States
| | - Kasper D. Rand
- Department
of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Thomas J. D. Jørgensen
- Department
of Biochemistry and Molecular Biology, University
of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark
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2
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James EI, Murphree TA, Vorauer C, Engen JR, Guttman M. Advances in Hydrogen/Deuterium Exchange Mass Spectrometry and the Pursuit of Challenging Biological Systems. Chem Rev 2021; 122:7562-7623. [PMID: 34493042 PMCID: PMC9053315 DOI: 10.1021/acs.chemrev.1c00279] [Citation(s) in RCA: 87] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
![]()
Solution-phase hydrogen/deuterium
exchange (HDX) coupled to mass
spectrometry (MS) is a widespread tool for structural analysis across
academia and the biopharmaceutical industry. By monitoring the exchangeability
of backbone amide protons, HDX-MS can reveal information about higher-order
structure and dynamics throughout a protein, can track protein folding
pathways, map interaction sites, and assess conformational states
of protein samples. The combination of the versatility of the hydrogen/deuterium
exchange reaction with the sensitivity of mass spectrometry has enabled
the study of extremely challenging protein systems, some of which
cannot be suitably studied using other techniques. Improvements over
the past three decades have continually increased throughput, robustness,
and expanded the limits of what is feasible for HDX-MS investigations.
To provide an overview for researchers seeking to utilize and derive
the most from HDX-MS for protein structural analysis, we summarize
the fundamental principles, basic methodology, strengths and weaknesses,
and the established applications of HDX-MS while highlighting new
developments and applications.
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Affiliation(s)
- Ellie I James
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Taylor A Murphree
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Clint Vorauer
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - John R Engen
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Miklos Guttman
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
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3
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Modzel M, Wollenberg DTW, Trelle MB, Larsen MR, Jørgensen TJD. Ultraviolet Photodissociation of Protonated Peptides and Proteins Can Proceed with H/D Scrambling. Anal Chem 2021; 93:691-696. [PMID: 33295747 DOI: 10.1021/acs.analchem.0c02957] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ultraviolet photodissociation (UVPD) has recently been introduced as an ion activation method for the determination of single-residue deuterium levels in H/D exchange tandem mass spectrometry experiments. In this regard, it is crucial to know which fragment ion types can be utilized for this purpose. UVPD yields rich product ion spectra where all possible backbone fragment ion types (a/x, b/y, and c/z) are typically observed. Here we provide a detailed investigation of the level of H/D scrambling for all fragment ion types upon UVPD of the peptide scrambling probe P1 (HHHHHHIIKIIK) using an Orbitrap tribrid mass spectrometer equipped with a solid-state 213 nm UV laser. The most abundant UVPD-generated fragment ions (i.e., b/y ions) exhibit extensive H/D scrambling. Similarly, a/x and c/z ions have also undergone H/D scrambling due to UV-induced heating of the precursor ion population. Therefore, dominant b/y ions upon UVPD of protonated peptides are a strong indicator for the occurrence of extensive H/D scrambling of the precursor ion population. In contrast to peptide P1, UV-irradiation of ubiquitin did not induce H/D scrambling in the nonfragmented precursor ion population. However, the UVPD-generated b2 and a4 ions from ubiquitin exhibit extensive H/D scrambling. To minimize H/D scrambling, short UV-irradiation time and high gas pressures are recommended.
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Affiliation(s)
- Maciej Modzel
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, Odense M 5230, Denmark.,Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland
| | - Daniel T Weltz Wollenberg
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, Odense M 5230, Denmark.,Novozymes A/S, Krogshøjvej 36, Bagsværd 2880, Denmark
| | - Morten Beck Trelle
- Department of Clinical Biochemistry, Svendborg Hospital, Baagøes Allé 15, SVB Building 17.01, 5700 Svendborg, Denmark
| | - Martin R Larsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, Odense M 5230, Denmark
| | - Thomas J D Jørgensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, Odense M 5230, Denmark
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4
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Guan S, Rabus JM, Maître P, Bythell BJ. Gas-Phase Dissociation Chemistry of Deprotonated RGD. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:55-63. [PMID: 32267154 DOI: 10.1021/jasms.0c00074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We investigate the structure and dissociation pathways of the deprotonated amphoteric peptide arginylglycylasparic acid, [RGD-H]-. We model the pertinent gas-phase structures and fragmentation chemistry of the precursor anions and predominant sequence-informative bond cleavages (b2+H2O, c2, and z1 peaks) and compare these predictions to our tandem mass spectra and infrared spectroscopy experiments. Formation of the b2+H2O anions requires rate-limiting intramolecular back biting to cleave the second amide bond and generate an anhydride structure. Facile cleavage of the newly formed ester bond with concerted expulsion of a cyclic anhydride neutral generates the product structure. IR spectroscopy supports this b2+H2O anion having structures that are essentially identical to C-terminally deprotonated arginylglycine, [RG-H]-. Formation of the c2 anion is predicted to require concerted expulsion of CO2 from the aspartyl side chain carboxylate and cleavage of the N-Calpha bond to produce a proton-bound dimer of arginylglycinamide and acrylate. Proton transfers within the dimer then enable predominant detection of a c2 anion with the negative charge nominally on the central, glycine nitrogen (amidate structure) as the proton affinity of this structure is predicted to be lower than acrylate by ∼27 kJ mol-1. Alternate means of cleaving the same N-Calpha bond produce deprotonated cis-1,4-dibut-2-enoic acid z1 anion structures. These lowest energy processes involve C-H proton mobilization from the aspartyl side chain prior to N-Calpha bond cleavage consistent with proposals from the literature.
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Affiliation(s)
- Shanshan Guan
- Department of Chemistry and Biochemistry, Ohio University, 391 Clippinger Laboratories, Athens, Ohio 45701, United States
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, 1 University Boulevard, St. Louis, Missouri 63121, United States
| | - Jordan M Rabus
- Department of Chemistry and Biochemistry, Ohio University, 391 Clippinger Laboratories, Athens, Ohio 45701, United States
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, 1 University Boulevard, St. Louis, Missouri 63121, United States
| | - Philippe Maître
- Université Paris-Saclay, CNRS, Institut de Chimie Physique, 91405 Orsay, France
| | - Benjamin J Bythell
- Department of Chemistry and Biochemistry, Ohio University, 391 Clippinger Laboratories, Athens, Ohio 45701, United States
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, 1 University Boulevard, St. Louis, Missouri 63121, United States
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Wollenberg DTW, Pengelley S, Mouritsen JC, Suckau D, Jørgensen CI, Jørgensen TJD. Avoiding H/D Scrambling with Minimal Ion Transmission Loss for HDX-MS/MS-ETD Analysis on a High-Resolution Q-TOF Mass Spectrometer. Anal Chem 2020; 92:7453-7461. [PMID: 32427467 DOI: 10.1021/acs.analchem.9b05208] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Hydrogen/deuterium exchange monitored by mass spectrometry (HDX-MS) enables the study of protein dynamics by measuring the time-resolved deuterium incorporation into a protein incubated in D2O. Using electron-based fragmentation in the gas phase it is possible to measure deuterium uptake at single-residue resolution. However, a prerequisite for this approach is that the solution-phase labeling is conserved in the gas phase prior to precursor fragmentation. It is therefore essential to reduce or even avoid intramolecular hydrogen/deuterium migration, which causes randomization of the deuterium labels along the peptide (hydrogen scrambling). Here, we describe an optimization strategy for reducing scrambling to a negligible level while minimizing the impact on sensitivity on a high-resolution Q-TOF equipped with ETD and an electrospray ionization interface consisting of a glass transfer capillary followed by a dual ion funnel. In our strategy we narrowed down the optimization to two accelerating potentials, and we defined the optimization of these in a simple rule by accounting for their interdependency in relation to scrambling and transmission efficiency. Using this rule, we were able to reduce scrambling from 75% to below 5% on average using the highly scrambling-sensitive quadruply charged P1 peptide scrambling probe resulting in a minor 33% transmission loss. To demonstrate the applicability of this approach, we probe the dynamics of certain regions in cytochrome c.
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Affiliation(s)
- Daniel T Weltz Wollenberg
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, Odense M 5230, Denmark.,Novozymes A/S, Krogshøjvej 36, Bagsværd 2280, Denmark
| | - Stuart Pengelley
- Bruker Daltonik GmbH, Fahrenheitstrasse 4, Bremen, 28359, Germany
| | | | - Detlev Suckau
- Bruker Daltonik GmbH, Fahrenheitstrasse 4, Bremen, 28359, Germany
| | | | - Thomas J D Jørgensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, Odense M 5230, Denmark
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6
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Kling NG, Díaz-Tendero S, Obaid R, Disla MR, Xiong H, Sundberg M, Khosravi SD, Davino M, Drach P, Carroll AM, Osipov T, Martín F, Berrah N. Time-resolved molecular dynamics of single and double hydrogen migration in ethanol. Nat Commun 2019; 10:2813. [PMID: 31249306 PMCID: PMC6597707 DOI: 10.1038/s41467-019-10571-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Accepted: 04/30/2019] [Indexed: 11/17/2022] Open
Abstract
Being the lightest, most mobile atom that exists, hydrogen plays an important role in the chemistry of hydrocarbons, proteins and peptides and most biomolecules. Hydrogen can undergo transfer, exchange and migration processes, having considerable impact on the chemical behavior of these molecules. Although much has been learned about reaction dynamics involving one hydrogen atom, less is known about those processes where two or more hydrogen atoms participate. Here we show that single and double hydrogen migrations occurring in ethanol cations and dications take place within a few hundred fs to ps, using a 3D imaging and laser pump-probe technique. For double hydrogen migration, the hydrogens are not correlated, with the second hydrogen migration promoting the breakup of the C-O bond. The probability of double hydrogen migration is quite significant, suggesting that double hydrogen migration plays a more important role than generally assumed. The conclusions are supported by state-of-the-art molecular dynamics calculations.
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Affiliation(s)
- Nora G Kling
- Department of Physics, University of Connecticut, Storrs, CT, 06269, USA.
| | - S Díaz-Tendero
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049, Madrid, Spain.
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049, Madrid, Spain.
- Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049, Madrid, Spain.
| | - R Obaid
- Department of Physics, University of Connecticut, Storrs, CT, 06269, USA
| | - M R Disla
- Department of Physics, University of Connecticut, Storrs, CT, 06269, USA
| | - H Xiong
- Department of Physics, University of Connecticut, Storrs, CT, 06269, USA
| | - M Sundberg
- Department of Physics, University of Connecticut, Storrs, CT, 06269, USA
| | - S D Khosravi
- Department of Physics, University of Connecticut, Storrs, CT, 06269, USA
| | - M Davino
- Department of Physics, University of Connecticut, Storrs, CT, 06269, USA
| | - P Drach
- Department of Physics, University of Connecticut, Storrs, CT, 06269, USA
| | - A M Carroll
- Department of Physics, University of Connecticut, Storrs, CT, 06269, USA
| | - T Osipov
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - F Martín
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049, Madrid, Spain.
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049, Madrid, Spain.
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nano), Campus de Cantoblanco, 28049, Madrid, Spain.
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018, Donostia-San Sebastián, Spain.
| | - N Berrah
- Department of Physics, University of Connecticut, Storrs, CT, 06269, USA.
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7
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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.
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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.
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Wright P, Alex A, Pullen F. Predicting collision-induced dissociation mass spectra: understanding the role of the mobile proton in small molecule fragmentation. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2016; 30:1163-1175. [PMID: 27525343 DOI: 10.1002/rcm.7521] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
RATIONALE Intramolecular proton migration has been reported to be required for fragmentation by collision-induced dissociation (CID). If the collision energy is required to provide energy for proton movement to a ‘dissociative’ site, it may be possible to predict the optimal collision energy for fragmentation using quantum computational chemistry software. A greater understanding of the mechanism(s) of proton migration is necessary. METHODS The product ion spectra of seven compounds were obtained at collision energies stepped in the range from 5 to 50 eV, with precursor ions being generated in positive ion mode by both atmospheric pressure chemical ionization (APCI) and electrospray ionisation (ESI) (using an ESCi ionisation source with or without corona discharge, respectively). The products ions observed at each collision energy were assessed in terms of structure to ascertain if they were formed as a result of protonation at the initial ionisation site or if the proton had migrated to a dissociative site. RESULTS Proton migration was shown to be independent of collision energy, stability of the protonated molecule and the distance that the proton moved. Therefore, proton migration is not a barrier to fragmentation as the proton appears to be fully mobile at 5 eV. As proton migration is independent of collision energy for these compounds, whereas fragmentation is energy dependent, protonation at the dissociative site alone is not sufficient to cause bond cleavage. CONCLUSIONS The role of collision energy in bond cleavage may be to increase the vibrational energy of the bond and/or increase the rate of bond cleavage such that it occurs within the residence time of the ion within the collision cell rather than to supply the energy for proton migration. Therefore, quantum chemistry alone cannot predict the collision energies appropriate for fragmentation on the basis of modelling proton movements.
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9
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Khakinejad M, Kondalaji SG, Donohoe GC, Valentine SJ. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 2. Assessing Charge Site Location and Isotope Scrambling. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:451-61. [PMID: 26802030 PMCID: PMC4814291 DOI: 10.1007/s13361-015-1304-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/28/2015] [Accepted: 11/02/2015] [Indexed: 05/17/2023]
Abstract
Ion mobility spectrometry (IMS) coupled with gas-phase hydrogen deuterium exchange (HDX)-mass spectrometry (MS) and molecular dynamic simulations (MDS) has been used for structural investigation of anions produced by electrospraying a sample containing a synthetic peptide having the sequence KKDDDDDIIKIIK. In these experiments the potential of the analytical method for locating charge sites on ions as well as for utilizing collision-induced dissociation (CID) to reveal the degree of deuterium uptake within specific amino acid residues has been assessed. For diffuse (i.e., more elongated) [M - 2H](2-) ions, decreased deuterium content along with MDS data suggest that the D4 and D6 residues are charge sites, whereas for the more diffuse [M - 3H](3-) ions, the data suggest that the D4, D7, and the C-terminus are deprotonated. Fragmentation of mobility-selected, diffuse [M - 2H](2-) ions to determine deuterium uptake at individual amino acid residues reveals a degree of deuterium retention at incorporation sites. Although the diffuse [M - 3H](3-) ions may show more HD scrambling, it is not possible to clearly distinguish HD scrambling from the expected deuterium uptake based on a hydrogen accessibility model. The capability of the IMS-HDX-MS/MS approach to provide relevant details about ion structure is discussed. Additionally, the ability to extend the approach for locating protonation sites on positively-charged ions is presented.
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Affiliation(s)
- Mahdiar Khakinejad
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | | | - Gregory C Donohoe
- 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.
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10
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Khakinejad M, Kondalaji SG, Donohoe GC, Valentine SJ. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 3. Estimating Surface Area Exposure by Deuterium Uptake. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:462-73. [PMID: 26620531 PMCID: PMC4872623 DOI: 10.1007/s13361-015-1305-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/28/2015] [Accepted: 11/02/2015] [Indexed: 05/17/2023]
Abstract
Gas-phase hydrogen deuterium exchange (HDX), collision cross section (CCS) measurement, and molecular dynamics simulation (MDS) techniques were utilized to develop and compare three methods for estimating the relative surface area exposure of separate peptide chains within bovine insulin ions. Electrosprayed [M - 3H](3-) and [M - 5H](5-) insulin ions produced a single conformer type with respective collision cross sections of 528 ± 5 Å(2) and 808 ± 2 Å(2). [M - 4H](4-) ions were comprised of more compact (Ω = 676 ± 3 Å(2)) and diffuse (i.e., more elongated, Ω = 779 ± 3 Å(2)) ion conformer types. Ions were subjected to HDX in the drift tube using D2O as the reagent gas. Collision-induced dissociation was used to fragment mobility-selected, isotopically labeled [M - 4H](4-) and [M - 5H](5-) ions into the protein subchains. Deuterium uptake levels of each chain can be explained by limited inter-chain isotopic scrambling upon collisional activation. Using nominal ion structures from MDS and a hydrogen accessibility model, the deuterium uptake for each chain was correlated to its exposed surface area. In separate experiments, the per-residue deuterium content for the protonated and deprotonated ions of the synthetic peptide KKDDDDDIIKIIK were compared. The differences in deuterium content indicated the regional HDX accessibility for cations versus anions. Using ions of similar conformational type, this comparison highlights the complementary nature of HDX data obtained from positive- and negative-ion analysis.
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Affiliation(s)
- Mahdiar Khakinejad
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | | | - Gregory C Donohoe
- 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.
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11
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Feketeová L, Khairallah GN, O'Hair RAJ, Nielsen SB. Gas-phase fragmentation of deprotonated tryptophan and its clusters [Trpn -H]- induced by different activation methods. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2015; 29:1395-1402. [PMID: 26147479 DOI: 10.1002/rcm.7233] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 05/19/2015] [Accepted: 05/19/2015] [Indexed: 06/04/2023]
Abstract
RATIONALE Non-covalent amino acid clusters are the subject of intense research in diverse areas including peptide bond formation studies or the determination of proton affinities or methylating abilities of amino acids. However, most of the research has focused on positive ions and little is known about anionic clusters. METHODS Fragmentation reactions of deprotonated tryptophan (Trp), [Trp-H](-) and Trp singly deprotonated non-covalently bound clusters [Trp(n) -H](-), n = 2, 3, 4, were investigated using low-energy collision-induced dissociation (CID) with He atoms, high-energy CID with Na atoms, and electron-induced dissociation (EID) with 20-35 eV electrons. Fragmentation of the monomeric Trp anion, where all labile hydrogens were exchanged for deuterium [d(4) -Trp-D](-), was investigated using low-energy CID and EID, in order to shed light on the dissociation mechanisms. RESULTS The main fragmentation channel for Trp cluster anions, [Trp(n) -H](-), n >1, is the loss of the neutral monomer. The fragmentation of the deprotonated Trp monomer induced by electrons resembles the fragmentation induced by high-energy collisions through electronic excitation of the parent. However, the excitation must precede in a different way, shown through only monomer loss from larger clusters, n >1, in case of EID, but intracluster chemistry in the case of high-energy CID. CONCLUSIONS The anion of the indole ring C(8)H(6) N(-) has been identified in the product ion spectra of [Trp(n) -H](-) using all activation methods, thus providing a diagnostic marker ion. No evidence was found for formation of peptide bonds as a route to prebiotic peptides in the fragmentation reactions of these singly deprotonated Trp cluster ions.
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Affiliation(s)
- Linda Feketeová
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Chemistry and Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, 30 Flemington Road, Parkville, Victoria, 3010, Australia
- Université de Lyon, 69003 Lyon, France; Université Claude Bernard Lyon1; Institut de Physique Nucléaire de Lyon, CNRS/IN2P3, UMR5822, 69622 Villeurbanne, France
| | - George N Khairallah
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Chemistry and Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, 30 Flemington Road, Parkville, Victoria, 3010, Australia
| | - Richard A J O'Hair
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Chemistry and Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, 30 Flemington Road, Parkville, Victoria, 3010, Australia
| | - Steen Brøndsted Nielsen
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Aarhus C, 8000, Denmark
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12
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Abstract
The structural analysis of viruses is often a complex task. In many cases, the details of the viral architecture, especially for enveloped viruses, are limited to low-resolution techniques such as electron microscopy. These structural proteins and assemblies of viruses often populate multiple conformational states and undergo dramatic structural changes, making them difficult to study by most structural methods. They also frequently include highly dynamic regions that are of key functional importance. Many viruses present large surface glycoproteins, which have also proved to be challenging for structural biology due to the intrinsic flexibility and heterogeneity of the glycan decorations. Over the past two decades, hydrogen deuterium exchange coupled to mass spectrometry (HDX-MS) has provided a wealth of information on many diverse viral proteins, glycoproteins, and complexes, in many cases, in multiple conformational states. Here, we describe the methodology for using HDX-MS to investigate the rich structural dynamics of viral systems, and we briefly review the type of systems that have been examined through this type of approach. Though the technique is relatively simple, several potential pitfalls exist at both the sample preparation and the data analysis stage that investigators should be aware of for obtaining reliable data.
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Affiliation(s)
- Miklos Guttman
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, USA.
| | - Kelly K Lee
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, USA.
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13
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Donohoe GC, Khakinejad M, Valentine SJ. Ion mobility spectrometry-hydrogen deuterium exchange mass spectrometry of anions: part 1. Peptides to proteins. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:564-576. [PMID: 25510931 DOI: 10.1007/s13361-014-1045-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 10/28/2014] [Accepted: 10/28/2014] [Indexed: 06/04/2023]
Abstract
Ion mobility spectrometry (IMS) coupled with hydrogen deuterium exchange (HDX)-mass spectrometry (MS) has been used to study the conformations of negatively-charged peptide and protein ions. Results are presented for ion conformers of angiotensin 1, a synthetic peptide (SP), bovine insulin, ubiquitin, and equine cytochrome c. In general, the SP ion conformers demonstrate a greater level of HDX efficiency as a greater proportion of the sites undergo HDX. Additionally, these ions exhibit the fastest rates of exchange. Comparatively, the angiotensin 1 ions exhibit a lower rate of exchange and HDX level presumably because of decreased accessibility of exchange sites by charge sites. The latter are likely confined to the peptide termini. Insulin ions show dramatically reduced HDX levels and exchange rates, which can be attributed to decreased conformational flexibility resulting from the disulfide bonds. For the larger ubiquitin and protein ions, increased HDX is observed for larger ions of higher charge state. For ubiquitin, a conformational transition from compact to more elongated species (from lower to higher charge states) is reflected by an increase in HDX levels. These results can be explained by a combination of interior site protection by compact conformers as well as decreased access by charge sites. The elongated cytochrome c ions provide the largest HDX levels where higher values correlate with charge state. These results are consistent with increased exchange site accessibility by additional charge sites. The data from these enhanced IMS-HDX experiments are described in terms of charge site location, conformer rigidity, and interior site protection.
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Affiliation(s)
- Gregory C Donohoe
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
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14
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Rand KD, Zehl M, Jørgensen TJD. Measuring the hydrogen/deuterium exchange of proteins at high spatial resolution by mass spectrometry: overcoming gas-phase hydrogen/deuterium scrambling. Acc Chem Res 2014; 47:3018-27. [PMID: 25171396 DOI: 10.1021/ar500194w] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Proteins are dynamic molecules that exhibit conformational flexibility to function properly. Well-known examples of this are allosteric regulation of protein activity and ligand-induced conformational changes in protein receptors. Detailed knowledge of the conformational properties of proteins is therefore pertinent to both basic and applied research, including drug development, since the majority of drugs target protein receptors and a growing number of drugs introduced to the market are therapeutic peptides or proteins. X-ray crystallography provides a static picture at atomic resolution of the lowest-energy structure of the native ensemble. There is a growing need for sensitive analytical tools to explore all of the significant molecular structures in the conformational landscape of proteins. Hydrogen/deuterium exchange monitored by mass spectrometry (HDX-MS) has recently emerged as a powerful method for characterizing protein conformational dynamics. The basis of this method is the fact that backbone amides in stable hydrogen-bonded structures (e.g., α-helices and β-sheets) are protected against exchange with the aqueous solvent. All protein structures are dynamic, however, and eventually all of the protecting hydrogen bonds will transiently break as the protein--according to thermodynamic principles--cycles through partially unfolded states that correspond to excited free energy levels. As a result, all of the backbone amides will eventually become temporarily solvent-exposed and exchange-competent over time. Consequently, a folded protein in D2O will gradually incorporate deuterium into its backbone amides, and the kinetics of the process can be readily monitored by mass spectrometry. The deuterium uptake kinetics for the intact protein (global exchange kinetics) represents the sum of the exchange kinetics for the individual backbone amides. Local exchange kinetics is typically achieved by using pepsin digestion under quench conditions (i.e., under cold acidic conditions where the amide hydrogen exchange rate is slowed by many orders of magnitude). The ability to localize the individual deuterated residues (the spatial resolution) is determined by the size (typically ∼7-15 residues) and the number of peptic peptides. These peptides provide a relatively coarse-grained picture of the protein dynamics. A fundamental understanding of the relationship between protein function/dysfunction and conformational dynamics requires in many cases higher resolution and ultimately single-residue resolution. In this Account, we summarize our efforts to achieve single-residue deuterium levels in proteins by electron-based or laser-induced gas-phase fragmentation methods. A crucial analytical requirement for this approach is that the pattern of deuterium labeling from solution is retained in the gas-phase fragment ions. It is therefore essential to control and minimize any occurrence of gas-phase randomization of the solution deuterium label (H/D scrambling) during the MS experiment. For this purpose, we have developed model peptide probes to accurately measure the onset and extent of H/D scrambling. Our analytical procedures to control the occurrence of H/D scrambling are detailed along with the physical parameters that induce it during MS analysis. In light of the growing use of gas-phase dissociation experiments to measure the HDX of proteins in order to obtain a detailed characterization and understanding of the dynamic conformations and interactions of proteins at the molecular level, we discuss the perspectives and challenges of future high-resolution HDX-MS methodology.
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Affiliation(s)
- Kasper D. Rand
- Department
of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Martin Zehl
- Department
of Pharmacognosy and Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Thomas J. D. Jørgensen
- Department
of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense, Denmark
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15
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Bobst CE, Kaltashov IA. Enhancing the quality of H/D exchange measurements with mass spectrometry detection in disulfide-rich proteins using electron capture dissociation. Anal Chem 2014; 86:5225-31. [PMID: 24820935 PMCID: PMC4051250 DOI: 10.1021/ac500904p] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
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Hydrogen/deuterium exchange (HDX)
mass spectrometry (MS) has become
a potent technique to probe higher-order structures, dynamics, and
interactions of proteins. While the range of proteins amenable to
interrogation by HDX MS continues to expand at an accelerating pace,
there are still a few classes of proteins whose analysis with this
technique remains challenging. Disulfide-rich proteins constitute
one of such groups: since the reduction of thiol–thiol bonds
must be carried out under suboptimal conditions (to minimize the back-exchange),
it frequently results in incomplete dissociation of disulfide bridges
prior to MS analysis, leading to a loss of signal, inadequate sequence
coverage, and a dramatic increase in the difficulty of data analysis.
In this work, the dissociation of disulfide-linked peptide dimers
produced by peptic digestion of the 80 kDa glycoprotein transferrin
in the course of HDX MS experiments is carried out using electron
capture dissociation (ECD). ECD results in efficient cleavage of the
thiol–thiol bonds in the gas phase on the fast LC time scale
and allows the deuterium content of the monomeric constituents of
the peptide dimers to be measured individually. The measurements appear
to be unaffected by hydrogen scrambling, even when high collisional
energies are utilized. This technique will benefit HDX MS measurements
for any protein that contains one or more disulfides and the potential
gain in sequence coverage and spatial resolution would increase with
disulfide bond number.
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Affiliation(s)
- Cedric E Bobst
- Department of Chemistry, University of Massachusetts Amherst , Amherst, Massachusetts 01003, United States
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16
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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.
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17
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Brock A. Fragmentation hydrogen exchange mass spectrometry: A review of methodology and applications. Protein Expr Purif 2012; 84:19-37. [DOI: 10.1016/j.pep.2012.04.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 04/13/2012] [Indexed: 01/19/2023]
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18
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Amon S, Trelle MB, Jensen ON, Jørgensen TJD. Spatially resolved protein hydrogen exchange measured by subzero-cooled chip-based nanoelectrospray ionization tandem mass spectrometry. Anal Chem 2012; 84:4467-73. [PMID: 22536891 DOI: 10.1021/ac300268r] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Mass spectrometry has become a valuable method for studying structural dynamics of proteins in solution by measuring their backbone amide hydrogen/deuterium exchange (HDX) kinetics. In a typical exchange experiment one or more proteins are incubated in deuterated buffer at physiological conditions. After a given period of deuteration, the exchange reaction is quenched by acidification (pH 2.5) and cooling (0 °C) and the deuterated protein (or a digest thereof) is analyzed by mass spectrometry. The unavoidable loss of deuterium (back-exchange) that occurs under quench conditions is undesired as it leads to loss of information. Here we describe the successful application of a chip-based nanoelectrospray ionization mass spectrometry top-down fragmentation approach based on cooling to subzero temperature (-15 °C) which reduces the back-exchange at quench conditions to very low levels. For example, only 4% and 6% deuterium loss for fully deuterated ubiquitin and β(2)-microglobulin were observed after 10 min of back-exchange. The practical value of our subzero-cooled setup for top-down fragmentation HDX analyses is demonstrated by electron-transfer dissociation of ubiquitin ions under carefully optimized mass spectrometric conditions where gas-phase hydrogen scrambling is negligible. Our results show that the known dynamic behavior of ubiquitin in solution is accurately reflected in the deuterium contents of the fragment ions.
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Affiliation(s)
- Sabine Amon
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
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19
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Grzetic J, Oomens J. Spectroscopic evidence for an oxazolone structure in anionic b-type peptide fragments. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:290-300. [PMID: 22170467 PMCID: PMC3264858 DOI: 10.1007/s13361-011-0297-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2011] [Revised: 10/31/2011] [Accepted: 11/02/2011] [Indexed: 05/31/2023]
Abstract
Infrared spectra of anionic b-type fragments generated by collision induced dissociation (CID) from deprotonated peptides are reported. Spectra of the b(2) fragments of deprotonated AlaAlaAla and AlaTyrAla have been recorded over the 800-1800 cm(-1) spectral range by multiple-photon dissociation (MPD) spectroscopy using an FTICR mass spectrometer in combination with the free electron laser FELIX. Structural characterization of the b-type fragments is accomplished by comparison with density functional theory calculated spectra at the B3LYP/6-31++G(d,p) level for different isomeric structures. Although diketopiperazine structures represent the energetically lowest isomers, the IR spectra suggest an oxazolone structure for the b(2) fragments of both peptides. Deprotonation is shown to occur on the oxazolone α-carbon, which leads to a conjugated structure in which the negative charge is practically delocalized over the entire oxazolone ring, providing enhanced gas-phase stability.
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Affiliation(s)
- Josipa Grzetic
- FOM Institute for Plasma Physics Rijnhuizen, Edisonbaan 14, 3439MN Nieuwegein, The Netherlands
| | - Jos Oomens
- FOM Institute for Plasma Physics Rijnhuizen, Edisonbaan 14, 3439MN Nieuwegein, The Netherlands
- van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
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20
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Marcsisin SR, Engen JR. Molecular insight into the conformational dynamics of the Elongin BC complex and its interaction with HIV-1 Vif. J Mol Biol 2010; 402:892-904. [PMID: 20728451 DOI: 10.1016/j.jmb.2010.08.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Revised: 08/12/2010] [Accepted: 08/13/2010] [Indexed: 11/29/2022]
Abstract
The human immunodeficiency virus type 1 virion infectivity factor (Vif) inhibits the innate viral immunity afforded by the APOBEC3 family of cytidine deaminases. Vif targets the APOBEC3 family for poly-ubiquitination and subsequent proteasomal degradation by linking the Elongin-BC-dependent ubiquitin ligase complex with the APOBEC3 proteins. The interaction between Vif and the heterodimeric Elongin BC complex, which is mediated by Vif's viral suppressor of cytokine signaling box, is essential for Vif function. The biophysical consequences of the full-length Vif:Elongin BC interaction have not been extensively reported. In this study, hydrogen exchange mass spectrometry was used to dissect the Vif:Elongin BC interaction. Elongin C was found to be highly dynamic in the Elongin BC complex while Elongin B was much more stable. Recombinant full-length Vif interacted with the Elongin BC complex in vitro with a K(d) of 1.9 μM and resulted in observable changes in deuterium uptake in both Elongin C and B. Upon binding to Elongin BC, no significant global conformational changes were detected in Vif by hydrogen exchange mass spectrometry, but a short fragment of Vif that consisted of the viral suppressor of cytokine signaling box showed decreased deuterium incorporation upon Elongin BC incubation, suggesting that this region folds upon binding.
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Affiliation(s)
- Sean R Marcsisin
- Department of Chemistry and Chemical Biology and the Barnett Institute of Chemical and Biological Analysis, Northeastern University, Boston, MA 02115, USA
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