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Park J, Fagerquist CK. Exploring the fragmentation efficiency of proteins analyzed by MALDI-TOF-TOF tandem mass spectrometry using computational and statistical analyses. PLoS One 2024; 19:e0299287. [PMID: 38701058 PMCID: PMC11068200 DOI: 10.1371/journal.pone.0299287] [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: 09/20/2023] [Accepted: 02/07/2024] [Indexed: 05/05/2024] Open
Abstract
Matrix-assisted laser desorption/ionization time-of-flight-time-of-flight (MALDI-TOF-TOF) tandem mass spectrometry (MS/MS) is a rapid technique for identifying intact proteins from unfractionated mixtures by top-down proteomic analysis. MS/MS allows isolation of specific intact protein ions prior to fragmentation, allowing fragment ion attribution to a specific precursor ion. However, the fragmentation efficiency of mature, intact protein ions by MS/MS post-source decay (PSD) varies widely, and the biochemical and structural factors of the protein that contribute to it are poorly understood. With the advent of protein structure prediction algorithms such as Alphafold2, we have wider access to protein structures for which no crystal structure exists. In this work, we use a statistical approach to explore the properties of bacterial proteins that can affect their gas phase dissociation via PSD. We extract various protein properties from Alphafold2 predictions and analyze their effect on fragmentation efficiency. Our results show that the fragmentation efficiency from cleavage of the polypeptide backbone on the C-terminal side of glutamic acid (E) and asparagine (N) residues were nearly equal. In addition, we found that the rearrangement and cleavage on the C-terminal side of aspartic acid (D) residues that result from the aspartic acid effect (AAE) were higher than for E- and N-residues. From residue interaction network analysis, we identified several local centrality measures and discussed their implications regarding the AAE. We also confirmed the selective cleavage of the backbone at D-proline bonds in proteins and further extend it to N-proline bonds. Finally, we note an enhancement of the AAE mechanism when the residue on the C-terminal side of D-, E- and N-residues is glycine. To the best of our knowledge, this is the first report of this phenomenon. Our study demonstrates the value of using statistical analyses of protein sequences and their predicted structures to better understand the fragmentation of the intact protein ions in the gas phase.
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Affiliation(s)
- Jihyun Park
- Western Regional Research Center, Agricultural Research Service, USDA, Albany, CA, United States of America
- U.S. Department of Energy, Research Participation Program Administered by the Oak Ridge Institute for Science and Education, Oak Ridge, TN, United States of America
| | - Clifton K. Fagerquist
- Western Regional Research Center, Agricultural Research Service, USDA, Albany, CA, United States of America
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2
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David J, Gómez S, Guerra D, Guerra D, Restrepo A. A Comprehensive Picture of the Structures, Energies, and Bonding in the Alanine Dimers. Chemphyschem 2021; 22:2401-2412. [PMID: 34554628 DOI: 10.1002/cphc.202100585] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/22/2021] [Indexed: 12/14/2022]
Abstract
High level quantum mechanical computations and extensive stochastic searches of the potential energy surfaces of the Alanine dimers uncover rich and complex structural and interaction landscapes. A total of 416 strongly bound (up 13.4 kcal mol-1 binding energies at the DLPNO-CCSD(T)/6-311++G(d,p) level corrected by the basis set superposition error and by the zero point vibrational energies over B3LYP-D3 geometries), close energy equilibrium structures were located, bonded via 32 specific types of intermolecular contacts including Y⋅⋅⋅H-X primary and Y⋅⋅⋅H-C secondary hydrogen bonds, H⋅⋅⋅H dihydrogen contacts, and non conventional anti-electrostatic Y δ - ⋯ X δ - interactions. The putative global minimum is triply degenerate, corresponding to the structure of the common dimer of a carboxylic acid. All quantum descriptors of chemical bonding point to a multitude of weak individual interactions within each dimer, whose cumulative effect results in large binding energies and in an attractive fluxional wall of non-covalent interactions in the interstitial region between the monomers.
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Affiliation(s)
- Jorge David
- Escuela de Ciencias, Departamento de Ciencias Físicas, Universidad Eafit, AA 3300, Medellín, Colombia
| | - Sara Gómez
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - Doris Guerra
- Instituto de Química, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia
| | - Dario Guerra
- Departamento de Educación y Ciencias Básicas, Instituto Tecnológico Metropolitano, Calle 73 No. 76 A-354, Medellín, Colombia
| | - Albeiro Restrepo
- Instituto de Química, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia
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Lee ZR, Quinn LJ, Jones CW, Hayes SE, Dixon DA. Predicting the Mechanism and Products of CO 2 Capture by Amines in the Presence of H 2O. J Phys Chem A 2021; 125:9802-9818. [PMID: 34748350 DOI: 10.1021/acs.jpca.1c05950] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An extensive correlated molecular orbital theory study of the reactions of CO2 with a range of substituted amines and H2O in the gas phase and aqueous solution was performed at the G3(MP2) level with a self-consistent reaction field approach. The G3(MP2) calculations were benchmarked at the CCSD(T)/CBS level for NH3 reactions. A catalytic NH3 reduces the energy barrier more than a catalytic H2O for the formation of H2NCOOH and H2CO3. In aqueous solution, the barriers to form both H2NCOOH and H2CO3 are reduced, with HCO3- formation possible with one amine present and H2NCOO- formation possible only with two amines. Further reactions of H2NCOOH to form HNCO and urea via the Bazarov reaction have high barriers and are unlikely in both the gas phase and aqueous solution. Reaction coordinates for CH3NH2, CH3CH2NH2, (CH3)2NH, CH3CH2CH2NH2, (CH3)3N, and DMAP were also calculated. The barrier for proton transfer correlates with amine basicity for alkylammonium carbamate (ΔG‡aq < 15 kcal/mol) and alkylammonium bicarbonate (ΔG‡aq < 30 kcal/mol) formation. In aqueous solution, carbamic acids, carbamates, and bicarbonates can all form in small amounts with ammonium carbamates dominating for primary and secondary alkylamines. These results have implications for CO2 capture by amines in both the gas phase and aqueous solution as well as in the solid state, if enough water is present.
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Affiliation(s)
- Zachary R Lee
- Department of Chemistry and Biochemistry, University of Alabama, Tuscaloosa, Alabama 35487, United States.,Department of Biology and Chemistry, Morehead State University, Morehead, Kentucky 40351, United States
| | - La'Darious J Quinn
- Department of Chemistry and Biochemistry, University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Christopher W Jones
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, Georgia 30332, United States
| | - Sophia E Hayes
- Department of Chemistry, Washington University, 1 Brookings Drive, Saint Louis, Missouri 63130, United States
| | - David A Dixon
- Department of Chemistry and Biochemistry, University of Alabama, Tuscaloosa, Alabama 35487, United States
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4
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Fossat M, Zeng X, Pappu RV. Uncovering Differences in Hydration Free Energies and Structures for Model Compound Mimics of Charged Side Chains of Amino Acids. J Phys Chem B 2021; 125:4148-4161. [PMID: 33877835 PMCID: PMC8154595 DOI: 10.1021/acs.jpcb.1c01073] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/07/2021] [Indexed: 02/07/2023]
Abstract
Free energies of hydration are of fundamental interest for modeling and understanding conformational and phase equilibria of macromolecular solutes in aqueous phases. Of particular relevance to systems such as intrinsically disordered proteins are the free energies of hydration and hydration structures of model compounds that mimic charged side chains of Arg, Lys, Asp, and Glu. Here, we deploy a Thermodynamic Cycle-based Proton Dissociation (TCPD) approach in conjunction with data from direct measurements to obtain estimates for the free energies of hydration for model compounds that mimic the side chains of Arg+, Lys+, Asp-, and Glu-. Irrespective of the choice made for the hydration free energy of the proton, the TCPD approach reveals clear trends regarding the free energies of hydration for Arg+, Lys+, Asp-, and Glu-. These trends include asymmetries between the hydration free energies of acidic (Asp- and Glu-) and basic (Arg+ and Lys+) residues. Further, the TCPD analysis, which relies on a combination of experimental data, shows that the free energy of hydration of Arg+ is less favorable than that of Lys+. We sought a physical explanation for the TCPD-derived trends in free energies of hydration. To this end, we performed temperature-dependent calculations of free energies of hydration and analyzed hydration structures from simulations that use the polarizable Atomic Multipole Optimized Energetics for Biomolecular Applications (AMOEBA) force field and water model. At 298 K, the AMOEBA model generates estimates of free energies of hydration that are consistent with TCPD values with a free energy of hydration for the proton of ca. -259 kcal/mol. Analysis of temperature-dependent simulations leads to a structural explanation for the observed differences in free energies of hydration of ionizable residues and reveals that the heat capacity of hydration is positive for Arg+ and Lys+ and negative for Asp- and Glu-.
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Affiliation(s)
| | | | - Rohit V. Pappu
- Department of Biomedical Engineering
and Center for Science & Engineering of Living Systems, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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5
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Fedorova I, Krestyaninov M, Safonova L. Structure and ion-ion interactions in trifluoroacetate-based ionic liquids: Quantum chemical and molecular dynamics simulation studies. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115449] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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6
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Crystallographic evidence of Watson-Crick connectivity in the base pair of anionic adenine with thymine. Proc Natl Acad Sci U S A 2020; 117:18224-18230. [PMID: 32680959 PMCID: PMC7414232 DOI: 10.1073/pnas.2008379117] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Utilizing an ionic liquid strategy, we report crystal structures of salts of free anionic nucleobases and base pairs previously studied only computationally and in the gas phase. Reaction of tetrabutylammonium ([N4444]+) or tetrabutylphosphonium ([P4444]+) hydroxide with adenine (HAd) and thymine (HThy) led to hydrated salts of deprotonated adenine, [N4444][Ad]·2H2O, and thymine, [P4444][Thy]·2H2O, as well as the double salt cocrystal, [P4444]2[Ad][Thy]·3H2O·2HThy. The cocrystal includes the anionic [Ad-(HThy)] base pair which is a stable formation in the solid state that has previously not even been suggested. It exhibits Watson-Crick connectivity as found in DNA but which is unusual for the free neutral base pairs. The stability of the observed anionic bases and their supramolecular formations and hydrates has also been examined by electronic structure calculations, contributing to more insight into how base pairs can bind when a proton is removed and highlighting mechanisms of stabilization or chemical transformation in the DNA chains.
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Persaud RR, Dieke NE, Jing X, Lambert S, Parsa N, Hartmann E, Vincent JB, Cassady CJ, Dixon DA. Mechanistic Study of Enhanced Protonation by Chromium(III) in Electrospray Ionization: A Superacid Bound to a Peptide. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:308-318. [PMID: 32031389 DOI: 10.1021/jasms.9b00078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Addition of trivalent chromium, Cr(III), to solutions undergoing electrospray ionization (ESI) enhances protonation and leads to formation of [M + 2H]2+ for peptides that normally produce [M + H]+. This effect is explored using electronic structure calculations at the density functional theory (DFT) level to predict the energetics of various species that are potentially important to the mechanism. Gas- and solution-phase reaction free energies for glycine and its anion reacting with [Cr(III)(H2O)6]3+ and for dehydration of these species have been predicted, where glycine is used as a simple model for a peptide. For comparison, calculations were also performed with Fe(III), Al(III), Sc(III), Y(III), and La(III). Removal of water from these complexes, as would occur during the ESI desolvation process, results in species that are highly acidic. The calculated pKa of Cr(III) with a single solvation shell is -10.8, making [Cr(III)(H2O)6]3+ a superacid that is more acidic than sulfuric acid (pKa = -8.8). Binding to glycine requires removal of two aqua ligands, which gives [Cr(III)(H2O)4]3+ that has an extremely acidic pKa of -28.8. Removal of additional water further enhances acidity, reaching a pKa of -84.7 for [Cr(III)(H2O)]3+. A mechanism for enhanced protonation is proposed that incorporates computational and experiment results, as well as information on the known chemistry of Cr(III), which is substitutionally inert. The initial step involves binding of [Cr(III)(H2O)4]3+ to the deprotonated C-terminus of a peptide. As the drying process during ESI strips water from the complex, the resulting superacid transfers protons to the bound peptide, eventually leading to formation of [M + 2H]2+.
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Affiliation(s)
- Rudradatt R Persaud
- Department of Chemistry & Biochemistry , The University of Alabama , Tuscaloosa , Alabama 35487-0336 , United States
| | - Nnenna E Dieke
- Department of Chemistry & Biochemistry , The University of Alabama , Tuscaloosa , Alabama 35487-0336 , United States
| | - Xinyao Jing
- Department of Chemistry & Biochemistry , The University of Alabama , Tuscaloosa , Alabama 35487-0336 , United States
| | - Skyler Lambert
- Department of Chemistry & Biochemistry , The University of Alabama , Tuscaloosa , Alabama 35487-0336 , United States
| | - Nicholas Parsa
- Department of Chemistry & Biochemistry , The University of Alabama , Tuscaloosa , Alabama 35487-0336 , United States
| | - Elizabeth Hartmann
- Department of Chemistry & Biochemistry , The University of Alabama , Tuscaloosa , Alabama 35487-0336 , United States
| | - John B Vincent
- Department of Chemistry & Biochemistry , The University of Alabama , Tuscaloosa , Alabama 35487-0336 , United States
| | - Carolyn J Cassady
- Department of Chemistry & Biochemistry , The University of Alabama , Tuscaloosa , Alabama 35487-0336 , United States
| | - David A Dixon
- Department of Chemistry & Biochemistry , The University of Alabama , Tuscaloosa , Alabama 35487-0336 , United States
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Lin YF, Yousef EN, Torres E, Truong L, Zahnow JM, Donald CB, Qin Y, Angel LA. Weak Acid-Base Interactions of Histidine and Cysteine Affect the Charge States, Tertiary Structure, and Zn(II)-Binding of Heptapeptides. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:2068-2081. [PMID: 31332742 DOI: 10.1007/s13361-019-02275-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 06/10/2019] [Accepted: 06/18/2019] [Indexed: 06/10/2023]
Abstract
Zinc fingers are proteins that are characterized by the coordination of zinc ions by an amino acid sequence that commonly contains two histidines and two cysteines (2His-2Cys motif). Investigations of oligopeptides that contain the 2His-2Cys motif, e.g., acetyl-His1-Cys2-Gly3-Pro4-Tyr5-His6-Cys7, have discovered they exhibit pH-dependent Zn(II) chelation and have redox activities with Cu(I/II), forming a variety of metal complexes. To further understand how these 2His-2Cys oligopeptides bind these metal ions, we have undertaken a series of ion mobility-mass spectrometry and B3LYP/LanL2DZ computational studies of structurally related heptapeptides. Starting with the sequence above, we have modified the potential His, Cys, or C-terminus binding sites and report how these changes in primary structure affect the oligopeptides positive and negative charge states, conformational structure, collision-induced breakdown energies, and how effectively Zn(II) binds to these sequences. The results show evidence that the weak acid-base properties of Cys-His are intrinsically linked and can result in an intramolecular salt-bridged network that affects the oligopeptide properties.
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Affiliation(s)
- Yu-Fu Lin
- Department of Chemistry, Texas A&M University-Commerce, 2600 S Neal St, Commerce, TX, 75428, USA
| | - Enas N Yousef
- Department of Chemistry, Texas A&M University-Commerce, 2600 S Neal St, Commerce, TX, 75428, USA
| | - Efren Torres
- Department of Chemistry, Texas A&M University-Commerce, 2600 S Neal St, Commerce, TX, 75428, USA
| | - Linh Truong
- Department of Chemistry, Texas A&M University-Commerce, 2600 S Neal St, Commerce, TX, 75428, USA
| | - James M Zahnow
- Department of Chemistry, Texas A&M University-Commerce, 2600 S Neal St, Commerce, TX, 75428, USA
| | - Cole B Donald
- Department of Chemistry, Texas A&M University-Commerce, 2600 S Neal St, Commerce, TX, 75428, USA
| | - Ying Qin
- Department of Chemistry, Texas A&M University-Commerce, 2600 S Neal St, Commerce, TX, 75428, USA
| | - Laurence A Angel
- Department of Chemistry, Texas A&M University-Commerce, 2600 S Neal St, Commerce, TX, 75428, USA.
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9
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Meißner R, Feketeová L, Bayer A, Postler J, Limão‐Vieira P, Denifl S. Positive and negative ions of the amino acid histidine formed in low-energy electron collisions. JOURNAL OF MASS SPECTROMETRY : JMS 2019; 54:802-816. [PMID: 31410948 PMCID: PMC6916310 DOI: 10.1002/jms.4427] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 07/29/2019] [Accepted: 08/05/2019] [Indexed: 05/28/2023]
Abstract
Histidine is an aromatic amino acid crucial for the biological functioning of proteins and enzymes. When biological matter is exposed to ionising radiation, highly energetic particles interact with the surrounding tissue which leads to efficient formation of low-energy electrons. In the present study, the interaction of low-energy electrons with gas-phase histidine is studied at a molecular level in order to extend the knowledge of electron-induced reactions with amino acids. We report both on the formation of positive ions formed by electron ionisation and negative ions induced by electron attachment. The experimental data were complemented by quantum chemical calculations. Specifically, the free energies for possible fragmentation reactions were derived for the τ and the π tautomer of histidine to get insight into the structures of the formed ions and the corresponding neutrals. We report the experimental ionisation energy of (8.48 ± 0.03) eV for histidine which is in good agreement with the calculated vertical ionisation energy. In the case of negative ions, the dehydrogenated parent anion is the anion with the highest mass observed upon dissociative electron attachment. The comparison of experimental and computational results was also performed in view of a possible thermal decomposition of histidine during the experiments, since the sample was sublimated in the experiment by resistive heating of an oven. Overall, the present study demonstrates the effects of electrons as secondary particles in the chemical degradation of histidine. The reactions induced by those electrons differ when comparing positive and negative ion formation. While for negative ions, simple bond cleav ages prevail, the observed fragment cations exhibit partly restructuring of the molecule during the dissociation process.
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Affiliation(s)
- Rebecca Meißner
- Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck (CMBI)Universität InnsbruckTechnikerstraße 256020InnsbruckAustria
- Atomic and Molecular Collisions Laboratory, CEFITEC, Department of PhysicsUniversidade NOVA de Lisboa2829‐516CaparicaPortugal
| | - Linda Feketeová
- Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck (CMBI)Universität InnsbruckTechnikerstraße 256020InnsbruckAustria
- Institut de Physique Nucléaire de Lyon; CNRS/IN2P3, UMR5822Université de Lyon, Université Claude Bernard Lyon 143 Bd du 11 novembre 191869622VilleurbanneFrance
| | - Andreas Bayer
- Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck (CMBI)Universität InnsbruckTechnikerstraße 256020InnsbruckAustria
| | - Johannes Postler
- Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck (CMBI)Universität InnsbruckTechnikerstraße 256020InnsbruckAustria
| | - Paulo Limão‐Vieira
- Atomic and Molecular Collisions Laboratory, CEFITEC, Department of PhysicsUniversidade NOVA de Lisboa2829‐516CaparicaPortugal
| | - Stephan Denifl
- Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck (CMBI)Universität InnsbruckTechnikerstraße 256020InnsbruckAustria
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Low K, Tan SYS, Izgorodina EI. An ab initio Study of the Structure and Energetics of Hydrogen Bonding in Ionic Liquids. Front Chem 2019; 7:208. [PMID: 31024894 PMCID: PMC6468050 DOI: 10.3389/fchem.2019.00208] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 03/18/2019] [Indexed: 01/09/2023] Open
Abstract
Unlike typical hydrogen-bonded networks such as water, hydrogen bonded ionic liquids display some unusual characteristics due to the complex interplay of electrostatics, polarization, and dispersion forces in the bulk. Protic ionic liquids in particular contain close-to traditional linear hydrogen bonds that define their physicochemical properties. This work investigates whether hydrogen bonded ionic liquids (HBILs) can be differentiated from aprotic ionic liquids with no linear hydrogen bonds using state-of-the-art ab initio calculations. This is achieved through geometry optimizations of a series of single ion pairs of HBILs in the gas phase and an implicit solvent. Using benchmark CCSD(T)/CBS calculations, the electrostatic and dispersion components of the interaction energy of these systems are compared with those of aprotic ionic liquids. The inclusion of the implicit solvent significantly influenced geometries of single ion pairs, with the gas phase shortening the hydrogen bond to reduce electrostatic interactions. HBILs were found to have stronger interactions by at least 10EtMeNH0 kJ mol−1 over aprotic ILs, clearly highlighting the electrostatic nature of hydrogen bonding. Geometric and energetic parameters were found to complement each other in determining the extent of hydrogen bonding present in these ionic liquids.
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Affiliation(s)
- Kaycee Low
- Monash Computational Chemistry Group, School of Chemistry, Monash University, Melbourne, VIC, Australia
| | - Samuel Y S Tan
- Monash Computational Chemistry Group, School of Chemistry, Monash University, Melbourne, VIC, Australia
| | - Ekaterina I Izgorodina
- Monash Computational Chemistry Group, School of Chemistry, Monash University, Melbourne, VIC, Australia
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11
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Macaluso V, Scuderi D, Crestoni ME, Fornarini S, Corinti D, Dalloz E, Martinez-Nunez E, Hase WL, Spezia R. l-Cysteine Modified by S-Sulfation: Consequence on Fragmentation Processes Elucidated by Tandem Mass Spectrometry and Chemical Dynamics Simulations. J Phys Chem A 2019; 123:3685-3696. [DOI: 10.1021/acs.jpca.9b01779] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Veronica Macaluso
- LAMBE, Univ Evry, CNRS, CEA, Université Paris-Saclay, 91025 Évry, France
| | - Debora Scuderi
- LCP, Laboratoire de Chimie Physique, Université Paris-Sud, Bat. 349, CNRS UMR8000, 15 rue Georges Clemenceau, 91405 Orsay Cedex, France
| | - Maria Elisa Crestoni
- Dipartimento di Chimica e Tecnologie del Farmaco, Università degli Studi di Roma La Sapienza, P.le A. Moro 5, 00185 Roma, Italy
| | - Simonetta Fornarini
- Dipartimento di Chimica e Tecnologie del Farmaco, Università degli Studi di Roma La Sapienza, P.le A. Moro 5, 00185 Roma, Italy
| | - Davide Corinti
- Dipartimento di Chimica e Tecnologie del Farmaco, Università degli Studi di Roma La Sapienza, P.le A. Moro 5, 00185 Roma, Italy
| | - Enzo Dalloz
- LCP, Laboratoire de Chimie Physique, Université Paris-Sud, Bat. 349, CNRS UMR8000, 15 rue Georges Clemenceau, 91405 Orsay Cedex, France
- Dipartimento di Chimica e Tecnologie del Farmaco, Università degli Studi di Roma La Sapienza, P.le A. Moro 5, 00185 Roma, Italy
| | - Emilio Martinez-Nunez
- Departamento de Química Física, Facultade de Química, Campus Vida, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - William L. Hase
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Riccardo Spezia
- LAMBE, Univ Evry, CNRS, CEA, Université Paris-Saclay, 91025 Évry, France
- CNRS, Laboratoire de Chimie Théorique, LCT, Sorbonne Université, 4, Place Jussieu, 75252 Paris Cedex 05, France
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12
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Cui C, McNeill AS, Jackson WC, Raddatz MA, Stover ML, Dixon DA, Cassady CJ. Experimental and Computational Study of the Gas-Phase Acidities of Acidic Di- and Tripeptides. J Phys Chem B 2019; 123:606-613. [DOI: 10.1021/acs.jpcb.8b10924] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Can Cui
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Ashley S. McNeill
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Will C. Jackson
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Michael A. Raddatz
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Michele L. Stover
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - David A. Dixon
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Carolyn J. Cassady
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
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13
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Alnajeebi AM, Vickerman JC, Lockyer NP. The influence of polyatomic primary ion chemistry on matrix effects in secondary ion mass spectrometry analysis. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2018; 32:1962-1970. [PMID: 30133034 DOI: 10.1002/rcm.8265] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/01/2018] [Accepted: 08/10/2018] [Indexed: 06/08/2023]
Abstract
RATIONALE The application of mass spectrometry imaging techniques to determine two- (2D) and three- (3D) dimensional chemical distribution ideally provides uniform, high sensitivity to multiple components and reliable quantification. These criteria are typically not met due to variations in sensitivity due to the chemistry of the analyte and surrounding surface chemistry. Here we explore the influence of projectile beam chemistry and sample chemistry in time-of-flight secondary ion mass spectrometry (TOF-SIMS). To the authors' knowledge this is the first time the combined effects of projectile chemistry and sample environment on the quantitative determination of mixed samples have been systematically studied. METHODS Secondary ion yields of lipid and amino acid mixtures were measured under 20 keV C60 , Arn , and (H2 O)n cluster ion bombardment (n = 2000 or 4000) using TOF-SIMS. Ion suppression/enhancement effects were studied in dry sample films and in trehalose and water ice matrices. RESULTS The extent of the matrix effects and the secondary ion yield were found to depend on the chemistry of the primary ion beam and (for C60 , Arn ) on the nature of the sample matrix. Under (H2 O)n bombardment the sample matrix had negligible effect on the analysis. CONCLUSIONS Compared with C60 and Arn , water-containing cluster projectiles enhanced the sensitivity of TOF-SIMS determination of the chosen analytes and reduced the effect of signal suppression/enhancement in multicomponent samples and in different sample matrices. One possible explanation for this is that the (H2 O)4000 projectile initiates on impact a nanoscale matrix environment that is very similar to that in frozen-hydrated samples in terms of the resulting ionisation effects. The competition between analytes for protons and the effect of the sample matrix are reduced with water-containing cluster projectiles. These chemically reactive projectile beams have improved characteristics for quantitative chemical imaging by TOF-SIMS compared with their non-reactive counterparts.
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Affiliation(s)
- Afnan M Alnajeebi
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess St, Manchester, M1 7DN, UK
- School of Chemistry, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK
| | - John C Vickerman
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess St, Manchester, M1 7DN, UK
- School of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK
| | - Nicholas P Lockyer
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess St, Manchester, M1 7DN, UK
- School of Chemistry, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK
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Corinti D, Gregori B, Guidoni L, Scuderi D, McMahon TB, Chiavarino B, Fornarini S, Crestoni ME. Complexation of halide ions to tyrosine: role of non-covalent interactions evidenced by IRMPD spectroscopy. Phys Chem Chem Phys 2018; 20:4429-4441. [PMID: 29372198 DOI: 10.1039/c7cp06657k] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The binding motifs in the halide adducts with tyrosine ([Tyr + X]-, X = Cl, Br, I) have been investigated and compared with the analogues with 3-nitrotyrosine (nitroTyr), a biomarker of protein nitration, in a solvent-free environment by mass-selected infrared multiple photon dissociation (IRMPD) spectroscopy over two IR frequency ranges, namely 950-1950 and 2800-3700 cm-1. Extensive quantum chemical calculations at B3LYP, B3LYP-D3 and MP2 levels of theory have been performed using the 6-311++G(d,p) basis set to determine the geometry, relative energy and vibrational properties of likely isomers and interpret the measured spectra. A diagnostic carbonyl stretching band at ∼1720 cm-1 from the intact carboxylic group characterizes the IRMPD spectra of both [Tyr + X]- and [nitroTyr + X]-, revealing that the canonical isomers (maintaining intact amino and carboxylic functions) are the prevalent structures. The spectroscopic evidence reveals the presence of multiple non-covalent forms. The halide complexes of tyrosine conform to a mixture of plane and phenol isomers. The contribution of phenol-bound isomers is sensitive to anion size, increasing from chloride to iodide, consistent with the decreasing basicity of the halide, with relative amounts depending on the relative energies of the respective structures. The stability of the most favorable phenol isomer with respect to the reference plane geometry is in fact 1.3, -2.1, -6.8 kJ mol-1, for X = Cl, Br, I, respectively. The change in π-acidity by ring nitration also stabilizes anion-π interactions yielding ring isomers for [nitroTyr + X]-, where the anion is placed above the face of the aromatic ring.
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Affiliation(s)
- Davide Corinti
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma "La Sapienza", P.le A. Moro 5, I-00185 Roma, Italy.
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15
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Khreis JM, Reitshammer J, Vizcaino V, Klawitter K, Feketeová L, Denifl S. High-energy collision-induced dissociation of histidine ions [His + H] + and [His - H] - and histidine dimer [His 2 + H] . RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2018; 32:113-120. [PMID: 29108138 DOI: 10.1002/rcm.8027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 10/05/2017] [Accepted: 10/26/2017] [Indexed: 06/07/2023]
Abstract
RATIONALE Histidine (His) is an essential amino acid, whose side group consists of an aromatic imidazole moiety that can bind a proton or metal cation and act as a donor in intermolecular interactions in many biological processes. While the dissociation of His monomer ions is well known, information on the kinetic energy released in the dissociation is missing. METHODS Using a new home-built electrospray ionization (ESI) source adapted to a double-focusing mass spectrometer of BE geometry, we investigated the fragmentation reactions of protonated and deprotonated His, [His + H]+ and [His - H]- , and the protonated His dimer [His2 + H]+ , accelerated to 6 keV in a high-energy collision with helium gas. We evaluated the kinetic energy release (KER) for the observed dissociation channels. RESULTS ESI of His solution in positive mode led to the formation of His clusters [Hisn + H]+ , n = 1-6, with notably enhanced stability of the tetramer. [His + H]+ dissociates predominantly by loss of (H2 O + CO) with a KER of 278 meV, while the dominant dissociation channel of [His - H]- involves loss of NH3 with a high KER of 769 meV. Dissociation of [His2 + H]+ is dominated by loss of the monomer but smaller losses are also observed. CONCLUSIONS The KER for HCOOH loss from both [His + H]+ and [His - H]- is similar at 278 and 249 meV, respectively, which suggests that the collision-induced dissociation takes place via a similar mechanism. The loss of COOH and C2 H5 NO2 from the dimer suggests that the dimer of His binds through a shared proton between the imidazole moieties.
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Affiliation(s)
- Jusuf M Khreis
- Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck (CMBI), Leopold Franzens Universität Innsbruck, Technikerstrasse 25, 6020, Innsbruck, Austria
| | - Julia Reitshammer
- Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck (CMBI), Leopold Franzens Universität Innsbruck, Technikerstrasse 25, 6020, Innsbruck, Austria
| | | | - Kevin Klawitter
- Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck (CMBI), Leopold Franzens Universität Innsbruck, Technikerstrasse 25, 6020, Innsbruck, Austria
| | - Linda Feketeová
- Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck (CMBI), Leopold Franzens Universität Innsbruck, Technikerstrasse 25, 6020, Innsbruck, Austria
- Université de Lyon, Université Claude Bernard Lyon1, CNRS/IN2P3, UMR5822, Institut de Physique Nucléaire de Lyon, 43 Bd du 11 novembre 1918, 69622, Villeurbanne, France
| | - Stephan Denifl
- Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck (CMBI), Leopold Franzens Universität Innsbruck, Technikerstrasse 25, 6020, Innsbruck, Austria
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Chan B, Moran D, Easton CJ, Radom L. Impact of Hydrogen Bonding on the Susceptibility of Peptides to Oxidation. Chem Asian J 2017; 12:1485-1489. [PMID: 28544486 DOI: 10.1002/asia.201700492] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Indexed: 01/12/2023]
Abstract
The tendency of peptides to be oxidized is intimately connected with their function and even their ability to exist in an oxidative environment. Here we report high-level theoretical studies that show that hydrogen bonding can alter the susceptibility of peptides to oxidation, with complexation to a hydrogen-bond acceptor facilitating oxidation, and vice versa, impacting the feasibility of a diverse range of biological processes. It can even provide an energetically viable mechanistic alternative to direct hydrogen-atom abstraction. We find that hydrogen bonding to representative reactive groups leads to a broad (≈400 kJ mol-1 ) spectrum of ionization energies in the case of model amide, thiol and phenol systems. While some of the oxidative processes at the extreme ends of the spectrum are energetically prohibitive, subtle environmental and solvent effects could potentially mitigate the situation, leading to a balance between hydrogen bonding and oxidative susceptibility.
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Affiliation(s)
- Bun Chan
- Graduate School of Engineering, Nagasaki University, Nagasaki, 852-8521, Japan
| | - Damian Moran
- School of Chemistry, University of Sydney, Sydney, NSW, 2006, Australia
| | - Christopher J Easton
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia
| | - Leo Radom
- School of Chemistry, University of Sydney, Sydney, NSW, 2006, Australia
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17
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Darii E, Alves S, Gimbert Y, Perret A, Tabet JC. Meaning and consequence of the coexistence of competitive hydrogen bond/salt forms on the dissociation orientation of non-covalent complexes. J Chromatogr B Analyt Technol Biomed Life Sci 2017; 1047:45-58. [DOI: 10.1016/j.jchromb.2016.09.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 07/23/2016] [Accepted: 09/25/2016] [Indexed: 10/20/2022]
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18
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Barbier Saint Hilaire P, Warnet A, Gimbert Y, Hohenester UM, Giorgi G, Olivier MF, Fenaille F, Colsch B, Junot C, Tabet JC. Mechanistic study of competitive releases of H 2O, NH 3 and CO 2 from deprotonated aspartic and glutamic acids: Role of conformation. J Chromatogr B Analyt Technol Biomed Life Sci 2016; 1047:64-74. [PMID: 27592168 DOI: 10.1016/j.jchromb.2016.08.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 07/22/2016] [Accepted: 08/22/2016] [Indexed: 11/27/2022]
Abstract
The aims of this study were to highlight the impact of minor structural differences (e.g. an aminoacid side chain enlargement by one methylene group), on ion dissociation under collision-induced dissociation conditions, and to determine the underlying chemical mechanisms. Therefore, we compared fragmentations of deprotonated aspartic and glutamic acids generated in negative electrospray ionization. Energy-resolved mass spectrometry breakdown curves were recorded and MS3 experiments performed on an Orbitrap Fusion for high-resolution and high-mass accuracy measurements. Activated fragmentations were performed using both the resonant and non-resonant excitation modes (i.e., CID and HCD, respectively) in order to get complementary information on the competitive and consecutive dissociative pathways. These experiments showed a specific loss of ammonia from the activated aspartate but not from the activated glutamate. We mainly focused on this specific observed loss from aspartate. Two different mechanisms based on intramolecular reactions (similar to those occurring in organic chemistry) were proposed, such as intramolecular elimination (i.e. Ei-like) and nucleophilic substitution (i.e. SNi-like) reactions, respectively, yielding anions as fumarate and α lactone from a particular conformation with the lowest steric hindrance (i.e. with antiperiplanar carboxyl groups). The detected deaminated aspartate anion can then release CO2 as observed in the MS3 experimental spectra. However, quantum calculations did not indicate the formation of such a deaminated aspartate product ion without loss of carbon dioxide. Actually, calculations displayed the double neutral (NH3+CO2) loss as a concomitant pathway (from a particular conformation) with relative high activation energy instead of a consecutive process. This disagreement is apparent since the concomitant pathway may be changed into consecutive dissociations according to the collision energy i.e., at higher collision energy and at lower excitation conditions, respectively. The latter takes place by stabilization of the deaminated aspartate solvated with two residual molecules of water (present in the collision cell). This desolvated anion formed is an α lactone substituted by a methylene carboxylate group. The vibrational excitation acquired by [(D-H)-NH3]-during its isolation is enough to allow its prompt decarboxylation with a barrier lower than 8.4kJ/mol. In addition, study of glutamic acid-like diastereomers constituted by a cyclopropane, hindering any side chain rotation, confirms the impact of the three-dimensional geometry on fragmentation pathways. A significant specific loss of water is only observed for one of these diastereomers. Other experiments, such as stable isotope labeling, need to be performed to elucidate all the observed losses from activated aspartate and glutamate anions. These first mechanistic interpretations enhance understanding of this dissociative pathway and underline the necessity of studying fragmentation of a large number of various compounds to implement properly new algorithms for de novo elucidation of unknown metabolites.
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Affiliation(s)
| | - Anna Warnet
- CEA, iBiTec-S, SPI, LEMM, Metabohub Gif Sur Yvette, France; Université Paris VI (UPMC), CNRS UMR 7201, Paris Cedex 05, France.
| | - Yves Gimbert
- Université Grenoble Alpes et CNRS, DCM UMR 5250, Grenoble, France
| | | | - Gianluca Giorgi
- University of Siena, Department of Biotechnology, Chemistry and Pharmacy, Via Aldo Moro, I-53100 Siena, Italy
| | | | | | - Benoît Colsch
- CEA, iBiTec-S, SPI, LEMM, Metabohub Gif Sur Yvette, France
| | | | - Jean-Claude Tabet
- CEA, iBiTec-S, SPI, LEMM, Metabohub Gif Sur Yvette, France; Université Paris VI (UPMC), CNRS UMR 7201, Paris Cedex 05, France
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19
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Calculated bond dissociation energies and enthalpy of formation of α-amino acid radicals. Theor Chem Acc 2016. [DOI: 10.1007/s00214-016-1975-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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20
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Schauperl M, Podewitz M, Waldner BJ, Liedl KR. Enthalpic and Entropic Contributions to Hydrophobicity. J Chem Theory Comput 2016; 12:4600-10. [PMID: 27442443 PMCID: PMC5024328 DOI: 10.1021/acs.jctc.6b00422] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hydrophobic hydration plays a key role in a vast variety of biological processes, ranging from the formation of cells to protein folding and ligand binding. Hydrophobicity scales simplify the complex process of hydration by assigning a value describing the averaged hydrophobic character to each amino acid. Previously published scales were not able to calculate the enthalpic and entropic contributions to the hydrophobicity directly. We present a new method, based on Molecular Dynamics simulations and Grid Inhomogeneous Solvation Theory, that calculates hydrophobicity from enthalpic and entropic contributions. Instead of deriving these quantities from the temperature dependence of the free energy of hydration or as residual of the free energy and the enthalpy, we directly obtain these values from the phase space occupied by water molecules. Additionally, our method is able to identify regions with specific enthalpic and entropic properties, allowing to identify so-called "unhappy water" molecules, which are characterized by weak enthalpic interactions and unfavorable entropic constraints.
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Affiliation(s)
- Michael Schauperl
- Institute of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck , Innrain 80-82, A-6020 Innsbruck, Tyrol, Austria
| | - Maren Podewitz
- Institute of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck , Innrain 80-82, A-6020 Innsbruck, Tyrol, Austria
| | - Birgit J Waldner
- Institute of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck , Innrain 80-82, A-6020 Innsbruck, Tyrol, Austria
| | - Klaus R Liedl
- Institute of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck , Innrain 80-82, A-6020 Innsbruck, Tyrol, Austria
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Hadadi N, Ataman M, Hatzimanikatis V, Panayiotou C. Molecular thermodynamics of metabolism: quantum thermochemical calculations for key metabolites. Phys Chem Chem Phys 2016; 17:10438-53. [PMID: 25799954 DOI: 10.1039/c4cp05825a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The present work is the first of a series of papers aiming at a coherent and unified development of the thermodynamics of metabolism and the rationalization of feasibility analysis of metabolic pathways. The focus in this part is on high-level quantum chemical calculations of the thermochemical quantities of relatively heavy metabolites such as amino acids/oligopeptides, nucleosides, saccharides and their derivatives in the ideal gas state. The results of this study will be combined with the corresponding hydration/solvation results in subsequent parts of this work in order to derive the desired thermochemical quantities in aqueous solutions. The above metabolites exist in a vast conformational/isomerization space including rotational conformers, tautomers or anomers exhibiting often multiple or cooperative intramolecular hydrogen bonding. We examine the challenges posed by these features for the reliable estimation of thermochemical quantities. We discuss conformer search, conformer distribution and averaging processes. We further consider neutral metabolites as well as protonated and deprotonated metabolites. In addition to the traditional presentation of gas-phase acidities, basicities and proton affinities, we also examine heats and free energies of ionic species. We obtain simple linear relations between the thermochemical quantities of ions and the formation quantities of their neutral counterparts. Furthermore, we compare our calculations with reliable experimental measurements and predictive calculations from the literature, when available. Finally, we discuss the next steps and perspectives for this work.
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Affiliation(s)
- N Hadadi
- Laboratory of Computational Systems Biotechnology (LCSB), Swiss Federal Institute of Technology (EPFL), CH-1015 Lausanne, Switzerland
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22
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Stover ML, Plummer CE, Miller SR, Cassady CJ, Dixon DA. Gas-Phase Acidities of Phosphorylated Amino Acids. J Phys Chem B 2015; 119:14604-21. [DOI: 10.1021/acs.jpcb.5b08616] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michele L. Stover
- Chemistry
Department, Shelby
Hall, The University of Alabama, Shelby Hall, Box
870336, Tuscaloosa, Alabama 35487-0336, United States
| | - Chelsea E. Plummer
- Chemistry
Department, Shelby
Hall, The University of Alabama, Shelby Hall, Box
870336, Tuscaloosa, Alabama 35487-0336, United States
| | - Sean R. Miller
- Chemistry
Department, Shelby
Hall, The University of Alabama, Shelby Hall, Box
870336, Tuscaloosa, Alabama 35487-0336, United States
| | - Carolyn J. Cassady
- Chemistry
Department, Shelby
Hall, The University of Alabama, Shelby Hall, Box
870336, Tuscaloosa, Alabama 35487-0336, United States
| | - David A. Dixon
- Chemistry
Department, Shelby
Hall, The University of Alabama, Shelby Hall, Box
870336, Tuscaloosa, Alabama 35487-0336, United States
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Brea O, Mó O, Yáñez M. Ga(+) Basicity and Affinity Scales Based on High-Level Ab Initio Calculations. Chemphyschem 2015; 16:3206-13. [PMID: 26269224 DOI: 10.1002/cphc.201500574] [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: 07/20/2015] [Indexed: 11/12/2022]
Abstract
The structure, relative stability and bonding of complexes formed by the interaction between Ga(+) and a large set of compounds, including hydrocarbons, aromatic systems, and oxygen-, nitrogen-, fluorine and sulfur-containing Lewis bases have been investigated through the use of the high-level composite ab initio Gaussian-4 theory. This allowed us to establish rather accurate Ga(+) cation affinity (GaCA) and Ga(+) cation basicity (GaCB) scales. The bonding analysis of the complexes under scrutiny shows that, even though one of the main ingredients of the Ga(+) -base interaction is electrostatic, it exhibits a non-negligible covalent character triggered by the presence of the low-lying empty 4p orbital of Ga(+) , which favors a charge donation from occupied orbitals of the base to the metal ion. This partial covalent character, also observed in AlCA scales, is behind the dissimilarities observed when GaCA are compared with Li(+) cation affinities, where these covalent contributions are practically nonexistent. Quite unexpectedly, there are some dissimilarities between several Ga(+) -complexes and the corresponding Al(+) -analogues, mainly affecting the relative stability of π-complexes involving aromatic compounds.
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Affiliation(s)
- Oriana Brea
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, Campus de Excelencia UAM-CSIC, Cantoblanco, 28049, Madrid, Spain), Fax
| | - Otilia Mó
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, Campus de Excelencia UAM-CSIC, Cantoblanco, 28049, Madrid, Spain), Fax
| | - Manuel Yáñez
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, Campus de Excelencia UAM-CSIC, Cantoblanco, 28049, Madrid, Spain), Fax.
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Khairallah GN, Maccarone AT, Pham HT, Benton TM, Ly T, da Silva G, Blanksby SJ, O'Hair RAJ. Radical Formation in the Gas-Phase Ozonolysis of Deprotonated Cysteine. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201506019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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25
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Khairallah GN, Maccarone AT, Pham HT, Benton TM, Ly T, da Silva G, Blanksby SJ, O'Hair RAJ. Radical Formation in the Gas‐Phase Ozonolysis of Deprotonated Cysteine. Angew Chem Int Ed Engl 2015; 54:12947-51. [DOI: 10.1002/anie.201506019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Indexed: 11/07/2022]
Affiliation(s)
- George N. Khairallah
- School of Chemistry and Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010 (Australia)
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology (Australia)
| | - Alan T. Maccarone
- School of Chemistry, University of Wollongong, New South Wales 2522 (Australia)
| | - Huong T. Pham
- School of Chemistry, University of Wollongong, New South Wales 2522 (Australia)
| | - Timothy M. Benton
- School of Chemistry and Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010 (Australia)
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology (Australia)
| | - Tony Ly
- School of Chemistry, University of Wollongong, New South Wales 2522 (Australia)
| | - Gabriel da Silva
- Department of Chemical and Biomolecular Engineering, The University of Melbourne, Melbourne, Victoria 3010 (Australia)
| | - Stephen J. Blanksby
- Central Analytical Research Facility, Queensland University of Technology, Queensland 4001 (Australia)
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology (Australia)
| | - Richard A. J. O'Hair
- School of Chemistry and Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010 (Australia)
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology (Australia)
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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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Plummer CE, Stover ML, Bokatzian SS, Davis JTM, Dixon DA, Cassady CJ. An Experimental and Computational Study of the Gas-Phase Acidities of the Common Amino Acid Amides. J Phys Chem B 2015. [PMID: 26196065 DOI: 10.1021/acs.jpcb.5b04486] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Using proton-transfer reactions in a Fourier transform ion cyclotron resonance mass spectrometer and correlated molecular orbital theory at the G3(MP2) level, gas-phase acidities (GAs) and the associated structures for amides corresponding to the common amino acids have been determined for the first time. These values are important because amino acid amides are models for residues in peptides and proteins. For compounds whose most acidic site is the C-terminal amide nitrogen, two ions populations were observed experimentally with GAs that differ by 4-7 kcal/mol. The lower energy, more acidic structure accounts for the majority of the ions formed by electrospray ionization. G3(MP2) calculations predict that the lowest energy anionic conformer has a cis-like orientation of the [-C(═O)NH](-) group whereas the higher energy, less acidic conformer has a trans-like orientation of this group. These two distinct conformers were predicted for compounds with aliphatic, amide, basic, hydroxyl, and thioether side chains. For the most acidic amino acid amides (tyrosine, cysteine, tryptophan, histidine, aspartic acid, and glutamic acid amides) only one conformer was observed experimentally, and its experimental GA correlates with the theoretical GA related to side chain deprotonation.
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Affiliation(s)
- Chelsea E Plummer
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Michele L Stover
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Samantha S Bokatzian
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - John T M Davis
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - David A Dixon
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Carolyn J Cassady
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
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Bokatzian SS, Stover ML, Plummer CE, Dixon DA, Cassady CJ. An Experimental and Computational Investigation into the Gas-Phase Acidities of Tyrosine and Phenylalanine: Three Structures for Deprotonated Tyrosine. J Phys Chem B 2014; 118:12630-43. [DOI: 10.1021/jp510037c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Samantha S. Bokatzian
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Michele L. Stover
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Chelsea E. Plummer
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - David A. Dixon
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Carolyn J. Cassady
- Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
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Sengupta A, Raghavachari K. Prediction of Accurate Thermochemistry of Medium and Large Sized Radicals Using Connectivity-Based Hierarchy (CBH). J Chem Theory Comput 2014; 10:4342-50. [DOI: 10.1021/ct500484f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Arkajyoti Sengupta
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Krishnan Raghavachari
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
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Sengupta A, Ramabhadran RO, Raghavachari K. Accurate and Computationally Efficient Prediction of Thermochemical Properties of Biomolecules Using the Generalized Connectivity-Based Hierarchy. J Phys Chem B 2014; 118:9631-43. [DOI: 10.1021/jp505544y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Arkajyoti Sengupta
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | | | - Krishnan Raghavachari
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
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Grossert JS, Cubero Herrera L, Ramaley L, Melanson JE. Studying the chemistry of cationized triacylglycerols using electrospray ionization mass spectrometry and density functional theory computations. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:1421-1440. [PMID: 24867430 DOI: 10.1007/s13361-014-0917-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 04/01/2014] [Accepted: 04/02/2014] [Indexed: 06/03/2023]
Abstract
Analysis of triacylglycerols (TAGs), found as complex mixtures in living organisms, is typically accomplished using liquid chromatography, often coupled to mass spectrometry. TAGs, weak bases not protonated using electrospray ionization, are usually ionized by adduct formation with a cation, including those present in the solvent (e.g., Na(+)). There are relatively few reports on the binding of TAGs with cations or on the mechanisms by which cationized TAGs fragment. This work examines binding efficiencies, determined by mass spectrometry and computations, for the complexation of TAGs to a range of cations (Na(+), Li(+), K(+), Ag(+), NH4(+)). While most cations bind to oxygen, Ag(+) binding to unsaturation in the acid side chains is significant. The importance of dimer formation, [2TAG + M](+) was demonstrated using several different types of mass spectrometers. From breakdown curves, it became apparent that two or three acid side chains must be attached to glycerol for strong cationization. Possible mechanisms for fragmentation of lithiated TAGs were modeled by computations on tripropionylglycerol. Viable pathways were found for losses of neutral acids and lithium salts of acids from different positions on the glycerol moiety. Novel lactone structures were proposed for the loss of a neutral acid from one position of the glycerol moiety. These were studied further using triple-stage mass spectrometry (MS(3)). These lactones can account for all the major product ions in the MS(3) spectra in both this work and the literature, which should allow for new insights into the challenging analytical methods needed for naturally occurring TAGs.
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Affiliation(s)
- J Stuart Grossert
- National Research Council Canada, Halifax, Nova Scotia, B3H 3Z1, Canada,
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Dorofeeva OV, Ryzhova ON. Gas-phase enthalpies of formation and enthalpies of sublimation of amino acids based on isodesmic reaction calculations. J Phys Chem A 2014; 118:3490-502. [PMID: 24766636 DOI: 10.1021/jp501357y] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Accurate gas-phase enthalpies of formation (ΔfH298°) of 20 common α-amino acids, seven uncommon amino acids, and three small peptides were calculated by combining G4 theory calculations with an isodesmic reaction approach. The internal consistency over a set of ΔfH298°(g) values was achieved by sequential adjustment of their values through the isodesmic reactions. Four amino acids, alanine, β-alanine, sarcosine, and glycine, with reliable internally self-consistent experimental data, were chosen as the key reference compounds. These amino acids together with about 100 compounds with reliable experimental data (their accuracy was supported by G4 calculations) were used to estimate the enthalpies of formation of remaining amino acids. All of the amino acids with the previously established enthalpies of formation were later used as the reference species in the isodesmic reactions for the other amino acids. A systematic comparison was made of 14 experimentally determined enthalpies of formation with the results of calculations. The experimental enthalpies of formation for 10 amino acids were reproduced with good accuracy, but the experimental and calculated values for 4 compounds differed by 11–21 kJ/mol. For these species, the theoretical ΔfH298°(g) values were suggested as more reliable than the experimental values. On the basis of theoretical results, the recommended values for the gas-phase enthalpies of formation were also provided for amino acids for which the experimental ΔfH298°(g) were not available. The enthalpies of sublimation were evaluated for all compounds by taking into account the literature data on the solid-phase enthalpies of formation and the ΔfH298°(g) values recommended in our work. A special attention was paid to the accurate prediction of enthalpies of formation of amino acids from the atomization reactions. The problems associated with conformational flexibility of these compounds and harmonic treatment of low frequency torsional modes were discussed. The surprisingly good agreement between the ΔfH298°(g) values calculated from the atomization and isodesmic reactions is largely the result of a fortuitous mutual compensation of various corrections used in the atomization reaction procedure.
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Affiliation(s)
- Olga V Dorofeeva
- Department of Chemistry, Lomonosov Moscow State University , Moscow 119991, Russia
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33
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Karton A, Yu LJ, Kesharwani MK, Martin JML. Heats of formation of the amino acids re-examined by means of W1-F12 and W2-F12 theories. Theor Chem Acc 2014. [DOI: 10.1007/s00214-014-1483-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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34
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Kang YK, Park HS. Assessment of CCSD(T), MP2, DFT-D, CBS-QB3, and G4(MP2) methods for conformational study of alanine and proline dipeptides. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.03.067] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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35
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DeBlase AF, Kass SR, Johnson MA. On the character of the cyclic ionic H-bond in cryogenically cooled deprotonated cysteine. Phys Chem Chem Phys 2014; 16:4569-75. [DOI: 10.1039/c3cp54117g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Gupta M, da Silva EF, Svendsen HF. Explicit Solvation Shell Model and Continuum Solvation Models for Solvation Energy and pKa Determination of Amino Acids. J Chem Theory Comput 2013; 9:5021-37. [DOI: 10.1021/ct400459y] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mayuri Gupta
- Department
of Chemical Engineering, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Eirik F. da Silva
- Department
of Process Technology, SINTEF Materials and Chemistry, N-7465 Trondheim, Norway
| | - Hallvard F. Svendsen
- Department
of Chemical Engineering, Norwegian University of Science and Technology, 7491 Trondheim, Norway
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Martins-Costa MTC, Ruiz-Lopez MF. Amino Acid Capture by Aqueous Interfaces. Implications for Biological Uptake. J Phys Chem B 2013; 117:12469-74. [DOI: 10.1021/jp4083689] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marilia T. C. Martins-Costa
- SRSMC,
UMR 7565, University of Lorraine, BP 70239, 54506, Vandoeuvre-les-Nancy, France
- SRSMC, UMR 7565, CNRS, BP 70239, 54506, Vandoeuvre-les-Nancy, France
| | - Manuel F. Ruiz-Lopez
- SRSMC,
UMR 7565, University of Lorraine, BP 70239, 54506, Vandoeuvre-les-Nancy, France
- SRSMC, UMR 7565, CNRS, BP 70239, 54506, Vandoeuvre-les-Nancy, France
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38
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Amorim Madeira PJ, Vaz PD, Bettencourt da Silva RJN, Florêncio MH. Can Semi-empirical Calculations Help Solve Mass Spectrometry Problems? Protonation Sites and Proton Affinities of Amino Acids. Chempluschem 2013; 78:1149-1156. [DOI: 10.1002/cplu.201300173] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/19/2013] [Indexed: 11/10/2022]
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Ramabhadran RO, Sengupta A, Raghavachari K. Application of the Generalized Connectivity-Based Hierarchy to Biomonomers: Enthalpies of Formation of Cysteine and Methionine. J Phys Chem A 2013; 117:4973-80. [DOI: 10.1021/jp403123c] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Arkajyoti Sengupta
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United
States
| | - Krishnan Raghavachari
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United
States
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40
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Schmidt J, Kass SR. Zwitterion vs Neutral Structures of Amino Acids Stabilized by a Negatively Charged Site: Infrared Photodissociation and Computations of Proline–Chloride Anion. J Phys Chem A 2013; 117:4863-9. [DOI: 10.1021/jp402267c] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Jacob Schmidt
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Steven R. Kass
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
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Bokatzian-Johnson SS, Stover ML, Dixon DA, Cassady CJ. Gas-Phase Deprotonation of the Peptide Backbone for Tripeptides and Their Methyl Esters with Hydrogen and Methyl Side Chains. J Phys Chem B 2012. [DOI: 10.1021/jp3113528] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
| | - Michele L. Stover
- Department
of Chemistry, University of Alabama, Tuscaloosa, Alabama 35487, United
States
| | - David A. Dixon
- Department
of Chemistry, University of Alabama, Tuscaloosa, Alabama 35487, United
States
| | - Carolyn J. Cassady
- Department
of Chemistry, University of Alabama, Tuscaloosa, Alabama 35487, United
States
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42
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Bokatzian-Johnson SS, Stover ML, Dixon DA, Cassady CJ. A comparison of the effects of amide and acid groups at the C-terminus on the collision-induced dissociation of deprotonated peptides. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:1544-1557. [PMID: 22833234 DOI: 10.1007/s13361-012-0431-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 05/10/2012] [Accepted: 06/12/2012] [Indexed: 06/01/2023]
Abstract
The dissociative behavior of peptide amides and free acids was explored using low-energy collision-induced dissociation and high level computational theory. Both positive and negative ion modes were utilized, but the most profound differences were observed for the deprotonated species. Deprotonated peptide amides produce a characteristic c(m-2)(-) product ion (where m is the number of residues in the peptide) that is either absent or in low abundance in the analogous peptide acid spectrum. Peptide acids show an enhanced formation of c(m-3)(-); however, this is not generally as pronounced as c(m-2)(-) production from amides. The most notable occurrence of an amide-specific product ion is for laminin amide (YIGSR-NH(2)) and this case was investigated using several modified peptides. Mechanisms involving 6- and 9-membered ring formation were proposed, and their energetic properties were investigated using G3(MP2) molecular orbital theory calculations. For example, with C-terminal deprotonation of pentaglycine amide, formation of c(m-2)(-) and a 6-membered ring diketopiperazine neutral requires >31.6 kcal/mol, which is 26.1 kcal/mol less than the analogous process involving the peptide acid. The end group specific fragmentation of peptide amides in the negative ion mode may be useful for identifying such groups in proteomic applications.
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Roux MV, Notario R, Segura M, Chickos JS, Liebman JF. The enthalpy of formation of methionine revisited. J PHYS ORG CHEM 2012. [DOI: 10.1002/poc.2961] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- María Victoria Roux
- Institute of Physical Chemistry “Rocasolano”; CSIC; Serrano 119 28006 Madrid Spain
| | - Rafael Notario
- Institute of Physical Chemistry “Rocasolano”; CSIC; Serrano 119 28006 Madrid Spain
| | - Marta Segura
- Perkin Elmer España S.L.; Ronda de Poniente 19, 28760 Tres Cantos Madrid Spain
| | - James S. Chickos
- Department of Chemistry and Biochemistry; University of Missouri-St. Louis; One University Boulevard St. Louis Missouri 63121-4499 USA
| | - Joel F. Liebman
- Department of Chemistry and Biochemistry; University of Maryland; Baltimore County Baltimore MD 21250 USA
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