1
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Ruppert M, Creon A, Tidow H, Huse N. Population Dynamics of Stretching Excitations of p-Azido-phenylalanine Incorporated in Calmodulin-Peptide Complexes. J Phys Chem B 2022; 126:368-375. [PMID: 34990136 DOI: 10.1021/acs.jpcb.1c06775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We genetically incorporated the unnatural amino acid p-azido-phenylalanine (AzF) into the ubiquitous Ca2+ sensor protein calmodulin (CaM) in complex with different peptides to explore the response of the azido stretching line shape to varying binding motifs with femtosecond infrared spectroscopy. The dynamic response of the azido stretching mode varies in different CaM-peptide complexes. We model these dynamics as coherent excitations of Fermi resonances and extract a lifetime of the azido stretching vibration of about 1 ps. The resulting model parameters are commensurate with the linear infrared absorption lineshapes which suggests that the conformation-sensitive vibrational lineshape could be composed of Fermi resonances that differ between the protein-peptide complexes.
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Affiliation(s)
- Matthias Ruppert
- Hamburg Advanced Research Centre for Bioorganic Chemistry, Institute for Nanostructure and Solid-State Physics, Department of Physics, and Center for Free-Electron Laser Science, University of Hamburg, Luruper Chaussee 149, D-22761 Hamburg, Germany
| | - Anne Creon
- Hamburg Advanced Research Centre for Bioorganic Chemistry, Institute for Nanostructure and Solid-State Physics, Department of Physics, and Center for Free-Electron Laser Science, University of Hamburg, Luruper Chaussee 149, D-22761 Hamburg, Germany.,Hamburg Advanced Research Centre for Bioorganic Chemistry, Institute for Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, D-20146 Hamburg, Germany
| | - Henning Tidow
- Hamburg Advanced Research Centre for Bioorganic Chemistry, Institute for Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, D-20146 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, University of Hamburg, Luruper Chaussee, 149, D-22761 Hamburg, Germany
| | - Nils Huse
- Hamburg Advanced Research Centre for Bioorganic Chemistry, Institute for Nanostructure and Solid-State Physics, Department of Physics, and Center for Free-Electron Laser Science, University of Hamburg, Luruper Chaussee 149, D-22761 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, University of Hamburg, Luruper Chaussee, 149, D-22761 Hamburg, Germany
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2
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Malm C, Prädel LA, Marekha BA, Grechko M, Hunger J. Composition-Dependent Hydrogen-Bonding Motifs and Dynamics in Brønsted Acid-Base Mixtures. J Phys Chem B 2020; 124:7229-7238. [PMID: 32701282 PMCID: PMC7443859 DOI: 10.1021/acs.jpcb.0c04714] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
In
recent years the interaction of organophosphates and imines,
which is at the core of Brønsted acid organocatalysis, has been
established to be based on strong ionic hydrogen bonds. Yet, besides
the formation of homodimers consisting of two acid molecules and heterodimers
consisting of one acid and one base, also multimeric molecular aggregates
are formed in solution. These multimeric aggregates consist of one
base and several acid molecules. The details of the intermolecular
bonding in such aggregates, however, have remained elusive. To characterize
composition-dependent bonding and bonding dynamics in these aggregates,
we use linear and nonlinear infrared (IR) spectroscopy at varying
molar ratios of diphenyl phosphoric acid and quinaldine. We identify
the individual aggregate species, giving rise to the structured, strong,
and very broad infrared absorptions, which span more than 1000 cm–1. Linear infrared spectra and density functional theory
calculations of the proton transfer potential show that doubly ionic
intermolecular hydrogen bonds between the acid and the base lead to
absorptions which peak at ∼2040 cm–1. The
contribution of singly ionic hydrogen bonds between an acid anion
and an acid molecule is observed at higher frequencies. As common
to such strong hydrogen bonds, ultrafast IR spectroscopy reveals rapid,
∼ 100 fs, dissipation of energy from the proton transfer coordinate.
Yet, the full dissipation of the excess energy occurs on a ∼0.8–1.1
ps time scale, which becomes longer when multimers dominate. Our results
thus demonstrate the coupling and collectivity of the hydrogen bonds
within these complexes, which enable efficient energy transfer.
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Affiliation(s)
- Christian Malm
- Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Leon A Prädel
- Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Bogdan A Marekha
- Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Maksim Grechko
- Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Johannes Hunger
- Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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3
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Giubertoni G, Sofronov OO, Bakker HJ. Effect of intramolecular hydrogen-bond formation on the molecular conformation of amino acids. Commun Chem 2020; 3:84. [PMID: 36703397 PMCID: PMC9814578 DOI: 10.1038/s42004-020-0329-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 05/21/2020] [Indexed: 01/29/2023] Open
Abstract
The molecular conformation of the carboxyl group can be crucial for its chemical properties and intermolecular interactions, especially in complex molecular environments such as polypeptides. Here, we study the conformational behaviour of the model amino acid N-acetylproline in solution at room temperature with two-dimensional infrared spectroscopy. We find that the carboxyl group of N-acetylproline adopts two distinct conformations, syn- and anti-. In the syn-conformer the O-H group is oriented at ~60∘ with respect to the C=O and in the anti-conformer the O-H is anti-parallel to the C=O. In hydrogen-bond accepting solvents such as dimethyl sulfoxide or water, we observe that, similar to simple carboxylic acids, around 20% of the -COOH groups adopt an anti-conformation. However, when N-acetylproline is dissolved in a weakly hydrogen-bond accepting solvent (acetonitrile), we observe the formation of a strong intramolecular hydrogen bond between the carboxyl group in the anti-conformation and the amide group, which stabilizes the anti-conformer, increasing its relative abundance to ~60%.
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Affiliation(s)
- Giulia Giubertoni
- grid.417889.b0000 0004 0646 2441AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Oleksandr O. Sofronov
- grid.417889.b0000 0004 0646 2441AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Huib J. Bakker
- grid.417889.b0000 0004 0646 2441AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
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4
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Sofronov O, Giubertoni G, Pérez de Alba Ortíz A, Ensing B, Bakker HJ. Peptide Side-COOH Groups Have Two Distinct Conformations under Biorelevant Conditions. J Phys Chem Lett 2020; 11:3466-3472. [PMID: 32293901 PMCID: PMC7212517 DOI: 10.1021/acs.jpclett.0c00711] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 04/15/2020] [Indexed: 06/11/2023]
Abstract
The carboxyl (COOH) side chain groups of amino acids, such as aspartic acid, play an important role in biochemical processes, including enzymatic proton transport. In many theoretical studies, it was found that the (bio)chemical reactivity of the carboxyl group strongly depends on the conformation of this group. Interestingly, up to now there has been no experimental investigation of the geometry and the stability of different COOH conformers under biorelevant conditions. Here, we investigate the conformational isomerism of the side chain COOH group of N-acetyl aspartic acid amide using polarization-resolved two-dimensional infrared spectroscopy. We find that the carboxyl group shows two distinct near-planar conformers (syn and anti) when dissolved in water at room temperature. Both conformers are significantly populated in aqueous solution (75 ± 10% and 25 ± 10% for syn and anti, respectively). Molecular dynamics simulations show that the anti conformer interacts more strongly with water molecules than the syn conformer, explaining why this conformer is significantly present in aqueous solution.
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Affiliation(s)
| | | | - Alberto Pérez de Alba Ortíz
- Amsterdam
Center for Multiscale Modeling and Van ’t Hoff Institute for
Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bernd Ensing
- Amsterdam
Center for Multiscale Modeling and Van ’t Hoff Institute for
Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Huib J. Bakker
- AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
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5
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Pagano P, Guo Q, Ranasinghe C, Schroeder E, Robben K, Häse F, Ye H, Wickersham K, Aspuru-Guzik A, Major DT, Gakhar L, Kohen A, Cheatum CM. Oscillatory Active-site Motions Correlate with Kinetic Isotope Effects in Formate Dehydrogenase. ACS Catal 2019; 9:11199-11206. [PMID: 33996196 PMCID: PMC8118594 DOI: 10.1021/acscatal.9b03345] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Thermal motions of enzymes have been invoked to explain the temperature dependence of kinetic isotope effects (KIE) in enzyme-catalyzed hydride transfers. Formate dehydrogenase (FDH) from Candida boidinii exhibits a temperature independent KIE that becomes temperature dependent upon mutation of hydrophobic residues in the active site. Ternary complexes of FDH that mimic the transition state structure allow investigation of how these mutations influence active-site dynamics. A combination of X-ray crystallography, two-dimensional infrared (2D IR) spectroscopy, and molecular dynamic simulations characterize the structure and dynamics of the active site. FDH exhibits oscillatory frequency fluctuations on the picosecond timescale, and the amplitude of these fluctuations correlates with the temperature dependence of the KIE. Both the kinetic and dynamic phenomena can be reproduced computationally. These results provide experimental evidence for a connection between the temperature dependence of KIEs and motions of the active site in an enzyme-catalyzed reaction consistent with activated tunneling models of the hydride transfer reaction.
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Affiliation(s)
- Philip Pagano
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, United States
| | - Qi Guo
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, United States
| | - Chethya Ranasinghe
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, United States
| | - Evan Schroeder
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, United States
| | - Kevin Robben
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, United States
| | - Florian Häse
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States
| | - Hepeng Ye
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, United States
| | - Kyle Wickersham
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, United States
| | - Alán Aspuru-Guzik
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States
- Senior Fellow, Canadian Institute for Advanced Research (CIFAR), Toronto, Ontario M5G 1Z8, Canada
| | - Dan T. Major
- Chemistry Department, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Lokesh Gakhar
- Protein Crystallography Facility and Department of Biochemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Amnon Kohen
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, United States
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6
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Balasubramanian M, Reynolds A, Blair TJ, Khalil M. Probing ultrafast vibrational dynamics of intramolecular hydrogen bonds with broadband infrared pump-probe spectroscopy. Chem Phys 2019. [DOI: 10.1016/j.chemphys.2018.11.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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7
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Zhang J, Wang L, Zhang J, Zhu J, Pan X, Cui Z, Wang J, Fang W, Li Y. Identifying and Modulating Accidental Fermi Resonance: 2D IR and DFT Study of 4-Azido-l-phenylalanine. J Phys Chem B 2018; 122:8122-8133. [DOI: 10.1021/acs.jpcb.8b03887] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Jia Zhang
- Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Li Wang
- Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Jin Zhang
- Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Jiangrui Zhu
- Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Xin Pan
- Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
- College of Physics and Electric Information, Anhui Normal University, Wuhu 241000, People’s Republic of China
| | - Zhifeng Cui
- College of Physics and Electric Information, Anhui Normal University, Wuhu 241000, People’s Republic of China
| | - Jiangyun Wang
- Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
| | - Weihai Fang
- College of Chemistry, Beijing Normal University, Beijing 100875, People’s Republic of China
| | - Yunliang Li
- Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
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8
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Stingel AM, Petersen PB. Interpreting Quasi-Thermal Effects in Ultrafast Spectroscopy of Hydrogen-Bonded Systems. J Phys Chem A 2018; 122:2670-2676. [PMID: 29466009 DOI: 10.1021/acs.jpca.7b12372] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Vibrational excitation of molecules in the condensed phase relaxes through vibrational modes of decreasing energy to ultimately generate an equilibrium state in which the energy is distributed among low-frequency modes. In ultrafast vibrational spectroscopy, changes in the vibrational features of hydrogen-bonded NH and OH stretch modes are typically observed to persist long after these high-frequency vibrations have relaxed. Due to the resemblance to the spectral changes caused by heating the sample, these features are typically described as arising from a hot ground state. However, these spectral features appear on ultrafast time scales that are much too fast to result from a true thermal state, and significant differences between the thermal difference spectrum and the induced quasi-thermal changes in ultrafast spectroscopy are often observed. Here, we examine and directly compare the thermal and quasi-thermal responses of the hydrogen-bonded homodimer of 7-azaindole with temperature-dependent FTIR spectroscopy and ultrafast mid-IR continuum spectroscopy. We find that the thermal difference spectra contain contributions from both dissociation of the hydrogen bonds and from frequency shifts due to changes in the thermal population of low-frequency modes. The transient spectra in ultrafast vibrational spectroscopy are also found to contain two contributions: initial frequency shifts over 2.3 ± 0.11 ps associated with equilibration of the initial excitation, and frequency shifts associated with the excitation of several fingerprint modes, which decay over 21.8 ± 0.11 ps, giving rise to a quasi-thermal response caused by a distribution of fingerprint modes being excited within the sample ensemble. This resembles the thermal frequency shifts due to population changes of low-frequency modes, but not the overall thermal spectrum, which is dominated by features caused by dimer dissociation. These findings provide insight into the changes in the vibrational spectrum from different origins and are important for assigning, analyzing, and comparing features in thermal and ultrafast vibrational spectroscopy of hydrogen-bonded complexes.
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Affiliation(s)
- Ashley M Stingel
- Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
| | - Poul B Petersen
- Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
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9
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Stingel AM, Petersen PB. Couplings Across the Vibrational Spectrum Caused by Strong Hydrogen Bonds: A Continuum 2D IR Study of the 7-Azaindole–Acetic Acid Heterodimer. J Phys Chem B 2016; 120:10768-10779. [DOI: 10.1021/acs.jpcb.6b05049] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Ashley M. Stingel
- Department
of Chemistry and
Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Poul B. Petersen
- Department
of Chemistry and
Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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10
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Wierzbicka E, Boczar M, Wójcik MJ. Investigation of hydrogen bonds properties in the terephthalic acid crystal, using molecular dynamics method. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 130:488-493. [PMID: 24813277 DOI: 10.1016/j.saa.2014.03.125] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 03/19/2014] [Accepted: 03/29/2014] [Indexed: 06/03/2023]
Abstract
The aim of this study was to perform calculations using the method of Car-Parrinello molecular dynamics, leading to the optimized geometry of the molecules of 1,4-benzenedicarboxylic acid (terephthalic acid) in crystals, for the hydrogen form and three variants of substitution of deuterium atoms inside a carboxyl group. Based on the results, trajectories and dipole moments were calculated, what makes possible to simulate vibrations in different systems, and to make calculation of theoretical infrared spectra and atomic power spectra. Theoretical results were compared with the experimental spectra, which verifies the correctness of the method and also was compared with the results obtained by quantum-mechanical calculations using DFT for the isolated dimer. Comparison of the spectra of different forms, allowed for in-depth analysis of the effect of isotopic substitution on the frequency of vibrations and shapes of bands, and confirm the presence of possible coupling effects and intra- and intermolecular interactions. Comparison with the DFT results for the dimer show influence of the crystal structure on the spectra.
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Affiliation(s)
- Ewa Wierzbicka
- Department of Physical Chemistry & Electrochemistry, Faculty of Chemistry, Jagiellonian University in Krakow, Ingardena 3, 30060 Krakow, Poland
| | - Marek Boczar
- Department of Physical Chemistry & Electrochemistry, Faculty of Chemistry, Jagiellonian University in Krakow, Ingardena 3, 30060 Krakow, Poland
| | - Marek J Wójcik
- Department of Physical Chemistry & Electrochemistry, Faculty of Chemistry, Jagiellonian University in Krakow, Ingardena 3, 30060 Krakow, Poland.
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11
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Tomkins J, Hanna G. Signatures of nanoconfinement on the linear and nonlinear vibrational spectroscopy of a model hydrogen-bonded complex dissolved in a polar solvent. J Phys Chem B 2013; 117:13619-30. [PMID: 24079369 DOI: 10.1021/jp407469f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The one-dimensional IR (1D-IR) absorption and IR pump-probe spectra of a hydrogen stretch in a model hydrogen-bonded complex dissolved in a polar solvent confined in spherical hydrophobic cavities of different sizes were simulated using ground-state mixed quantum-classical dynamics. Due to a thorough analysis of key properties of the complex and solvent from equilibrium trajectory data, we were able to gain insight into the microscopic details underlying the spectra. Both the 1D-IR and IR pump-probe spectra manifested the effects of confinement on the relative stabilities of the covalent and ionic forms of the complex through pronounced changes in their peak intensities and numbers. However, in contrast to the 1D-IR spectra, the time-resolved pump-probe spectra were found to be uniquely sensitive to the changes in the molecular dynamics as the cavity size is varied. In particular, it was found that the variations in the time evolutions of the peak intensities in the pump-probe spectra reflect the differences in the solvation dynamics associated with the various forms of the complex in different locations within the cavities. The ability to detect these differences underscores the advantage of using pump-probe spectroscopy for studying nanoconfined systems.
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Affiliation(s)
- Joseph Tomkins
- Department of Chemistry, University of Alberta , Edmonton, Alberta, Canada T6G 2G2
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12
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Nydegger MW, Rock W, Cheatum CM. 2D IR Spectroscopy of the C–D stretching vibration of the deuterated formic acid dimer. Phys Chem Chem Phys 2011; 13:6098-104. [DOI: 10.1039/c0cp01087a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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13
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Nydegger MW, Dutta S, Cheatum CM. Two-dimensional infrared study of 3-azidopyridine as a potential spectroscopic reporter of protonation state. J Chem Phys 2010; 133:134506. [DOI: 10.1063/1.3483688] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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14
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Characterizing the dynamics of functionally relevant complexes of formate dehydrogenase. Proc Natl Acad Sci U S A 2010; 107:17974-9. [PMID: 20876138 DOI: 10.1073/pnas.0912190107] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The potential for femtosecond to picosecond time-scale motions to influence the rate of the intrinsic chemical step in enzyme-catalyzed reactions is a source of significant controversy. Among the central challenges in resolving this controversy is the difficulty of experimentally characterizing thermally activated motions at this time scale in functionally relevant enzyme complexes. We report a series of measurements to address this problem using two-dimensional infrared spectroscopy to characterize the time scales of active-site motions in complexes of formate dehydrogenase with the transition-state-analog inhibitor azide (N(3)(-)). We observe that the frequency-frequency time correlation functions (FFCF) for the ternary complexes with NAD(+) and NADH decay completely with slow time constants of 3.2 ps and 4.6 ps, respectively. This result suggests that in the vicinity of the transition state, the active-site enzyme structure samples a narrow and relatively rigid conformational distribution indicating that the transition-state structure is well organized for the reaction. In contrast, for the binary complex, we observe a significant static contribution to the FFCF similar to what is seen in other enzymes, indicating the presence of the slow motions that occur on time scales longer than our measurement window.
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15
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Hanna G, Geva E. Computational study of the signature of hydrogen-bond strength on the infrared spectra of a hydrogen-bonded complex dissolved in a polar liquid. Chem Phys 2010. [DOI: 10.1016/j.chemphys.2010.01.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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16
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Ghalla H, Rekik N, Michta A, Oujia B, Flakus HT. Theoretical modeling of infrared spectra of the hydrogen and deuterium bond in aspirin crystal. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2010; 75:37-47. [PMID: 19884041 DOI: 10.1016/j.saa.2009.09.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Revised: 09/06/2009] [Accepted: 09/13/2009] [Indexed: 05/28/2023]
Abstract
An extended quantum theoretical approach of the nu(X-H) IR lineshape of cyclic dimers of weakly H-bonded species is proposed. We have extended a previous approach [M.E.-A. Benmalti, P. Blaise, H.T. Flakus, O. Henri-Rousseau, Chem. Phys. 320 (2006) 267] by accounting for the anharmonicity of the slow mode which is described by a "Morse" potential in order to reproduce the polarized infrared spectra of the hydrogen and deuterium bond in acetylsalicylic acid (aspirin) crystals. From comparison of polarized IR spectra of isotopically neat and isotopically diluted aspirin crystals it resulted that centrosymmetric aspirin dimer was the bearer of the crystal main spectral properties. In this approach, the adiabatic approximation is performed for each separate H-bond bridge of the dimer and a strong non-adiabatic correction is introduced into the model via the resonant exchange between the fast mode excited states of the two moieties. Within the strong anharmonic coupling theory, according to which the X-H...Y high-frequency mode is anharmonically coupled to the H-bond bridge, this model incorporated the Davydov coupling between the excited states of the two moieties, the quantum direct and indirect dampings and the anharmonicity for the H-bond bridge. The spectral density is obtained within the linear response theory by Fourier transform of the damped autocorrelation functions. The evaluated spectra are in fairly good agreement with the experimental ones by using a minimum number of independent parameters. The effect of deuteration has been well reproduced by reducing simply the angular frequency of the fast mode and the anharmonic coupling parameter.
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Affiliation(s)
- Houcine Ghalla
- Laboratoire de Physique Quantique, Faculté des Sciences de Monastir, 5000 route de Kairouan, Tunisia
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17
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Hill SE, Bandaria JN, Fox M, Vanderah E, Kohen A, Cheatum CM. Exploring the molecular origins of protein dynamics in the active site of human carbonic anhydrase II. J Phys Chem B 2009; 113:11505-10. [PMID: 19637848 PMCID: PMC2736349 DOI: 10.1021/jp901321m] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We present three-pulse vibrational echo measurements of azide ion bound to the active site Zn of human carbonic anhydrase II (HCA II) and of two separate active-site mutants Thr199 --> Ala (T199A) and Leu198 --> Phe (L198F). Because structural motions of the protein active site influence the frequency of bound ligands, the differences in the time scales of the frequency-frequency correlation functions (FFCFs) obtained from global fits to each set of data allow us to make inferences about the time scales of the active site dynamics of HCA II. Surprisingly, the deletion of a potential electrostatic interaction in results in very little change in the FFCF, but the insertion of the bulky phenylalanine ring in causes much faster dynamics. We conclude that the fast, sub-picosecond time scale in the correlation function is attributable to hydrogen bond dynamics, and the slow, apparently static contribution is due to the conformational flexibility of Zn-bound azide in the active site.
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Affiliation(s)
- Sarah E Hill
- Department of Chemistry and Optical Science and Technology Center, University of Iowa, Iowa City, Iowa 52242, USA.
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18
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Hanna G, Geva E. Multidimensional Spectra via the Mixed Quantum-Classical Liouville Method: Signatures of Nonequilibrium Dynamics. J Phys Chem B 2009; 113:9278-88. [DOI: 10.1021/jp902797z] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gabriel Hanna
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Eitan Geva
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055
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Hanna G, Geva E. Isotope Effects on the Vibrational Relaxation and Multidimensional Infrared Spectra of the Hydrogen Stretch in a Hydrogen-Bonded Complex Dissolved in a Polar Liquid. J Phys Chem B 2008; 112:15793-800. [DOI: 10.1021/jp8072816] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gabriel Hanna
- Department of Chemistry and FOCUS Center, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Eitan Geva
- Department of Chemistry and FOCUS Center, University of Michigan, Ann Arbor, Michigan 48109-1055
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20
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Petersen PB, Roberts ST, Ramasesha K, Nocera DG, Tokmakoff A. Ultrafast N-H vibrational dynamics of cyclic doubly hydrogen-bonded homo- and heterodimers. J Phys Chem B 2008; 112:13167-71. [PMID: 18821789 DOI: 10.1021/jp805338h] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Hydrogen-bonded interfaces are essential structural elements in biology. Furthermore, they can mediate electron transport by coupling the electron to proton transfer within the interface. The specific hydrogen-bonding configuration and strength have a large impact on the proton transfer, which exchanges the hydrogen-bonded donor and acceptor species (i.e., NH...O --> N...HO). Modulations of the hydrogen-bonding environment, such as the hydrogen-bond stretch and twist modes, affect the proton-transfer dynamics. Here, we present transient grating and echo peak shift measurements of the NH stretch vibrations of four doubly hydrogen-bonded cyclic dimers in their electronic ground state. The equilibrium vibrational dynamics exhibit strong coherent modulations that we attribute to coupling of the high-frequency NH vibration to the low-frequency interdimer stretch and twist modes and not to interference between multiple Fermi resonances that dominate the substructure of the linear spectra.
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21
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Hanna G, Geva E. Computational Study of the One and Two Dimensional Infrared Spectra of a Vibrational Mode Strongly Coupled to Its Environment: Beyond the Cumulant and Condon Approximations. J Phys Chem B 2008; 112:12991-3004. [DOI: 10.1021/jp804120v] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gabriel Hanna
- Department of Chemistry and FOCUS center, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Eitan Geva
- Department of Chemistry and FOCUS center, University of Michigan, Ann Arbor, Michigan 48109-1055
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22
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Nucci NV, Scott JN, Vanderkooi JM. Coupling of complex aromatic ring vibrations to solvent through hydrogen bonds: effect of varied on-ring and off-ring hydrogen-bonding substitutions. J Phys Chem B 2008; 112:4022-35. [PMID: 18331017 DOI: 10.1021/jp0758770] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this study, we examine the coupling of a complex ring vibration to solvent through hydrogen-bonding interactions. We compare phenylalanine, tyrosine, l-dopa, dopamine, norepinephrine, epinephrine, and hydroxyl-dl-dopa, a group of physiologically important small molecules that vary by single differences in H-bonding substitution. By examination of the temperature dependence of infrared absorptions of these molecules, we show that complex, many-atom vibrations can be coupled to solvent through hydrogen bonds and that the extent of that coupling is dependent on the degree of both on- and off-ring H-bonding substitution. The coupling is seen as a temperature-dependent frequency shift in infrared spectra, but the determination of the physical origin of that shift is based on additional data from temperature-dependent optical experiments and ab initio calculations. The optical experiments show that these small molecules are most sensitive to their immediate H-bonding environment rather than to bulk solvent properties. Ab initio calculations demonstrate H-bond-mediated vibrational coupling for the system of interest and also show that the overall small molecule solvent dependence is determined by a complex interplay of specific interactions and bulk solvation characteristics. Our findings indicate that a full understanding of biomolecule vibrational properties must include consideration of explicit hydrogen-bonding interactions with the surrounding microenvironment.
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Affiliation(s)
- Nathaniel V Nucci
- Department of Biochemistry and Biophysics, University of Pennsylvania, 422 Curie Boulevard, Philadelphia, Pennsylvania 19104, USA.
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