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Zhang N, Li J, Kou J, Sun C. Effects of Hydrogen Bonds between Ethoxylated Alcohols and Sodium Oleate on Collecting Performance in Flotation of Quartz. Molecules 2023; 28:6945. [PMID: 37836788 PMCID: PMC10574789 DOI: 10.3390/molecules28196945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/02/2023] [Accepted: 10/04/2023] [Indexed: 10/15/2023] Open
Abstract
Hydrogen bonds play an important role in the interaction between surfactants. In this study, the effect of three different ethoxylated alcohols (OP-10, NP-10, AEO-9) on the collecting behavior of sodium oleate (NaOL) in the flotation of quartz was investigated. To explore the mechanism, the hydrogen bond between ethoxylated alcohols and NaOL was analyzed using molecular dynamics (MD) simulation. The results showed that ethoxylated alcohols promoted the collecting performance of NaOL and reduced the dosage of the activator CaO and the collector NaOL in the flotation of quartz. The Zeta potential measurement illustrated that ethoxylated alcohols promoted the adsorption of OL- on the activated quartz surface and the degree of promotion was in the order of OP-10 > NP-10 > AEO-9. The MD simulation results showed that a hydrogen bond presented between ethoxylated alcohols and OL-. Due to the hydrogen bond between the ethoxylated alcohols and OL-, the attraction force between OL- and the quartz surface increased with the addition of ethoxylated alcohols in the order of OP-10 > NP-10 > AEO-9 based on the MD simulation results. As the result, the addition of ethoxylated alcohols increased the adsorption density of OL- on the activated quartz surface, which explained the promotion of the collecting performance of OL- in the flotation of quartz.
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Affiliation(s)
| | | | | | - Chunbao Sun
- School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China; (N.Z.)
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2
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Chen B, Mirrielees JA, Chen Y, Onasch TB, Zhang Z, Gold A, Surratt JD, Zhang Y, Brooks SD. Glass Transition Temperatures of Organic Mixtures from Isoprene Epoxydiol-Derived Secondary Organic Aerosol. J Phys Chem A 2023; 127:4125-4136. [PMID: 37129903 PMCID: PMC10863072 DOI: 10.1021/acs.jpca.2c08936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 04/18/2023] [Indexed: 05/03/2023]
Abstract
The phase states and glass transition temperatures (Tg) of secondary organic aerosol (SOA) particles are important to resolve for understanding the formation, growth, and fate of SOA as well as their cloud formation properties. Currently, there is a limited understanding of how Tg changes with the composition of organic and inorganic components of atmospheric aerosol. Using broadband dielectric spectroscopy, we measured the Tg of organic mixtures containing isoprene epoxydiol (IEPOX)-derived SOA components, including 2-methyltetrols (2-MT), 2-methyltetrol-sulfate (2-MTS), and 3-methyltetrol-sulfate (3-MTS). The results demonstrate that the Tg of mixtures depends on their composition. The Kwei equation, a modified Gordon-Taylor equation with an added quadratic term and a fitting parameter representing strong intermolecular interactions, provides a good fit for the Tg-composition relationship of complex mixtures. By combining Raman spectroscopy with geometry optimization simulations obtained using density functional theory, we demonstrate that the non-linear deviation of Tg as a function of composition may be caused by changes in the extent of hydrogen bonding in the mixture.
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Affiliation(s)
- Bo Chen
- Department
of Atmospheric Sciences, Texas A&M University, Eller O&M Building, 1204, 3150
TAMU, 797 Lamar Street, College Station, Texas 77843, United States
| | - Jessica A. Mirrielees
- Department
of Chemistry, University of Michigan, 930 N University Avenue, Ann Arbor, Michigan 48104, United States
| | - Yuzhi Chen
- Gillings
School of Global Public Health, Department of Environmental Sciences
and Engineering, University of North Carolina
at Chapel Hill, 170 Rosenau Hall, Campus Box #7400, 135 Dauer Drive, Chapel Hill, North Carolina 27599, United States
| | - Timothy B. Onasch
- Aerodyne
Research, Inc, 45 Manning
Road, Billerica, Massachusetts 01821, United States
| | - Zhenfa Zhang
- Gillings
School of Global Public Health, Department of Environmental Sciences
and Engineering, University of North Carolina
at Chapel Hill, 170 Rosenau Hall, Campus Box #7400, 135 Dauer Drive, Chapel Hill, North Carolina 27599, United States
| | - Avram Gold
- Gillings
School of Global Public Health, Department of Environmental Sciences
and Engineering, University of North Carolina
at Chapel Hill, 170 Rosenau Hall, Campus Box #7400, 135 Dauer Drive, Chapel Hill, North Carolina 27599, United States
| | - Jason D. Surratt
- Gillings
School of Global Public Health, Department of Environmental Sciences
and Engineering, University of North Carolina
at Chapel Hill, 170 Rosenau Hall, Campus Box #7400, 135 Dauer Drive, Chapel Hill, North Carolina 27599, United States
- College
of Arts and Sciences, Department of Chemistry, University of North Carolina at Chapel Hill, Campus Box #3290, 125 South Road, Chapel Hill, North Carolina 27599, United States
| | - Yue Zhang
- Department
of Atmospheric Sciences, Texas A&M University, Eller O&M Building, 1204, 3150
TAMU, 797 Lamar Street, College Station, Texas 77843, United States
| | - Sarah D. Brooks
- Department
of Atmospheric Sciences, Texas A&M University, Eller O&M Building, 1204, 3150
TAMU, 797 Lamar Street, College Station, Texas 77843, United States
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3
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The effect of collectors on froth stability of frother: Atomic-scale study by experiments and molecular dynamics simulations. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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4
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Fu X, He T, Zhang S, Lei X, Jiang Y, Wang D, Sun P, Zhao D, Hsu HY, Li X, Wang M, Yuan M. Halogen-halogen bonds enable improved long-term operational stability of mixed-halide perovskite photovoltaics. Chem 2021. [DOI: 10.1016/j.chempr.2021.08.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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5
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Kuznetsov ML. Strength of the [Z-I···Hal] - and [Z-Hal···I] - Halogen Bonds: Electron Density Properties and Halogen Bond Length as Estimators of Interaction Energy. Molecules 2021; 26:2083. [PMID: 33916483 PMCID: PMC8038634 DOI: 10.3390/molecules26072083] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 11/29/2022] Open
Abstract
Bond energy is the main characteristic of chemical bonds in general and of non-covalent interactions in particular. Simple methods of express estimates of the interaction energy, Eint, using relationships between Eint and a property which is easily accessible from experiment is of great importance for the characterization of non-covalent interactions. In this work, practically important relationships between Eint and electron density, its Laplacian, curvature, potential, kinetic, and total energy densities at the bond critical point as well as bond length were derived for the structures of the [Z-I···Hal]- and [Z-Hal···I]- types bearing halogen bonds and involving iodine as interacting atom(s) (totally 412 structures). The mean absolute deviations for the correlations found were 2.06-4.76 kcal/mol.
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Affiliation(s)
- Maxim L. Kuznetsov
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001 Lisbon, Portugal; ; Tel.: +351-218-419-236
- Institute of Chemistry, Saint Petersburg State University, Universitetskaya Nab. 7/9, 199034 Saint Petersburg, Russia
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6
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Multiresolution non-covalent interaction analysis for ligand–protein promolecular electron density distributions. Theor Chem Acc 2021. [DOI: 10.1007/s00214-020-02705-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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7
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Sethi A, Singh RP, Pathak R, Shukla D, Amandeep, Yadav P. One pot synthesis of novel pregnane-sulphur prodrugs, spectroscopic investigation, conformational analysis, chemical reactivity, Fukui function and their mathematical model. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2019.127136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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8
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Kuznetsov ML. Relationships between Interaction Energy and Electron Density Properties for Homo Halogen Bonds of the [(A) nY-X···X-Z(B) m] Type (X = Cl, Br, I). Molecules 2019; 24:E2733. [PMID: 31357615 PMCID: PMC6695802 DOI: 10.3390/molecules24152733] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/16/2019] [Accepted: 07/25/2019] [Indexed: 01/31/2023] Open
Abstract
Relationships between interaction energy (Eint) and electron density properties at the X···X bond critical point or the d(X···X) distance were established for the large set of structures [(A)nY-X···X-Z(B)m] bearing the halogen bonds Cl···Cl, Br···Br, and I···I (640 structures in total). The best estimator of Eint is the kinetic energy density (Gb), which reasonably approximates the whole set of the structures as -Eint = 0.128Gb2 - 0.82Gb + 1.66 (R2 = 0.91, mean absolute deviation 0.39 kcal/mol) and demonstrates low dispersion. The potential and kinetic energy densities, electron density, and the d(X···X) distance behave similarly as estimators of Eint for the individual series Cl···Cl, Br···Br, and I···I. A number of the Eint(property) correlations are recommended for the practical application in the express estimates of the strength of the homo-halogen bonds.
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Affiliation(s)
- Maxim L Kuznetsov
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001 Lisbon, Portugal.
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9
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Afonin AV, Sterkhova IV, Vashchenko AV, Sigalov MV. Estimating the energy of intramolecular bifurcated (three-centered) hydrogen bond by X-ray, IR and 1 H NMR spectroscopy, and QTAIM calculations. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2018.02.106] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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10
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Afonin AV, Vashchenko AV, Sigalov MV. Estimating the energy of intramolecular hydrogen bonds from 1H NMR and QTAIM calculations. Org Biomol Chem 2018; 14:11199-11211. [PMID: 27841888 DOI: 10.1039/c6ob01604a] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The values of the downfield chemical shift of the bridge hydrogen atom were estimated for a series of compounds containing an intramolecular hydrogen bond O-HO, O-HN, O-HHal, N-HO, N-HN, C-HO, C-HN and C-HHal. Based on these values, the empirical estimation of the hydrogen bond energy was obtained by using known relationships. For the compounds containing an intramolecular hydrogen bond, the DFT B3LYP/6-311++G(d,p) method was used both for geometry optimization and for QTAIM calculations of the topological parameters (electron density ρBCP and the density of potential energy V in the critical point of the hydrogen bond). The calculated geometric and topological parameters of hydrogen bonds were also used to evaluate the energy of the hydrogen bond based on the equations from the literature. Comparison of calibrating energies from the 1H NMR data with the energies predicted by calculations showed that the most reliable are the linear dependence on the topological ρBCP and V parameters. However, the correct prediction of the hydrogen bond energy is determined by proper fitting of the linear regression coefficients. To obtain them, new linear relationships were found between the calculated ρBCP and V parameters and the hydrogen bond energies obtained from empirical 1H NMR data. These relationships allow the comparison of the energies of different types of hydrogen bonds for various molecules and biological ensembles.
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Affiliation(s)
- Andrei V Afonin
- Institute of Chemistry, Siberian Division of Russian Academy of Sciences, 664033 Irkutsk, Russia.
| | - Alexander V Vashchenko
- Institute of Chemistry, Siberian Division of Russian Academy of Sciences, 664033 Irkutsk, Russia.
| | - Mark V Sigalov
- Department of Chemistry, Ben-Gurion University of the Negev, 84104, Beer Sheva, Israel.
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11
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Mota AJ, Neuhold J, Drescher M, Lemouzy S, González L, Maulide N. Intramolecular hydrogen bonding in conformationally semi-rigid α-acylmethane derivatives: a theoretical NMR study. Org Biomol Chem 2017; 15:7572-7579. [PMID: 28858370 DOI: 10.1039/c7ob01834g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Conformational mobility is a core property of organic compounds, and conformational analysis has become a pervasive tool for synthetic design. In this work, we present experimental and computational (employing Density Functional Theory) evidence for unusual intramolecular hydrogen bonding interactions in a series of α-acylmethane derivatives, as well as a discussion of the consequences thereof for their NMR spectroscopic properties.
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Affiliation(s)
- Antonio J Mota
- Department of Inorganic Chemistry, Faculty of Sciences, Avda. Fuentenueva s/n, 18002 Granada, Spain.
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12
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A quantum chemical study of molecular properties and QSPR modeling of oximes, amidoximes and hydroxamic acids with nucleophilic activity against toxic organophosphorus agents. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2016.12.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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13
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Viana MAA, Araújo RCMU, Neto JAM, Chame HC, Pereira AM, Oliveira BG. The interaction strengths and spectroscopy parameters of the C 2H 2∙∙∙HX and HCN∙∙∙HX complexes (X = F, Cl, CN, and CCH) and related ternary systems valued by fluxes of charge densities: QTAIM, CCFO, and NBO calculations. J Mol Model 2017; 23:110. [PMID: 28285444 DOI: 10.1007/s00894-017-3270-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 01/31/2017] [Indexed: 11/30/2022]
Abstract
This theoretical work exhibits a new systematic study of structural parameters, electronic properties, infrared vibration modes, and molecular topography of hydrogen complexes, namely linear-type HCN⋯HX and T-type C2H2⋯HX (X = F, Cl, CN, and CCH). Ideally, the knowledge of the ternary systems of C2H2⋯HCN⋯HF and HCN⋯HCN⋯HF whose subparts integrate the linear and T-shaped complexes were used to give support in this current research. By means of computational calculations carried out in both levels B3LYP and MP2, the variations of the HX bond lengths are clearly overestimated in the HCN⋯HX linear complexes. In agreement with the analyses of the electrostatic potentials, the higher intermolecular energies of these complexes agree with the larger red-shifts in the stretch frequencies in HX. Also, the QTAIM descriptors and NBO calculations were used to inspect the interaction strength as well as to confirm the π cloud as a proton accepting center. By taking into account the absorption intensity ratio as a standard parameter to predict the interaction strength and intermolecular characterization, the formalism of the charge-charge flux-overlap modified (CCFO) was applied.
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Affiliation(s)
- Marco A A Viana
- Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Norte, 59215-000, Nova Cruz, RN, Brazil
| | - Regiane C M U Araújo
- Departamento de Química - Centro das Ciências Exatas e da Natureza, Universidade Federal da Paraíba, 58051-900, João Pessoa, PB, Brazil
| | - José A Maia Neto
- Departamento de Química - Centro das Ciências Exatas e da Natureza, Universidade Federal da Paraíba, 58051-900, João Pessoa, PB, Brazil
| | - Henrique C Chame
- Departamento de Química - Centro das Ciências Exatas e da Natureza, Universidade Federal da Paraíba, 58051-900, João Pessoa, PB, Brazil
| | - Arquimedes M Pereira
- Ciência e Tecnologia da Paraíba, Instituto Federal de Educação, Campus Guarabira, 58200-000, Guarabira, PB, Brazil
| | - Boaz G Oliveira
- Centro das Ciências Exatas e das Tecnologias, Universidade Federal do Oeste da Bahia, Campus Reitor Edgard Santos, 47805-000, Barreiras, BA, Brazil.
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14
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Bouju X, Mattioli C, Franc G, Pujol A, Gourdon A. Bicomponent Supramolecular Architectures at the Vacuum–Solid Interface. Chem Rev 2017; 117:1407-1444. [DOI: 10.1021/acs.chemrev.6b00389] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Xavier Bouju
- CEMES-CNRS, 29 Rue J. Marvig, 31055 Toulouse, France
| | | | - Grégory Franc
- CEMES-CNRS, 29 Rue J. Marvig, 31055 Toulouse, France
| | - Adeline Pujol
- Université de Toulouse, UPS, CNRS, CEMES, 118 route de Narbonne, 31062 Toulouse, France
| | - André Gourdon
- CEMES-CNRS, 29 Rue J. Marvig, 31055 Toulouse, France
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15
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Pairas GN, Tsoungas PG. H-Bond: Τhe Chemistry-Biology H-Bridge. ChemistrySelect 2016; 1:4520-4532. [PMID: 32328512 PMCID: PMC7169486 DOI: 10.1002/slct.201600770] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Accepted: 07/29/2016] [Indexed: 12/19/2022]
Abstract
H-bonding, as a non covalent stabilizing interaction of diverse nature, has a central role in the structure, function and dynamics of chemical and biological processes, pivotal to molecular recognition and eventually to drug design. Types of conventional and non conventional (H-H, dihydrogen, H- π, CH- π, anti- , proton coordination and H-S) H-bonding interactions are discussed as well as features emerging from their interplay, such as cooperativity (σ- and π-) effects and allostery. Its utility in many applications is described. Catalysis, proton and electron transfer processes in various materials or supramolecular architectures of preorganized hosts for guest binding, are front-line technology. The H-bond-related concept of proton transfer (PT) addresses energy issues or deciphering the mechanism of many natural and synthetic processes. PT is also of paramount importance in the functions of cells and is assisted by large complex proteins embedded in membranes. Both intermolecular and intramolecular PT in H-bonded systems has received attention, theoretically and experimentally, using prototype molecules. It is found in rearrangement reactions, protein functions, and enzyme reactions or across proton channels and pumps. Investigations on the competition between intra- and intermolecular H bonding are discussed. Of particular interest is the H-bond furcation, a common phenomenon in protein-ligand binding. Multiple H-bonding (H-bond furcation) is observed in supramolecular structures.
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Affiliation(s)
- George N. Pairas
- Department of PharmacyLaboratory of Medicinal ChemistryUniversity of PatrasGR-265 04PatrasGreece
| | - Petros G. Tsoungas
- Laboratory of BiochemistryHellenic Pasteur Institute127 Vas. Sofias Ave.GR-115 21AthensGreece
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16
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Bogdan E, Quarré de Verneuil A, Besseau F, Compain G, Linclau B, Le Questel JY, Graton J. α-Fluoro-o-cresols: The Key Role of Intramolecular Hydrogen Bonding in Conformational Preference and Hydrogen-Bond Acidity. Chemphyschem 2016; 17:2702-9. [DOI: 10.1002/cphc.201600453] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Elena Bogdan
- CEISAM UMR CNRS 6230; Faculté des Sciences et des Techniques; Université de Nantes; 2, rue de la Houssinière-BP 92208 44322 NANTES Cedex 3 France
| | - Alexis Quarré de Verneuil
- CEISAM UMR CNRS 6230; Faculté des Sciences et des Techniques; Université de Nantes; 2, rue de la Houssinière-BP 92208 44322 NANTES Cedex 3 France
| | - François Besseau
- CEISAM UMR CNRS 6230; Faculté des Sciences et des Techniques; Université de Nantes; 2, rue de la Houssinière-BP 92208 44322 NANTES Cedex 3 France
| | - Guillaume Compain
- Chemistry; University of Southampton; Highfield Southampton SO17 1BJ UK
| | - Bruno Linclau
- Chemistry; University of Southampton; Highfield Southampton SO17 1BJ UK
| | - Jean-Yves Le Questel
- CEISAM UMR CNRS 6230; Faculté des Sciences et des Techniques; Université de Nantes; 2, rue de la Houssinière-BP 92208 44322 NANTES Cedex 3 France
| | - Jérôme Graton
- CEISAM UMR CNRS 6230; Faculté des Sciences et des Techniques; Université de Nantes; 2, rue de la Houssinière-BP 92208 44322 NANTES Cedex 3 France
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17
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Ayoub AT, Craddock TJA, Klobukowski M, Tuszynski J. Analysis of the strength of interfacial hydrogen bonds between tubulin dimers using quantum theory of atoms in molecules. Biophys J 2015; 107:740-750. [PMID: 25099813 DOI: 10.1016/j.bpj.2014.05.047] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 05/07/2014] [Accepted: 05/23/2014] [Indexed: 11/19/2022] Open
Abstract
Microtubules are key structural elements that, among numerous biological functions, maintain the cytoskeleton of the cell and have a major role in cell division, which makes them important cancer chemotherapy targets. Understanding the energy balance that brings tubulin dimers, the building blocks of microtubules, together to form a microtubule is especially important for revealing the mechanism of their dynamic instability. Several studies have been conducted to estimate various contributions to the free energy of microtubule formation. However, the hydrogen-bond contribution was not studied before as a separate component. In this work, we use concepts such as the quantum theory of atoms in molecules to estimate the per-residue strength of hydrogen bonds contributing to the overall stability that brings subunits together in pair of tubulin heterodimers, across both the longitudinal and lateral interfaces. Our study shows that hydrogen bonding plays a major role in the stability of tubulin systems. Several residues that are crucial to the binding of vinca alkaloids are shown to be strongly involved in longitudinal microtubule stabilization. This indicates a direct relation between the binding of these agents and the effect on the interfacial hydrogen-bonding network, and explains the mechanism of their action. Lateral contacts showed much higher stability than longitudinal ones (-462 ± 70 vs. -392 ± 59 kJ/mol), which suggests a dramatic lateral stabilization effect of the GTP cap in the β-subunit. The role of the M-loop in lateral stability in absence of taxol was shown to be minor. The B-lattice lateral hydrogen bonds are shown to be comparable in strength to the A-lattice ones (-462 ± 70 vs. -472 ± 46 kJ/mol). These findings establish the importance of hydrogen bonds to the stability of tubulin systems.
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Affiliation(s)
- Ahmed T Ayoub
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Travis J A Craddock
- Graduate School of Computer and Information Sciences and Center for Psychological Studies, Nova Southeastern University, Ft. Lauderdale, Florida
| | | | - Jack Tuszynski
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada.
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