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Pérez-Bitrián A, Baya M, Casas JM, Martín A, Menjón B. Hydrogen bonding to metals as a probe for an inverted ligand field. Dalton Trans 2021; 50:5465-5472. [PMID: 33908974 DOI: 10.1039/d1dt00597a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron-rich, late transition metals are known to act as hydrogen-bonding (HBd) acceptors. In this regard, Pt(ii) centres in square-planar environments are particularly efficient. It is however puzzling that no convincing experimental evidence is currently available for the isoelectronic neighbour Au(iii) being involved in HBd interactions. We report now on the synthesis and characterisation of two series of isoleptic and isoelectronic (d8) compounds [(CF3)3Pt(L)]- and (CF3)3Au(L), where the L ligands are based on the quinoline frame and have been selected to favour HBd with the metal centre. Strong HBd interactions were actually found in the Pt(ii) compounds, based on structural and spectroscopic evidence, and they were further confirmed by theoretical calculations. In contrast, no evidence was obtained in the Au(iii) case. In order to find the reason underlying this general disparity, we undertook a detailed theoretical analysis of the model systems [(CF3)3Pt(py)]- and (CF3)3Au(py). This study revealed that the filled dz2 orbital is the HOMO in the case of Pt(ii), but is buried in the lower energy levels in the case of Au(iii). The sharply different electronic configurations involve ligand-field inversion on going from Pt to the next element Au. This is not a gradual but an abrupt change, which invalidates Au(iii) as a HBd-acceptor wherever ligand-field inversion occurs.
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Affiliation(s)
- Alberto Pérez-Bitrián
- Instituto de Síntesis Química y Catálisis Homogénea (iSQCH), CSIC-Universidad de Zaragoza, Zaragoza, Spain.
| | - Miguel Baya
- Instituto de Síntesis Química y Catálisis Homogénea (iSQCH), CSIC-Universidad de Zaragoza, Zaragoza, Spain.
| | - José M Casas
- Instituto de Síntesis Química y Catálisis Homogénea (iSQCH), CSIC-Universidad de Zaragoza, Zaragoza, Spain.
| | - Antonio Martín
- Instituto de Síntesis Química y Catálisis Homogénea (iSQCH), CSIC-Universidad de Zaragoza, Zaragoza, Spain.
| | - Babil Menjón
- Instituto de Síntesis Química y Catálisis Homogénea (iSQCH), CSIC-Universidad de Zaragoza, Zaragoza, Spain.
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2
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Studies on hydrogen bonding of adrenaline/acetone and adrenaline/methanol complexes: computational and experimental approach. Struct Chem 2021. [DOI: 10.1007/s11224-021-01773-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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3
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Karimi P, Sanchooli M, Kiyanee-Ghaleno M. Assessment of O-H⋯O and O-H⋯S intramolecular hydrogen bond energies in some substituted pyrimidines using quantum chemistry methods. J Mol Graph Model 2021; 104:107847. [PMID: 33548910 DOI: 10.1016/j.jmgm.2021.107847] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/20/2021] [Accepted: 01/20/2021] [Indexed: 11/30/2022]
Abstract
Resonance-assisted hydrogen bond (RAHB) theory was studied in some substituted pyrimidines in which encompass O-H⋯Y unit (Y= O and S). Alteration of substituents (R 1, R2, R3 = H, C2H, C2F) on pyrimidine ring changes properties of electron charge density at this ring and influences indirectly on strength of intramolecular hydrogen bond (IHB) interactions in the mentioned structures. Then, IHB energies were estimated using cis-trans method (CTM), related rotamers method (RRM), Espinosa' method (EM), and a viewpoint based on properties of electron charge densities at ring critical point (RCP) of RAHB ring. Moreover, the estimated IHB energies with these methods were compared with those obtained using modified Espinosa' method (MEM), Iogansen's relationship, and chemical shift-based method to find more consistent method with the proposed viewpoint based on RCP characteristics. The linear correlations between the all estimated IHB energies and some hydrogen bonding descriptors such as geometrical, spectroscopic, topological, and molecular orbital factors were examined. Results indicated that the IHB energies that obtained by way of MEM and Iogansen's relationship have better correlations with hydrogen bonding descriptors. Also, there are good consistencies between results of these two methods with viewpoint based on properties of RCPs. Therefore, IHB energies can suitably estimate using properties of RCPs in heterocyclic molecular systems especially in cases that rotation around C-C/CC bonds makes additional interactions in isomers and influences on accuracy of calculated IHB energies using approaches such as CTM and RRM.
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Affiliation(s)
- Pouya Karimi
- Department of Chemistry, Faculty of Science, University of Zabol, P.O. Box 98615-538, Zabol, Iran.
| | - Mahmood Sanchooli
- Department of Chemistry, Faculty of Science, University of Zabol, P.O. Box 98615-538, Zabol, Iran
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4
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Goldsztejn G, Mundlapati VR, Donon J, Tardivel B, Gloaguen E, Brenner V, Mons M. An intraresidue H-bonding motif in selenocysteine and cysteine, revealed by gas phase laser spectroscopy and quantum chemistry calculations. Phys Chem Chem Phys 2021; 22:20409-20420. [PMID: 32914809 DOI: 10.1039/d0cp02825h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Models of protein chains containing a seleno-cysteine (Sec) residue have been investigated by gas phase laser spectroscopy in order to document the effect of the H-bonding properties of the SeH group in the folding of the Sec side chain, by comparison with recent data on Ser- and Cys-containing sequences. Experimental data, complemented by quantum chemistry calculations and natural bonding orbital (NBO) analyses, are interpreted in terms of the formation of a so-called 5γ intra-residue motif, which bridges the acceptor chalcogen atom of the side chain to the NH bond of the same residue. This local structure, in which the O/S/Se atom is close to the plane of the N-terminal side amide, is constrained by local backbone-side chain hyperconjugation effects involving the S and Se atoms. Theoretical investigations of the Cys/Sec side chain show that (i) this 5γ motif is an intrinsic feature of these residues, (ii) the corresponding H-bond is strongly non-linear and intrinsically weak, (iii) but enhanced by γ- and β-turn secondary structures, which promote a more favorable 5γ H-bonding approach and distance. The resulting H-bonds are slightly stronger in selenocysteine than in cysteine, but nearly inexistent in serine, whose side chain in contrast behaves as a H-bonding donor. The modest spectral shifts of the Cys/Sec NH stretches measured experimentally reflect the moderate strength of the 5γ H-bonding, in agreement with the correlation obtained with a NBO-based H-bond strength indicator. The evolution along the Ser, Cys and Sec series emphasizes the compromise between the several factors that control the H-bonding in a hyperconjugation-constrained geometry, among them the chalcogen van der Waals and covalent radii. It also illustrates the 5γ H-bond enhancements with the Sec and Cys residues favoured by the constraints imposed by the γ- and β-turn structures of the peptide chain.
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Affiliation(s)
- Gildas Goldsztejn
- Laboratoire Interactions Dynamiques et Lasers (LIDYL), Université Paris-Saclay, Paris, France.
| | | | - Jérémy Donon
- Laboratoire Interactions Dynamiques et Lasers (LIDYL), Université Paris-Saclay, Paris, France.
| | - Benjamin Tardivel
- Laboratoire Interactions Dynamiques et Lasers (LIDYL), Université Paris-Saclay, Paris, France.
| | - Eric Gloaguen
- Laboratoire Interactions Dynamiques et Lasers (LIDYL), Université Paris-Saclay, Paris, France.
| | - Valérie Brenner
- Laboratoire Interactions Dynamiques et Lasers (LIDYL), Université Paris-Saclay, Paris, France.
| | - Michel Mons
- Laboratoire Interactions Dynamiques et Lasers (LIDYL), Université Paris-Saclay, Paris, France.
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5
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Theoretical investigation on hydrogen bond interaction between adrenaline and hydrogen sulfide. J Mol Model 2020; 26:354. [PMID: 33244644 DOI: 10.1007/s00894-020-04602-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 11/08/2020] [Indexed: 10/22/2022]
Abstract
In this study, we elucidated the formation of hydrogen bond between adrenaline (AD) and hydrogen sulfide utilizing computational studies. Six potential complexes were studied including geometrical parameters, energy, vibrational frequency, topological analysis, natural bond orbital (NBO), quantum theory of atoms in molecules (QTAIM), and NMR analysis. Moreover, these calculations were examined through DFT/ωB97XD/6-311G++(d,p) level. It was found that there are no indication on formation on hydrogen bonding between the two catecholic OHs where the one formed between the amino group and the hydroxyl oxygen atom of adrenaline monomer was broken in AS1 to form two new interactions namely SH...N and O1H1...S, while it retained in other complexes. Furthermore, the bond became stronger due to cooperativity in AS3 and AS6, for the presence of withdrawing effect of the phenyl ring, the H-bonds formed with the side chain oxygen atom. The adrenaline and H2S interaction was experimentally examined via FT-IR spectrometry and thin layer chromatography for confirmation of our theoretical study. Graphical abstract.
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6
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Jabłoński M. A Critical Overview of Current Theoretical Methods of Estimating the Energy of Intramolecular Interactions. Molecules 2020; 25:molecules25235512. [PMID: 33255559 PMCID: PMC7728086 DOI: 10.3390/molecules25235512] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 11/19/2020] [Accepted: 11/23/2020] [Indexed: 11/16/2022] Open
Abstract
This article is probably the first such comprehensive review of theoretical methods for estimating the energy of intramolecular hydrogen bonds or other interactions that are frequently the subject of scientific research. Rather than on a plethora of numerical data, the main focus is on discussing the theoretical rationale of each method. Additionally, attention is paid to the fact that it is very often possible to use several variants of a particular method. Both of the methods themselves and their variants often give wide ranges of the obtained estimates. Attention is drawn to the fact that the applicability of a particular method may be significantly limited by various factors that disturb the reliability of the estimation, such as considerable structural changes or new important interactions in the reference system.
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Affiliation(s)
- Mirosław Jabłoński
- Faculty of Chemistry, Nicolaus Copernicus University in Toruń, 87-100 Toruń, Poland
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7
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Estévez L. C-HAu interactions and optical properties of [(P,P) 4Au 6] 2+ molecular gold nanoclusters. Dalton Trans 2020; 49:4797-4804. [PMID: 32211720 DOI: 10.1039/d0dt00464b] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Two hexagold diphosphine-stabilized [(P,P)4Au6]2+ molecular nanoclusters with the same [core + exo] arrangement differing in the linker (phenylene or trimethylene) connecting the two P-donor sites have been subjected to theoretical studies with the aim of shedding light on two main questions. On one hand, from a previous study [J. Vícha, C. Foroutan-Nejadand M. Straka,Nat. Commun., 2019, 10, 1643], it is still unclear whether short C-H2Au contacts revealed in the corresponding crystal structures are just forced by bulky P(Ph)2 groups and, on the other hand, to what extent the linker affects the visible band position [M. A. Bakar, M. Sugiuchi, M. Iwasaki, Y. Shichibuand K. Konishi, Nat. Commun., 2017, 8, 576]. Here, it is demonstrated that even in simpler model systems in which bulky groups were replaced by PH2 groups, C-H2Au hydrogen bonding interactions are retained and show comparable values, as measured by NBO and QTAIM analyses, to those of 1 and 2. These analyses further confirmed a stronger HB in 1 than in 2. Also, the comparison of model systems without and with a linker connecting the phosphine groups showed a bathochromic shift of 47 and 60 nm, revealing the key role of the linker. The Δρ(r)EE-GS plots of 1 and 2 revealed electron density depletion in the inter-nuclear C-H2 region upon electronic transition unveiling its contribution to their optical properties.
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Affiliation(s)
- Laura Estévez
- Departamento de Química Física, Universidade de Vigo, As Lagoas-Marcosende s/n, 36310 Galicia, Spain.
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8
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Brenner V, Gloaguen E, Mons M. Rationalizing the diversity of amide-amide H-bonding in peptides using the natural bond orbital method. Phys Chem Chem Phys 2019; 21:24601-24619. [PMID: 31670335 DOI: 10.1039/c9cp03825f] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Natural bond orbital (NBO) analysis of electron delocalization in a series of capped isolated peptides is used to diagnose amide-amide H-bonding and backbone-induced hyperconjugative interactions, and to rationalize their spectral effects. The sum of the stabilization energies corresponding to the interactions between NBOs that are involved in the H-bonding is demonstrated as an insightful indicator for the H-bond strength. It is then used to decouple the effect of the H-bond distance from that, intrinsic, of the donor/acceptor relative orientation, i.e., the geometrical approach. The diversity of the approaches given by the series of peptides studied enables us to illustrate the crucial importance of the approach when the acceptor is a carbonyl group, and emphasizes that efficient approaches can be achieved despite not matching the usual picture of a proton donor directly facing a lone pair of the proton acceptor, i.e., that encountered in intermolecular H-bonds. The study also illustrates the role of backbone flexibility, partly controlled by backbone-amide hyperconjugative interactions, in influencing the equilibrium structures, in particular by frustrating or enhancing the HB for a given geometrical approach. Finally, the presently used NBO-based HB strength indicator enables a fair prediction of the frequency of the proton donor amide NH stretching mode, but this simple picture is blurred by ubiquitous hyperconjugative effects between the backbone and amide groups, whose magnitude can be comparable to that of the weakest H-bonds.
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Affiliation(s)
- Valérie Brenner
- LIDYL, CEA, CNRS, Université Paris-Saclay, bât 522, CEA Paris-Saclay, 9119 Gif-sur-Yvette, France.
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9
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Afonin AV, Pavlov DV, Vashchenko AV. Case study of 2-vinyloxypyridine: Quantitative assessment of the intramolecular C H⋯N hydrogen bond energy and its contribution to the one-bond 13C1H coupling constant. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2018.08.050] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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10
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Tupikina E, Denisov G, Melikova S, Kucherov S, Tolstoy P. New look at the Badger-Bauer rule: Correlations of spectroscopic IR and NMR parameters with hydrogen bond energy and geometry. FHF complexes. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2018.03.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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11
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Tupikina EY, Efimova AA, Denisov GS, Tolstoy PM. NMR Chemical Shift of a Helium Atom as a Probe for Electronic Structure of FH, F–, (FHF)−, and FH2+. J Phys Chem A 2017; 121:9654-9662. [DOI: 10.1021/acs.jpca.7b10189] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- E. Yu. Tupikina
- Department
of Physics and ‡Center for Magnetic Resonance, St. Petersburg State University, St. Petersburg 198504, Russia
| | - A. A. Efimova
- Department
of Physics and ‡Center for Magnetic Resonance, St. Petersburg State University, St. Petersburg 198504, Russia
| | - G. S. Denisov
- Department
of Physics and ‡Center for Magnetic Resonance, St. Petersburg State University, St. Petersburg 198504, Russia
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12
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Aeschbacher T, Zierke M, Smieško M, Collot M, Mallet JM, Ernst B, Allain FHT, Schubert M. A Secondary Structural Element in a Wide Range of Fucosylated Glycoepitopes. Chemistry 2017; 23:11598-11610. [PMID: 28654715 DOI: 10.1002/chem.201701866] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Indexed: 01/12/2023]
Abstract
The increasing understanding of the essential role of carbohydrates in development, and in a wide range of diseases fuels a rapidly growing interest in the basic principles governing carbohydrate-protein interactions. A still heavily debated issue regarding the recognition process is the degree of flexibility or rigidity of oligosaccharides. Combining NMR structure determination based on extensive experimental data with DFT and database searches, we have identified a set of trisaccharide motifs with a similar conformation that is characterized by a non-conventional C-H⋅⋅⋅O hydrogen bond. These motifs are present in numerous classes of oligosaccharides, found in everything from bacteria to mammals, including Lewis blood group antigens but also unusual motifs from amphibians and marine invertebrates. The set of trisaccharide motifs can be summarized with the consensus motifs X-β1,4-[Fucα1,3]-Y and X-β1,3-[Fucα1,4]-Y-a secondary structure we name [3,4]F-branch. The wide spectrum of possible modifications of this scaffold points toward a large variety of glycoepitopes, which nature generated using the same underlying architecture.
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Affiliation(s)
- Thomas Aeschbacher
- Institute of Molecular Biology and Biophysics, ETH Zürich, 8093, Zurich, Switzerland
| | - Mirko Zierke
- Institute of Molecular Pharmacy, University of Basel, Klingelbergstr. 50, 4056, Basel, Switzerland.,Department of Chemistry, University of British Columbia, V6T 1Z1, Vancouver, British Columbia, Canada
| | - Martin Smieško
- Institute of Molecular Pharmacy, University of Basel, Klingelbergstr. 50, 4056, Basel, Switzerland
| | - Mayeul Collot
- Laboratoire des Biomolécules, Département de Chimie, École normale supérieure, PSL Research University, Sorbonne Universités, UPMC Univ. Paris 06, CNRS, 24 rue Lhomond, 75005, Paris, France.,UMR 7213 CNRS, Laboratoire de Biophotonique et Pharmacologie, Faculté de Pharmacie, 74 route du Rhin, CS 60024, 67401, Illkirch, France
| | - Jean-Maurice Mallet
- Laboratoire des Biomolécules, Département de Chimie, École normale supérieure, PSL Research University, Sorbonne Universités, UPMC Univ. Paris 06, CNRS, 24 rue Lhomond, 75005, Paris, France
| | - Beat Ernst
- Institute of Molecular Pharmacy, University of Basel, Klingelbergstr. 50, 4056, Basel, Switzerland
| | - Frédéric H-T Allain
- Institute of Molecular Biology and Biophysics, ETH Zürich, 8093, Zurich, Switzerland
| | - Mario Schubert
- Institute of Molecular Biology and Biophysics, ETH Zürich, 8093, Zurich, Switzerland.,Institute of Molecular Biology, University of Salzburg, Billrothstr. 11, 5020, Salzburg, Austria
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13
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Siskos MG, Choudhary MI, Gerothanassis IP. Hydrogen Atomic Positions of O-H···O Hydrogen Bonds in Solution and in the Solid State: The Synergy of Quantum Chemical Calculations with ¹H-NMR Chemical Shifts and X-ray Diffraction Methods. Molecules 2017; 22:E415. [PMID: 28272366 PMCID: PMC6155303 DOI: 10.3390/molecules22030415] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 02/27/2017] [Accepted: 03/03/2017] [Indexed: 12/21/2022] Open
Abstract
The exact knowledge of hydrogen atomic positions of O-H···O hydrogen bonds in solution and in the solid state has been a major challenge in structural and physical organic chemistry. The objective of this review article is to summarize recent developments in the refinement of labile hydrogen positions with the use of: (i) density functional theory (DFT) calculations after a structure has been determined by X-ray from single crystals or from powders; (ii) ¹H-NMR chemical shifts as constraints in DFT calculations, and (iii) use of root-mean-square deviation between experimentally determined and DFT calculated ¹H-NMR chemical shifts considering the great sensitivity of ¹H-NMR shielding to hydrogen bonding properties.
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Affiliation(s)
- Michael G Siskos
- Section of Organic Chemistry & Biochemistry, Department of Chemistry, University of Ioannina, Ioannina GR-45110, Greece.
| | - M Iqbal Choudhary
- H.E.J. Research Institute of Chemistry, International Center for Biological and Chemical Sciences, University of Karachi, Karachi 75270, Pakistan.
| | - Ioannis P Gerothanassis
- Section of Organic Chemistry & Biochemistry, Department of Chemistry, University of Ioannina, Ioannina GR-45110, Greece.
- H.E.J. Research Institute of Chemistry, International Center for Biological and Chemical Sciences, University of Karachi, Karachi 75270, Pakistan.
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14
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Mundlapati VR, Sahoo DK, Ghosh S, Purame UK, Pandey S, Acharya R, Pal N, Tiwari P, Biswal HS. Spectroscopic Evidences for Strong Hydrogen Bonds with Selenomethionine in Proteins. J Phys Chem Lett 2017; 8:794-800. [PMID: 28145117 DOI: 10.1021/acs.jpclett.6b02931] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Careful protein structure analysis unravels many unknown and unappreciated noncovalent interactions that control protein structure; one such unrecognized interaction in protein is selenium centered hydrogen bonds (SeCHBs). We report, for the first time, SeCHBs involving the amide proton and selenium of selenomethionine (Mse), i.e., amide-N-H···Se H-bonds discerned in proteins. Using mass selective and conformer specific high resolution vibrational spectroscopy, gold standard quantum chemical calculations at CCSD(T), and in-depth protein structure analysis, we establish that amide-N-H···Se and amide-N-H···Te H-bonds are as strong as conventional amide-NH···O and amide-NH···O═C H-bonds despite smaller electronegativity of selenium and tellurium than oxygen. It is in fact, electronegativity, atomic charge, and polarizability of the H-bond acceptor atoms are at play in deciding the strength of H-bonds. The amide-N-H···Se and amide-N-H···Te H-bonds presented here are not only new additions to the ever expanding world of noncovalent interactions, but also are of central importance to design new force-fields for better biomolecular structure simulations.
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Affiliation(s)
- V Rao Mundlapati
- School of Chemical Sciences, National Institute of Science Education and Research (NISER) , PO- Bhimpur-Padanpur, Via-Jatni, District- Khurda, PIN - 752050, Bhubaneswar, India
- Homi Bhabha National Institute , Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Dipak Kumar Sahoo
- School of Chemical Sciences, National Institute of Science Education and Research (NISER) , PO- Bhimpur-Padanpur, Via-Jatni, District- Khurda, PIN - 752050, Bhubaneswar, India
- Homi Bhabha National Institute , Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Sanat Ghosh
- Tata Institute of Fundamental Research , Homi Bhabha Road, Mumbai 400005, India
| | - Umesh Kumar Purame
- Homi Bhabha National Institute , Training School Complex, Anushakti Nagar, Mumbai 400094, India
- School of Biological Sciences, National Institute of Science Education and Research (NISER) , PO- Bhimpur-Padanpur, Via-Jatni, District- Khurda, PIN - 752050, Bhubaneswar, India
| | - Shubhant Pandey
- Homi Bhabha National Institute , Training School Complex, Anushakti Nagar, Mumbai 400094, India
- School of Biological Sciences, National Institute of Science Education and Research (NISER) , PO- Bhimpur-Padanpur, Via-Jatni, District- Khurda, PIN - 752050, Bhubaneswar, India
| | - Rudresh Acharya
- Homi Bhabha National Institute , Training School Complex, Anushakti Nagar, Mumbai 400094, India
- School of Biological Sciences, National Institute of Science Education and Research (NISER) , PO- Bhimpur-Padanpur, Via-Jatni, District- Khurda, PIN - 752050, Bhubaneswar, India
| | - Nitish Pal
- School of Chemical Sciences, National Institute of Science Education and Research (NISER) , PO- Bhimpur-Padanpur, Via-Jatni, District- Khurda, PIN - 752050, Bhubaneswar, India
- Homi Bhabha National Institute , Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Prince Tiwari
- School of Chemical Sciences, National Institute of Science Education and Research (NISER) , PO- Bhimpur-Padanpur, Via-Jatni, District- Khurda, PIN - 752050, Bhubaneswar, India
- Homi Bhabha National Institute , Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Himansu S Biswal
- School of Chemical Sciences, National Institute of Science Education and Research (NISER) , PO- Bhimpur-Padanpur, Via-Jatni, District- Khurda, PIN - 752050, Bhubaneswar, India
- Homi Bhabha National Institute , Training School Complex, Anushakti Nagar, Mumbai 400094, India
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15
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Wiedemann C, Ohlenschläger O, Mrestani-Klaus C, Bordusa F. NMR spectroscopic studies of a TAT-derived model peptide in imidazolium-based ILs: influence on chemical shifts and the cis/trans equilibrium state. Phys Chem Chem Phys 2017; 19:24115-24125. [DOI: 10.1039/c7cp03295a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The impact of ionic liquids on the chemical shifts and the cis/trans equilibrium state of a model peptide was systematically investigated by NMR spectroscopy.
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Affiliation(s)
- Christoph Wiedemann
- Institute of Biochemistry and Biotechnology
- Martin-Luther-University Halle-Wittenberg
- D-06120 Halle
- Germany
| | | | - Carmen Mrestani-Klaus
- Institute of Biochemistry and Biotechnology
- Martin-Luther-University Halle-Wittenberg
- D-06120 Halle
- Germany
| | - Frank Bordusa
- Institute of Biochemistry and Biotechnology
- Martin-Luther-University Halle-Wittenberg
- D-06120 Halle
- Germany
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16
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Assessment of the Presence and Strength of H-Bonds by Means of Corrected NMR. Molecules 2016; 21:molecules21111426. [PMID: 27801801 PMCID: PMC6274571 DOI: 10.3390/molecules21111426] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 10/19/2016] [Accepted: 10/21/2016] [Indexed: 11/30/2022] Open
Abstract
The downfield shift of the NMR signal of the bridging proton in a H-bond (HB) is composed of two elements. The formation of the HB causes charge transfer and polarization that lead to a deshielding. A second factor is the mere presence of the proton-accepting group, whose electron density and response to an external magnetic field induce effects at the position of the bridging proton, exclusive of any H-bonding phenomenon. This second positional shielding must be subtracted from the full observed shift in order to assess the deshielding of the proton caused purely by HB formation. This concept is applied to a number of H-bonded systems, both intramolecular and intermolecular. When the positional shielding is removed, the remaining chemical shift is in much better coincidence with other measures of HB strength.
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