1
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Sager E, Tzvetkova P, Lingel A, Gossert AD, Luy B. Hydrogen bond formation may enhance RDC-based discrimination of enantiomers. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2024. [PMID: 38785031 DOI: 10.1002/mrc.5448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 03/28/2024] [Accepted: 04/08/2024] [Indexed: 05/25/2024]
Abstract
The distinction of enantiomers based on residual anisotropic parameters obtained by alignment in chiral poly-γ-benzyl-L-glutamate (PBLG) is among the strongest in high-resolution NMR spectroscopy. However, large variations in enantiodifferentiation among different solutes are frequently observed. One hypothesis is that the formation of hydrogen bonds between solute and PBLG is important for the distinction of enantiomers. With a small set of three almost spherical enantiomeric pairs, for which 1DCH residual dipolar couplings are measured, we address this issue in a systematic way: borneol contains a single functional group that can act as a hydrogen bond donor, camphor has a single group that may act as a hydrogen bond acceptor, and quinuclidinol can act as both hydrogen bond donor and acceptor. The results are unambiguous: although camphor shows low enantiodifferentiation with PBLG and alignment that can be predicted well by the purely steric TRAMITE approach, the distinction of enantiomers for the other enantiomeric pairs is significantly higher with alignment properties that must involve a specific interaction in addition to steric alignment.
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Affiliation(s)
- Emine Sager
- Institute of Organic Chemistry and Institute for Biological Interfaces 4-Magnetic Resonance, Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
- Novartis Biomedical Research, Basel, Switzerland
| | - Pavleta Tzvetkova
- Institute of Organic Chemistry and Institute for Biological Interfaces 4-Magnetic Resonance, Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
| | | | | | - Burkhard Luy
- Institute of Organic Chemistry and Institute for Biological Interfaces 4-Magnetic Resonance, Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
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2
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Li GW, Wang XJ, Shi SH, Liu LT, Li JQ, Sun H, Wu ZQ, Lei X. Polyarylisocyanides Derived from an Alkyne-Pd(II) Catalyst as Robust Alignment Media with Excellent Enantiodiscimination. Anal Chem 2023; 95:18850-18858. [PMID: 38091507 DOI: 10.1021/acs.analchem.3c04240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
The development of chiral alignment media for measuring anisotropic NMR parameters provides an opportunity to determine the absolute configuration of chiral molecules without the need for derivatization. However, chiral alignment media with a high and robust enantiodiscriminating property for a wide range of chiral molecules are still scarce. In this study, we synthesized cholesterol-end-functionalized helical polyisocyanides from a chiral monomer using a cholesterol-based alkyne-Pd(II) initiator. These stereoregular polyisocyanides form stable and weak anisotropic lyotropic liquid crystals (LLCs) in dichloromethane systems, exhibiting highly optical activities in both single left- and right-handed helices. The preparation process of the media was straightforward, and the aligning property of the LLCs could be controlled by adjusting the concentration and temperature. Using the chiral polyisocyanides, we extracted the residual dipolar coupling for an enantiomeric pair of isopinocampheol (IPC), as well as a number of pharmaceutical molecules, demonstrating excellent enantiodiscriminating properties for a broad range of chiral compounds.
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Affiliation(s)
- Gao-Wei Li
- College of Chemistry and Chemical Engineering, Henan Engineering Research Center for Green Synthesis of Pharmaceuticals, Shangqiu Normal University, Shangqiu 476000, China
| | - Xiao-Juan Wang
- College of Chemistry and Chemical Engineering, Henan Engineering Research Center for Green Synthesis of Pharmaceuticals, Shangqiu Normal University, Shangqiu 476000, China
| | - Shuai-Hua Shi
- College of Chemistry and Chemical Engineering, Henan Engineering Research Center for Green Synthesis of Pharmaceuticals, Shangqiu Normal University, Shangqiu 476000, China
| | - Lan-Tao Liu
- College of Chemistry and Chemical Engineering, Henan Engineering Research Center for Green Synthesis of Pharmaceuticals, Shangqiu Normal University, Shangqiu 476000, China
| | - Jia-Qian Li
- School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan 430074, China
| | - Han Sun
- Research Unit of Structural Chemistry & Computational Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin 13125, Germany
- Institute of Chemistry, Technical University of Berlin, Berlin 10623, Germany
| | - Zong-Quan Wu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
| | - Xinxiang Lei
- State Key Laboratory of Applied Organic Chemistry, Lanzhou Magnetic Resonance Center, College of Chemistry and Chemi-cal Engineering, Lanzhou University, Lanzhou 730000, China
- School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan 430074, China
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3
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Fuentes-Monteverde JC, Noll M, Das A, Immel S, Reggelin M, Griesinger C, Nath N. Residual-Chemical-Shift-Anisotropy-Based Enantiodifferentiation in Lyotropic Liquid Crystalline Phases Based on Helically Chiral Polyacetylenes. Angew Chem Int Ed Engl 2023; 62:e202309981. [PMID: 37684219 DOI: 10.1002/anie.202309981] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/25/2023] [Accepted: 09/06/2023] [Indexed: 09/10/2023]
Abstract
Anisotropic NMR spectroscopy, revealing residual dipolar couplings (RDCs) and residual chemical shift anisotropies (RCSAs) has emerged as a powerful tool to determine the configurations of synthetic and complex natural compounds. The deduction of the absolute in addition to the relative configuration is one of the primary goals in the field. Therefore, the investigation of the enantiodiscriminating capabilities of chiral alignment media becomes essential. While RDCs and RCSAs are now used for the determination of the relative configuration routinely, RCSAs have not been measured in chiral alignment media such as chiral liquid crystals. Herein, we present this application by measuring RCSAs for chiral analytes such as indanol and isopinocampheol in the lyotropic liquid crystalline phase of an L-valine derived helically chiral polyacetylenes. We have also demonstrated that a single 1D 13 C-{1 H} NMR spectrum suffices to get the RCSAs circumventing the necessity to acquire two spectra at two alignment conditions.
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Affiliation(s)
- Juan Carlos Fuentes-Monteverde
- Max Planck Institute for Multidisciplinary Sciences, Department of NMR-Based Structural Biology, Am Fassberg 11, 37077, Göttingen, Germany
| | - Markus Noll
- Department of Chemistry, Technical University of Darmstadt, Alarich Weiss Straße 4, 64287, Darmstadt, Germany
| | - Akhi Das
- Department of Chemistry, Gauhati University Guwahati, Jalukbari, 781014, India
| | - Stefan Immel
- Department of Chemistry, Technical University of Darmstadt, Alarich Weiss Straße 4, 64287, Darmstadt, Germany
| | - Michael Reggelin
- Department of Chemistry, Technical University of Darmstadt, Alarich Weiss Straße 4, 64287, Darmstadt, Germany
| | - Christian Griesinger
- Max Planck Institute for Multidisciplinary Sciences, Department of NMR-Based Structural Biology, Am Fassberg 11, 37077, Göttingen, Germany
| | - Nilamoni Nath
- Department of Chemistry, Gauhati University Guwahati, Jalukbari, 781014, India
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4
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Hirschmann M, Soltwedel O, Ritzert P, von Klitzing R, Thiele CM. Light-Controlled Lyotropic Liquid Crystallinity of Polyaspartates Exploited as Photo-Switchable Alignment Medium. J Am Chem Soc 2023; 145:3615-3623. [PMID: 36749116 DOI: 10.1021/jacs.2c12760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Two polyaspartates bearing ortho-fluorinated azobenzenes (pFAB) as photo-responsive groups in the side chain were synthesized: PpFABLA (1) and co-polyaspartate PpFABLA-co-PBLA [11, 75%(n/n) PpFABLA content]. As a consequence of the E/Z-isomerization of the side chain, PpFABLA (1) undergoes a visible-light-induced reversible coil-helix transition in solution: Green light (525 nm) affords the coil, and violet light (400 nm) affords the helix. pFAB significantly increases the thermal stability of the Z-isomer at 20 °C (t1/2 = 66 d for the Z-isomer) and effectively counters the favored back formation of the helix. At 20%(w/w) polymer concentration, the helical polymer forms a lyotropic liquid crystal (LLC) that further orients unidirectionally inside a magnetic field, while the coil polymer results in an isotropic solution. The high viscosity of the polymer solution stabilizes the coexistence of liquid crystalline and isotropic domains, which were obtained with spatial control by partial light irradiation. When used as an alignment medium, PpFABLA (1) enables (i) the measurement of dipolar couplings without the need for a separate isotropic reference and (ii) the differentiation of enantiomers. PpFABLA-co-PBLA (11) preserves the helical structure, by intention, independently of the E/Z-isomerization of the side chain: Both photo-isomers of PpFABLA-co-PBLA (11) form a helix that─at a concentration of 16%(w/w)─form an LLC. Despite the absence of a change in the secondary structure, the E/Z-isomerization of the side chain changes the morphology of the liquid crystal and leads to different sets of dipolar coupling for the same probe molecule.
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Affiliation(s)
- Max Hirschmann
- Clemens-Schöpf-Institute, Technical University of Darmstadt (TUDa), Alarich-Weiss-Straße 4, DE 64287 Darmstadt, Germany
| | - Olaf Soltwedel
- Institute for Condensed Matter Physics, Technical University of Darmstadt (TUDa), Hochschulstraße 8, DE 64289 Darmstadt, Germany
| | - Philipp Ritzert
- Institute for Condensed Matter Physics, Technical University of Darmstadt (TUDa), Hochschulstraße 8, DE 64289 Darmstadt, Germany
| | - Regine von Klitzing
- Institute for Condensed Matter Physics, Technical University of Darmstadt (TUDa), Hochschulstraße 8, DE 64289 Darmstadt, Germany
| | - Christina M Thiele
- Clemens-Schöpf-Institute, Technical University of Darmstadt (TUDa), Alarich-Weiss-Straße 4, DE 64287 Darmstadt, Germany
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5
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Wang XJ, Li GW, Cheng YP, Sun QL, Hao YQ, Wang CH, Liu LT. Design and Synthesis of Dipeptidomimetic Isocyanonaphthalene as Enhanced-Fluorescent Chemodosimeter for Sensing Mercury Ion and Living Cells. Front Chem 2022; 10:813108. [PMID: 35317003 PMCID: PMC8934403 DOI: 10.3389/fchem.2022.813108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 01/24/2022] [Indexed: 12/29/2022] Open
Abstract
A novel valine-based isocyanonaphthalene (NpI) was designed and synthesized by using an easy method and enabled the selective fluorescence detection of Hg2+. The chemodosimeter can display an immediate turn-on fluorescence response (500-fold) towards target metal ions upon the Hg2+-mediated conversion of isocyano to amino within NpI. Based on this specific reaction, the fluorescence-enhancement probe revealed a high sensitivity toward Hg2+ over other common metal ions and exhibited excellent aqueous solubility, good antijamming capability, high sensitivity (detection limit: 14.2 nM), and real-time detection. The response mechanism of NpI was supported by NMR spectroscopy, MS analysis and DFT theoretical calculation using various techniques. Moreover, a dipeptidomimetic NpI probe was successfully applied to visualize intracellular Hg2+ in living cells and monitor Hg2+ in real water samples with good recoveries and small relative standard deviations.
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Affiliation(s)
| | - Gao-Wei Li
- *Correspondence: Gao-Wei Li, ; Yuan-Qiang Hao,
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6
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Li GW, Wang XJ, Lei X, Liu N, Wu ZQ. Self-assembly of Helical Polymers and Oligomers to Create Liquid Crystalline Alignment for Anisotropic NMR Parameters. Macromol Rapid Commun 2022; 43:e2100898. [PMID: 35076973 DOI: 10.1002/marc.202100898] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/22/2022] [Indexed: 11/07/2022]
Abstract
The measurement of anisotropic residual dipolar couplings (RDCs) parameters for the structure elucidation of organic molecules relies on suitable alignment media. Employment of self-assembled liquid crystalline systems to create anisotropic alignment can be an effective way to realize aligned samples and acquire RDCs. This Mini-review highlights the recent advances on amino acid-based helical polymers and supramolecular oligomers forming rigid, rod-like structures that aggregate into ordered liquid crystalline phases, including amino acid-based helical polyisocyanides, polyacetylenes, polypeptides, and oligopeptides assembled alignment media. The methodology for the determination of anisotropic liquid crystals was briefly discussed, and a summary of recent research progress in the enantiodifferentiation of helical polymers aligned media was followed. In addition, the self-assembled mechanism of oligopeptides and their RDCs structural analysis were also described. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Gao-Wei Li
- College of Chemistry and Chemical Engineering, and Henan Engineering Laboratory of Green Synthesis for Pharmaceuticals, Shangqiu Normal University, Shangqiu, Henan Province, 476000, China
| | - Xiao-Juan Wang
- College of Chemistry and Chemical Engineering, and Henan Engineering Laboratory of Green Synthesis for Pharmaceuticals, Shangqiu Normal University, Shangqiu, Henan Province, 476000, China
| | - Xinxiang Lei
- School of Pharmaceutical Sciences, South Central University for Nationalities, Wuhan, 430074, P. R. China
| | - Na Liu
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, and Anhui Key Laboratory of Advanced Functional Materials and Devices, Hefei University of Technology, Hefei, Anhui Province, 230009, China
| | - Zong-Quan Wu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin Province, 130012, China
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7
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Wesp S, Wolf K, Immel S, Reggelin M. Poly(arylisocyanides) as Versatile, Enantiodiscriminating Alignment Media for Small Molecules. Chempluschem 2022; 87:e202100507. [PMID: 35072980 DOI: 10.1002/cplu.202100507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/02/2022] [Indexed: 11/08/2022]
Abstract
Lyotropic liquid crystalline (LLC) phases of amino acid derived polyarylisocyanides were employed as chiral alignment media for the measurement of residual dipolar couplings (RDCs) of small chiral organic molecules. Anisotropic samples in CDCl3 displayed quadrupolar splittings of the deuterium signal in the range of several hundreds of Hertz. The LLC phases showed excellent orienting properties for a broad range of analytes bearing various functional groups. The precise extraction of RDCs in the range of up to ±40 Hertz from F2-coupled HSQC spectra was possible. Additionally, the chiral environment offers the opportunity for diastereomorphous interactions with the enantiomers of chiral analytes leading to two different sets of RDCs. This differential order effect was particularly pronounced with ketones and alcohols.
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Affiliation(s)
- Svenja Wesp
- Technische Universität Darmstadt, Clemens Schöpf Institut für Organische Chemie und Biochemie, Alarich-Weiss-Str. 4, 64287, Darmstadt, Germany
| | - Kai Wolf
- Technische Universität Darmstadt, Clemens Schöpf Institut für Organische Chemie und Biochemie, Alarich-Weiss-Str. 4, 64287, Darmstadt, Germany
| | - Stefan Immel
- Technische Universität Darmstadt, Clemens Schöpf Institut für Organische Chemie und Biochemie, Alarich-Weiss-Str. 4, 64287, Darmstadt, Germany
| | - Michael Reggelin
- Technische Universität Darmstadt, Clemens Schöpf Institut für Organische Chemie und Biochemie, Alarich-Weiss-Str. 4, 64287, Darmstadt, Germany
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8
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Roth FA, Schmidts V, Rettig J, Thiele CM. Model free analysis of experimental residual dipolar couplings in small organic compounds. Phys Chem Chem Phys 2021; 24:281-286. [PMID: 34881759 DOI: 10.1039/d1cp02324a] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Residual dipolar couplings (RDCs) contain information on the relative arrangement and dynamics of internuclear spin vectors in chemical compounds. Classically, RDC data is analyzed by fitting to structure models, while model-free approaches (MFA) directly relate RDCs to the corresponding internuclear vectors. The recently introduced software TITANIA implements the MFA and extracts structure and dynamics parameters directly from RDCs to facilitate de novo structure refinement for small organic compounds. Encouraged by our previous results on simulated data, we herein focus on the prerequisites and challenges faced when using purely experimental data for this approach. These concern mainly the fact that not all couplings are accessible in all media, leading to voids in the RDC matrix and the concomitant effects on the structure refinement. It is shown that RDC data sets obtained experimentally from currently available alignment media and measurement methods are of sufficient quality to allow relative configuration determination even when the relative configuration of the analyte is completely unknown.
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Affiliation(s)
- Felix A Roth
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technical University of Darmstadt, Alarich-Weiss-Str. 16, 64287 Darmstadt, Germany.
| | - Volker Schmidts
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technical University of Darmstadt, Alarich-Weiss-Str. 16, 64287 Darmstadt, Germany.
| | - Jan Rettig
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technical University of Darmstadt, Alarich-Weiss-Str. 16, 64287 Darmstadt, Germany.
| | - Christina M Thiele
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technical University of Darmstadt, Alarich-Weiss-Str. 16, 64287 Darmstadt, Germany.
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9
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Poveda A, Fittolani G, Seeberger PH, Delbianco M, Jiménez-Barbero J. The Flexibility of Oligosaccharides Unveiled Through Residual Dipolar Coupling Analysis. Front Mol Biosci 2021; 8:784318. [PMID: 34859057 PMCID: PMC8631391 DOI: 10.3389/fmolb.2021.784318] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 10/14/2021] [Indexed: 11/13/2022] Open
Abstract
The intrinsic flexibility of glycans complicates the study of their structures and dynamics, which are often important for their biological function. NMR has provided insights into the conformational, dynamic and recognition features of glycans, but suffers from severe chemical shift degeneracy. We employed labelled glycans to explore the conformational behaviour of a β(1-6)-Glc hexasaccharide model through residual dipolar couplings (RDCs). RDC delivered information on the relative orientation of specific residues along the glycan chain and provided experimental clues for the existence of certain geometries. The use of two different aligning media demonstrated the adaptability of flexible oligosaccharide structures to different environments.
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Affiliation(s)
- Ana Poveda
- CICbioGUNE, Basque Research and Technology Alliance (BRTA), Derio, Spain
| | - Giulio Fittolani
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Potsdam, Germany.,Department of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Peter H Seeberger
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Potsdam, Germany.,Department of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Martina Delbianco
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Potsdam, Germany
| | - Jesús Jiménez-Barbero
- CICbioGUNE, Basque Research and Technology Alliance (BRTA), Derio, Spain.,Ikerbasque, Basque Foundation for Science, Bilbao, Spain.,Department of Organic Chemistry II, Faculty of Science and Technology, University of the Basque Country, EHU-UPV, Leioa, Spain.,Centro de Investigacion Biomedica En Red de Enfermedades Respiratorias, Madrid, Spain
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10
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Roth FA, Schmidts V, Thiele CM. TITANIA: Model-Free Interpretation of Residual Dipolar Couplings in the Context of Organic Compounds. J Org Chem 2021; 86:15387-15402. [PMID: 34677977 DOI: 10.1021/acs.joc.1c01926] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Residual dipolar couplings (RDCs) become increasingly important as additional NMR parameters in the structure elucidation of organic compounds but are usually used in fitting procedures to discriminate between (computed) structures that are in accordance with RDCs and others that can be ruled out. Thus, the determination of configurations requires prior structural information. The direct use of RDCs as restraints to construct structures based on RDCs has only recently begun also in organic compounds. No protocol has been published though that uses the vector and dynamics information available in multialignment data sets directly for the joint determination of conformation and configuration of organic compounds. This is proposed in the current study. We show that by employing these data, even a flat or random start structure converges into the correctly configured structure when employing multiple alignment data sets in our iterative procedure. The requirements in terms of the number of RDCs and alignment media necessary are discussed in detail.
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Affiliation(s)
- Felix A Roth
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technical University of Darmstadt, Alarich-Weiss-Str. 16, 64287 Darmstadt, Germany
| | - Volker Schmidts
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technical University of Darmstadt, Alarich-Weiss-Str. 16, 64287 Darmstadt, Germany
| | - Christina M Thiele
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technical University of Darmstadt, Alarich-Weiss-Str. 16, 64287 Darmstadt, Germany
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11
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Krupp A, Noll M, Reggelin M. Valine derived poly (acetylenes) as versatile chiral lyotropic liquid crystalline alignment media for RDC-based structure elucidations. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:577-586. [PMID: 32012341 DOI: 10.1002/mrc.5003] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 01/22/2020] [Accepted: 01/27/2020] [Indexed: 06/10/2023]
Abstract
Anisotropic samples of lyotropic liquid crystalline (LLC) phases of valine derived polyaryl acetylenes were employed as chiral alignment media for the measurement of residual dipolar couplings (RDCs) of 12 small, chiral, organic molecules. The quadrupolar splitting of the deuterium signal of CDCl3 can be adjusted by temperature and concentration changes from 0 to 350 Hz. The LLC phases showed excellent orienting properties for all analytes bearing various functional groups. The precise extraction of RDCs in the range of up to ±30 Hz from F2-coupled HSQC spectra was possible. Additionally, the chiral environment led to diastereomorphous interactions with the enantiomers of chiral analytes leading to two different sets of RDCs. This differential order effect was particularly pronounced with H-bond donors like alcohols and 2° amines.
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Affiliation(s)
- Alexis Krupp
- Clemens Schöpf Institut for Organic Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Germany
- Nitrochemie Aschau GmbH, Aschau am Inn, Germany
| | - Markus Noll
- Clemens Schöpf Institut for Organic Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Germany
| | - Michael Reggelin
- Clemens Schöpf Institut for Organic Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Germany
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12
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Ibáñez de Opakua A, Zweckstetter M. Extending the applicability of P3D for structure determination of small molecules. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2021; 2:105-116. [PMID: 37904779 PMCID: PMC10539764 DOI: 10.5194/mr-2-105-2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 03/15/2021] [Indexed: 11/01/2023]
Abstract
The application of anisotropic nuclear magnetic resonance (NMR) parameters for the correct structural assignment of small molecules requires the use of partially ordered media. Previously we demonstrated that the use of P3D simulations using poly(γ -benzyl-L-glutamate) (PBLG) as an alignment medium allows for the determination of the correct diastereomer from extremely sparse NMR data. Through the analysis of the structural characteristics of small molecules in different alignment media, here we show that when steric or electrostatic factors dominate the alignment, P3D-PBLG retains its diastereomer discrimination power. We also demonstrate that P3D simulations can define the different conformations of a flexible small molecule from sparse NMR data.
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Affiliation(s)
- Alain Ibáñez de Opakua
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, 37075 Göttingen, Germany
| | - Markus Zweckstetter
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, 37075 Göttingen, Germany
- Department for NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Faßberg 11, 37077 Göttingen, Germany
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13
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da Silva DGB, Hallwass F, Navarro-Vázquez A. Single experiment measurement of residual dipolar couplings in aqueous solution using a biphasic bisperylene imide chromonic liquid crystal. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:408-413. [PMID: 33295034 DOI: 10.1002/mrc.5120] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/01/2020] [Accepted: 12/06/2020] [Indexed: 06/12/2023]
Abstract
The use of the biphasic isotropic/nematic region in a bisperylene imide-based lyotropic liquid crystal system allows the extraction of proton-carbon 1 DCH residual dipolar couplings in aqueous solution from a single F1-coupled HSQC experiment. The method was successfully applied to the RDC-based conformational analysis of sucrose.
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Affiliation(s)
- Danilo G B da Silva
- Departamento de Química Fundamental, CCEN, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Fernando Hallwass
- Departamento de Química Fundamental, CCEN, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Armando Navarro-Vázquez
- Departamento de Química Fundamental, CCEN, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
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14
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Recchia MJJ, Cohen RD, Liu Y, Sherer EC, Harper JK, Martin GE, Williamson RT. "One-Shot" Measurement of Residual Chemical Shift Anisotropy Using Poly-γ-benzyl-l-glutamate as an Alignment Medium. Org Lett 2020; 22:8850-8854. [PMID: 33140974 DOI: 10.1021/acs.orglett.0c03225] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A method for the measurement of residual chemical shift anisotropy in one experiment using a biphasic isotropic/anisotropic lyotropic liquid crystalline medium based on poly-γ-benzyl-l-glutamate as the alignment medium is presented. This approach is demonstrated on the model compound strychnine and neotricone, a depsidone natural product with a questionable structural assignment based on comparison with the closely related excelsione and in-depth density functional theory calculations.
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Affiliation(s)
- Michael J J Recchia
- Department of Chemistry & Biochemistry, University of North Carolina Wilmington, Wilmington, North Carolina 28409, United States
| | - Ryan D Cohen
- Analytical Research & Development, Merck & Company Inc., Rahway, New Jersey 07065, United States
| | - Yizhou Liu
- Analytical Research & Development, Pfizer Worldwide Research and Development, Groton, Connecticut 06340, United States
| | - Edward C Sherer
- Analytical Research & Development, Merck & Company Inc., Rahway, New Jersey 07065, United States
| | - James K Harper
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Gary E Martin
- Department of Chemistry, Seton Hall University, South Orange, New Jersey 07079, United States
| | - R Thomas Williamson
- Department of Chemistry & Biochemistry, University of North Carolina Wilmington, Wilmington, North Carolina 28409, United States
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15
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Bodor A, Haller JD, Bouguechtouli C, Theillet FX, Nyitray L, Luy B. Power of Pure Shift HαCα Correlations: A Way to Characterize Biomolecules under Physiological Conditions. Anal Chem 2020; 92:12423-12428. [PMID: 32786451 DOI: 10.1021/acs.analchem.0c02182] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Intrinsically disordered proteins (IDPs) constitute an important class of biomolecules with high flexibility. Atomic-resolution studies for these molecules are essentially limited to NMR spectroscopy, which should be performed under physiological pH and temperature to populate relevant conformational ensembles. In this context, however, fundamental problems arise with established triple resonance NMR experiments: high solvent accessibility of IDPs promotes water exchange, which disfavors classical amide 1H-detection, while 13C-detection suffers from significantly reduced sensitivity. A favorable alternative, the conventional detection of nonexchangeable 1Hα, so far resulted in broad signals with insufficient resolution and sensitivity. To overcome this, we introduce here a selective Hα,Cα-correlating pure shift detection scheme, the selective Hα,Cα-HSQC (SHACA-HSQC), using extensive hetero- and homonuclear decoupling applicable to aqueous samples (≥90% H2O) and tested on small molecules and proteins. SHACA-HSQC spectra acquired on IDPs provide uncompromised resolution and sensitivity (up to fivefold increased S/N compared to the standard 1H,13C-HSQC), as shown for resonance distinction and unambiguous assignment on the disordered transactivation domain of the tumor suppressor p53, α-synuclein, and folded ubiquitin. The detection scheme can be implemented in any 1Hα-detected triple resonance experiment and may also form the basis for the detection of isotope-labeled markers in biological studies or compound libraries.
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Affiliation(s)
- Andrea Bodor
- Institute of Chemistry, Eötvös Loránd University, Pázmány Péter sétány 1/a, Budapest 1117, Hungary
| | - Jens D Haller
- Institut für Organische Chemie and Institut für Biologische Grenzflächen 4-Magnetische Resonanz, Karlsruher Institut für Technologie (KIT), Fritz-Haber-Weg 6, Karlsruhe 76133, Germany
| | - Chafiaa Bouguechtouli
- Institute of Integrative Biology of the Cell, UMR9198, CNRS/CEA/ University of Paris Saclay, Gif-Sur-Yvette 911991, France
| | - Francois-Xavier Theillet
- Institute of Integrative Biology of the Cell, UMR9198, CNRS/CEA/ University of Paris Saclay, Gif-Sur-Yvette 911991, France
| | - László Nyitray
- Department of Biochemistry, Eötvös Loránd University, Pázmány Péter sétány 1/c, Budapest 1117, Hungary
| | - Burkhard Luy
- Institut für Organische Chemie and Institut für Biologische Grenzflächen 4-Magnetische Resonanz, Karlsruher Institut für Technologie (KIT), Fritz-Haber-Weg 6, Karlsruhe 76133, Germany
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16
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Köck M, Reggelin M, Immel S. The Advanced Floating Chirality Distance Geometry Approach-How Anisotropic NMR Parameters Can Support the Determination of the Relative Configuration of Natural Products. Mar Drugs 2020; 18:md18060330. [PMID: 32599876 PMCID: PMC7344786 DOI: 10.3390/md18060330] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/16/2020] [Accepted: 06/18/2020] [Indexed: 11/16/2022] Open
Abstract
The configurational analysis of complex natural products by NMR spectroscopy is still a challenging task. The assignment of the relative configuration is usually carried out by analysis of interproton distances from NOESY or ROESY spectra (qualitative or quantitative) and scalar (J) couplings. About 15 years ago, residual dipolar couplings (RDCs) were introduced as a tool for the configurational determination of small organic molecules. In contrast to NOEs/ROEs which are local parameters (distances up to 400 pm can be detected for small organic molecules), RDCs are global parameters which allow to obtain structural information also from long-range relationships. RDCs have the disadvantage that the sample needs a setup in an alignment medium in order to obtain the required anisotropic environment. Here, we will discuss the configurational analysis of five complex natural products: axinellamine A (1), tetrabromostyloguanidine (2), 3,7-epi-massadine chloride (3), tubocurarine (4), and vincristine (5). Compounds 1-3 are marine natural products whereas 4 and 5 are from terrestrial sources. The chosen examples will carefully work out the limitations of NOEs/ROEs in the configurational analysis of natural products and will also provide an outlook on the information obtained from RDCs.
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Affiliation(s)
- Matthias Köck
- Alfred-Wegener-Institut für Polar-und Meeresforschung in der Helmholtz-Gemeinschaft, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Michael Reggelin
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 4, 64287 Darmstadt, Germany
| | - Stefan Immel
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 4, 64287 Darmstadt, Germany
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17
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Alcaraz Janßen M, Thiele CM. Poly-γ-S-perillyl-l-glutamate and Poly-γ-S-perillyl-d-glutamate: Diastereomeric Alignment Media Used for the Investigation of the Alignment Process. Chemistry 2020; 26:7831-7839. [PMID: 32134524 PMCID: PMC7384199 DOI: 10.1002/chem.201905447] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Indexed: 11/09/2022]
Abstract
Residual dipolar couplings (RDCs) offer additional information for structure elucidation by NMR spectroscopy. They are measured in anisotropic media, such as lyotropic liquid crystalline phases of polypeptides. Today, some suitable polypeptides are known. Nevertheless, structural influences of these polypeptides on the alignment properties are not really understood. Thus, which influence a chiral side chain has on enantiodiscrimination and whether we can improve the enantiodifferentiation significantly by adding an additional chiral center in the side chain are questions of interest. Therefore, new diastereomeric polypeptide-based alignment media with an additional chiral center in the side chain derived from perillyl alcohol were synthesized and their properties were investigated (secondary structure, liquid crystallinity, etc.). The enantiomers of isopinocampheol and β-pinene were used as model analytes for the study of enantiodiscrimination. Additionally, the usage of 1 H-1 H-RDCs to improve the alignment tensor quality is demonstrated.
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Affiliation(s)
- Marcel Alcaraz Janßen
- Clemens-Schöpf-Institut für Organische Chemie und BiochemieTechnical University of DarmstadtAlarich-Weiss-Str. 1664287DarmstadtGermany
| | - Christina M. Thiele
- Clemens-Schöpf-Institut für Organische Chemie und BiochemieTechnical University of DarmstadtAlarich-Weiss-Str. 1664287DarmstadtGermany
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18
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Lesot P, Aroulanda C, Berdagué P, Meddour A, Merlet D, Farjon J, Giraud N, Lafon O. Multinuclear NMR in polypeptide liquid crystals: Three fertile decades of methodological developments and analytical challenges. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 116:85-154. [PMID: 32130960 DOI: 10.1016/j.pnmrs.2019.10.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 10/24/2019] [Indexed: 06/10/2023]
Abstract
NMR spectroscopy of oriented samples makes accessible residual anisotropic intramolecular NMR interactions, such as chemical shift anisotropy (RCSA), dipolar coupling (RDC), and quadrupolar coupling (RQC), while preserving high spectral resolution. In addition, in a chiral aligned environment, enantiomers of chiral molecules or enantiopic elements of prochiral compounds adopt different average orientations on the NMR timescale, and hence produce distinct NMR spectra or signals. NMR spectroscopy in chiral aligned media is a powerful analytical tool, and notably provides unique information on (pro)chirality analysis, natural isotopic fractionation, stereochemistry, as well as molecular conformation and configuration. Significant progress has been made in this area over the three last decades, particularly using polypeptide-based chiral liquid crystals (CLCs) made of organic solutions of helically chiral polymers (as PBLG) in organic solvents. This review presents an overview of NMR in polymeric LCs. In particular, we describe the theoretical tools and the major NMR methods that have been developed and applied to study (pro)chiral molecules dissolved in such oriented solvents. We also discuss the representative applications illustrating the analytical potential of this original NMR tool. This overview article is dedicated to thirty years of original contributions to the development of NMR spectroscopy in polypeptide-based chiral liquid crystals.
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Affiliation(s)
- Philippe Lesot
- Université Paris Sud/Université Paris-Saclay, UMR CNRS 8182, Institut de Chimie Moléculaire et des Matériaux d'Orsay, ICMMO, Equipe RMN en Milieu Orienté, Bât. 410, 15 rue du Doyen Georges Poitou, F-91405 Orsay cedex, France; Centre National de la Recherche Scientifique (CNRS), France.
| | - Christie Aroulanda
- Université Paris Sud/Université Paris-Saclay, UMR CNRS 8182, Institut de Chimie Moléculaire et des Matériaux d'Orsay, ICMMO, Equipe RMN en Milieu Orienté, Bât. 410, 15 rue du Doyen Georges Poitou, F-91405 Orsay cedex, France
| | - Philippe Berdagué
- Université Paris Sud/Université Paris-Saclay, UMR CNRS 8182, Institut de Chimie Moléculaire et des Matériaux d'Orsay, ICMMO, Equipe RMN en Milieu Orienté, Bât. 410, 15 rue du Doyen Georges Poitou, F-91405 Orsay cedex, France
| | - Abdelkrim Meddour
- Université Paris Sud/Université Paris-Saclay, UMR CNRS 8182, Institut de Chimie Moléculaire et des Matériaux d'Orsay, ICMMO, Equipe RMN en Milieu Orienté, Bât. 410, 15 rue du Doyen Georges Poitou, F-91405 Orsay cedex, France
| | - Denis Merlet
- Université Paris Sud/Université Paris-Saclay, UMR CNRS 8182, Institut de Chimie Moléculaire et des Matériaux d'Orsay, ICMMO, Equipe RMN en Milieu Orienté, Bât. 410, 15 rue du Doyen Georges Poitou, F-91405 Orsay cedex, France
| | - Jonathan Farjon
- Centre National de la Recherche Scientifique (CNRS), France; Faculté des Sciences et Techniques de Nantes, UMR CNRS 6230, Chimie et Interdisciplinarité, Synthèse, Analyse, Modélisation, CEISAM, Equipe EBSI, BP 92208, 2 rue de la Houssinière, F-44322 Nantes cedex 3, France
| | - Nicolas Giraud
- Université Paris Descartes, Sorbonne Paris Cité, UMR CNRS 8601, Laboratory of Pharmacological and Toxicological Chemistry and Biochemistry, LPTCB, 45 rue des Saints Pères, F-75006 Paris, France
| | - Olivier Lafon
- Universite de Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR CNRS 8181, Unité de Catalyse et Chimie du Solide, UCCS, F-59000 Lille, France; Institut Universitaire de France (IUF), France
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19
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Haller JD, Bodor A, Luy B. Real-time pure shift measurements for uniformly isotope-labeled molecules using X-selective BIRD homonuclear decoupling. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 302:64-71. [PMID: 30965191 DOI: 10.1016/j.jmr.2019.03.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 03/28/2019] [Accepted: 03/29/2019] [Indexed: 06/09/2023]
Abstract
We introduce a novel selective inversion element for chunked homonuclear decoupling that combines isotope selection via BIRD-filtering with band-selective inversion on the X-heteronucleus and allows efficient real-time decoupling of homonuclear and heteronuclear couplings. It is especially suitable for uniformly isotope-labeled compounds. We discuss in detail the inversion element based on band-selective refocusing on the X-nuclei (BASEREX), highlighting in particular the role of appropriate band-selective shaped refocusing pulses and the application of broadband X-pulses for an effective BIRDd element during homodecoupling. The approach is experimentally verified and studied in detail using uniformly 13C-labeled glucose and a uniformly 15N,13C-labeled amino acid mixture.
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Affiliation(s)
- Jens D Haller
- Institut für Organische Chemie and Institut für Biologische Grenzflächen 4 - Magnetische Resonanz, Karlsruher Institut für Technologie (KIT), Fritz-Haber-Weg 6, 76133 Karlsruhe, Germany
| | - Andrea Bodor
- Eötvös Loránd University, Institute of Chemistry, Laboratory of Structural Chemistry and Biology, Pázmány Péter sétány 1/a, Budapest 1117, Hungary
| | - Burkhard Luy
- Institut für Organische Chemie and Institut für Biologische Grenzflächen 4 - Magnetische Resonanz, Karlsruher Institut für Technologie (KIT), Fritz-Haber-Weg 6, 76133 Karlsruhe, Germany.
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20
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Nepravishta R, Monaco S, Muñoz-García JC, Khimyak YZ, Angulo J. Spatially Resolved STD-NMR Applied to the Study of Solute Transport in Biphasic Systems: Application to Protein-Ligand Interactions. Nat Prod Commun 2019. [DOI: 10.1177/1934578x19849789] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Fluid biphasic systems are one of the most interesting dynamic systems in chemistry and biochemistry. In nuclear magnetic resonance (NMR) spectroscopy, the study of the solute dynamics across fluid biphasic systems requires the introduction of dedicated NMR methods, due to their intrinsic heterogeneity. Diffusion and spatially resolved NMR techniques represent a useful approach for dealing with the study of solutes in biphasic systems and have been applied lately with success. Nevertheless, other potential applications of NMR spectroscopy for biphasic systems remain to be explored. In this proof-of-concept communication, we specifically aimed to investigate whether solute exchange between two immiscible phases can be followed by NMR experiments involving transfer of magnetization. To that aim, we have used spatially resolved saturation transfer difference NMR (SR-STD NMR) experiments to analyze solute exchange by transfer of saturation from one phase to the other in a biphasic system and have explored which are the underlying mechanisms leading to the transfer of magnetization between phases and the limits of the approach. We hereby demonstrate that SR-STD NMR is feasible and that it might be implemented in pharmacological screening for binders of biological receptors or in the study of chemical and biochemical reactions occurring at interfaces.
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Affiliation(s)
- Ridvan Nepravishta
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Serena Monaco
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Juan C. Muñoz-García
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Yaroslav Z. Khimyak
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Jesus Angulo
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, UK
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21
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Lesot P, Berdagué P, Meddour A, Kreiter A, Noll M, Reggelin M. 2 H and 13 C NMR-Based Enantiodetection Using Polyacetylene versus Polypeptide Aligning Media: Versatile and Complementary Tools for Chemists. Chempluschem 2019; 84:144-153. [PMID: 31950698 DOI: 10.1002/cplu.201800493] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Indexed: 12/12/2022]
Abstract
In this work, the practical/analytical potential of an L-valine-derived polyacetylene (PLA) lyotropic liquid crystal (LLC) is examined to spectrally discriminate enantiomers (racemic mixture) or enantiotopic directions of a large collection (23) of (pro)chiral model compounds (from rigid to flexible and polar to apolar ones), thus covering various important aspects of enantiomorphism. Experimental 2 H-{1 H} (deuterated analytes and at natural abundance level) and 13 C-{1 H} NMR results are discussed in terms of the difference of 2 H-RQCs or 13 C-RCSAs and compared to those obtained in polypeptide-type LLCs (PBLG). The analysis of the NMR results provides an overview of the enantiodifferentiation capabilities of PLA and gives useful/practical hints for the chemist to select the most appropriate chiral oriented system. Astonishing NAD NMR results were obtained in the case of one of the simplest, chiral alkanes, 3-methylhexane. From a theoretical viewpoint, the data collected highlight the key molecular factors involved in orientation/discrimination processes, as a basis for optimizing computational prediction (molecular dynamics simulation), as well as designing novel helically chiral polymers as new enantiodiscriminating aligning media. In addition, a new, robust and efficient protocol to synthesize PLA and its enantiomer (PDA) on a large scale and with small polydispersities is proposed.
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Affiliation(s)
- Philippe Lesot
- RMN en Milieu Orienté, ICMMO, UMR CNRS 8182, Université Paris-Sud/Université Paris-Saclay, Bât. 410, 91405, Orsay cedex, France
| | - Philippe Berdagué
- RMN en Milieu Orienté, ICMMO, UMR CNRS 8182, Université Paris-Sud/Université Paris-Saclay, Bât. 410, 91405, Orsay cedex, France
| | - Abdelkrim Meddour
- RMN en Milieu Orienté, ICMMO, UMR CNRS 8182, Université Paris-Sud/Université Paris-Saclay, Bât. 410, 91405, Orsay cedex, France
| | - Alexander Kreiter
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Strasse 4, 64287, Darmstadt, Germany
| | - Markus Noll
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Strasse 4, 64287, Darmstadt, Germany
| | - Michael Reggelin
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Strasse 4, 64287, Darmstadt, Germany
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22
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Parella T. Towards perfect NMR: Spin-echo versus perfect-echo building blocks. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2019; 57:13-29. [PMID: 29927497 DOI: 10.1002/mrc.4776] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/10/2018] [Accepted: 06/12/2018] [Indexed: 06/08/2023]
Abstract
The development of new tools to improve the quality of nuclear magnetic resonance (NMR) spectra is a challenging task. The concept of "perfect NMR" includes the design of robust pulse sequences that allow an investigator to obtain undistorted pure in-phase signals, with pure absorption lineshapes that are free of phase anomalies derived from undesired J modulations. Here, alternative NMR building blocks to the spin-echo that are based on a general double SE module, known as a perfect-echo, are reviewed. Several implementations to minimize/remove unwanted dispersive contributions in homonuclear and heteronuclear NMR experiments are described and illustrated with some examples of broad interest for small molecules.
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Affiliation(s)
- Teodor Parella
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain
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23
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Niklas T, Schulze P, Farès C. Cromolyn/gelatin mixtures as aqueous alignment media and utilization of their mechanical stability for a layering technique. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:1176-1182. [PMID: 30091791 DOI: 10.1002/mrc.4786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 07/26/2018] [Accepted: 07/27/2018] [Indexed: 06/08/2023]
Abstract
In this study, aqueous blends of cromolyn and gelatin ("cromogels") are introduced as anisotropic media. The addition of gelatin enables an advantageous adjustability of the strength, the homogeneity, and the stability of the cromolyn alignment. The mechanical stability of these polymer-dispersed liquid crystals is further utilized by stacking layers of D2 O/cromolyn/gelatin with varying component ratio. The resulting distinct phases with correspondingly different degrees of alignment can be targeted by spatially resolved NMR techniques. As a case study, we investigated sucrose in a two-phase system with neat D2 O and analyte layered over the anisotropic medium. A recently presented spatially selective coupled-type HSQC experiment allows the determination of one-bond C-H splitting in both phases.
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Affiliation(s)
- Thomas Niklas
- Chromatography Department, Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr, Germany
- NMR Department, Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr, Germany
| | - Philipp Schulze
- Chromatography Department, Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr, Germany
| | - Christophe Farès
- NMR Department, Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr, Germany
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24
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Görling B, Bermel W, Bräse S, Luy B. Homonuclear decoupling by projection reconstruction. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:1006-1020. [PMID: 30058249 DOI: 10.1002/mrc.4784] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/16/2018] [Accepted: 07/10/2018] [Indexed: 06/08/2023]
Abstract
Similar to J-resolved spectroscopy, also, heteronuclear multiple bond correlation (HMBC), heteronuclear single bond correlation (HSBC), and heteronuclear multiple quantum coherence (HMQC) types of correlation experiments result in homonuclear tilted multiplet patterns. On the example of the high-resolution heteronuclear single bond correlation (HR-HSBC) pulse sequence, it is shown how the tilt angle can be varied within a wide range of positive and negative values. Projection along the tilt angles in all cases results in homonuclear decoupling. Using well-known projection reconstruction techniques, the different tilt angles can be used to reconstruct a homonuclear decoupled two-dimensional correlation spectrum. The concept is proven and further refined by segmental projection reconstruction and the use of a clean in-phase heteronuclear single quantum correlation (CLIP-HSQC) spectrum with an effective zero tilt angle for further filtering. The proof of principle, its application to one-bond coupling measurement, as well as a basic HMBC, and a detailed discussion with comparison to other homodecoupling techniques are given.
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Affiliation(s)
- Benjamin Görling
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- Institute for Biological Interfaces 4 - Magnetic Resonance, Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
- Bruker Biospin GmbH, Rheinstetten, Germany
| | | | - Stefan Bräse
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Burkhard Luy
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- Institute for Biological Interfaces 4 - Magnetic Resonance, Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
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25
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Li GW, Liu H, Qiu F, Wang XJ, Lei XX. Residual Dipolar Couplings in Structure Determination of Natural Products. NATURAL PRODUCTS AND BIOPROSPECTING 2018; 8:279-295. [PMID: 29943349 PMCID: PMC6102172 DOI: 10.1007/s13659-018-0174-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 06/14/2018] [Indexed: 05/16/2023]
Abstract
The determination of natural products stereochemistry remains a formidable task. Residual dipolar couplings (RDCs) induced by anisotropic media are a powerful tool for determination of the stereochemistry of organic molecule in solution. This review will provide a short introduction on RDCs-based methodology for the structural elucidation of natural products. Special attention is given to the current availability of alignment media in organic solvents. The applications of RDCs for structural analysis of some examples of natural products were discussed and summarized. This review provides a short introduction on RDCs-based methodology for the structural elucidation of natural products. Special attention is given to the current availability of alignment media in organic solvents. The applications of RDCs for structural analysis of some examples of natural products were discussed and summarized.
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Affiliation(s)
- Gao-Wei Li
- College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu, 476000, People's Republic of China
| | - Han Liu
- School of Pharmaceutical Sciences, South Central University for Nationalities, Wuhan, 430074, People's Republic of China
| | - Feng Qiu
- School of Pharmaceutical Sciences, South Central University for Nationalities, Wuhan, 430074, People's Republic of China
| | - Xiao-Juan Wang
- College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu, 476000, People's Republic of China
| | - Xin-Xiang Lei
- School of Pharmaceutical Sciences, South Central University for Nationalities, Wuhan, 430074, People's Republic of China.
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26
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Liu Y, Cohen RD, Martin GE, Williamson RT. A practical strategy for the accurate measurement of residual dipolar couplings in strongly aligned small molecules. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 291:63-72. [PMID: 29723716 DOI: 10.1016/j.jmr.2018.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 04/05/2018] [Accepted: 04/05/2018] [Indexed: 06/08/2023]
Abstract
Accurate measurement of residual dipolar couplings (RDCs) requires an appropriate degree of alignment in order to optimize data quality. An overly weak alignment yields very small anisotropic data that are susceptible to measurement errors, whereas an overly strong alignment introduces extensive anisotropic effects that severely degrade spectral quality. The ideal alignment amplitude also depends on the specific pulse sequence used for the coupling measurement. In this work, we introduce a practical strategy for the accurate measurement of one-bond 13C-1H RDCs up to a range of ca. -300 to +300 Hz, corresponding to an alignment that is an order of magnitude stronger than typically employed for small molecule structural elucidation. This strong alignment was generated in the mesophase of the commercially available poly-γ-(benzyl-L-glutamate) polymer. The total coupling was measured by the simple and well-studied heteronuclear two-dimensional J-resolved experiment, which performs well in the presence of strong anisotropic effects. In order to unequivocally determine the sign of the total coupling and resolve ambiguities in assigning total couplings in the CH2 group, coupling measurements were conducted at an isotropic condition plus two anisotropic conditions of different alignment amplitudes. Most RDCs could be readily extracted from these measurements whereas more complicated spectral effects resulting from strong homonuclear coupling could be interpreted either theoretically or by simulation. Importantly, measurement of these very large RDCs actually offers significantly improved data quality and utility for the structure determination of small organic molecules.
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Affiliation(s)
- Yizhou Liu
- Structure Elucidation Group, Process and Analytical Research and Development, Merck & Co. Inc., 126 East Lincoln Avenue, Rahway, NJ 07065, USA.
| | - Ryan D Cohen
- Structure Elucidation Group, Process and Analytical Research and Development, Merck & Co. Inc., 126 East Lincoln Avenue, Rahway, NJ 07065, USA
| | - Gary E Martin
- Structure Elucidation Group, Process and Analytical Research and Development, Merck & Co. Inc., 126 East Lincoln Avenue, Rahway, NJ 07065, USA
| | - R Thomas Williamson
- Structure Elucidation Group, Process and Analytical Research and Development, Merck & Co. Inc., 126 East Lincoln Avenue, Rahway, NJ 07065, USA
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Liu Y, Cohen RD, Gustafson KR, Martin GE, Williamson RT. Enhanced measurement of residual chemical shift anisotropy for small molecule structure elucidation. Chem Commun (Camb) 2018; 54:4254-4257. [PMID: 29505044 PMCID: PMC6322199 DOI: 10.1039/c8cc00552d] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A method is introduced to measure residual chemical shift anisotropies conveniently and accurately in the mesophase of poly-γ-(benzyl-l-glutamate). The alignment amplitude is substantially enhanced over common methods which greatly benefits measurements particularly on sp3 carbons. The approach offers significant improvements in data accuracy and utility for small molecule structure determination.
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Affiliation(s)
- Yizhou Liu
- Structure Elucidation Group, Process and Analytical Research and Development, Merck & Co. Inc., 126 East Lincoln Avenue, Rahway, NJ 07065, USA.
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