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Tichotová MC, Tučková L, Kocek H, Růžička A, Straka M, Procházková E. Exploring the impact of alignment media on RDC analysis of phosphorus-containing compounds: a molecular docking approach. Phys Chem Chem Phys 2024; 26:2016-2024. [PMID: 38126374 DOI: 10.1039/d3cp04099b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Residual dipolar couplings (RDCs) are employed in NMR analysis when conventional methods, such as J-couplings and nuclear Overhauser effects (NOEs) fail. Low-energy (optimized) conformers are often used as input structures in RDC analysis programs. However, these low-energy structures do not necessarily resemble conformations found in anisotropic environments due to interactions with the alignment medium, especially if the analyte molecules are flexible. Considering interactions with alignment media in RDC analysis, we developed and evaluated a molecular docking-based approach to generate more accurate conformer ensembles for compounds in the presence of the poly-γ-benzyl-L-glutamate alignment medium. We designed chiral phosphorus-containing compounds that enabled us to utilize 31P NMR parameters for the stereochemical analysis. Using P3D/PALES software to evaluate diastereomer discrimination, we found that our conformer ensembles outperform moderately the standard, low-energy conformers in RDC analysis. To further improve our results, we (i) averaged the experimental values of the molecular docking-based conformers by applying the Boltzmann distribution and (ii) optimized the structures through normal mode relaxation, thereby enhancing the Pearson correlation factor R and even diastereomer discrimination in some cases. Nevertheless, we presume that significant differences between J-couplings in isotropic and in anisotropic environments may preclude RDC measurements for flexible molecules. Therefore, generating conformer ensembles based on molecular docking enhances RDC analysis for mildly flexible systems while flexible molecules may require applying more advanced approaches, in particular approaches including dynamical effects.
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Affiliation(s)
- Markéta Christou Tichotová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 160 00 Prague, Czech Republic.
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, 116 28 Prague, Czech Republic
| | - Lucie Tučková
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 160 00 Prague, Czech Republic.
| | - Hugo Kocek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 160 00 Prague, Czech Republic.
| | - Aleš Růžička
- Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Pardubice 532 10, Czech Republic
| | - Michal Straka
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 160 00 Prague, Czech Republic.
| | - Eliška Procházková
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 160 00 Prague, Czech Republic.
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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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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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Carvalho DS, da Silva DGB, Hallwass F, Navarro-Vázquez A. An Acrylonitrile-Based Copolymer Gel as an NMR Alignment Medium for Extraction of Residual Dipolar Couplings of Small Molecules in Aqueous Solution. Chempluschem 2023; 88:e202200446. [PMID: 36782376 DOI: 10.1002/cplu.202200446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/19/2023] [Indexed: 01/24/2023]
Abstract
An NMR weakly-aligning polymer gel has been prepared by copolymerization of acrylonitrile and 2-acrylamide-2-methyl-1-propanesulfonic acid in the presence of 1,4-butanediol diacrylate as a cross-linker. The polymer readily swells in water in a large range of temperatures, although the swelling ratio is decreased in saline solutions. The swollen gel can be mechanically compressed, in a reversible way, generating anisotropy, as easily shown in 2 H NMR experiments, and allowing measurement of 1 DCH residual dipolar couplings (RDCs) through F1-coupled HSQC experiments. The performance of this gel as a NMR alignment medium was evaluated in several water-soluble organic molecules and, while it provided RDCs of proper size for sucrose and even such as small molecule as 5-norbornen-2-ol, in the case of azidothymidine and cefuroxime sodium salt the strong interaction of these molecules with the gel prevented successful extraction of the RDCs.
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Affiliation(s)
- Daiane S Carvalho
- Departamento de Química Fundamental, Universidade Federal de Pernambuco Cidade Universitria, CEP, 50.740-540, Recife, PE, Brazil
| | - Danilo G B da Silva
- Departamento de Química Fundamental, Universidade Federal de Pernambuco Cidade Universitria, CEP, 50.740-540, Recife, PE, Brazil
| | - Fernando Hallwass
- Departamento de Química Fundamental, Universidade Federal de Pernambuco Cidade Universitria, CEP, 50.740-540, Recife, PE, Brazil
| | - Armando Navarro-Vázquez
- Departamento de Química Fundamental, Universidade Federal de Pernambuco Cidade Universitria, CEP, 50.740-540, Recife, PE, Brazil
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Immel S, Köck M, Reggelin M. NMR-Based Configurational Assignments of Natural Products: How Floating Chirality Distance Geometry Calculations Simplify Gambling with 2 N-1 Diastereomers. JOURNAL OF NATURAL PRODUCTS 2022; 85:1837-1849. [PMID: 35820115 DOI: 10.1021/acs.jnatprod.2c00427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Using NMR data, the assignment of the correct 3D configuration and conformation to unknown natural products is of pivotal importance in pharmaceutical and medicinal chemistry. In this report, we quantify the probability of configurational assignments to judge the quality of structural elucidations using Bayesian inference in combination with floating-chirality distance geometry simulations. Based on reference-free NOE/ROE data, residual dipolar couplings (RDCs), and residual quadrupolar couplings (RQCs) in various combinations, we demonstrate how the relative configurations of three natural compounds, namely, jatrohemiketal (1), artemisinin (2), and Taxol (3), can be unambiguously established without the necessity to carry out time-consuming DFT-based configurational and conformational analyses. Our results quantitatively describe how reliably molecular geometries can be inferred from experimental NMR data, thereby unequivocally unveiling remaining assignment ambiguities. The methodology presented here will dramatically reduce the risk of incorrect structural assignments based on the overinterpretation of incomplete data and DFT-based structure models in chemistry.
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Affiliation(s)
- Stefan Immel
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 4, 64287 Darmstadt, Germany
| | - 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
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Schirra DS, Götz P, Lehmann M, Thiele CM. Atropisomerism in a polyglutamate-based thermoresponsive alignment medium. Chem Commun (Camb) 2022; 58:7511-7514. [PMID: 35708488 DOI: 10.1039/d2cc01982e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Structure elucidation via residual dipolar couplings (RDCs) relies on alignment media. We report on lyotropic liquid crystals (LLCs) of poly-γ-p-biphenyl(2'-methoxy-2-methyl)methyl-L-glutamate (PBPM3LG). Temperature dependent atropisomerism within the biphenyl group enables the acquisition of multiple RDC-datasets within one sample.
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Affiliation(s)
- Dominic S Schirra
- Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Research and Laboratory Center M3, Technical University of Darmstadt, Alarich-Weiss-Str. 16, 64287 Darmstadt, Germany.
| | - Philipp Götz
- Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Research and Laboratory Center M3, Technical University of Darmstadt, Alarich-Weiss-Str. 16, 64287 Darmstadt, Germany.
| | - Matthias Lehmann
- Institute for Organic Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Christina M Thiele
- Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Research and Laboratory Center M3, Technical University of Darmstadt, Alarich-Weiss-Str. 16, 64287 Darmstadt, Germany.
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Lin Y, Li J, Qin SY, Sun H, Yang YL, Navarro-Vázquez A, Lei X. Programmable alignment media from self-assembled oligopeptide amphiphiles for the measurement of independent sets of residual dipolar couplings in organic solvents. Chem Sci 2022; 13:5838-5845. [PMID: 35685790 PMCID: PMC9131869 DOI: 10.1039/d2sc01057g] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 04/14/2022] [Indexed: 11/27/2022] Open
Abstract
NMR spectroscopy in anisotropic media has emerged as a powerful technique for the structural elucidation of organic molecules. Its application requires weak alignment of analytes by means of suitable alignment media. Although a number of alignment media, that are compatible with organic solvents, have been introduced in the last 20 years, acquiring a number of independent, non-linearly related sets of anisotropic NMR data from the same organic solvent system remains a formidable challenge, which is however crucial for the alignment simulations and deriving dynamic and structural information of organic molecules unambiguously. Herein, we introduce a programmable strategy to construct several distinct peptide-based alignment media by adjusting the amino acid sequence, which allows us to measure independent sets of residual dipolar couplings (RDCs) in a highly efficient and accurate manner. This study opens a new avenue for de novo structure determination of organic compounds without requiring prior structural information. We report a programmable strategy to construct multi-alignment media via peptide self-assembly for the measurement of independent sets of residual dipolar couplings (RDCs).![]()
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Affiliation(s)
- Yuexiao Lin
- School of Pharmaceutical Sciences, South-Central University for Nationalities Wuhan 430074 China
| | - Jiaqian Li
- School of Pharmaceutical Sciences, South-Central University for Nationalities Wuhan 430074 China
| | - Si-Yong Qin
- Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, South-Central University for Nationalities Wuhan 430074 China
| | - Han Sun
- Group of Structural Chemistry and Computational Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) 13125 Berlin Germany
| | - Yan-Ling Yang
- School of Pharmaceutical Sciences, South-Central University for Nationalities Wuhan 430074 China
| | - Armando Navarro-Vázquez
- Departamento de Química Fundamental, Universidade Federal de Pernambuco Cidade Universitária CEP 50740-540 Recife PE Brazil
| | - Xinxiang Lei
- School of Pharmaceutical Sciences, South-Central University for Nationalities Wuhan 430074 China .,Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, South-Central University for Nationalities Wuhan 430074 China
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Schirra DS, Jeziorowski S, Lehmann M, Thiele CM. Thermoreversible Gelation of Homopolyglutamates PBPMLG, PBPELG, and PBPHLG: Another Step toward de Novo RDC-Based Structure Elucidation. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00176] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Dominic S. Schirra
- Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Sharon Jeziorowski
- Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Matthias Lehmann
- Institute for Organic Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - Christina M. Thiele
- Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Technical University of Darmstadt, 64287 Darmstadt, Germany
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Immel S, Köck M, Reggelin M. NMR-Based Configurational Assignments of Natural Products: Gibbs Sampling and Bayesian Inference Using Floating Chirality Distance Geometry Calculations. Mar Drugs 2021; 20:14. [PMID: 35049868 PMCID: PMC8781118 DOI: 10.3390/md20010014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 12/12/2021] [Accepted: 12/20/2021] [Indexed: 02/07/2023] Open
Abstract
Floating chirality restrained distance geometry (fc-rDG) calculations are used to directly evolve structures from NMR data such as NOE-derived intramolecular distances or anisotropic residual dipolar couplings (RDCs). In contrast to evaluating pre-calculated structures against NMR restraints, multiple configurations (diastereomers) and conformations are generated automatically within the experimental limits. In this report, we show that the "unphysical" rDG pseudo energies defined from NMR violations bear statistical significance, which allows assigning probabilities to configurational assignments made that are fully compatible with the method of Bayesian inference. These "diastereomeric differentiabilities" then even become almost independent of the actual values of the force constants used to model the restraints originating from NOE or RDC data.
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Affiliation(s)
- Stefan Immel
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 4, 64287 Darmstadt, Germany
| | - 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
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