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Liu P, Jimaja S, Immel S, Thomas C, Mayer M, Weder C, Bruns N. Mechanically triggered on-demand degradation of polymers synthesized by radical polymerizations. Nat Chem 2024:10.1038/s41557-024-01508-x. [PMID: 38609710 DOI: 10.1038/s41557-024-01508-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 03/15/2024] [Indexed: 04/14/2024]
Abstract
Polymers that degrade on demand have the potential to facilitate chemical recycling, reduce environmental pollution and are useful in implant immolation, drug delivery or as adhesives that debond on demand. However, polymers made by radical polymerization, which feature all carbon-bond backbones and constitute the most important class of polymers, have proven difficult to render degradable. Here we report cyclobutene-based monomers that can be co-polymerized with conventional monomers and impart the resulting polymers with mechanically triggered degradability. The cyclobutene residues act as mechanophores and can undergo a mechanically triggered ring-opening reaction, which causes a rearrangement that renders the polymer chains cleavable by hydrolysis under basic conditions. These cyclobutene-based monomers are broadly applicable in free radical and controlled radical polymerizations, introduce functional groups into the backbone of polymers and allow the mechanically gated degradation of high-molecular-weight materials or cross-linked polymer networks into low-molecular-weight species.
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Affiliation(s)
- Peng Liu
- Adolphe Merkle Institute, University of Fribourg, Fribourg, Switzerland.
- Swiss National Center of Competence in Research Bio-Inspired Materials, Fribourg, Switzerland.
- Department of Materials, ETH Zürich, Zürich, Switzerland.
| | - Sètuhn Jimaja
- Adolphe Merkle Institute, University of Fribourg, Fribourg, Switzerland
- Swiss National Center of Competence in Research Bio-Inspired Materials, Fribourg, Switzerland
| | - Stefan Immel
- Department of Chemistry and Centre for Synthetic Biology, University of Darmstadt, Darmstadt, Germany
| | | | - Michael Mayer
- Adolphe Merkle Institute, University of Fribourg, Fribourg, Switzerland
- Swiss National Center of Competence in Research Bio-Inspired Materials, Fribourg, Switzerland
| | - Christoph Weder
- Adolphe Merkle Institute, University of Fribourg, Fribourg, Switzerland
- Swiss National Center of Competence in Research Bio-Inspired Materials, Fribourg, Switzerland
| | - Nico Bruns
- Swiss National Center of Competence in Research Bio-Inspired Materials, Fribourg, Switzerland.
- Department of Chemistry and Centre for Synthetic Biology, University of Darmstadt, Darmstadt, Germany.
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, UK.
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2
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Julien T, Gouilleux B, Rousseau B, Immel S, Reggelin M, Lesot P. Spatially Resolved Anisotropic Natural Abundance Deuterium 2D-NMR Spectroscopy Using Bimesophasic Lyotropic Chiral Systems. J Phys Chem Lett 2024; 15:2089-2095. [PMID: 38358651 DOI: 10.1021/acs.jpclett.3c03302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
In this paper, we describe, for the first time, the combined and original use of spatially resolved anisotropic natural abundance deuterium (ANAD) 2D-NMR experiments and bimesophasic lyotropic chiral systems to extract two independent sets of anisotropic parameters such as 2H-RQCs from a single NMR sample. As a pioneering example, we focus on a mixture of immiscible polypeptides (PBLG) and polyacetylene helical polymers (L-MSP) dissolved in weakly polar organic solvents (chloroform). Nondeuterated (D)-(+)-camphor is used as a model chiral solute. By providing two series of 2H-RQCs, this new analytical approach paves the way for applications in 3D structure elucidation with increased reliability and also opens up original investigations in terms of spectral enantiomeric discriminations and mixing of helical polymers.
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Affiliation(s)
- Thomas Julien
- RMN en Milieu Orienté, Institut de Chimie moléculaire et des Matériaux d'Orsay (ICMMO), UMR 8182, Université Paris-Saclay, UFR des Sciences d'Orsay, 17-19, Avenue des Sciences, F-91400 Orsay, France
| | - Boris Gouilleux
- RMN en Milieu Orienté, Institut de Chimie moléculaire et des Matériaux d'Orsay (ICMMO), UMR 8182, Université Paris-Saclay, UFR des Sciences d'Orsay, 17-19, Avenue des Sciences, F-91400 Orsay, France
| | - Bernard Rousseau
- RMN en Milieu Orienté, Institut de Chimie moléculaire et des Matériaux d'Orsay (ICMMO), UMR 8182, Université Paris-Saclay, UFR des Sciences d'Orsay, 17-19, Avenue des Sciences, F-91400 Orsay, France
- Centre National de la Recherche Scientifique (CNRS), 3, Rue Michel Ange, F-75016 Paris, France
| | - Stefan Immel
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie Technische, Universität Darmstadt, Peter Grünberg-Strasse 4, 64287 Darmstadt, Germany
| | - Michael Reggelin
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie Technische, Universität Darmstadt, Peter Grünberg-Strasse 4, 64287 Darmstadt, Germany
| | - Philippe Lesot
- RMN en Milieu Orienté, Institut de Chimie moléculaire et des Matériaux d'Orsay (ICMMO), UMR 8182, Université Paris-Saclay, UFR des Sciences d'Orsay, 17-19, Avenue des Sciences, F-91400 Orsay, France
- Centre National de la Recherche Scientifique (CNRS), 3, Rue Michel Ange, F-75016 Paris, France
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Rubin M, Immel S, Chatwani B, Katz JL, Moreida M, Montes J, Drouin A, Fusco D. Post-acute sequelae of COVID-19 in a longitudinal cohort in New Orleans, Louisiana. Am J Med Sci 2023. [DOI: 10.1016/s0002-9629(23)00581-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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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. J Nat Prod 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] [What about the content of this article? (0)] [Affiliation(s)] [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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6
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Immel S, Köck M, Reggelin M. Bayesian Inference Applied to NMR-Based Configurational Assignments by Floating Chirality Distance Geometry Calculations. J Am Chem Soc 2022; 144:6830-6838. [PMID: 35412312 DOI: 10.1021/jacs.2c00813] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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 quality and probability of structural elucidations using Bayesian inference in combination with floating chirality distance geometry simulations. Here, we will discuss the configurational analysis of three complex natural products including isopinocampheol (1), plakilactone H (2), and iodocallophycoic acid A (3) using NMR restraints of various types and in different combinations (residual dipolar couplings (RDCs) and NOE-derived distances). Our results quantitatively demonstrate how reliably molecular geometries can be inferred from experimental NMR data, unequivocally unveiling remaining assignment ambiguities. The methodology presented here can dramatically reduce the risk of incorrect structural assignments based on the overinterpretation of incomplete data 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- and 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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Berdagué P, Gouilleux B, Noll M, Immel S, Reggelin M, Lesot P. Study and quantification of enantiodiscrimination power of four polymeric chiral LLCs using NAD 2D-NMR. Phys Chem Chem Phys 2022; 24:7338-7348. [DOI: 10.1039/d1cp04915a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Identifying and understanding the role of key molecular factors involved in the orientation/discrimination phenomena of analytes in polymer-based chiral liquid crystals (CLCs) are essential tasks for optimizing computational predictions (molecular...
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9
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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10
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Köck M, Reggelin M, Immel S. Model-Free Approach for the Configurational Analysis of Marine Natural Products. Mar Drugs 2021; 19:md19060283. [PMID: 34063741 PMCID: PMC8223791 DOI: 10.3390/md19060283] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/09/2021] [Accepted: 05/11/2021] [Indexed: 12/17/2022] Open
Abstract
The NMR-based configurational analysis of complex marine natural products is still not a routine task. Different NMR parameters are used for the assignment of the relative configuration: NOE/ROE, homo- and heteronuclear J couplings as well as anisotropic parameters. The combined distance geometry (DG) and distance bounds driven dynamics (DDD) method allows a model-free approach for the determination of the relative configuration that is invariant to the choice of an initial starting structure and does not rely on comparisons with (DFT) calculated structures. Here, we will discuss the configurational analysis of five complex marine natural products or synthetic derivatives thereof: the cis-palau’amine derivatives 1a and 1b, tetrabromostyloguanidine (1c), plakilactone H (2), and manzamine A (3). The certainty of configurational assignments is evaluated in view of the accuracy of the NOE/ROE data available. These case studies will show the prospective breadth of application of the DG/DDD method.
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Affiliation(s)
- Matthias Köck
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
- Correspondence: (M.K.); (S.I.)
| | - Michael Reggelin
- Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Technical University of Darmstadt, Alarich-Weiss-Straße 4, 64287 Darmstadt, Germany;
| | - Stefan Immel
- Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Technical University of Darmstadt, Alarich-Weiss-Straße 4, 64287 Darmstadt, Germany;
- Correspondence: (M.K.); (S.I.)
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11
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Reggelin M, Immel S. Configurational Analysis by Residual Dipolar Couplings: Critical Assessment of "Structural Noise" from Thermal Vibrations. Angew Chem Int Ed Engl 2021; 60:3412-3416. [PMID: 33137233 PMCID: PMC7898695 DOI: 10.1002/anie.202011081] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Indexed: 12/11/2022]
Abstract
The certainty of configurational assignments of natural products based on anisotropic NMR parameters, such as residual dipolar couplings (RDCs), must be amended by estimates on structural noise emerging from thermal vibrations. We show that vibrational analysis significantly affects the error margins with which RDCs can be back-calculated from molecular models, and the implications of thermal motions on the differentiability of diastereomers are derived.
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Affiliation(s)
- Michael Reggelin
- Technische Universität DarmstadtClemens Schöpf Institut für Organische Chemie und BiochemieAlarich-Weiss-Strasse 464287DarmstadtGermany
| | - Stefan Immel
- Technische Universität DarmstadtClemens Schöpf Institut für Organische Chemie und BiochemieAlarich-Weiss-Strasse 464287DarmstadtGermany
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12
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Reggelin M, Immel S. Configurational Analysis by Residual Dipolar Couplings: Critical Assessment of “Structural Noise” from Thermal Vibrations. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202011081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Michael Reggelin
- Technische Universität Darmstadt Clemens Schöpf Institut für Organische Chemie und Biochemie Alarich-Weiss-Strasse 4 64287 Darmstadt Germany
| | - Stefan Immel
- Technische Universität Darmstadt Clemens Schöpf Institut für Organische Chemie und Biochemie Alarich-Weiss-Strasse 4 64287 Darmstadt Germany
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13
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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14
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Immel S, Köck M, Reggelin M. Cover Image, Volume 31, Issue 5. Chirality 2019. [DOI: 10.1002/chir.23073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Immel S, Köck M, Reggelin M. Configurational analysis by residual dipolar couplings: A critical assessment of diastereomeric differentiabilities. Chirality 2019; 31:384-400. [PMID: 30916829 DOI: 10.1002/chir.23065] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/20/2019] [Accepted: 02/21/2019] [Indexed: 11/06/2022]
Abstract
Two independent statistical models for evaluating the certainties of configurational assignments of compounds based on nuclear magnetic resonance (NMR) data are evaluated and compared. Both methods yield weights or probabilities with which two or more structure models (constitutional or configurational isomers or even conformers) could be differentiated based on experimental parameters. Although this paper focusses on the use of residual dipolar couplings (RDCs) for the differentiation of diastereomers, the concept can be expanded to any set of experimental NMR-derived parameters. It is demonstrated that highly reliable configurational assignments crucially must depend on thorough statistical analysis, which is frequently neglected in the literature.
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Affiliation(s)
- Stefan Immel
- Clemens Schöpf Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
| | - Matthias Köck
- Alfred-Wegener-Institut (AWI), Helmholtz-Zentrum für Polar- und Meeresforschung, Sektion Ökologische Chemie, Bremerhaven, Germany.,Helmholtz-Zentrum für Infektionsforschung (HZI), Abteilung Chemische Biologie, Braunschweig, Germany
| | - Michael Reggelin
- Clemens Schöpf Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
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16
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Immel S, Köck M, Reggelin M. Configurational Analysis by Residual Dipolar Coupling Driven Floating Chirality Distance Geometry Calculations. Chemistry 2018; 24:13918-13930. [PMID: 29999551 DOI: 10.1002/chem.201802800] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Indexed: 11/06/2022]
Abstract
A new method implemented into a computer program (ConArch+ ) has been developed and applied to demonstrate the successful implementation of residual dipolar couplings (RDCs) in distance geometry (DG) calculations for the configurational assignment of chiral compounds. Unlike established protocols, the new approach combines floating chirality (fc) in 4D- and 3D-distance bounds driven dynamics (DDD) calculations with structural information from RDCs. Thus, relative configurations of chiral compounds were generated only by observables (e.g., NOEs, RDCs) rendering tedious evaluations of calculated structures against RDCs obsolete. We demonstrate the potential of this novel procedure by the simultaneous determination of the configuration and the conformation of three natural products, (-)-isopinocampheol (1), tubocurarine (2), and vincristine (3), as well as for diisopropylidene-β-d-fructopyranose (4).
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Affiliation(s)
- Stefan Immel
- Technische Universität Darmstadt, Clemens Schöpf Institut für Organische Chemie und Biochemie, Alarich-Weiss-Strasse 4, 64287, Darmstadt, Germany
| | - Matthias Köck
- Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, 27570, Bremerhaven, Germany.,Helmholtz-Institut für Pharmazeutische Forschung Saarland (HIPS), Abteilung Mikrobielle Naturstoffe, Universität des Saarlandes, Universitätscampus E8.1, 66123, Saarbrücken, Germany
| | - Michael Reggelin
- Technische Universität Darmstadt, Clemens Schöpf Institut für Organische Chemie und Biochemie, Alarich-Weiss-Strasse 4, 64287, Darmstadt, Germany
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Mokhtari A, Blancato VS, Repizo GD, Henry C, Pikis A, Bourand A, de Fátima Álvarez M, Immel S, Mechakra-Maza A, Hartke A, Thompson J, Magni C, Deutscher J. Enterococcus faecalis utilizes maltose by connecting two incompatible metabolic routes via a novel maltose 6'-phosphate phosphatase (MapP). Mol Microbiol 2013; 88:234-53. [PMID: 23490043 DOI: 10.1111/mmi.12183] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2013] [Indexed: 11/30/2022]
Abstract
Similar to Bacillus subtilis, Enterococcus faecalis transports and phosphorylates maltose via a phosphoenolpyruvate (PEP):maltose phosphotransferase system (PTS). The maltose-specific PTS permease is encoded by the malT gene. However, E. faecalis lacks a malA gene encoding a 6-phospho-α-glucosidase, which in B. subtilis hydrolyses maltose 6'-P into glucose and glucose 6-P. Instead, an operon encoding a maltose phosphorylase (MalP), a phosphoglucomutase and a mutarotase starts upstream from malT. MalP was suggested to split maltose 6-P into glucose 1-P and glucose 6-P. However, purified MalP phosphorolyses maltose but not maltose 6'-P. We discovered that the gene downstream from malT encodes a novel enzyme (MapP) that dephosphorylates maltose 6'-P formed by the PTS. The resulting intracellular maltose is cleaved by MalP into glucose and glucose 1-P. Slow uptake of maltose probably via a maltodextrin ABC transporter allows poor growth for the mapP but not the malP mutant. Synthesis of MapP in a B. subtilis mutant accumulating maltose 6'-P restored growth on maltose. MapP catalyses the dephosphorylation of intracellular maltose 6'-P, and the resulting maltose is converted by the B. subtilis maltose phosphorylase into glucose and glucose 1-P. MapP therefore connects PTS-mediated maltose uptake to maltose phosphorylase-catalysed metabolism. Dephosphorylation assays with a wide variety of phospho-substrates revealed that MapP preferably dephosphorylates disaccharides containing an O-α-glycosyl linkage.
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Affiliation(s)
- Abdelhamid Mokhtari
- INRA, Microbiologie de l'alimentation au service de la santé humaine (MICALIS), UMR1319, F-78350, Jouy en Josas, France
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Weise CF, Immel S, Richter F, Schneider C. The Oxy-Cope Rearrangement of Aldol Products. A Combined Experimental and Theoretical Study. European J Org Chem 2012. [DOI: 10.1002/ejoc.201101690] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Schwalm T, Wiesecke J, Immel S, Rehahn M. Macromol. Rapid Commun. 12/2009. Macromol Rapid Commun 2009. [DOI: 10.1002/marc.200990034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Schwalm T, Wiesecke J, Immel S, Rehahn M. The Gilch Synthesis of Poly(p-phenylene vinylenes): Mechanistic Knowledge in the Service of Advanced Materials. Macromol Rapid Commun 2009; 30:1295-322. [DOI: 10.1002/marc.200900104] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Accepted: 02/17/2009] [Indexed: 11/12/2022]
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an der Heiden M, Plenio H, Immel S, Burello E, Rothenberg G, Hoefsloot H. Insights into Sonogashira Cross-Coupling by High-Throughput Kinetics and Descriptor Modeling. Chemistry 2008; 14:2857-66. [DOI: 10.1002/chem.200701418] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Brickmann J, Riemann RN, Immel S, Wallrapp C. A theoretical investigation on the geometries of glucagon-like peptide-1 and its interactions with dipeptidyl peptidase DPP-IV. Chem Cent J 2008. [PMCID: PMC4235179 DOI: 10.1186/1752-153x-2-s1-p31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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23
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Schwalm T, Wiesecke J, Immel S, Rehahn M. Toward Controlled Gilch Synthesis of Poly(p-phenylene vinylenes): Anionic vs Radical Chain Propagation, a Mechanistic Reinvestigation. Macromolecules 2007. [DOI: 10.1021/ma071337p] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Thorsten Schwalm
- Ernst-Berl-Institute for Chemical Engineering and Macromolecular Science and Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Darmstadt University of Technology, Petersenstrasse 22, D-64287 Darmstadt, Germany
| | - Jens Wiesecke
- Ernst-Berl-Institute for Chemical Engineering and Macromolecular Science and Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Darmstadt University of Technology, Petersenstrasse 22, D-64287 Darmstadt, Germany
| | - Stefan Immel
- Ernst-Berl-Institute for Chemical Engineering and Macromolecular Science and Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Darmstadt University of Technology, Petersenstrasse 22, D-64287 Darmstadt, Germany
| | - Matthias Rehahn
- Ernst-Berl-Institute for Chemical Engineering and Macromolecular Science and Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Darmstadt University of Technology, Petersenstrasse 22, D-64287 Darmstadt, Germany
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Grube A, Immel S, Baran P, Köck M. Massadinchlorid: eine Vorstufe in der Biosynthese von Massadin und Stylissadin. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200790221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Grube A, Immel S, Baran P, Köck M. Inside Cover: Massadine Chloride: A Biosynthetic Precursor of Massadine and Stylissadine (Angew. Chem. Int. Ed. 35/2007). Angew Chem Int Ed Engl 2007. [DOI: 10.1002/anie.200790172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Grube A, Immel S, Baran P, Köck M. Innentitelbild: Massadinchlorid: eine Vorstufe in der Biosynthese von Massadin und Stylissadin (Angew. Chem. 35/2007). Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200790172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Affiliation(s)
- Achim Grube
- Alfred-Wegener-Institut für Polar- und Meeresforschung in der Helmholtz-Gemeinschaft, Am Handelshafen 12, 27570 Bremerhaven, Deutschland
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Gembus A, Corzilius B, Eichel RA, Dinse KP, Immel S, Stumm D, Flauaus M, Plenio H. Electron Paramagnetic Resonance Structure Investigation of Copper Complexation in a Hemicarcerand. J Phys Chem B 2006; 110:15012-20. [PMID: 16869616 DOI: 10.1021/jp062158x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The double-bridged hemicarcerand [A,B-(CH2OH)2-cavitand]-(CH2NHCH2)2-[A,B-(CH2OH)2-cavitand] 23 (and several other related compounds) was synthesized by the condensation of the two complementary precursors A,B-(CH2NH2)2(CH2OH)2-cavitand and A,B-(CH2Br)2(CH2OAc)2-cavitand followed by hydrolysis of the acetate groups. This hemicarcerand has nitrogen and oxygen donor atoms located on the interior of the spherical cavity and thus allows endohedral coordination of metal ions. The cavity has a volume of approximately 0.12 nm3, a value obtained by calculating a Connolly-type contact surface and the molecular electrostatic potential. The Cu2+ complex of hemicarcerand 23 was studied in detail by EPR and DFT calculations at the UB3LYP/6-31G level to verify the anticipated endohedral nature of the metal complex. It could be shown that the copper ion is coordinated to four oxygen donor atoms and no deviation from axial symmetry at the copper site could be detected. No direct coordination to nitrogen atoms of the hemicarcerand could be observed; however, complexation with DMF solvent molecules was detected by ESEEM and HYSCORE experiments. The closed structure of the hemicarcerand was also confirmed by an evaluation of proton-copper distances. Results from DFT calculations are in accord with the EPR results, and further support suggested coordination of the Cu(II) within the hemicarcerand cavity by four oxygen donor atoms.
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Affiliation(s)
- A Gembus
- Eduard-Zintl-Institute for Inorganic and Physical Chemistry, Petersenstr. 19-21, and Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Petersenstr. 22, Darmstadt University of Technology, D-64287 Darmstadt, Germany
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Lichtenthaler FW, Immel S. Molecular Modelling of Saccharides, 9!! On the Hydrophobic Characteristics of Cyclodextrins: Computer-Aided Visualization of Molecular Lipophilicity Patterns. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/jlac.199619960105] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Immel S, Lichtenthaler FW. Molecular Modelling of Saccharides, 10 Studies on Ketoses, 12 The Electrostatic and Lipophilic Potential Profiles of α-Cyclofructin: Computation, Visualization and Conclusions. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/jlac.199619960106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Fukudome M, Shiratani T, Immel S, Nogami Y, Yuan DQ, Fujita K. Synthesis of a Cycloallin Derivative from β-Cyclodextrin: Heptakis(2,3-dideoxy-2,3-epithio)-β-cycloallin. Angew Chem Int Ed Engl 2005; 44:4201-4. [PMID: 15942974 DOI: 10.1002/anie.200462678] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Makoto Fukudome
- Department of Molecular Medicinal Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
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Hakkarainen B, Fujita K, Immel S, Kenne L, Sandström C. 1H NMR studies on the hydrogen-bonding network in mono-altro-β-cyclodextrin and its complex with adamantane-1-carboxylic acid. Carbohydr Res 2005; 340:1539-45. [PMID: 15885670 DOI: 10.1016/j.carres.2005.03.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2004] [Revised: 03/25/2005] [Accepted: 03/31/2005] [Indexed: 10/25/2022]
Abstract
The hydrogen-bond network in mono-altro-beta-cyclodextrin and in its inclusion complex with adamantane-1-carboxylic acid were investigated by (1)H NMR spectroscopy using the chemical shifts, temperature coefficients and vicinal coupling constants of the exchangeable hydroxy protons. The chemical shifts of the 3-OH signals indicated that the hydrogen-bond network between the 2-OH and 3-OH groups was disturbed not only on each side of the altrose residue, but also along the whole dextrin chain. Upon addition of adamantane-1-carboxylic acid, altrose underwent a conformational change from the (1)C(4) to the (O)S(2) form, allowing a more continuous belt of hydrogen bonding, as evidenced by the downfield shift experienced by the 3-OH proton signals of the glucose residues.
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Affiliation(s)
- Birgit Hakkarainen
- Department of Chemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Yuan DQ, Immel S, Koga K, Yamaguchi M, Fujita K. The first successful crystallographic characterization of a cyclodextrin dimer: efficient synthesis and molecular geometry of a doubly sulfur-bridged beta-cyclodextrin. Chemistry 2003; 9:3501-6. [PMID: 12898677 DOI: 10.1002/chem.200204310] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Beta-cyclodextrin is transannularly disulfonylated at the 6(A)- and 6(B)-positions, and then converted to the corresponding 6(A),6(B)-diiodide and 6(A),6(B)-dithiol. Cross-coupling of the latter two species yields a single head-to-head-coupled beta-cyclodextrin dimer 5 with two sulfur linkers at adjacent 6-methylene carbons. NMR and X-ray analysis revealed the trans-type ("aversive") linkage of both beta-cyclodextrin units. In the solid-state structure of 5.5 MeOH.23 H(2)O, the undistorted cyclodextrin macrocycles feature almost parallel ring planes pointing away from each other, leaving 5 with a "handcuff-like" appearance of approximate C(2) symmetry. This work represents the first successful crystallographic study on a cyclodextrin dimer.
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Affiliation(s)
- De-Qi Yuan
- Faculty of Pharmaceutical Sciences, Nagasaki University Bunkyo-machi, Nagasaki 852-8521, Japan
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Lichtenthaler FW, Schneider-Adams T, Immel S. Practical Synthesis of .beta.-D-Xyl-(1.fwdarw.2)-.beta.-D-Man-(1.fwdarw.4)-.alpha.-D-Glc-OMe, a Trisaccharide Component of the Hyriopsis schlegelii Glycosphingolipid. J Org Chem 2002. [DOI: 10.1021/jo00101a036] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Fusobacterium mortiferum utilizes sucrose [glucose-fructose in alpha(1-->2) linkage] and its five isomeric alpha-D-glucosyl-D-fructoses as energy sources for growth. Sucrose-grown cells are induced for both sucrose-6-phosphate hydrolase (S6PH) and fructokinase (FK), but the two enzymes are not expressed above constitutive levels during growth on the isomeric compounds. Extracts of cells grown previously on the sucrose isomers trehalulose alpha(1-->1), turanose alpha(1-->3), maltulose alpha(1-->4), leucrose alpha(1-->5) and palatinose alpha(1-->6) contained high levels of an NAD+ plus metal-dependent phospho-alpha-glucosidase (MalH). The latter enzyme was not induced during growth on sucrose. MalH catalysed the hydrolysis of the 6'-phosphorylated derivatives of the five isomers to yield glucose 6-phosphate and fructose, but sucrose 6-phosphate itself was not a substrate. Unexpectedly, MalH hydrolysed both alpha- and beta-linked stereomers of the chromogenic analogue p-nitrophenyl glucoside 6-phosphate. The gene malH is adjacent to malB and malR, which encode an EII(CB) component of the phosphoenolpyruvate-dependent sugar:phosphotransferase system and a putative regulatory protein, respectively. The authors suggest that for F. mortiferum, the products of malB and malH catalyse the phosphorylative translocation and intracellular hydrolysis of the five isomers of sucrose and of related alpha-linked glucosides. Genes homologous to malB and malH are present in both Klebsiella pneumoniae and the enterohaemorrhagic strain Escherichia coli O157:H7. Both these organisms grew well on sucrose, but only K. pneumoniae exhibited growth on the isomeric compounds.
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Affiliation(s)
- Andreas Pikis
- Department of Infectious Diseases, Children's National Medical Center, Washington DC 20010-2970, USA2
- Microbial Biochemistry and Genetics Unit, Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892-4350, USA1
| | - Stefan Immel
- Institut für Organische Chemie, Technische Universität Darmstadt,D-64287 Darmstadt, Germany3
| | - Stanley A Robrish
- Microbial Biochemistry and Genetics Unit, Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892-4350, USA1
| | - John Thompson
- Microbial Biochemistry and Genetics Unit, Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892-4350, USA1
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Abstract
Regioselective epoxide ring opening of 2(I),3(I)-(2(I)S)-anhydro-alpha-cyclodextrin (1) through intramolecular attack of hydroxyl groups of neighboring glucose rings occurs in diequatorial fashion to yield 3(I),2(II)-anhydro-alpha-cyclodextrin (3) with a rigid glucopyranose-dioxane-glucopyranose tricyclic ring system, the usual diaxial opening and the gluco/altro-configured stereoisomer 2 cannot be detected. Molecular dynamic simulations in water were used to analyze the conformations of 1-3 and the stereochemical implications of this reaction. Due to the contracted 2,3-OH side of the torus, 3 features an inverted conicity compared to the parent alpha-cyclodextrin. A crystallographic study on the bis-3.3 n-PrOH nonahydrate not only displays little variations between the solid-state and solution geometries of 3, but also provides a molecular picture of a unique inclusion complex in which three n-propanol molecules are distributed in the cavity of a dimeric unit of 3 (monoclinic, space group P2(1), a=14.257(1), b=22.623(2), c=16.644(1) A, beta=104.82(1) degrees, all 19,278 reflections with I>2 sigma(I) yield R(F)=0.1017).
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Affiliation(s)
- S Immel
- Institut für Organische Chemie, Technische Universität Darmstadt, Petersenstrasse 22, D-64287 Darmstadt, Germany.
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Thompson J, Robrish SA, Immel S, Lichtenthaler FW, Hall BG, Pikis A. Metabolism of sucrose and its five linkage-isomeric alpha-D-glucosyl-D-fructoses by Klebsiella pneumoniae. Participation and properties of sucrose-6-phosphate hydrolase and phospho-alpha-glucosidase. J Biol Chem 2001; 276:37415-25. [PMID: 11473129 DOI: 10.1074/jbc.m106504200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Klebsiella pneumoniae is presently unique among bacterial species in its ability to metabolize not only sucrose but also its five linkage-isomeric alpha-d-glucosyl-d-fructoses: trehalulose, turanose, maltulose, leucrose, and palatinose. Growth on the isomeric compounds induced a protein of molecular mass approximately 50 kDa that was not present in sucrose-grown cells and which we have identified as an NAD(+) and metal ion-dependent 6-phospho-alpha-glucosidase (AglB). The aglB gene has been cloned and sequenced, and AglB (M(r) = 49,256) has been purified from a high expression system using the chromogenic p-nitrophenyl alpha-glucopyranoside 6-phosphate as substrate. Phospho-alpha-glucosidase catalyzed the hydrolysis of a wide variety of 6-phospho-alpha-glucosides including maltose-6'-phosphate, maltitol-6-phosphate, isomaltose-6'-phosphate, and all five 6'-phosphorylated isomers of sucrose (K(m) approximately 1-5 mm) yet did not hydrolyze sucrose-6-phosphate. By contrast, purified sucrose-6-phosphate hydrolase (M(r) approximately 53,000) hydrolyzed only sucrose-6-phosphate (K(m) approximately 80 microm). Differences in molecular shape and lipophilicity potential between sucrose and its isomers may be important determinants for substrate discrimination by the two phosphoglucosyl hydrolases. Phospho-alpha-glucosidase and sucrose-6-phosphate hydrolase exhibit no significant homology, and by sequence-based alignment, the two enzymes are assigned to Families 4 and 32, respectively, of the glycosyl hydrolase superfamily. The phospho-alpha-glucosidase gene (aglB) lies adjacent to a second gene (aglA), which encodes an EII(CB) component of the phosphoenolpyruvate-dependent sugar:phosphotransferase system. We suggest that the products of the two genes facilitate the phosphorylative translocation and subsequent hydrolysis of the five alpha-d-glucosyl-d-fructoses by K. pneumoniae.
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Affiliation(s)
- J Thompson
- Microbial Biochemistry and Genetics Unit, Oral Infection and Immunity Branch, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Immel S, Lichtenthaler FW, Lindner HJ, Nakagawa T. Hydroxymethyl-substituted crown acetals with 35-C-14 and 40-C-16 skeletal backbones: synthesis and molecular geometries. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s0957-4166(01)00469-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
Periodate oxidation of alpha-cyclodextrin followed by borohydride reduction readily provided an octadeca-hydroxymethyl-substituted 30-crown-12 polyacetal 1, its 30-membered macrocycle being composed of six meso-butanetetrol/glycolaldehyde acetal units, which is, consequently, optically inactive. Its solid-state molecular geometry emerged from the X-ray structural analysis of the well-crystallizing octadeca-acetate 2, which revealed the undulated macrocycle to be molded into three loops with a unique order of succession of the -CHR-CHR-O-CHR-O- units: alternating gauche- and anti-conformations of the meso-butanetetrol portions and consecutive disposition of the glycolaldehyde-acetoxymethyl groups above and below the mean-plane of the macrocycle. In solution, however, as evidenced by 1H- and 13C-NMR spectra, the macrocycle is highly flexible at ambient and higher temperatures, its mobility becoming distinctly restricted only below -20 degrees C.
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Affiliation(s)
- S Immel
- Institut fur Organische Chemie, Technische Universitat Darmstadt, Germany
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Abstract
Readily available from alpha-cyclodextrin in three steps, 2,3-anhydro-alpha-cyclomannin composed of six alpha-(1-->4)-linked 2,3-anhydro-D-mannopyranose residues, crystallizes well when precipitated from aqueous ethanol. An X-ray structure reveals the macrocycle to contain ethanol in its cavity, thus representing the first inclusion complex of a non-glucose cyclooligosaccharide. The wider rim of the torus-shaped macrocycle holds the six epoxide rings whose oxygens point away from the cavity, thereby sculpturing the unique over-all shape of a six-pointed star.
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Affiliation(s)
- S Immel
- Institut für Organische Chemie, Technische Universität Darmstadt, Germany
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Immel S, Khanbabaee K. Atropdiastereoisomers of ellagitannin model compounds: configuration, conformation, and relative stability of d-glucose diphenoyl derivatives. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s0957-4166(00)00179-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abstract
Dissolution of alpha-cyclodextrin (alpha-CD) in 9:1 water-nitromethane smoothly generates the title compound, which crystallizes as the pentahydrate in the orthorhombic space group P2(1)2(1)2(1) with a = 9.452(4), b = 14.299(3), c = 37.380(10) A, and Z = 4. Its crystal structure analysis revealed the alpha-CD macrocycle in an unstrained conformation stabilized through a ring of O-2...O-3' hydrogen bonds between five of the six adjacent glucose residues. The nitromethane is located in the alpha-CD cavity in an orientation parallel to the plane of the macrocycle, and assumes two sites of equal population with the nitro group in excessive thermal motion; the guest is held by van der Waals contacts and C-H...O-type hydrogen bonds to the pyranose H-3 and H-5 protons. The packing of the macrocycles in the crystal lattice is of cage herringbone-type with an extensive intra- and intermolecular hydrogen bonding network. The ready formation of a nitromethane inclusion complex in aqueous nitromethane, and the subtleties of its molecular structure amply demonstrate the ease with which water is expelled from the alpha-CD cavity by a more hydrophobic co-solvent.
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Affiliation(s)
- T Nakagawa
- Institut für Organische Chemie, Technische Universität Darmstadt, Germany
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Immel S, Lichtenthaler FW, Lindner HJ, Fujita K, Fukudome M, Nogami Y. The 2,3-anhydro-α-cyclomannin−1-propanol hexahydrate: topography, lipophilicity pattern and solid-state architecture. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s0957-4166(99)00583-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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49
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Gohlke H, Immel S, Lichtenthaler FW. Conformations and lipophilicity profiles of some cyclic β-(1→3)- and β-(1→6)-linked oligogalactofuranosides. Carbohydr Res 1999. [DOI: 10.1016/s0008-6215(99)00174-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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