Article
Biochemical Research Methods
Julian Ilgen, Jens Nowag, Lukas Kaltschnee, Volker Schmidts, Christina M. Thiele
Summary: NMR experiments like NOESY, ROESY, and EXSY have been used in solution to elucidate molecular structure and dynamics by providing interatomic distance restraints or rates for chemical exchange. Pure shift methods are becoming popular to improve spectral resolution in order to reduce signal overlap.
JOURNAL OF MAGNETIC RESONANCE
(2021)
Article
Chemistry, Physical
Lia Zaharani, Nader Ghaffari Khaligh, Mohd Rafie Johan
Summary: The acid-base reaction of piperazine and sulfuric acid was conducted to obtain a new molten salt, whose structure was elucidated using FTIR, NMR, and mass spectrometry. Contrary to expectations, no characteristic signal was detected for the existence of hydrogen sulfate anion in 1H NMR of the molten salt in DMSO-d(6). The formation of 1H,4H-piperazineN,N'-diium dication was supported by NMR studies of its bromide derivative.
JOURNAL OF MOLECULAR STRUCTURE
(2021)
Article
Biochemistry & Molecular Biology
Biljana Arsic, Jill Barber, Ana Cikos, Manikandan Kadirvel, Emilija Kostic, Andrew J. McBain, Jelena Milicevic, Angela Oates, Andrew Regan
Summary: In this study, a combination of in silico (electron ion-interaction potential, molecular docking, ADMET), NMR, and microbiological investigations was used to explore the design pattern of macrolides active against Gram-negative bacteria. The research focused on the less studied 16-membered macrolides and their representative, tylosin A. The complete characterization and 3D solution structure of tylosin A were determined using NMR and molecular modeling. The antibacterial activity of tylosin A and B against selected Gram-positive and Gram-negative bacteria was also studied.
Article
Biochemistry & Molecular Biology
Alexey A. Kotlobay, Maxim A. Dubinnyi, Sergey I. Kovalchuk, Aleksandr P. Makhin, Vasily S. Miturich, Maria S. Lyakhovich, Danielle M. Fontaine, Tara L. Southworth, Vladimir I. Shmygarev, Oleg N. Yatskin, Bruce R. Branchini, Ilia Yampolsky, Zinaida M. Kaskova
Summary: This study investigates the bioluminescence phenomenon in insects, specifically focusing on the chemistry of light emission in Diptera species. The authors identify the oxyluciferin structure in Keroplatus spp. as 3-hydroxykynurenic acid. Additionally, they provide evidence of the relationship between the bioluminescent systems of Orfelia and Keroplatus, while noting that the mechanisms of light emission are not identical.
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Anna-Lena Wuebker, Jonas Koppe, Henrik Bradtmueller, Lukas Keweloh, Damian Pleschka, Werner Uhl, Michael Ryan Hansen, Hellmut Eckert
Summary: The first comprehensive solid-state nuclear magnetic resonance (NMR) characterization of geminal alane-phosphane frustrated Lewis pairs (Al/P FLPs) was reported in this study. Through numerical analysis of experimental NMR line shapes, relevant NMR parameters were determined and compared with values computed from known crystal structures using density functional theory (DFT) methods. The study demonstrates the sensitivity of P-31 NMR chemical shifts to slight structural inequivalences and the spread of Al-27 NMR central transition signals over a broad frequency range, indicating a clear distinction between three- and four-coordinate aluminum environments. An efficient saturation technique, RESPDOR, was developed for measuring internuclear Al...P distances within a precision of +/- 0.1 angstrom.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Multidisciplinary Sciences
Mingzhang Maple Wang, Caitlin N. Wappelhorst, Erika L. Jensen, Ying-Chih Thomas Chi, Jason C. Rouse, Qin Zou
Summary: This study investigates the lipid composition at the surface of mRNA-LNPs using high-field nuclear magnetic resonance spectroscopy. The results identify the presence of PEG chains and partial ionizable lipids on the surface of intact LNPs, and reveal the brush-like conformation of PEG on the surface of mRNA-LNPs. In addition, a diffusion NMR strategy is implemented for routine testing of drug formulations, providing a global view of the mRNA-LNP surface structure for enhanced product knowledge.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Multidisciplinary
Franziska Ruettger, Tim Patten, Johannes Kretsch, Anna Krawczuk, Dietmar Stalke, Michael John
Summary: A new NMR method utilizing Li-7 residual quadrupolar couplings (RQCs) in a stretched polystyrene (PS) gel is proposed for the structure determination of lithium compounds under solution-like conditions, by comparing the experimental RQCs with those predicted from crystal or DFT-derived model structures. This method was successfully applied to five lithium model complexes, revealing the monomeric structures of four complexes with Li coordinated fourfold by two additional THF molecules, and the limited space for an additional THF molecule in one complex due to bulky tBu groups.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Alexander Scholte, Christoph Hubner, Dieter Strohl, Olaf Scheufler, Steffen Czich, Julia M. Borke, Gerhard Hildebrand, Klaus Liefeith
Summary: Tetraether lipids are essential elements of archaeal membranes due to their unique chemical structure, providing these organisms with extraordinary properties. In this study, a newly isolated TEL fragment GDNT-beta-Glu was characterized from Sulfolobus metallicus, revealing dissimilarities to established structures and re-determined binding relationships in the polar head group. This work contributes an important step towards elucidating the structure of intact TEL in other Sulfolobus strains such as Solfulobus acidocaldarius and Sulfolobus solfataricus.
Article
Chemistry, Multidisciplinary
Joao Pedro A. Souza, Leociley R. A. Menezes, Francielle P. Garcia, Debora B. Scariot, Pamela T. Bandeira, Mateus B. Bespalhok, Siddhartha O. K. Giese, David L. Hughes, Celso Nakamura, Andersson Barison, Alfredo R. M. Oliveira, Renan B. Campos, Leandro Piovan
Summary: A series of multi-ring organotelluranes containing a Te-O bond were synthesized and characterized, with theoretical calculations elucidating the oxidation-cyclization mechanism involved in the formation of heterocycles. Anti-diastereoisomers were identified as major products for compounds with two chirality centers. Antileishmanial assays revealed that three compounds exhibited higher activity and selectivity than the reference, with stability studies showing no structural modifications in different media or temperatures up to 65 degrees C.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Forestry
Yuki Tokunaga, Takashi Nagata, Keiko Kondo, Masato Katahira, Takashi Watanabe
Summary: This study synthesized short- and long-chain lignin oligomer model compounds composed solely of interunit beta-O-4 bonds to evaluate molecular structural changes induced by the addition of water to an organic solvent through NMR spectroscopy. The lignin models were found to have folded conformations, with more compact structures observed in D2O compared to DMSO-d(6).
Article
Environmental Sciences
Valentin Goeldner, Michael Speitling, Uwe Karst
Summary: The environmental impact of pesticides and other pollutants depends on degradation and accumulation processes. This study investigated the environmental metabolism of a specific herbicide called tritosulfuron, observing a new metabolite through soil degradation studies and using high performance liquid chromatography and mass spectrometry. The structure of the metabolite was elucidated using electrochemistry coupled to mass spectrometry and NMR spectroscopy, highlighting the potential of these techniques in environmental fate studies.
Article
Chemistry, Physical
Alexander Klein, Suresh K. Vasa, Benedikt Soeldner, Kristof Grohe, Rasmus Linser
Summary: Proton-detected solid-state NMR facilitated the analysis of insoluble, crystalline, sedimented, and membrane proteins due to fast-magic-angle-spinning technology. However, limited access to side chain resonances has restricted potential applications. The recent availability of high spinning frequencies allows direct probing of all protons, but their low dispersion compromises their chemical-shift assignment.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Applied
Barbara Gehring, Yvonne Traa, Michael Hunger
Summary: The study revealed systematic differences in crystallinity, morphology, and acidity between nanosized and microsized H-ZSM-5 zeolites. Only a portion of framework aluminium atoms in nanosized materials contribute to forming Br?nsted acidic bridging OH groups, while the rest lead to the formation of silanol groups with weakly enhanced Br?nsted acidity.
MICROPOROUS AND MESOPOROUS MATERIALS
(2021)
Article
Chemistry, Organic
Marton Weber, Aron Szigetvari, Monika Halmai, Peter Keglevich, Csaba Szantay
Summary: Scientific publications rarely mention the possibility of man-made errors in scientific conclusions, which often arise from mental traps or a lack of professional experience. This article discusses the learning process of a scientist's professional expertise, focusing on mental leaps and their role in redefining problem-solving approaches. It reports on the resolution of three intriguing NMR-based structure-elucidation problems by an NMR spectroscopist working in an industrial R&D and QC environment.
Article
Chemistry, Organic
Antonio Hernandez Daranas, Ariel M. Sarotti
Summary: This report introduces a method that combines quantum mechanical NMR calculations with conformer selection to solve the structure of large, complex, and highly flexible molecules.
Article
Chemistry, Organic
Kevin Knoll, Tobias Kostner, Christian Lorenz, Christina M. Thiele
Summary: New supramolecular lyotropic liquid crystals (LLC) based on 1,3,5-benzenetricarboxamides (BTAs) with n-alkylaniline sidechains are investigated in this study. The effects of different chain lengths along the homologous series and non-BTA additives on liquid crystalline behavior are examined using NMR spectroscopy. The results provide insights into how aliphatic chain length and the addition of aromatic rings impact the self-assembly process, and whether these modifications enhance the resilience of resulting LLC phases against disruptive effects of non-BTA additives.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Polymer Science
Dominic S. Schirra, Sharon Jeziorowski, Matthias Lehmann, Christina M. Thiele
Summary: Residual dipolar couplings (RDCs) have potential in structure elucidation of organic compounds. Current research focuses on smart alignment media that can change alignment via external stimuli. A new thermoresponsive alignment medium, poly-gamma-p-biphenylmethyl-L-glutamate (PBPMLG), was introduced with enantiodiscriminating properties. The effects of spacer groups on the alignment and gelation were investigated, and their implications on RDC-based structure elucidation were discussed.
Article
Chemistry, Multidisciplinary
Kevin Knoll, Dominik Herold, Max Hirschmann, Christina M. Thiele
Summary: This article describes a supramolecular lyotropic liquid crystalline alignment medium based on azobenzene, and its application in the study of water-soluble analytes. The alignment strength can be varied by adjusting the temperature, and reversible collapse into an isotropic solution is possible. This simplifies structure elucidation techniques.
MAGNETIC RESONANCE IN CHEMISTRY
(2022)
Article
Multidisciplinary Sciences
Alena K. Bell, Jonas Kind, Maximilian Hartmann, Benjamin Kresse, Mark V. Hoefler, Benedikt B. Straub, Guenter K. Auernhammer, Michael Vogel, Christina M. Thiele, Robert W. Stark
Summary: Understanding the evaporation process of binary sessile droplets is crucial for optimizing technical processes. This study employs confocal Raman microscopy and spatially resolved NMR spectroscopy to measure the concentration gradients in evaporating droplets on a hydrophobic surface.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Chemistry, Physical
Peter Weigl, Susann Weissheit, Florian Pabst, Harald Kolmar, Christina Marie Thiele, Thomas Walther, Thomas Blochowicz
Summary: The dynamics of protein hydration shell plays a crucial role in biochemical processes such as protein folding, enzyme function, molecular recognition, and interaction with biological membranes. In this study, we investigate the dynamics of the hydration shell using a phosphorescent subgroup of the biomolecule itself, instead of adding separate dye molecules. We find a significant slowdown of molecules in the solvation shell compared to the bulk in a small heptapeptide in a glycerol-water mixture under cryoconservation conditions, providing the possibility to unravel relaxation processes in the solvation shell that usually overlap at room temperature.
JOURNAL OF PHYSICAL CHEMISTRY B
(2022)
Correction
Polymer Science
Dominic S. Schirra, Sharon Jeziorowski, Matthias Lehmann, Christina M. Thiele
Article
Biochemistry & Molecular Biology
Matthias Brauser, Tim Heymann, Christina Marie Thiele
Summary: In this study, the intermediate responsible for the acyl transfer in a highly enantioselective tetrapeptide organocatalyst was successfully detected and characterized using NMR-spectroscopy and mass spectrometry. The formation of complexes between the tetrapeptide and trans-cyclohexane-1,2-diols was also observed, along with monitoring of the acetylation reaction. These findings provide important insights into the understanding of this organocatalyst's mechanism.
Article
Chemistry, Organic
Marketa Tichotova, Tomas Landovsky, Jan Lang, Sharon Jeziorowski, Volker Schmidts, Michal Kohout, Martin Babor, Pavel Lhotak, Christina M. Thiele, Hana Dvorakova
Summary: By using polyglutamates with different side-chain moieties (PBLG and PBPMLG) as alignment media, we achieved enantiodiscrimination of inherently chiral compounds for the first time. The experimental results not only provided more accurate structural information, but also revealed the conformational preferences and chiral alignment differences of phenoxathiin-based thiacalix[4]arenes in solution.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Biochemical Research Methods
J. Kind, M. Stein, T. Gambaryan-Roisman, P. Stephan, T. L. Zankel, C. M. Thiele
Summary: Controlling and understanding the wetting and evaporation of complex fluids is crucial for improving processes like the production of organic semiconductors via printing. This study focuses on examining the time-dependent composition of complex fluid droplets during wetting or evaporation. The evaporation rate of water droplets depends on vapor pressures and humidity, thus it is necessary to measure and control humidity and temperature during measurements. By using MRI and spatially resolved NMR spectroscopy, the evaporation of droplets can be studied and compared with diffusive evaporation models and finite element numerical simulations. The findings reveal different evaporation regimes depending on flow rate and distance between gas outlet and droplet. The presented approach allows for comparative measurements and the observation of droplet evaporation in various environments. The setup can also control the evaporation rate of water from complex mixtures.
JOURNAL OF MAGNETIC RESONANCE
(2023)
Article
Chemistry, Multidisciplinary
Max Hirschmann, Olaf Soltwedel, Philipp Ritzert, Regine von Klitzing, Christina M. Thiele
Summary: Two polyaspartates, PpFABLA (1) and co-polyaspartate PpFABLA-co-PBLA [11, 75% (n/n) PpFABLA content], bearing ortho-fluorinated azo-benzenes (pFAB) as photo-responsive groups, undergo reversible coil-helix transition in solution through the E/Z-isomerization of the side chain. The thermal stability of the Z-isomer is increased by pFAB, and the helix formation is effectively prevented. The helical polymer forms a lyotropic liquid crystal (LLC) and orients unidirectionally inside a magnetic field, while the coil polymer results in an isotropic solution.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Polymer Science
Timo Imhof, Jonas Kind, Christina M. Thiele
Summary: We studied the temperature-dependent LLC behavior of helically chiral polypeptides, specifically PBPMLG and PBLA-co-PPLA. We observed a characteristic jump in the quadrupolar splittings Delta nu Q of the solvent's 2H signal during the transition of polymer rods from perpendicular to parallel orientation with respect to the magnetic field. By correlating Delta nu Q with the diffusion coefficients measured parallelly (D parallel to) and perpendicularly (D perpendicular to) to the magnetic field, we found a significant change in the D parallel to/D perpendicular to ratio at the transition temperature of the LLC phases.
Article
Multidisciplinary Sciences
Franziska Theiss, Laura Wienands, Jonas Lins, Marcel Alcaraz-Janssen, Christina M. Thiele, Gerd Buntkowsky
Summary: Nuclear magnetic resonance (NMR) experiments using parahydrogen-induced polarization (PHIP) were conducted to investigate the activity of the synthetic biopolymer poly-γ-(4-propargyloxy)-benzyl-L-glutamate) (PPOBLG). The homopolypeptide was successfully hyperpolarized and the enhanced signals were detected in 11.7 T solution NMR as a function of PPOBLG concentration. Hydrogenation with parahydrogen resulted in signal enhancements of over 800 times for the vinyl protons of the side chain at low substrate concentration. Due to the high enhancement factor, even at a concentration of 13 nM PPOBLG, the hyperpolarized protons could be detected with a single scan H-1-NMR, thanks to the combination of hyperpolarization and density of PHIP active sites.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Multidisciplinary
Johann J. Primozic, Julian Ilgen, Patrick Maibach, Matthias Brauser, Jonas Kind, Christina M. Thiele
Summary: The Pd-catalyzed allylic alkylation of 3,4-disubstituted, racemic cyclobutene electrophiles shows an unusual stereoselectivity. Stereoinduction is controlled by the choice of ligand and is independent of the substrate's configuration. Mechanistic investigations reveal deviations from the commonly accepted double inversion rule and the formation of unreactive syn-Pd-cyclobutene complexes due to strong internal Pd-O chelation.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Max Hirschmann, Olaf Soltwedel, Philipp Ritzert, Regine von Klitzing, Christina M. Thiele
Summary: Two polyaspartates with ortho-fluorinated azo-benzenes (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]. PpFABLA (1) undergoes a visible-light-induced reversible coil-helix transition in solution due to the E/Z-isomerization of the side chain. PpFABLA-co-PBLA (11) forms a helix independently of the E/Z-isomerization of the side chain and exhibits changes in the morphology and dipolar coupling.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Dominic S. Schirra, Philipp Goetz, Matthias Lehmann, Christina M. Thiele
Summary: Structure elucidation via residual dipolar couplings relies on alignment media. We report on lyotropic liquid crystals of poly-gamma-p-biphenyl(2'-methoxy-2-methyl)methyl-L-glutamate, which enables the acquisition of multiple RDC datasets within one sample.
CHEMICAL COMMUNICATIONS
(2022)
