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Hareendran C, Alsirawan B, Paradkar A, Ajithkumar TG. In Situ Monitoring of Competitive Coformer Exchange Reaction by 1H MAS Solid-State NMR. Mol Pharm 2024; 21:1479-1489. [PMID: 38373877 DOI: 10.1021/acs.molpharmaceut.3c01118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
In a competitive coformer exchange reaction, a recent topic of interest in pharmaceutical research, the coformer in a pharmaceutical cocrystal is exchanged with another coformer that is expected to form a cocrystal that is more stable. There will be a competition between coformers to form the most stable product through the formation of hydrogen bonds. This will cause destabilization of the pharmaceutical products during processing or storage. Therefore, it is important to develop a mechanistic understanding of this transformation by monitoring each and every step of the reaction, employing a technique such as 1H nuclear magnetic resonance (NMR). In this study, an in situ monitoring of a coformer exchange reaction is carried out by 1H magic angle spinning (MAS) solid-state NMR (SSNMR) at a spinning frequency of 60 kHz. The changes in caffeine maleic acid cocrystals on addition of glutaric acid and caffeine glutaric cocrystals on addition of maleic acid were monitored. In all of the reactions, it has been observed that caffeine glutaric acid Form I is formed. When glutaric acid was added to 2:1 caffeine maleic acid, the formation of metastable 1:1 caffeine glutaric acid Form I was observed at the start of the experiment, indicating that the centrifugal pressure is enough for the formation. The difference in the end product of the reactions with a similar reaction pathway of 1:1 and 2:1 reactant stoichiometry indicates that a complete replacement of maleic acid has occurred only in the 1:1 stoichiometry of the reactants. The polymorphic transition of caffeine glutaric acid Form II to Form I at higher temperatures was a crucial reason that triggered the exchange of glutaric acid with maleic acid in the reaction of caffeine glutaric acid and maleic acid. Our results are novel since the new reaction pathways in competitive coformer exchange reactions enabled understanding the remarkable role of stoichiometry, polymorphism, temperature, and centrifugal pressure.
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Affiliation(s)
- Chaithanya Hareendran
- Central NMR Facility, and Physical/Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Bashir Alsirawan
- Centre for Pharmaceutical Engineering Science, School of Pharmacy and Medical Sciences, University of Bradford, Bradford BD7 1DP, United Kingdom
| | - Anant Paradkar
- Centre for Pharmaceutical Engineering Science, School of Pharmacy and Medical Sciences, University of Bradford, Bradford BD7 1DP, United Kingdom
| | - T G Ajithkumar
- Central NMR Facility, and Physical/Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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2
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Suzuki Y, Morie S, Okamura H, Asakura T, Naito A. Real-Time Monitoring of the Structural Transition of Bombyx mori Liquid Silk under Pressure by Solid-State NMR. J Am Chem Soc 2023; 145:22925-22933. [PMID: 37828719 DOI: 10.1021/jacs.3c04361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
Silk fibroin is stored in the silk glands of Bombyx mori silkworms as a condensed aqueous solution called liquid silk. It is converted into silk fibers at the silkworm's spinnerets under mechanical forces including shear stress and pressure. However, the detailed mechanism of the structural transition of liquid silk to silk fibers under pressure is not well understood. Magic angle spinning (MAS) in solid-state nuclear magnetic resonance (NMR) can exert pressure on liquid samples in a quantitative manner. In this study, solid-state NMR was used to quantitatively analyze the impact of pressure on the structural transition of liquid silk. A combination of 13C DD-MAS and CP-MAS NMR measurements enabled the conformation and dynamics of the crystalline region of the silk fibroin (both before (Silk Ip) and after (Silk IIp) the structural transition) to be detected in real time with atomic resolution. Spectral analyses proposed that the pressure-induced structural transition from Silk Ip to Silk IIp proceeds by a two-step autocatalytic reaction mechanism. The first reaction step is a nucleation step in which Silk Ip transforms to single lamellar Silk IIp, and the second is a growth step in which the single lamellar Silk IIp acts as a catalyst that reacts with Silk Ip molecules to further form Silk IIp molecules, resulting in stacked lamellar Silk IIp. Furthermore, the rate constant in the second step shows a significant pressure dependence, with an increase in pressure accelerating the formation of large stacked lamellar Silk IIp.
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Affiliation(s)
- Yu Suzuki
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1, Bunkyo, Fukui-shi, Fukui 9108507, Japan
| | - Shota Morie
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1, Bunkyo, Fukui-shi, Fukui 9108507, Japan
| | - Hideyasu Okamura
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1, Bunkyo, Fukui-shi, Fukui 9108507, Japan
| | - Tetsuo Asakura
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan
| | - Akira Naito
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan
- Graduate School of Engineering, Yokohama National University, Tokiwadai 79-5, Hodogaya-ku, Yokohama 240-8501, Japan
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3
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Bartalucci E, Schumacher C, Hendrickx L, Puccetti F, d'Anciães Almeida Silva I, Dervişoğlu R, Puttreddy R, Bolm C, Wiegand T. Disentangling the Effect of Pressure and Mixing on a Mechanochemical Bromination Reaction by Solid-State NMR Spectroscopy. Chemistry 2023; 29:e202203466. [PMID: 36445819 DOI: 10.1002/chem.202203466] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 11/29/2022] [Accepted: 11/29/2022] [Indexed: 11/30/2022]
Abstract
Mechanical forces, including compressive stresses, have a significant impact on chemical reactions. Besides the preparative opportunities, mechanochemical conditions benefit from the absence of any organic solvent, the possibility of a significant synthetic acceleration and unique reaction pathways. Together with an accurate characterization of ball-milling products, the development of a deeper mechanistic understanding of the occurring transformations at a molecular level is critical for fully grasping the potential of organic mechanosynthesis. We herein studied a bromination of a cyclic sulfoximine in a mixer mill and used solid-state nuclear magnetic resonance (NMR) spectroscopy for structural characterization of the reaction products. Magic-angle spinning (MAS) was applied for elucidating the product mixtures taken from the milling jar without introducing any further post-processing on the sample. Ex situ 13 C-detected NMR spectra of ball-milling products showed the formation of a crystalline solid phase with the regioselective bromination of the S-aryl group of the heterocycle in position 4. Completion is reached in less than 30 minutes as deduced from the NMR spectra. The bromination can also be achieved by magnetic stirring, but then, a longer reaction time is required. Mixing the solid educts in the NMR rotor allows to get in situ insights into the reaction and enables the detection of a reaction intermediate. The pressure alone induced in the rotor by MAS is not sufficient to lead to full conversion and the reaction occurs on slower time scales than in the ball mill, which is crucial for analysing mixtures taken from the milling jar by solid-state NMR. Our data suggest that on top of centrifugal forces, an efficient mixing of the starting materials is required for reaching a complete reaction.
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Affiliation(s)
- Ettore Bartalucci
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470, Mülheim/Ruhr, Germany
| | - Christian Schumacher
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Leeroy Hendrickx
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, 52074, Aachen, Germany
| | - Francesco Puccetti
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | | | - Rıza Dervişoğlu
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470, Mülheim/Ruhr, Germany
| | - Rakesh Puttreddy
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.,University of Jyvaskyla, Department of Chemistry P. O. Box. 35, Survontie 9B, 40014, Jyväskylä, Finland
| | - Carsten Bolm
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Thomas Wiegand
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470, Mülheim/Ruhr, Germany.,Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, 52074, Aachen, Germany
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Kawamura I, Seki H, Tajima S, Makino Y, Shigeta A, Okitsu T, Wada A, Naito A, Sudo Y. Structure of a retinal chromophore of dark-adapted middle rhodopsin as studied by solid-state nuclear magnetic resonance spectroscopy. Biophys Physicobiol 2021; 18:177-185. [PMID: 34434690 PMCID: PMC8354847 DOI: 10.2142/biophysico.bppb-v18.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 07/12/2021] [Indexed: 12/01/2022] Open
Abstract
Middle rhodopsin (MR) found from the archaeon Haloquadratum walsbyi is evolutionarily located between two different types of rhodopsins, bacteriorhodopsin (BR) and sensory rhodopsin II (SRII). Some isomers of the chromophore retinal and the photochemical reaction of MR are markedly different from those of BR and SRII. In this study, to obtain the structural information regarding its active center (i.e., retinal), we subjected MR embedded in lipid bilayers to solid-state magic-angle spinning nuclear magnetic resonance (NMR) spectroscopy. The analysis of the isotropic 13C chemical shifts of the retinal chromophore revealed the presence of three types of retinal configurations of dark-adapted MR: (13-trans, 15-anti (all-trans)), (13-cis, 15-syn), and 11-cis isomers. The higher field resonance of the 20-C methyl carbon in the all-trans retinal suggested that Trp182 in MR has an orientation that is different from that in other microbial rhodopsins, owing to the changes in steric hindrance associated with the 20-C methyl group in retinal. 13Cζ signals of Tyr185 in MR for all-trans and 13-cis, 15-syn isomers were discretely observed, representing the difference in the hydrogen bond strength of Tyr185. Further, 15N NMR analysis of the protonated Schiff base corresponding to the all-trans and 13-cis, 15-syn isomers in MR showed a strong electrostatic interaction with the counter ion. Therefore, the resulting structural information exhibited the property of stable retinal conformations of dark-adapted MR.
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Affiliation(s)
- Izuru Kawamura
- Graduate School of Engineering, Yokohama National University, Yokohama, Kanagawa 240-8501, Japan.,Graduate School of Engineering Science, Yokohama National University, Yokohama, Kanagawa 240-8501, Japan
| | - Hayato Seki
- Graduate School of Engineering, Yokohama National University, Yokohama, Kanagawa 240-8501, Japan
| | - Seiya Tajima
- Graduate School of Engineering Science, Yokohama National University, Yokohama, Kanagawa 240-8501, Japan
| | - Yoshiteru Makino
- Graduate School of Engineering, Yokohama National University, Yokohama, Kanagawa 240-8501, Japan.,Present address: Graduate School of Medicine, Kobe University, Kobe, Hyogo 657-8501, Japan
| | - Arisu Shigeta
- Graduate School of Engineering, Yokohama National University, Yokohama, Kanagawa 240-8501, Japan
| | - Takashi Okitsu
- Laboratory of Organic Chemistry for Life Science, Kobe Pharmaceutical University, Kobe, Hyogo 658-8558, Japan
| | - Akimori Wada
- Laboratory of Organic Chemistry for Life Science, Kobe Pharmaceutical University, Kobe, Hyogo 658-8558, Japan
| | - Akira Naito
- Graduate School of Engineering, Yokohama National University, Yokohama, Kanagawa 240-8501, Japan
| | - Yuki Sudo
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan
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Messinger RJ, Vu Huynh T, Bouchet R, Sarou-Kanian V, Deschamps M. Magic-angle-spinning-induced local ordering in polymer electrolytes and its effects on solid-state diffusion and relaxation NMR measurements. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2020; 58:1118-1129. [PMID: 32324938 DOI: 10.1002/mrc.5033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 04/15/2020] [Accepted: 04/17/2020] [Indexed: 06/11/2023]
Abstract
Magic-angle-spinning (MAS) enhances sensitivity and resolution in solid-state nuclear magnetic resonance (NMR) measurements. MAS is obtained by aerodynamic levitation and drive of a rotor, which results in large centrifugal forces that may affect the physical state of soft materials, such as polymers, and subsequent solid-state NMR measurements. Here, we investigate the effects of MAS on the solid-state NMR measurements of a polymer electrolyte for lithium-ion battery applications, poly(ethylene oxide) (PEO) doped with the lithium salt LiTFSI. We show that MAS induces local chain ordering, which manifests itself as characteristic lineshapes with doublet-like splittings in subsequent solid-state 1 H, 7 Li, and 19 F static NMR spectra characterizing the PEO chains and solvated ions. MAS results in distributions of stresses and hence local chain orientations within the rotor, yielding distributions in the local magnetic susceptibility tensor that give rise to the observed NMR anisotropy and lineshapes. The effects of MAS were investigated on solid-state 7 Li and 19 F pulsed-field-gradient (PFG) diffusion and 7 Li longitudinal relaxation NMR measurements. Activation energies for ion diffusion were affected modestly by MAS. 7 Li longitudinal relaxation rates, which are sensitive to lithium-ion dynamics in the nanosecond regime, were essentially unchanged by MAS. We recommend that NMR researchers studying soft polymeric materials use only the spin rates necessary to achieve the desired enhancements in sensitivity and resolution, as well as acquire static NMR spectra after MAS experiments to reveal any signs of stress-induced local ordering.
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Affiliation(s)
- Robert J Messinger
- Department of Chemical Engineering, The City College of New York, CUNY, New York, NY, 10031, USA
| | - Tan Vu Huynh
- CEMHTI, CNRS UPR 3079, Université d'Orléans, Orléans, F-45071, France
- RS2E, Réseau sur le Stockage Électrochimique de l'Énergie, FR CNRS 3459, F-80039, Amiens, France
| | - Renaud Bouchet
- LEPMI, CNRS UMR 5279, Université Grenoble Alpes, Grenoble, F-38000, France
| | - Vincent Sarou-Kanian
- CEMHTI, CNRS UPR 3079, Université d'Orléans, Orléans, F-45071, France
- RS2E, Réseau sur le Stockage Électrochimique de l'Énergie, FR CNRS 3459, F-80039, Amiens, France
| | - Michaël Deschamps
- CEMHTI, CNRS UPR 3079, Université d'Orléans, Orléans, F-45071, France
- RS2E, Réseau sur le Stockage Électrochimique de l'Énergie, FR CNRS 3459, F-80039, Amiens, France
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6
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Wiegand T, Lacabanne D, Torosyan A, Boudet J, Cadalbert R, Allain FHT, Meier BH, Böckmann A. Sedimentation Yields Long-Term Stable Protein Samples as Shown by Solid-State NMR. Front Mol Biosci 2020; 7:17. [PMID: 32154263 PMCID: PMC7047159 DOI: 10.3389/fmolb.2020.00017] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 01/30/2020] [Indexed: 01/02/2023] Open
Abstract
Today, the sedimentation of proteins into a magic-angle spinning (MAS) rotor gives access to fast and reliable sample preparation for solid-state Nuclear Magnetic Resonance (NMR), and this has allowed for the investigation of a variety of non-crystalline protein samples. High protein concentrations on the order of 400 mg/mL can be achieved, meaning that around 50–60% of the NMR rotor content is protein; the rest is a buffer solution, which includes counter ions to compensate for the charge of the protein. We have demonstrated herein the long-term stability of four sedimented proteins and complexes thereof with nucleotides, comprising a bacterial DnaB helicase, an ABC transporter, an archaeal primase, and an RNA polymerase subunit. Solid-state NMR spectra recorded directly after sample filling and up to 5 years later indicated no spectral differences and no loss in signal intensity, allowing us to conclude that protein sediments in the rotor can be stable over many years. We have illustrated, using an example of an ABC transporter, that not only the structure is maintained, but that the protein is still functional after long-term storage in the sedimented state.
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Affiliation(s)
| | | | | | - Julien Boudet
- Institute of Molecular Biology and Biophysics, ETH Zürich, Zurich, Switzerland
| | | | - Frédéric H-T Allain
- Institute of Molecular Biology and Biophysics, ETH Zürich, Zurich, Switzerland
| | - Beat H Meier
- Physical Chemistry, ETH Zürich, Zurich, Switzerland
| | - Anja Böckmann
- Molecular Microbiology and Structural Biochemistry, UMR 5086 CNRS/Université de Lyon, Labex Ecofect, Lyon, France
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7
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Kozak A, Pindelska E. Spectroscopic analysis of the influence of various external factors on ethenzamide-glutaric acid (1:1) cocrystal formation. Eur J Pharm Sci 2019; 133:59-68. [PMID: 30910648 DOI: 10.1016/j.ejps.2019.03.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/14/2019] [Accepted: 03/21/2019] [Indexed: 11/27/2022]
Abstract
Cocrystal formation may affect manufacturability (flow, compaction and processability) as well as solubility/dissolution, hygroscopicity and stability properties of drugs. Therefore, cocrystallization could be used to improve the pharmaceutical properties of low-soluble drugs such as ethenzamide. In this project, solid-state nuclear magnetic resonance and Fourier transform infrared spectroscopy studies were performed for ethenzamide-glutaric acid to obtain more information about the ethenzamide cocrystallization process. The impact of the grinding time of the physical mixture (ethenzamide-glutaric acid) on cocrystal formation and the further spontaneous cocrystallization was evaluated using spectroscopic methods and curve-fitting analysis of the spectra. The influence of pressure on the yield of cocrystal formation was also described. Additionally, studies on the effect of magic-angle spinning during solid-state nuclear magnetic resonance spectra collection on the initiation of cocrystal formation, have been performed. Based on this research, conclusions regarding the influence of the different external factors, such as pressure during the tableting process and grinding time, on the cocrystal formation have been drawn for ethenzamide cocrystals.
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Affiliation(s)
- Agnieszka Kozak
- Medical University of Warsaw, Faculty of Pharmacy with the Laboratory Medicine Division, Department of Analytical Chemistry and Biomaterials, Banacha 1, 02-093 Warsaw, Poland.
| | - Edyta Pindelska
- Medical University of Warsaw, Faculty of Pharmacy with the Laboratory Medicine Division, Department of Analytical Chemistry and Biomaterials, Banacha 1, 02-093 Warsaw, Poland
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8
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Yu X, Ge X, Lan H, Li Y, Geng L, Zhen X, Yi T. Tunable and Switchable Control of Luminescence through Multiple Physical Stimulations in Aggregation-Based Monocomponent Systems. ACS APPLIED MATERIALS & INTERFACES 2015; 7:24312-24321. [PMID: 26462144 DOI: 10.1021/acsami.5b08402] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This report describes how the luminescence of naphthalimide could be tuned by various physical stimuli, including heat, sonication, and grinding. Herein, instant and switchable control of color and fluorescent emissions has been achieved by the sonication-triggered gelation of an organic liquid with naphthalimide-based organogelators (N3-N7). Green emissive suspensions of the gelators in organic liquids are transformed into orange emissive gels upon brief irradiation with ultrasound with an emission wavelength red-shift of approximately 60 nm and fluorescence intensity quenching by a factor of 20, which can subsequently be reversed by heating. When sonication-triggered S-gels are evaporated to S-xerogels, the solid state xerogels (N3, N4, N6, N7) exhibit mechanochromism, the color of which changes from red to yellow and the emission color of which changes from orange to green with enhanced intensity by grinding. This mechanochromic property can be reversed through a regelation process. The mechanochromic character of the S-xerogel of N3 is thus applied to quantitatively sense the mechanical pressure range from 2 to 40 MPa through fluorescence changes, reflecting a new type of application for gelation assembly. The physical stimuli triggered fluorescence changes of these compounds strongly depend on the molecular structure and solvent. The results demonstrate that the different aggregation modes and long-range order arrangement of the molecules regulated by the stimulus may affect the internal charge transfer (ICT) process of the naphthalimide groups, resulting in the tunability of the photophysical properties of the gelators. This report provides a new strategy for tunable and switchable control of luminescence through nonchemical stimuli in aggregation-based monocomponent systems.
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Affiliation(s)
- Xudong Yu
- Department of Chemistry and Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University , 220 Handan Road, Shanghai 200433, China
- College of Science and Hebei Research Center of Pharmaceutical and Chemical Engineering, Hebei University of Science and Technology , Yuhua Road 70, Shijiazhuang 050080, China
| | - Xiaoting Ge
- College of Science and Hebei Research Center of Pharmaceutical and Chemical Engineering, Hebei University of Science and Technology , Yuhua Road 70, Shijiazhuang 050080, China
| | - Haichuang Lan
- Department of Chemistry and Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University , 220 Handan Road, Shanghai 200433, China
| | - Yajuan Li
- College of Science and Hebei Research Center of Pharmaceutical and Chemical Engineering, Hebei University of Science and Technology , Yuhua Road 70, Shijiazhuang 050080, China
| | - Lijun Geng
- College of Science and Hebei Research Center of Pharmaceutical and Chemical Engineering, Hebei University of Science and Technology , Yuhua Road 70, Shijiazhuang 050080, China
| | - Xiaoli Zhen
- College of Science and Hebei Research Center of Pharmaceutical and Chemical Engineering, Hebei University of Science and Technology , Yuhua Road 70, Shijiazhuang 050080, China
| | - Tao Yi
- Department of Chemistry and Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University , 220 Handan Road, Shanghai 200433, China
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Li P, Chen Q, Zhang S. Analytical solution of cross polarization dynamics. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 250:76-79. [PMID: 25514062 DOI: 10.1016/j.jmr.2014.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 11/03/2014] [Accepted: 11/04/2014] [Indexed: 06/04/2023]
Abstract
The first analytical solution under Hartman-Hahn match (ω1I=ω1S) for a stationary sample was derived by Müller et al. After the introduction of magic angle spinning (MAS), the dynamics becomes much more complicated. By transferring the Hamiltonian into a rotating frame, Stejskal et al. derived the effective Hamiltonian and the new condition of Hartman-Hahn match (ω1I-ω1S=nωr,n=±1,±2), which leads to an analytical solution of CP dynamics under very fast MAS. For both stationary and fast MAS results, the effective Hamiltonians are time-independent in the rotating frame. Under Hartman-Hahn match (ω1I=ω1S) and arbitrary MAS speed condition, the Hamiltonian is no longer time-independent, making the CP dynamics very intriguing. In this work, the solution is derived analytically in the zero- and double-quantum spaces. The initial polarization in the double-quantum space is a constant of motion under strong pulse condition (|ω1I+ω1S|≫|d(t)|), while the Hamiltonian in the zero-quantum space reduces to d(t)σz(Δ), which is time dependent but self commuting all the time. This Hamilontian acts on the initial density matrix successively, leading to an analytical solution of CP dynamics. Based on the result, a phenomenological solution is derived. When the MAS speed ωr→0 , this solution reduces to Müller's formula except a spin-lattice relaxation time in the rotating frame (T1ρ). Computer simulations and experimental results agree well with the solutions.
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Affiliation(s)
- Peng Li
- Department of Physics and Shanghai key Laboratory of Magnetic Resonance, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, PR China
| | - Qun Chen
- Department of Physics and Shanghai key Laboratory of Magnetic Resonance, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, PR China.
| | - Shanmin Zhang
- Department of Physics and Shanghai key Laboratory of Magnetic Resonance, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, PR China.
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10
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Han X, Bian S, Liang Y, Houk KN, Braunschweig AB. Reactions in Elastomeric Nanoreactors Reveal the Role of Force on the Kinetics of the Huisgen Reaction on Surfaces. J Am Chem Soc 2014; 136:10553-6. [DOI: 10.1021/ja504137u] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Xu Han
- Department
of Chemistry, University of Miami, Coral Gables, Florida 33146, United States
| | - Shudan Bian
- Department
of Chemistry, University of Miami, Coral Gables, Florida 33146, United States
| | - Yong Liang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - K. N. Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Adam B. Braunschweig
- Department
of Chemistry, University of Miami, Coral Gables, Florida 33146, United States
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11
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Tateishi K, Negoro M, Kagawa A, Kitagawa M. Dynamic Nuclear Polarization with Photoexcited Triplet Electrons in a Glassy Matrix. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201305674] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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12
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Tateishi K, Negoro M, Kagawa A, Kitagawa M. Dynamic Nuclear Polarization with Photoexcited Triplet Electrons in a Glassy Matrix. Angew Chem Int Ed Engl 2013; 52:13307-10. [DOI: 10.1002/anie.201305674] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 09/04/2013] [Indexed: 11/08/2022]
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13
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14
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Change in local dynamics of bacteriorhodopsin with retinal isomerization under pressure as studied by fast magic angle spinning NMR. Polym J 2012. [DOI: 10.1038/pj.2012.116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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15
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Jezowski SR, Zhu L, Wang Y, Rice AP, Scott GW, Bardeen CJ, Chronister EL. Pressure catalyzed bond dissociation in an anthracene cyclophane photodimer. J Am Chem Soc 2012; 134:7459-66. [PMID: 22486461 DOI: 10.1021/ja300424h] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The anthracene cyclophane bis-anthracene (BA) can undergo a [4 + 4] photocycloaddition reaction that results in a photodimer with two cyclobutane rings. We find that the subsequent dissociation of the dimer, which involves the rupture of two carbon-carbon bonds, is strongly accelerated by the application of mild pressures. The reaction kinetics of the dimer dissociation in a Zeonex (polycycloolefin) polymer matrix were measured at various pressures and temperatures. Biexponential reaction kinetics were observed for all pressures, consistent with the presence of two different isomers of bis(anthracene). One of the rates showed a strong dependence on pressure, yielding a negative activation volume for the dissociation reaction of ΔV(++) = -16 Å(3). The 93 kJ/mol activation energy for the dissociation reaction at ambient pressure is lowered by more than an order of magnitude from 93 to 7 kJ/mol with the application of modest pressure (0.9 GPa). Both observations are consistent with a transition state that is stabilized at higher pressures, and a mechanism for this is proposed in terms of a two-step process where a flattening of the anthracene rings precedes rupture of the cyclobutane rings. The ability to catalyze covalent bond breakage in isolated small molecules using compressive forces may present opportunities for the development of materials that can be activated by acoustic shock or stress.
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Affiliation(s)
- Sebastian R Jezowski
- Department of Chemistry, University of California, Riverside, California 92521, USA
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Asano A, Hori S, Kitamura M, Nakazawa CT, Kurotsu T. Influence of magic angle spinning on T1H of SBR studied by solid state 1H NMR. Polym J 2012. [DOI: 10.1038/pj.2012.10] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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17
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Tang M, Sperling LJ, Berthold DA, Nesbitt AE, Gennis RB, Rienstra CM. Solid-state NMR study of the charge-transfer complex between ubiquinone-8 and disulfide bond generating membrane protein DsbB. J Am Chem Soc 2011; 133:4359-66. [PMID: 21375236 DOI: 10.1021/ja107775w] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ubiquinone (Coenzyme Q) plays an important role in the mitochondrial respiratory chain and also acts as an antioxidant in its reduced form, protecting cellular membranes from peroxidation. De novo disulfide bond generation in the E. coli periplasm involves a transient complex consisting of DsbA, DsbB, and ubiquinone (UQ). It is hypothesized that a charge-transfer complex intermediate is formed between the UQ ring and the DsbB-C44 thiolate during the reoxidation of DsbA, which gives a distinctive ~500 nm absorbance band. No enzymological precedent exists for an UQ-protein thiolate charge-transfer complex, and definitive evidence of this unique reaction pathway for DsbB has not been fully demonstrated. In order to study the UQ-8-DsbB complex in the presence of native lipids, we have prepared isotopically labeled samples of precipitated DsbB (WT and C41S) with endogenous UQ-8 and lipids, and we have applied advanced multidimensional solid-state NMR methods. Double-quantum filter and dipolar dephasing experiments facilitated assignments of UQ isoprenoid chain resonances not previously observed and headgroup sites important for the characterization of the UQ redox states: methyls (~20 ppm), methoxys (~60 ppm), olefin carbons (120-140 ppm), and carbonyls (150-160 ppm). Upon increasing the DsbB(C41S) pH from 5.5 to 8.0, we observed a 10.8 ppm upfield shift for the UQ C1 and C4 carbonyls indicating an increase of electron density on the carbonyls. This observation is consistent with the deprotonation of the DsbB-C44 thiolate at pH 8.0 and provides direct evidence of the charge-transfer complex formation. A similar trend was noted for the UQ chemical shifts of the DsbA(C33S)-DsbB(WT) heterodimer, confirming that the charge-transfer complex is unperturbed by the DsbB(C41S) mutant used to mimic the intermediate state of the disulfide bond generating reaction pathway.
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Affiliation(s)
- Ming Tang
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
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Saitô H, Ando I, Ramamoorthy A. Chemical shift tensor - the heart of NMR: Insights into biological aspects of proteins. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2010; 57:181-228. [PMID: 20633363 PMCID: PMC2905606 DOI: 10.1016/j.pnmrs.2010.04.005] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 04/26/2010] [Indexed: 05/19/2023]
Affiliation(s)
- Hazime Saitô
- Department of Life Science, Himeji Institute of Technology, University of Hyogo, Kamigori, Hyog, 678-1297, Japan
| | - Isao Ando
- Department of Chemistry and Materials Science, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, 152-0033, Japan
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, MI 48109-1055, USA
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Kawamura I, Yoshida H, Ikeda Y, Yamaguchi S, Tuzi S, Saitô H, Kamo N, Naito A. Dynamics change of phoborhodopsin and transducer by activation: study using D75N mutant of the receptor by site-directed solid-state 13C NMR. Photochem Photobiol 2008; 84:921-30. [PMID: 18363620 DOI: 10.1111/j.1751-1097.2008.00326.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pharaonis phoborhodopsin (ppR or sensory rhodopsin II) is a negative phototaxis receptor of Natronomonas pharaonis, and forms a complex, which transmits the photosignal into cytoplasm, with its cognate transducer (pHtrII). We examined a possible local dynamics change of ppR and its D75N mutant complexed with pHtrII, using solid-state (13)C NMR of [3-(13)C]Ala- and [1-(13)C]Val-labeled preparations. We distinguished Ala C(beta) (13)C signals of relatively static stem (Ala221) in the C-terminus of the receptors from those of flexible tip (Ala228, 234, 236 and 238), utilizing a mutant with truncated C-terminus. The local fluctuation frequency at the C-terminal tip was appreciably decreased when ppR was bound to pHtrII, while it was increased when D75N, that mimics the signaling state because of disrupted salt bridge between C and G helices prerequisite for the signal transfer, was bound to pHtrII. This signal change may be considered with the larger dissociation constant of the complex between pHtrII and M-state of ppR. At the same time, it turned out that fluctuation frequency of cytoplasmic portion of pHtrII is lowered when ppR is replaced by D75N in the complex with pHtrII. This means that the C-terminal tip partly participates in binding with the linker region of pHtrII in the dark, but this portion might be released at the signaling state leading to mutual association of the two transducers in the cytoplasmic regions within the ppR/pHtrII complex.
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Affiliation(s)
- Izuru Kawamura
- Graduate School of Engineering, Yokohama National University, Hodogaya-ku, Yokohama, Japan
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Kawamura I, Ohmine M, Tanabe J, Tuzi S, Saitô H, Naito A. Dynamic aspects of extracellular loop region as a proton release pathway of bacteriorhodopsin studied by relaxation time measurements by solid state NMR. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:3090-7. [DOI: 10.1016/j.bbamem.2007.11.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2007] [Revised: 11/02/2007] [Accepted: 11/05/2007] [Indexed: 11/30/2022]
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Saitô H, Naito A. NMR studies on fully hydrated membrane proteins, with emphasis on bacteriorhodopsin as a typical and prototype membrane protein. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:3145-61. [PMID: 17964534 DOI: 10.1016/j.bbamem.2007.08.026] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Revised: 08/24/2007] [Accepted: 08/29/2007] [Indexed: 11/30/2022]
Abstract
The 3D structures or dynamic feature of fully hydrated membrane proteins are very important at ambient temperature, in relation to understanding their biological activities, although their data, especially from the flexible portions such as surface regions, are unavailable from X-ray diffraction or cryoelectron microscope at low temperature. In contrast, high-resolution solid-state NMR spectroscopy has proved to be a very convenient alternative means to be able to reveal their dynamic structures. To clarify this problem, we describe here how we are able to reveal such structures and dynamic features, based on intrinsic probes from high-resolution solid-state NMR studies on bacteriorhodopsin (bR) as a typical membrane protein in 2D crystal, regenerated preparation in lipid bilayer and detergents. It turned out that their dynamic features are substantially altered upon their environments where bR is present. We further review NMR applications to study structure and dynamics of a variety of membrane proteins, including sensory rhodopsin, rhodopsin, photoreaction centers, diacylglycerol kinases, etc.
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Affiliation(s)
- Hazime Saitô
- Center for Quantum Life Sciences, Hiroshima University, Higashi-Hiroshima 739-8526, Japan.
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