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Order Blubervirales: Core Protein
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
Fourth, the solid-state NMR spectroscopy at 100 and 150 kHz magic-angle spinning (MAS) was applied to the high-resolution 3D elucidation of the HBc VLPs and their assembly modulation (Lecoq et al. 2018a, b, 2019; Wang S et al. 2019; Schleedorn et al. 2020). Recently, using solid-state NMR, Lecoq et al. (2021) identified a stable alternative conformation of the HBc protein, where the structural variations focused on the hydrophobic pocket of the HBc, a hot spot in capsid-envelope interactions. This structural switch was triggered by specific, high-affinity binding of a pocket factor, and the conformational change induced by the binding was reminiscent of a maturation signal, leading formulation of the “synergistic double interaction” hypothesis, which explained the regulation of capsid envelopment and indicated a concept for therapeutic interference with HBV envelopment (Lecoq et al. 2021).
3D Particles
Published in Paul Pumpens, Single-Stranded RNA Phages, 2020
It is noteworthy, however, that the phage AP205, due to the initiative of Kaspars Tārs’ group, served as a model by the pioneering 3D studies using solid-state nuclear magnetic resonance under ultra-fast magic-angle spinning (MAS) (Barbet-Massin et al. 2013, 2014; Andreas et al. 2015). As an appropriate result, the phage AP205 contributed to the first examples of protein structure determination by the MAS NMR (Andreas et al. 2016; Stanek et al. 2016; Cala-De Paepe et al. 2017). Finally, dynamic nuclear polarization (DNP) made it possible to overcome the sensitivity limitation of the MAS NMR experiments (Jaudzems et al. 2018). Thus, the high-quality DNP-enhanced NMR spectra were obtained for the phage AP205 by combining high magnetic field (800 MHz) and fast MAS (40 kHz). These conditions yielded enhanced resolution and long coherence lifetimes, allowing the acquisition of resolved 2D correlation spectra and of previously unfeasible scalar-based experiments. This enabled the assignment of aromatic resonances of the AP205 coat protein and its packaged RNA, as well as the detection of long-range contacts (Jaudzems et al. 2018).
Application of Genomic, Proteomic, and Metabolomic Technologies to the Development of Countermeasures against Chemical Warfare Agents
Published in Brian J. Lukey, James A. Romano, Salem Harry, Chemical Warfare Agents, 2019
Jennifer W. Sekowski, James F. Dillman III
NMR, and specifically 1H magic angle spinning NMR, has been used for years (Nicholson et al., 1999). Its main advantages lie in the fact that NMR does not require any upfront chromatographic separation, nor does it destroy the samples during analysis. It has the ability to measure molecular compartmentalization and dynamic biochemical changes in real time. Thus, it is not surprising that its data output is more information dense than that of MS. Although it can be more difficult to define the individual peaks in NMR, NMR is slightly better than MS at identifying and defining very dense patterns of peaks (Nicholson et al., 1999). For these reasons, NMR is routinely used to define relative concentrations of hundreds of compounds in complex, undefined mixtures.
Exploring the influence factors and improvement strategies of drug polymorphic transformation combined kinetic and thermodynamic perspectives during the formation of nanosuspensions
Published in Drug Development and Industrial Pharmacy, 2021
Tingting Meng, Fangxia Qiao, Shijie Ma, Ting Gao, Li Li, Yanhui Hou, Jianhong Yang
The NMR can assess the physicochemical properties of the drug at the molecular level, which is based on using intrinsic reporter moieties and regardless of the sample conditions [93]. Recently, suspended-state NMR has been applied to analyze suspensions of solid and dissolved components without preprocessing [94]. Magic angle rotation (MAS) technology is combined with solid-state NMR to characterize solid powder. In suspended NMR, capsules containing suspension are placed under MAS conditions. Cross polarization (CP) technology can selectively observe solid components because it inhibits molecular mobility and induces effective CP [60]. Hasegawa et al. [60] used the 13C CP/MAS NMR spectra to analyze the molecular state of PXC. The characteristic peaks of crystal PXC were broadened, and the relative intensities of Ca, Cb, and Ck peaks compared to other peaks were significantly reduced after media milling, which may indicate that amorphous PXC appears in the nanosuspension. The suitable pulse delay times (PD) (T1 amorphous < PD<T1 crystal) showed a core–shell structure with the coexistence of crystalline and amorphous PXC enclosed by poloxamer chains, which shows partial amorphization during wet milling, as shown in Figure 6.
Effect of coating excipients on chemical stability of active coated tablets
Published in Pharmaceutical Development and Technology, 2021
Umesh Kestur, Divyakant Desai, Zhixin Zong, Anuji Abraham, John Fiske
Carbon-13 cross polarization magic angle spinning (CPMAS) solid-state NMR experiments were conducted on a Bruker AV III instrument operating at a proton frequency of 500 MHz. Solid samples were spun at 13 kHz in a 4-mm ZrO2 rotor. The contact time was 4 milliseconds and was ramped on the proton channel from 50% to 100% (Metz et al. 1994; Bennett et al. 1995). The relaxation delay was maintained at 5x 1H T1 of API, which was 20 s. Proton decoupling was applied using a TPPM sequence with a 4.0 microsecond pulse (62.5-kHz nominal bandwidth). The spectral sweep width was 300 ppm centered at 100 ppm. A total of 4380 data points were acquired (giving a digital resolution of 20 Hz) and zero filled to 8192 prior to apodization with 20 Hz line broadening. A total of 2048 free induction decays were co-added. The spectra were referenced indirectly to TMS using 3-methylglutaric acid. Approximately 80 mg of sample was used for each experiment. The temperature was set to 280 K (Barich et al. 2006).
Hydroxypropyl-β-cyclodextrin as an effective carrier of curcumin – piperine nutraceutical system with improved enzyme inhibition properties
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2020
Anna Stasiłowicz, Ewa Tykarska, Kornelia Lewandowska, Maciej Kozak, Andrzej Miklaszewski, Joanna Kobus-Cisowska, Daria Szymanowska, Tomasz Plech, Jacek Jenczyk, Judyta Cielecka-Piontek
NMR 13C spectra were recorded on a 400 MHz Agilent spectrometer equipped with Wide Bore Triple Resonance T3 MAS XY probe. Cross-Polarisation (CP) pulse sequence with Magic Angle Spinning (MAS) and dipolar decoupling of protons was applied. Samples were placed into a 4 mm diameter zirconia rotor and spun with 7 kHz.