Multiple sclerosis (MS) is a T cell-mediated autoimmune disease modeled by experimental autoimmune encephalomyelitis (EAE); given that SPTLC2 is a key enzyme in sphingolipid biosynthesis linked to MS pathology, this NMR-based metabolomics study aimed to characterize the metabolic signature resulting from T cell-specific SPTLC2 conditional knock-out (KO) in EAE mice. Serum samples from unrecombined control EAE mice and T cell-specific SPTLC2 KO EAE mice were analyzed using OPLS-DA and the Mann-Whitney test (FDR < 0.05). Multivariate analysis revealed a complete and statistically robust separation between the two groups (OPLS-DA: R2Y = 0.902, Q2 = 0.899, p < 0.001), indicating a massive metabolic alteration induced by the T cell-specific SPTLC2 deletion. Univariate analysis and the S-Plot confirmed that core metabolites, including Lactate, Alanine, Glutamine, Pyruvate, Citrate, and Trimethylamine, were significantly upregulated in the T cell-specific SPTLC2 KO group, while Glucose and Phenylalanine were downregulated (FDR << 0.05). These findings collectively demonstrate that T cell-specific SPTLC2 deletion fundamentally disrupts central energy and amino acid metabolism in the EAE model, positioning this sphingolipid biosynthesis enzyme as a critical metabolic regulator of T cell function and autoimmune disease pathology.

A calix[4]pyrrole derivative (2) bearing two amidoinodole substituents at the diagonal meso positions was synthesized and its anion-binding properties were investigated by ¹H NMR spectroscopic analysis in CD₂Cl₂. In comparison to the parent calix[4]pyrrole (1), receptor 2, incorporating additional hydrogen-bond donor and acceptor sites, exhibited markedly enhanced binding affinities toward a series of anions (F^-, Cl^-, Br^-, I^-, HSO₄^-, and H₂PO₄^-). The introduction of amidoinodole groups significantly strengthened the anion-receptor interactions, as evidenced by substantial downfield shifts of the pyrrolic and indolic NH resonances upon anion addition. Notably, receptor 2 was found to bind H₂PO₄^- via a distinct binding mode compared to those observed for the parent calix[4]pyrrole (1) and for the other anions examined, suggesting a unique cooperative hydrogen-bonding network involving both the core pyrrolic NH units and the appended indole-amide moieties.

The projected quantum Liouville equation method was used to investigate the dependence of the line-width of cyclotron resonance in a semiconductor material on magnetic field, revealing transitions within Landau levels. Direct application of this method to the semiconductor material ZnO, which considers electron-piezoelectric phonon interactions, revealed that the line-widths increase with increasing magnetic field. However, the increase in line-widths abruptly slows around 7 T, followed by a slight decrease around 10 T, likely due to the interaction between the magnetic field and distribution function.

The line shape functions (LSF) electron spin resonance for Mn²⁺ in LiNbO₃ and the resulting crystal structure were investigated using a projection operator method. The LSF, which directly apply the spin Hamiltonian describing the system to the projection operator, can be obtained relatively easily by series expansion of propagation factors. Mn, a transition metal with electron spin S=5/2, has unfilled 3d electron shells in its outermost shell, which causes spin crystal structure interactions to spread in the LSFs. The magnetic field dependence of the LSFs the +1/2↔-1/2 and +5/2↔-5/2 optical transitions, among several allowable optical transitions, and the optical absorption power for the resonance magnetic field were investigated at magnetic field dependence when an external incident electromagnetic wave of 9.27 GHz was applied. The calculation results show that the line-widths decrease slightly with increasing magnetic field, which is believed to be due to the hoping of Nb⁵⁺ and Li⁺ toward the oxygen layer center or plane with increasing magnetic field. The LSF of the system was obtained by the projection operator method, and it was found that Mn²⁺ was substituted for Li or Nb, which had axial symmetry with respect to the c-axis.

MCM6 is a core subunit of the eukaryotic MCM2 to 7 helicase essential for DNA replication and often overexpressed in various cancers. We report backbone assignments for the human MCM6 N-terminal domain 1 (NTD1), spanning residues 15-115, and test its binding to BLM peptides MBD-N and MBD-D. The [¹H¹⁵N] HSQC spectrum indicates that the MCM6 NTD1 is well folded. Chemical shift-based analysis supports a compact α/β architecture consistent with AlphaFold and cryo-EM models of the MCM complex. HSQC titrations with both BLM peptides show no significant chemical shift perturbations, indicating no detectable binding under the conditions used. These data suggest that additional regions or oligomeric context are required for stable MCM6-BLM interaction.

Methicillin-resistant Staphylococcus aureus (MRSA) remains a major cause of difficult-to-treat infections, due to cell-envelope remodeling pathways that reduce susceptibility to antibiotics and host defenses. One key pathway is D-alanylation of teichoic acids, mediated by the DltABCD system, which reduces the net negative charge of the cell wall and thereby contributes resistance to antimicrobial peptides and multiple antibiotic classes. Within this pathway, the adenylation enzyme DltA first activates D-alanine, which is then transferred to the carrier protein DltC via its 4'-phosphopantetheine (Ppant) cofactor for subsequent transport from the cytosol to the cell surface. Here, we report the expression, purification, and backbone NMR resonance assignment of S. aureus DltC. The assignments provide a solution-state framework for probing DltC dynamics and for mapping its interfaces with binding partners, including DltA and DltB. Our work lays the groundwork for future structural and functional studies targeting the Dlt pathway as a route to new anti-staphylococcal therapeutics.

The CRISPR-Cas system employs RNA-guided endonucleases that recognize and cleave invading foreign nucleic acids. Phages produce anti-CRISPR proteins that inhibit target Cas proteins and facilitate subsequent infection. AcrIIC4 was identified from prophages of Haemophilus parainfluenza and potently inhibits type II-C Cas9. Previous crystal structures reported two distinct helical conformations of AcrIIC4. Here, we measured residual dipolar coupling constants of amide resonances to determine the conformational state of AcrIIC4 in solution. Our results unambiguously illustrate that AcrIIC4 forms a three-helical bundle in solution at neutral pH, which is maintained in the AcrIIC4-Cas9 complex. We also report the backbone resonance assignments of AcrIIC4.

Huntingtin exon 1 (HttEx1) is a key fragment associated with Huntington's disease (HD), whose conformational behavior that is strongly influenced by environmental conditions. Here, we investigated the pH-dependent conformational and aggregation behavior of non-pathogenic HttEx1-17Q using thioflavin T (ThT) fluorescence, circular dichroism (CD), and solution nuclear magnetic resonance (NMR) spectroscopy. Although pathogenic polyQ-expanded huntingtin has been extensively studied, non-pathogenic HttEx1 remains comparatively unexplored. In particular, protonation-driven effects on the monomeric conformational ensemble and association processes of HttEx1-17Q have not been fully clarified. In this work, we provide characterization of pH-dependent structural and dynamic features of HttEx1-17Q in solution.

Hsp90 is a dynamic chaperone protein whose ATP-driven conformational cycle plays critical roles in the maturation and regulation of client proteins. Due to its large size and multi-domain architecture, however, conventional structural methods provide only limited insight into its dynamic features and related functionalities. Recent advances in ¹⁹F NMR spectroscopy have enabled residue-specific and background-free monitoring of Hsp90 dynamics across multiple structural scales. This mini-review highlights three representative studies that employed ¹⁹F NMR to dissect Hsp90's mechanistic cycle. These studies demonstrate the unique power of 19F NMR to probe conformational populations, exchange kinetics, and allosteric regulation in large protein systems.

²⁹Si and ²⁷Al solid-state nuclear magnetic resonance (NMR) spectroscopy has been established as a powerful technique for investigating the network connectivity and coordination environments for diverse crystalline and amorphous silicate materials. Recently, zeolite-geopolymer composites, emerging as sustainable and functional construction materials, have garnered significant interest for their mechanical properties and adsorption capabilities. However, the coexistence of crystalline and amorphous phases, as well as complex Si-Al coordination environments, makes detailed structural characterization challenging. In this mini-review, recent applications of ²⁹Si and ²⁷Al solid-state NMR to zeolite-geopolymer composites are summarized, highlighting the isotopic chemical shift ranges of geopolymer gels in comparison with coexisting crystalline phases. Perspectives on future studies are also discussed.

Eleutherococcus sessiliflorus (Ogapi) is a medicinal plant widely used as a functional food material in East Asia. In this study, a ¹H nuclear magnetic resonance (NMR) based metabolomics was applied to characterize primary metabolite profiles of bark and fruit tissues. A total of 34 and 33 metabolites were identified in bark and fruit, respectively. Fruit exhibited a monosaccharide dominated profile with high levels of fructose and glucose, whereas bark was sucrose-rich and contained characteristic amino and phenolic metabolites such as arginine, proline, and chlorogenate. These profiles indicate functional differentiation, with fruits specialized for sugar-based carbon storage supporting growth and reproduction, while bark metabolism is oriented toward cellular signaling and stress-related defense. In addition, solvent-dependent analysis of fruit reflux extracts revealed that water extracts were enriched in organic acids (e.g., lactate and succinate), whereas ethanol extracts contained higher levels of sugars. Collectively, this study provides the first comprehensive primary metabolite profiles for E. sessiliflorus, offering a foundation for its functional evaluation and targeted utilization as a bioresource.

Licorice (Glycyrrhiza spp.) is an important medicinal plant, and a new hybrid cultivar, Wongam (G. korshinskyi), has recently been developed in Korea through interspecific hybridization between G. uralensis and G. glabra. In this study, ¹H NMR based metabolomic approach was employed to compare the primary metabolite profiles of Wongam and G. uralensis. A total of 33 primary metabolites, including sugars, organic acids, and amino acids, were identified and quantified. Multivariate statistical analyses revealed clear metabolic discrimination between the two cultivars. In particular, sucrose, malate, and trigonelline were more abundant in G. uralensis, whereas lactate, acetate, and several amino acid-related metabolites were present at higher levels in Wongam, indicating their potential as discriminative markers for licorice differentiation. These findings provide fundamental insight into the primary metabolic characteristics of licorice and establish a basis for future studies on quality evaluation and breeding improvement.

The M9 minimal medium is widely used for producing isotope-labeled proteins in Escherichia coli (E. coli). However, the original M9 formulation does not fully support optimal E. coli growth. To address this limitation, several modified versions featuring increased potassium concentrations, enhanced buffering capacity, and other improvements have been developed to promote robust growth and high-yield protein production. In this protocol, we aimed to identify the best conditions that support E. coli survival and adaptation by comparing the performance of modified minimal medium variants with the original M9 medium, and proposed the optimized formulation of a minimal medium (M-opt) suitable for efficient isotope-labeled protein production.

Solid-state nuclear magnetic resonance (NMR) spectroscopy is widely used to investigate the structure and dynamics of a broad range of materials. In the case of paramagnetic materials, interactions with unpaired electrons lead to markedly broadened NMR frequency ranges, increased linewidths, and shortened longitudinal relaxation times (T₁). These features necessitate experimental approaches and spectral interpretation strategies that differ from those used for diamagnetic systems. In this paper, we summarize key spectroscopic characteristics of paramagnetic materials in solid-state NMR and present several representative examples illustrating these phenomena.