No abstract available

[en] Functional interaction between Drosophila orphan receptor FTZ-F1 (NR5A3) and a segmentation gene product fushi tarazu (FTZ) is crucial for regulating genes related to define the identities of alternate segmental regions in the Drosophila embryo. FTZ binding to the ligand-binding domain (LBD) of FTZ-F1 is of essence in activating its transcription process. We determined solution structures of the cofactor peptide (FTZ^PEP) derived from FTZ by NMR spectroscopy. The cofactor peptide showed a nascent helical conformation in aqueous solution, however, the helicity was increased in the presence of TFE. Furthermore, FTZ^PEP formed α- helical conformation upon FTZ-F1 binding, which provides a receptor bound structure of FTZ^PEP. The solution structure of FTZ^PEP in the presence of FTZ-F1 displays a long stretch of the α-helix with a bend in the middle of helix

[en] A method for five-dimensional spectral reconstruction of non-uniformly sampled NMR data sets is proposed. It is derived from the previously published signal separation algorithm, with major alterations to avoid unfeasible processing of an entire five-dimensional spectrum. The proposed method allows credible reconstruction of spectra from as little as a few hundred data points and enables sensitive resonance detection in experiments with a high dynamic range of peak intensities. The efficiency of the method is demonstrated on two high-resolution spectra for rapid sequential assignment of intrinsically disordered proteins, namely 5D HN(CA)CONH and 5D (HACA)CON(CO)CONH.

[en] Functional interaction between Drosophila orphan receptor FTZ-F1 (NR5A3) and a segmentation gene product fushi tarazu (FTZ) is crucial for regulating genes related to define the identities of alternate segmental regions in the Drosophila embryo. FTZ binding to the ligand-binding domain (LBD) of FTZ-F1 is of essence in activating its transcription process. We determined solution structures of the cofactor peptide (FTZ^PEP) derived from FTZ by NMR spectroscopy. The cofactor peptide showed a nascent helical conformation in aqueous solution, however, the helicity was increased in the presence of TFE. Furthermore, FTZ^PEP formed α- helical conformation upon FTZ-F1 binding, which provides a receptor bound structure of FTZ^PEP. The solution structure of FTZ^PEP in the presence of FTZ-F1 displays a long stretch of the α-helix with a bend in the middle of helix

[en] Oximation of 20-hydroxyecdysone oxo derivatives proceeds regio- and stereoselectively and provides (E)-configured oximes in quantitative yields. The Ni-Ra-catalyzed hydrogenation of the oximes affords novel α-aminoecdysteroids with the unchanged 14α-hydroxy-7-en-6-on native chromophore of ecdysteroids. The structures of synthesized compounds were confirmed by the means of homo- and heteronuclear one-dimensional and two-dimensional ¹H and ¹³C NMR spectroscopy and X-ray crystallography. (author)

No abstract available

[en] The modern quantum chemical methods for calculating spin–spin coupling constants in NMR spectra are reviewed. The theoretical basis of these methods and author's vision of the prospects of their development and practical applications in structural and stereochemical studies are presented. The bibliography includes 288 references.

[en] Series of (E)-1-aryl-3-(2-pyrrolyl)-2-propenones, that were aldol condensation products between pyrrole-2-carbaldehyde and m- and p-substituted acetophenones, were prepared and their ¹H and ¹³C NMR spectra were examined to obtain the information on the conformation of the enone system. Similar studies were carried out with (E)-3-aryl-1-(2-pyrrolyl)-2-propenones that were prepared from 2-acetylpyrrole and m- and p-substituted benzaldehydes. The substituent chemical shifts were studied by applying the Hammett relationship

[en] As the concentration of aqueous CD₃OH solutions was decreased, the OD peaks in ²H NMR spectra grew relative to the CD₃ peaks. Isotope impurity for OH groups of CD₃OH and deuterium naturally present in water contributed to the OD peaks. Using these peak area data, the site-specific isotope populations of isotope enriched chemicals were measured. In addition, the method using both ¹H and ²H NMR spectroscopy was demonstrated with neat CD₃OH to measure the site-specific isotope populations. The results indicate that although it represents only ∼0.015% of hydrogen isotopes, the deuterium naturally present in solvents cannot be ignored, especially when the concentration of deuterium-enriched solutes is varied. Proton/deuteron exchange between methyl and methyl/hydroxyl groups was confirmed to be negligible, while that among hydroxyl groups was detectable

[en] It was regarded that the "3"1P resonances of inherent nucleotides in F_1-ATPase (EF1), as large as 380KDa, could not be observed by "3"1P NMR spectroscopy. However, our "3"1P NMR spectroscopy could differentiate between different nucleotide binding sites on EF1 from Escherichia coli. When EF1 was prepared in the absence of Mg"2"+, EF1 contained only ADP. Multiple "3"1P resonances from β-phosphates of ADP bound to the EF1 were observed from the enzyme prepared without Mg"2"+, suggesting asymmetry or flexibility amongst nucleotide binding sites. "3"1P resonances from enzyme bound ATP could be observed only from EF1, when the enzyme was prepared in the presence of Mg"2"+. This Mg"2"+ dependent ATP binding was very tight that, once bound, nucleotide could not be removed even after removal of Mg"2"+. "3"1P NMR proved to be a valuable tool for investigating phosphorous related enzymes