• Applied Biological Chemistry
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• v.41 no.8
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• pp.572-577
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• 1998

The solution conformation of the human insulin precursor, preproinsulin, is described in terms of NMR spectral data. NMR experiments were performed on preproinsulin, whose structure was compared with the NMR structure of native human insulin. Despite the presence of the C-peptide and/or the signal peptide, secondary structure analyses indicate that the native structures of the A and B chains are well conserved even in preproinsulin. The observed relative robustness of the native structure in precursor forms permits further protein engineering experiments where the C-peptide or N-terminal signal sequence can be altered for the purpose of increasing expression or purification yields when producing recombinant human insulin.

• Natural Product Sciences
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• v.26 no.2
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• pp.171-175
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• 2020

Liriodendron tulipifera, belonging to the family Magnoliaceae, is commonly called tulip tree. Four N-acetylated aporphine alkaloids, N-acetylnornuciferine (1), N-acetylanonaine (2), N-acetyl-3-methoxynornuciferine (3), and N-acetyl-3-methoxynornantenine (4) were isolated from the roots of L. tulipifera. Although the purity of each compound (1 - 4) was determined to be 97, 96, 99, and 98%, respectively, the ¹H and ¹³C NMR spectroscopic data of the aporphine alkaloids 1 - 4 displayed all signals in duplicate, indicating the presence of two rotamers due to restricted rotation of N-COCH₃ functionality in solution status. The absolute configurations of 1 - 4 w ere established by measuring specific rotation and comparison with the reported data. This is the first report on the ¹H and ¹³C NMR assignments of N-acetyl-3-methoxynornuciferine (3) and N-acetyl-3-methoxynornantenine (4). This study provides advanced NMR spectroscopic data for the structure determination of rotameric aporphine alkaloids.

• Bulletin of the Korean Chemical Society
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• v.6 no.2
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• pp.63-67
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• 1985

The NMR chemical shift arising from 3d electron spin dipolar nuclear spin angular momentum interactions for a 3d$^2$ system in a strong crystal field environment of octahedral symmetry has been investigated when the fourfold axis is chosen to be our axis of quantization. The NMR shift is separated into the contribution of 1/R$^5$ and 1/R$^7$ terms. A comparision of the multipolar terms with nonmultipolar results shows that the 1/R$^5$ term contributes dominantly to the NMR shift and there is in good agreement between the exact solution and the multipolar results when R ${\ge}$ 0.25. A temperature dependence analysis may lead to the results that the 1/T$^2$ term has the dominant contribution to the NMR shift for a paramagnetic 3d$^2$ system but the contribution of the 1/T term may not be negligible.

• Journal of the Korean Magnetic Resonance Society
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• v.19 no.2
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• pp.83-87
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• 2015

Syndesmos, which is co-localized with syndecan-4 cytoplasmic domain ($Syn4^{cyto}$) in focal contacts, interacts with various cell adhesion adaptor proteins including $Syn4^{cyto}$ to control cell signaling. Syndesmos consists of 211 amino acids and it exists as a dimer (44kDa) in solution. Recently, we have determined the structure of syndesmos by x-ray crystallography, however, dynamics related to syndecan binding still remain elusive. In this report, we performed NMR experiments to acquire biochemical and structural information of syndesmos. Based on a series of three-dimensional triple resonance experiments on a $^{13}C/^{15}N/^2H$ labeled protein, NMR spectra were obtained with well dispersed and homogeneous NMR data. We present the sequence specific backbone assignment of syndesmos and assigned NMR data with combination structural information can be directly used for the studies on interaction with $Syn4^{cyto}$ and other binding molecules.

• Journal of the Korean Magnetic Resonance Society
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• v.11 no.2
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• pp.73-84
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• 2007

MTH1821 (UniProtKB/TrEMBL ID O27849) is a 96-residue hypothetical protein from the open reading frame of Methanobacterium thermoautotrophicum H one of the target organisms of structural genomics pilot project. Proteins which contain conserved sequence compared with MTH1821 have not been discovered yet and the functional and structural information for MTH1821 is not available. Here, we present the sequence-specific backbone resonance using multidimensional heteronuc1ear NMR spectroscopy and propose the secondary structure using GetSBY software. The backbone resonances of N, HN, $C_{\alpha}$, $C_{\beta}$, CO and $H_{\alpha}$ which are necessary for a prediction of secondary structure by GetSBY were assigned about 98% (557/568). The secondary structure of MTH1821 confirmed that it is comprised of four strand regions and two helical regions. This report will provide a valuable resource for the calculation solution structure of MTH1821 and for the other hypothetical protein that is targeted for structural-based functional discovery.

• BMB Reports
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• v.37 no.5
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• pp.565-573
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• 2004

Orexin-A and orexin-B (hypocretin-1 and hypocretin-2, respectively) are important hypothalamic neuro-peptides, which are encoded by a single mRNA transcript and stimulate food intake as well as regulate wakefulness. Here we determined the solution structure of orexin-A by NMR spectroscopy and by simulated-annealing calculation. The structural features of orexin-A involve two $\alpha$-helices, with the hydrophobic residues disposed to on one side of helix, and hydrophilic residues to the other. A hydrophilic turn induced by two disulfide bonds provides the key difference between orexin-A and -B. With previous mutagenic studies, the derived structure of orexin-A provides us with a structure-functional view for novel drug design.

• Journal of Microbiology and Biotechnology
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• v.10 no.5
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• pp.733-736
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• 2000

Since pathogens resistant against vancomycin occur rapidly, the development of a new drug is needed. To make a new drug based on a rational drug design, the structural study of vancomycin is necessary. Accordingly, this study reports on a comparison of the solution structure of vancomycin determined by NMR spectroscopy, which was performed in the present work, with the X-ray crystallographic structure previously deposited in the Protein Data Bank (PDB).

• Journal of the Korean Magnetic Resonance Society
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• v.22 no.4
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• pp.76-81
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• 2018

Investigation of the protein-protein interaction mode at atomic resolution is essential for understanding on the underlying functional mechanisms of proteins as well as for discovering druggable compounds blocking deleteriou interprotein interactions. Solution NMR spectroscopy provides accurate and precise information on intermolecular interactions even for weak and transient interactions, and it is also markedly useful for examining the change in the conformation and dynamics of target proteins upon binding events. In this mini-review, we comprehensively describe three unique and powerful methods of solution NMR spectroscopy, paramagnetic relaxation enhancement (PRE), pseudo-contact shift (PCS), and residual dipolar coupling (RDC), for the study on protein-protein interactions.

• Applied Chemistry for Engineering
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• v.23 no.3
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• pp.284-288
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• 2012

This work deals with the chemical characterization of glycine aqueous solution in $CO_2$ absorption. Three alkali elements were impregnated into the glycine in order to facilitate the formation of amino functionalities. The analysis by IR revealed the transformation of ammonium ions to the amino group. In addition, the NMR analysis showed that the substitution of metal cations to the chemical shift of hydrogen and carbon atoms in glycine; in order of lithium glycinate, sodium glycinate and potassium glycinate depending on the electro negativity. Meanwhile, the $CO_2$ absorption at room temperature was the highest in primary amine solution, but at the increasing temperature sodium glycinate could capture more $CO_2$ than that of the pure amine solution.

• Polymer(Korea)
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• v.39 no.3
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• pp.403-411
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• 2015

A series of hydrophobically associating fluorinated amphiphilic polyacrylamide copolymers with remarkably high heat resistance and salt tolerance were synthesized by free radical micellar copolymerization, using acrylamide (AM) and sodium 2-acrylamido-tetradecane sulfonate ($AMC_{14}S$) as amphiphilic monomers, and 2-(perfluorooctyl) ethyl acrylate (PFHEA) as hydrophobic monomer. The structure of the terpolymer was characterized by FTIR, $^1H$ NMR and $^{19}F$ NMR. The solution properties of the terpolymers were investigated in details, and the results showed that the terpolymer solution had strong intermolecular hydrophobic association as the concentration exceeded the critical association concentration 1.5 g/L. The terpolymer solution possessed high surface activity, viscoelasticity, excellent heat resistance, salt tolerance and shearing resistance. The viscosity retention rate of copolymer solution was as high as 59.9% under the condition of fresh wastewater, $85^{\circ}C$ and a 60-days aging test.