• Bulletin of the Korean Chemical Society
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• 제32권9호
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• pp.3425-3428
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• 2011

Apolipoprotein A-I (Apo A-I) is a major component for high density lipoproteins (HDL). A number of mimetic peptides of Apo A-I were screened from the phase-displayed random peptide library by utilizing monoclonal antibodies (A12). Mimetic peptide for A12 epitope against Apo A-I was selected as CPFARLPVEHHDVVGL (pA1). From the BLAST search, the mimetic peptide pA1 had 40% homology with Apo A-I. As a result of the structural determination of this mimotope using homo/hetero nuclear 2D-NMR techniques and NMR-based distance geometry (DG)/molecular dynamic (MD) computations, DG structure had low penalty value of 0.3-0.7 ${\AA}^2$ and the total RMSD was 0.6-1.6 ${\AA}$. The mimotope pA1 exhibited characteristic conformation including a ${\beta}$-turn from Pro[7] to His[11].

• Bulletin of the Korean Chemical Society
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• 제24권3호
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• pp.339-344
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• 2003

The conformation of synthetic oligosaccharide can be elucidated by employing molecular modeling and highfield proton NMR (nuclear magnetic resonance) spectroscopy. Information with respect to the composition and configuration of saccharide residues and the sequence and linkage positions of the oligosaccharide can be obtained by employing a variety of one- and two-dimensional NMR techniques and molecular modeling. These techniques are also useful in establishing the solution conformation of the oligosaccharide moiety. This study is focused on the elucidation of linkage positions of synthetic trisaccharides, Gal(β1-4)Glc(β1-3)Glc, Gal(β1-4)Glc(β1-4)Glc and Gal(β1-4)Glc(β1-6)Glc.

• Bulletin of the Korean Chemical Society
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• 제28권9호
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• pp.1549-1552
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• 2007

The cytoplasmic domain of syndecan-4, a type I transmembrane heparan sulfate proteoglycan, was overexpressed as a fused form with the ubiquitin molecule in Escherichia coli, and the fusion protein was purified using immobilized metal affinity chromatography (IMAC). The cytoplasmic domain was released from its fusion partner by using yeast ubiquitin hydrolase (YUH), and subsequently purified by reverse phase chromatography. The integrity of the resulting peptide fragment was checked by MALDI-TOF and NMR spectroscopy. The yield of the peptide was 3.0-1.5 mg per liter in LB or minimal medium, respectively. The recombinant expression and purification of this domain will enable us its structural and functional studies using multidimensional NMR spectroscopy.

• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.183-185
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• 2011

Adenylate kinase-like activity and phosphotransferase-like activity from $F_1$-ATPase of Escherichia coli was revealed by $^{31}P$ NMR spectroscopy. Incubation of F1-ATPase with ADP in the presence of $Mg^{2+}$ shows the appearance of $^{31}P$ resonances from AMP and Pi, suggesting generation of AMP and ATP by adenylate kinase-like activity and the subsequent hydrolysis to Pi. Incubation of $F_1$-ATPase with ADP in the presence of methanol shows additional peak from methyl phosphate, suggesting phosphotransferase-like activity of $F_1$-ATPase. Both adenylate kinase-like activity and phosphotransferase-like activity has not been reported from $F_1$-ATPase of Escherichia coli. $^{31}P$ NMR could be a valuable tool for the investigation of phosphorous related enzyme.

• Bulletin of the Korean Chemical Society
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• 제30권7호
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• pp.1559-1562
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• 2009

The influence of hot pressing on the pore structures of Nafion membranes was investigated by observing the Nafion before and after hot pressing with $^1H$ nuclear magnetic resonance (NMR) spectroscopy. The freezing point depression and chemical shift data of water in the Nafion indicated the presence of two different pore size ranges in Nafion. Hot pressing mainly reduced the sizes and number of the big pores. The reduction of water uptake and proton conductivity after hot pressing was explained by this variation of pore size and number. We demonstrated the potential application of chemical shift data and NMR cryoporometry experiments to measure the relative pore sizes, on a nano scale, and numbers.

• 한국자기공명학회논문지
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• 제23권2호
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• pp.56-60
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• 2019

Study on the structure and dynamics of molecules at the atomic level is of great significance for understanding their function and stability as well as roles for various chemico-physical and biological processes. $^{17}O$ NMR spectroscopy has appeared as an elegant technique for investigating of the physicochemical and structural properties of oxygen-containing compounds such as metal organic frameworks and nanosized oxides. This method has drawn much attention as it provides unique insights into the properties of targets based on atomistic information of local oxygen environments which is otherwise difficult to obtain using other methods. In this mini review, we introduce and discuss the recent study and developments of $^{17}O$ NMR techniques which are tailored for the investigation on the structure and dynamics of water and inorganic materials.

• 한국자기공명학회논문지
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• 제25권1호
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• pp.8-11
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• 2021

Transthyretin (TTR) is an important transporter protein for thyroxine (T4) and a holo-retinol protein in human. In its native state, TTR forms a tetrameric complex to construct the hydrophobic binding pocket for T4. On the other hand, this protein is also infamous for its amyloidogenic propensity, which causes various human diseases, such as senile systemic amyloidosis and familial amyloid polyneuropathy/cardiomyopathy. In this work, to investigate various structural features of TTR with solution-state nuclear magnetic resonance (NMR) spectroscopy, we conducted backbone NMR signal assignments. Except the N-terminal two residues and prolines, backbone 1H-15N signals of all residues were successfully assigned with additional chemical shift information of 13CO, 13Cα, and 13Cβ for most residues. The chemical shift information reported here will become an important basis for subsequent structural and functional studies of TTR.

• 대한화학회지
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• 제38권10호
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• pp.749-752
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• 1994

하와이 Pohnpei에서 채집한 soft coral Sinularia lochmodes로부터 2개의 furanosesquiterpenes인 (5'E)-5-(2',6'-dimethylocta-5',7'-dienyl) furan-3-carboxylic acid (1)와 (1'E,5'E)-5-(2',6'-dimethylocta-l',5',7'-trienyl) furan-3-carboxylic acid (2)가 검출되었다. 이들의 구조를 $^1H$ , $^{13}C$ NMR, Homo-COSY, $^1H$-$^{13}C$ (1 bond) Heteronuclear Multiple Quantum Coherence Spectroscopy (HMQC), $^1H$-$^{13}C$ (2 and 3 bond) Heteronuclear Multiple Bond Coherence Spectroscopy (HMBC), Electron Impact Mass Spectroscopy (EI-ms) 및 Infrared Spectroscopy (IR)에 의해 밝혔다.

• Bulletin of the Korean Chemical Society
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• 제26권8호
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• pp.1225-1228
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• 2005

C-terminal fragments of APP (APP-CTs), that contain A$\beta$ sequence, are found in neurotic plaques, neurofibrillary tangles and the cytosol of lymphoblastoid cells obtained from AD patients. CT26, Thr639-Asp664 (TVIVITLVMLKKKQYTSIHH GVVEVD) includes not only the transmembrane domain but also the cytoplasmic domain of APP. This sequence is produced from cleavage of APP by caspase and $\gamma$-secretase. In this study, the solution structure of CT26 was investigated using NMR spectroscopy and circular dichroism (CD) spectropolarimeter in various membrane-mimicking environments. According to CD spectra and the tertiary structure of CT26 determined in TFE-containing aqueous solution, CT26 has an α-helical structure from $Val^{2}\;to\;Lys^{11}$ in TFE-containing aqueous solution. However, according to CD data, CT26 adopts a $\beta$-sheet structure in the SDS micelles and DPC micelles. This result implies that CT26 may have a conformational transition between $\alpha$-helix and $\beta$-sheet structure. This study may provide an insight into the conformational basis of the pathological activity of the C-terminal fragments of APP in the model membrane.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.3114-3114
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• 2001

During the last years phytochemistry and phytopharmaceutical applications have developed rapidly and so there exists a high demand for faster and more efficient analysis techniques. Therefore we have established a near infrared transflectance spectroscopy (NIRS) method that allows a qualitative and quantitative determination of new polyphenolic pharmacological active leading compounds within a few seconds. As the NIR spectrometer has to be calibrated the compound of interest has at first to be characterized by using one or other a combination of chromatographic or electrophoretic separation techniques such as thin layer chromatography (TLC), high performance liquid chromatography (HPLC), capillary electrophoresis (CE), gas chromatography (GC) and capillary electrochromatography (CEC). Both structural elucidation and quantitative analysis of the phenolic compound is possible by direct coupling of the mentioned separation methods with a mass spectrometer (GC-MS, LC-MS/MS, CE-MS, CEC-MS) and a NMR spectrometer (LC-NMR). Furthermore the compound has to be isolated (NPLC, MPLC, prep. TLC, prep. HPLC) and its structure elucidated by spectroscopic techniques (UV, IR, HR-MS, NMR) and chemical synthesis. After that HPLC can be used to provide the reference data for the calibration step of the near infrared spectrometer. The NIRS calibration step is time consuming, which is compensated by short analysis times. After validation of the established NIRS method it is possible to determine the polyphenolic compound within seconds which allows to raise the efficiency in quality control and to reduce costs especially in the phytopharmaceutical industry.