• 한국자기공명학회논문지
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• 제13권1호
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• pp.56-63
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• 2009

SWIRM domain, a core domain of SRG3 is well conserved in SW13, RSC8, and MOIRA family proteins. To understand structural basis for cellular functions of the SWIRM domain, we have initiated biochemical and structural studies on SWIRM domain and mutants using gelfiltration chromatography, circular dichroism and NMR spectroscopy. The structural properties of the mutant SWIRM domains (K34A and M75A) have been characterized, showing that the structures of both wild-type and mutant proteins are a-helical conformation. The data conclude that mutations at interaction sites of its binding partner protein do not affect its secondary and tertiary structure.

• 한국자기공명학회논문지
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• 제12권1호
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• pp.40-50
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• 2008

Ghrelin is a unique peptide hormone that releases growth factor and it stimulates appetite. It comes from pre pro-ghrelin by the post translational modification process and its innate functions are known as food up-take and the growth hormone regulation. Therefore, the structural information of ghrelin precursor is of importance in understanding it function. From our results, we found that the solution structure of ghrelin is mostly random coil conformation at neutral pH value and the structural population changes with pH environments. Data from circular dichroism in different TFE concentrations revealed that the secondary structure changes from random coil to a-helix and the isodichroic point is observed at 202nm, implying that two equilibrium states exist between random coil and helical structure.

• 한국자기공명학회논문지
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• 제21권2호
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• pp.55-62
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• 2017

It is now well established that RNAs exhibit fundamental roles in regulating cellular processes. Many of these RNAs do not exist in a single conformation. Rather, they undergo dynamic transitions among many different conformations to mediate critical interactions with other biomolecules such as proteins, RNAs, DNAs, or small molecules. Here, we briefly review NMR techniques that describe the dynamic behavior of RNA by determining structural, kinetic, and thermodynamic properties.

• Bulletin of the Korean Chemical Society
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• 제1권1호
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• pp.17-22
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• 1980

The CNDO/2 method was used to compute relative stabilities of various configurations and conformations of acetamide, N-methylacetamide and diacetamide and their protonated forms. It was found that: (a) nonbonded interactions play important roles in determining structural preferences of the compounds, (b)$n-{\sigma}^{\ast}$ "throughbond" interactions always favor cis-protonation (relative to C-N).

• Bulletin of the Korean Chemical Society
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• 제10권6호
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• pp.554-559
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• 1989

The electronic structure, conformational preferences, and rotational barriers have been studied for transition metal indenyl allyl complexes by means of extended Huckel calculations. After geometrical optimization the exo conformation of allyl moiety is favored over the endo. The rotational barrier of indenyl ring in (Indenyl)Mo(CO)_2(Allyl)$ is computed to be 3.8 kcal/mol. Population analysis is applied to account for the conformational preferences and rotational barriers. A series of substituted allyl complexes has been also optimized. It shows steric hindrance plays a crucial role in setting the allyl orientation.

• 한국잠사곤충학회지
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• 제53권2호
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• pp.118-123
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• 2015

알코올의 농도 변화에 따른 실크단백질의 구조전이 효과에 대하여 살펴보기 위하여 백옥잠 누에고치를 이용하여 실크단백질 용액을 제조하였다. 알코올의 농도를 100%, 70%, 50%로 조절하여 제조한 실크 비드의 적외선 분광 분석을 하였다. 고농도(100%) 알코올로 처리한 실크단백질은 전형적인 ${\beta}-sheet$ 구조를 반영하는 $1265cm^{-1}$ 부근에서 흡수대를 보였으며 모델 약물로 사용한 4HR의 특성 피크는 관찰되지 않았다. 알코올의 농도를 70%, 50%로 조절하여 처리한 경우에는 모델 약물의 흡수대인 $2933cm^{-1}$ 부근, $1069cm^{-1}$ 부근, 그리고 $973cm^{-1}$ 부근의 흡수대가 발현되었다. 이러한 결과는 알코올의 농도에 따라 조성되는 실크단백질의 미세 구조에 차이가 있음을 나타내며, 보다 정밀한 실크단백질 구조 제어를 위한 추가 연구가 필요한 것으로 생각된다.

• Molecules and Cells
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• 제19권2호
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• pp.205-211
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• 2005

The Arg-Gly-Asp (RGD) sequence serves as the primary recognition site in extracellular matrix proteins, and peptides containing this sequence can mimic the biological activities of matrix proteins. We have initiated structure-function studies of two RGD containing peptides, RGD-5(AGGDD) and cyclic RGD-6(CARGDDC). Assays have shown that cyclic RGD-peptides inhibit platelet aggregation more efficiently than linear ones. NMR data revealed that RGD-5 and RGD-6 have entirely different conformation. RGD-5 has a linear extended structure and RGD-6 has a stable loop conformation. In RGD-5 the guanidinium group of Arg2 and the carboxyl group of Asp4 lie in parallel, whereas the side-chains of Arg3 and Asp5 of RGD-6 are located in different planes, supporting the idea that the stability of the cyclic form derives from the packing of the side chain of the Arg and Asp residues. The structural features of these peptides could provide a basis for designing new drugs against diseases related to platelet aggregation and as cancer antagonists.

• 통합자연과학논문집
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• 제8권4호
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• pp.258-266
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• 2015

Xanthine Oxidase is an enzyme, which oxidizes hypoxanthine to xanthine, and xanthine to uric acid. It is widely distributed throughout various organs including the liver, gut, lung, kidney, heart, brain and plasma. It is involved in gout pathogenesis. In this study, we have performed Comparative Molecular Field Analysis (CoMFA) on a series of 2-(indol-5-yl) thiazole derivatives as xanthine oxidase (XO) inhibitors to identify the structural variations with their inhibitory activities. Ligand based CoMFA models were generated based on atom-by-atom matching alignment. In atom-by-atom matching, the bioactive conformation of highly active molecule 11 was generated using systematic search. Compounds were aligned using the bioactive conformation and it is used for model generation. Different CoMFA models were generated using different alignments and the best model yielded a cross-validated $q^2$ of 0.698 with five components and non-cross-validated correlation coefficient ($r^2$) of 0.992 with Fisher value as 236.431, and an estimated standard error of 0.068. The predictive ability of the best CoMFA models was found to be $r^2_{pred}$0.653. The CoMFA study revealed that the $R_3$ position of the structure is important in influencing the biological activity of the inhibitors. Electro positive groups and bulkier substituents in this position enhance the biological activity.

• 통합자연과학논문집
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• 제8권3호
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• pp.192-203
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• 2015

In view of the growing medicinal importance of pyrazole and its derivatives, the single crystal X-ray diffraction study was carried out for the potential active 2-Benzyl-3-[3-(4-bromo-phenyl)-1-phenyl-1H-pyrazol-4yl]-4,6-dioxo-5-phenyl-octahydro-pyrrolo[3,4-C]pyrrole-1-carboxylic acid ethyl ester ($C_{37}H_{31}BrN_4O_4$, H2O). In the title compound are two molecules exist in the asymmetric unit. It crystallizes in the monoclinic space group $P{\hat{i}}$ with unit cell dimension $a=13.361(18){\AA}$, $b=13.424(17){\AA}$ and $c=21.649(2){\AA}$ [${\alpha}=80.745(9)^{\circ}$, ${\beta}=79.770(10)^{\circ}$ and ${\gamma}=60.788(6)^{\circ}$]. The pyrazole ring adopts planar conformation. The sum of the bond angles at nitrogen atom of the pyrazole ring indicates the $Sp^2$ hybridized state. The crystal structure is stabilized by intramolecular C-H...O hydrogen bond interaction.

• BMB Reports
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• 제31권1호
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• pp.48-52
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• 1998

$p16^{INK4}$, which is a 16-kDa polypeptide protein, inhibits the catalytic activity of the CDK4-cyclinD complex to suppress rumor growth. Both unlabeled and isotope-labeled human tumor suppressor $p16^{INK4}$ protein were overexpressed and purified to characterize biochemical and structural properties. The purified p16 binds to monomeric GST-CDK4 and exists in a monomer conformation for several weeks at $4^{\circ}C$. The circular dichroism (CD) data indicates that p16 contains high percentage of ${\alpha}$-helix and that the helix percentage maximized at pH value of 7.0. One-and two-dimensional nuclear magnetic resonance (NMR) data suggest that purified p16 from our construct has a unique folded conformation under our experimental conditions and exhibits quite stable conformational characteristics.