• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 1997년도 학술발표회
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• pp.38-38
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• 1997

Serpins (serine protease inhibitor) are single polypeptide proteins of around 400 amino acids, and have a conserved secondary structure consisted of three ${\beta}$-sheets and nine ${\alpha}$-helices. Native conformation of inhibitory serpins is a metastable and requires conformational changes to inhibit target protease.(omitted)

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 1997년도 학술발표회
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• pp.9-10
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• 1997

Calmodulin: very large conformation change of helix uncoiling, hinge-bending and domain rotation. Calmodulin (CaM) is the principal Ca$\^$2＋/ -dependent regulator of a variety of important eukaryotic cellular processes. In many of these processes, calmodulin activates a plethora of target enzymes, and the calmodulin-binding domains in several targets have been shown to residue in a region of about 18-residue peptide segment.(omitted)

• 한국식품영양과학회지
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• 제23권3호
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• pp.414-419
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• 1994

This study was trying to find what physical changes occurred to albumin when it reacted with estrogen and other ligands. Each concentration of human serum albumin with 100$\mu$l estradiol reacted at the highest binding capacity of 280nm. In addition, 1 hr of reaction time showed the highest binding rate. Conformational changes in human serum albumin with dietylstillbesterol and N-ethyl-maleimide produced strong binding capacities. The changes were immediate and they did not increase or decrease over time. Effects of human serum albumin with estriol induced no interaction each other. The binding capacity of human serum albumin with vitamin D$_2$was lower than estradiol. and the highest binding rate showed 1 hr of reaction time. Vitamin D$_2$ was very similar to the binding capacity of estradiol.

• Bulletin of the Korean Chemical Society
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• 제17권11호
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• pp.1004-1009
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• 1996

The interactions between a rod-coil liquid crystalline oligomer, ethyl 4-[4'-oxy-4-biphenylcarbonyloxy]-4'-biphenylcarboxylate with poly(ethylene oxide) (DP=12) (12-4) and LiCF3SO3 have been characterized by using Raman spectroscopy. Band assignments were made comparing the spectrum of 12-4 with those of the poly(ethylene glycol) monomethyl ether(PEGME) (Mw=550) and the ethyl-4'-hydroxybiphenyl-4-carboxylate (EHBPC), which are the coil and mesogen analogues, respectively. Analyzing characteristic bands of the 12-4-salt complex, we have found that the bands belonging to the coil and mesogenic units are changed in both intensities and frequencies. The spectral changes were interpreted from the viewpoint of the complexation between 12-4 and the Li+ ion. However, the possibility that the spectral changes in the mesogenic unit are not due to the complexation with the Li+ ion, but due to the conformational changes by the intercalation of nondissociated LiCF3SO3, is not ruled out.

• BMB Reports
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• 제30권4호
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• pp.240-245
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• 1997

Interactions between ganglioside $G_{M3}$ and glucose transporter, GLUT1 were studied by measuring the effect of $G_{M3}$ on steady-state and time-resolved fluorescence of purified GLUT1 in synthetic lipids and on the 3-O-methylglucose uptake by human erythrocytes. The intrinsic tryptophan fluorescence showed a GLUT 1 emission maximum of 335 nm, and increased in the presence of $G_{M3}$ by 12% without shifting the emission maximum, The fluorescence lifetimes of intrinsic tryptophan on GLUT1 consisted of a long component of 7.8 ns and a short component of 2,3 ns and $G_{M3}$ increased both lifetime components. Lifetime components were quenched by acrylamide and KI. Acrylarnide-mduced quenching of long-lifetime components was partly recovered by $G_{M3}$ However. KI-induccd quenching of short- and long-lifetime components was not rescued by $G_{M3}$. The anisotropy of 1.6-diphenyl-1.3.5-hexatriene (DPH)-probed dimyristoylphosphatidylcholine (DMPC) model membrane was also increased with $G_{M3}$ incorporation, The transport rate of 3-O-methylglucose increased by 20% with $G_{M3}$ incorporation on the erythrocytes, Therefore, $G_{M3}$ altered the environment of lipid membrane and induced the conformational change of GLUT1.

• 생명과학회지
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• 제2권2호
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• pp.97-107
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• 1992

비록 국소마취제가 신경세포막 당단백질중의 하나인 sodium channel과의 직접적인 상호작용에 의하여 그 특유의 국소마취제를 나타낸다고 할지라도 신경세포막의 골격을 형성하고 있는 지질과 국소마취제와의 상호작용을 분자적 국소마취제 작용기전을 설명함에 있어 배제할 수는 없다. 왜냐하면 sodium channel은 지질과의 공유 또는 비공유결합을 통해 단단하게 결합되어 있기 때문이다. 따라서 국소마취제가 직접 sodium channel과 결합, 상호작용하여 Na+의 유입을 차단할 뿐만 아니라 직접 지질의 측방 및 회전확산 운동을 증가시킴으로써 간접적으로 sodium channel의 conformational change가 유발되어 Na+의 유입이 차단되는 등의 복합적인 기전에 의하여 그 특유의 국소마취작용이 나타나는 것이다.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3385-3390
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• 2010

$Li^+$ ion complex of azacrown ether with restricted motion of freedom and pseudo-bilateral symmetry was studied by infrared spectroscopy, which has shown simplified and broadened vibrational features. The C=O and N-H stretching bands, in particular, shows anomalous broadening nearly ${\sim}50\;cm^{-1}$. The density functional calculation at the level of BP86/6-31+$G^{**}$ shows that $Li^+$ ion is trapped and rather free to move around inside the cavity, as much as about $0.70\;{\AA}$. Through the relocation of $Li^+$ ion inside the cavity, the conformational changes would occur rapidly in its symmetry $C_1\;{\rightleftarrows}\;C_2\;{\rightleftarrows}\;C_1$$. The potential barrier was obtained to be merely ~2.2 kJ/mol for $C_1\;{\rightarrow}\;C_2$. During this conformational alteration, the amide backbone twists concurrently its dihedral angle side to side about up to ${\pm}3$ degree. Selected vibrational modes were interpreted in terms of the force constant variations of local symmetry coordinates between conformations in the framework of $C_1\;{\rightleftarrows}\;C_2\;{\rightleftarrows}\;C_1$.

• 한국자기공명학회논문지
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• 제6권2호
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• pp.94-102
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• 2002

An interesting recent application of intermolecular NOE experiment is the saturation transfer difference NMR(STD-NMR) method that is useful in screening compound libraries to identify bio-active ligands. This technique also identifies the group epitopes of the bound ligand in a reversibly forming protein-ligand complex. We present here a complete relaxation and conformational exchange matrix (CORCEMA) theory (Moseley et al., J. Magn. Reson. B, 108, 243-261 (1995)) applicable for the STD-NMR experiment. Using some ideal model systems we have analyzed the factors that influence the STD intensity changes in the ligand proton NMR spectrum when the resonances from some protons on the receptor protein are saturated. These factors will be discussed and some examples of its application in some model systems will be presented. This CORCEMA theory for STD-NMR and the associated algorithm are useful in a quantitative interpretation of the STD-NMR effects, and are likely to be useful in structure-based drug design efforts. They are also useful in a quantitative characterization of protein-protein (or protein-nucleic acid) contact surfaces from an intermolecular cross-saturation NMR experiment.

• 미생물학회지
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• 제46권1호
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• pp.104-108
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• 2010

Leucine-responsive regulatory protein (Lrp)는 대장균 (Escherichia coli)에서 발견된 '글로벌 조절자(global regulator)'로서 Lrp-regulon이 leucine에 의하여 상이한 형태의 조절 양상을 나타낸다. 6XHis-tag 시스템으로 제조한 야생형 Lrp (Lrp Wt)와 돌연변이 Lrp (Lrp R145W) 단백질을 정제하여 그들의 생화학적 성질을 조사하였다. 이들은 gel retardation assay를 통하여 ilv 오페론의 프로모터 영역 consensus 염기서열인 21bp의 이중가닥 DNA와 결합하여 복합체를 형성하는 것을 확인 하였다. 형광성 아미노산인 tryptophan을 지닌 Lrp R145W은 단백질의 농도가 증가함에 따라 형광이 커졌으며, 아미노산 leucine에 의하여 형광성의 변화가 관찰되었다. 즉 1 ${\mu}M$의 Lrp R145W 단백질에 leucine을 첨가하여 결합시키면 약 20 ${\mu}M$까지는 형광이 증가하다가 그 이상의 농도에서는 감소하는 양상을 얻었다. 이들 실험 결과는 leucine과 Lrp의 결합 양상 및 구조변이에 관한 심층연구에 있어서 Lrp의 고유 형광성이 요긴하게 쓰일 수 있음을 시사한다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1995년도 춘계학술대회
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• pp.81-81
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• 1995

It is well known that Src Homology 2(SH2) domain in many intracellular signal transduction proteins is very important. The domain has about 100 amino acid residues and bind phosphotyrosine-containing peptide with high affinity and specificity. Lck SH2 domain is a Src-like, lymphocyte-specific tyrosine kinase. An 11-residue phosphopeptide derived from the hamster polvoma middle-T antigen, EPQp YEEIPIYL, binds with an 1 nM dissociation constant to Lck SH2 domain. And it is known that the phosphotyrosine and isoleucine residues of the peptide are tightly bound by two well-defined pockets on Lck SH2 domain's surface. To investigate the conformational changes during complexation of SH2 domain with phosphopeptide we have performed the molecular dynamics simulation for Lck SH2 domain with peptide and peptide-free form at look in aqueous solution. More than 3000 water molecules were incorporated to solvate Lck SH2 domain and peptide. Periodic boundary condition has been applied in molecular dynamics simulation. Data analysis with the results of that simulation shows that the phosphopeptide makes primary interaction with the Lck SH2 domain at six central residues, The comparison of the complexed and uncomplexed SH2 domain structures in solution has revealed only relatively small change. But the hydrophilic and hydrophobic pockets in the protein surface show the conformational changes in spite of the small structural difference between the complex and peptide-free forms.