• 생명과학회지
• /
• 제23권4호
• /
• pp.510-517
• /
• 2013

본 연구에서는 초임계를 이용한 계피 오일 추출물(SFC)과 오일 추출 후 남은 부산물인 박(SFM), 그리고 80% methanol (ME) 계피추출물을 이용하여 항비만 효과를 비교하고 어떤 계피의 어떤 성질의 성분이 비만에 더 효과적인지 알아보았다. 3T3-L1 preadipocyte의 성숙한 지방세포로 분화시키기 위해 iso-butylmethylanthine (IBMX), dexamathasone, insulin을 SFC, SFM, ME를 처리하고 Real time PCR을 이용하여 전사인자 발현을 확인하였다. 그 결과 SFC에서 mRNA 수준에서 peroxisome-proliferators-activated-receptor-${\gamma}$ ($PPAR{\gamma}$), CCAAT enhancer-binding-protein ${\alpha}$ ($C/EBP{\alpha}$)의 저해능이 세 가지 조건 중에서 가장 높았으며, 또한 SFC는 peroxisome-proliferators-activated-receptor-${\gamma}$ ($PPAR{\gamma}$), CCAAT enhancer-binding-protein ${\alpha}$ ($C/EBP{\alpha}$) sterol-regulatory-element-binding protein-1c (SREBP1c)와 acyl-CoA synthetase-1 (ASC1), fatty acid synthesis (FAS), fatty acid transport-1 (FATP1), fatty acid binding protein-4 (FABP4) 그리고 perilipin의 전사인자도 농도유의적으로 감소시켰다.

• Bulletin of the Korean Chemical Society
• /
• 제25권4호
• /
• pp.539-544
• /
• 2004

The ability of protoberberine alkaloids, berberine and berberrubine, to act as topoisomerase II poisons is linked to the anti-cancer activity. Minor alterations in structure have a significant effect on their relative activity. Berberine, which has methoxy group at the 19-position, is significantly less potent than berberrubine. Several observations support non-specific binding to HP14 by the berberine: (i) nonspecific upfield changes in $^1H$ chemical shift for protons of the berberine; (ii) the broadening of imino protons of HP14 upon binding of the berberine; (iii) very small increases in duplex melting temperature in the presence of the berberine. Our results reveal that substitution of a hydroxyl group to a methoxy group on the 19-position, thereby converting the berberrubine to the berberine is associated with a non-specific DNA binding affinity and a reduced topoisomerase II poisoning. The presence of a bulky 19-methoxy substituent decreases intercalating properties of berberine and makes it inactive as topoisomerase II poison.

• Journal of Plant Biology
• /
• 제39권3호
• /
• pp.173-177
• /
• 1996

A novel calcium binding protein (CaBP) was purified to electrophoretic homogeneity from Dunaliella salina. In the course of purification experiment, this CaBP was identified as a monomer and its molecular weight was about 21 kDand isoelectric point (pI) value was about 4.1 using isoelectrofocusing. This CaBP was able to bind Ca2+ even in the pressence of an excess MgCl2 and KCI both in solution. In the SDS-PAGE, the Ca2+-bound form was slower than the Ca2+-free form in the nondenaturing PAGE. This means that the CaBP undergoes conformational change in the Ca2+-bound condition. Furthermore, UV absorption spectrum and fluorescence intensity of this CaBP was investigated. UV absorption peak was appeared at about 258 nm and decreased somewhat in Ca2+-bound condition. In the measurement of fluorescence, maximum intensity was appeared at 303 nm and decreased in Ca2+-bound state, similarly as UV absorption spectrum. These show distinct changes upon Ca2+-binding, which indicate of structural and/or dynamic changes largely reminiscent of other members of the EF-hand Ca2+-binding protein family.

• BMB Reports
• /
• 제34권1호
• /
• pp.1-7
• /
• 2001

Structural and physical properties of type wild type and various selected mutants of the vnd/NK-2 homeodomain, the protein product of the homeobox, and the implication in genetic disease are reviewed. The structure, dynamics and thermodynamics have been Investigated by NMR and by calorimetry. The interactions responsible for the nucleotide sequence-specific binding of the homeodomain to its consensus DNA binding site have been identified. There is a strong correlation between significant structural alterations within the homeodomain or its DNA complex and the appearance of genetic disease. Mutations in positions known to be important in genetic disease have been examined carefully For example, mutation of position 52 of vnd/NK-2 results in a significant structural modification and mutation of position 54 alters the DNA binding specificity and amity The $^{15}N$ relaxation behavior and heteronuclear Overhauser effect data was used to characterize and describe the protein backbone dynamics. These studies were carried out on the wild type and the double mutant proteins both in the free and in the DNA bound states. Finally, the thermodynamic properties associated with DNA binding are described for the vnd/NK-2 homeodomain. These thermodynamic measurements reinforce the hypothesis that water structure around a protein and around DNA significantly contribute to the protein-DNA binding behavior. The results, taken together, demonstrate that structure and dynamic studies of proteins combined with thermodynamic measurements provide a significantly more complete picture of the solution behavior than the individual studies.

• 한국식품위생안전성학회지
• /
• 제7권2호
• /
• pp.77-82
• /
• 1992

천연색소 Brazilin 및 Hematoxylin의 BSA에 대한 결합 특성을 fluorescence probe 법을 이용하여 측정하였다. Brazilin 및 Hematoxylin은 BSA에 대해 강한 결합 친화력을 보였으며 Hematoxylin은 Brazilin 보다 더 강한 결합력을 보였다. Brazilin 및 Hematoxylin의 농도 증가에 따라 결합상수는 감소하였으며, 이는 probe-단백 결합체와 양화합물간의 상호작용 또는 Probe와 양화합물간의 결합체 형성에 기인하는 것으로 추정되었다. 양화합물과 BSA의 결합은 pH 및 이온강도에 의존적이었으며, 이 결합에는 electrostatic force 및 hydrophobic force 가 관여하는 것으로 추정되었다.

• Journal of Microbiology and Biotechnology
• /
• 제11권6호
• /
• pp.1002-1010
• /
• 2001

The D-xylose operon in Escherichia coli is known to be regulated by a transcriptional activator protein, XyIR, which is responsible for the expression of both xylAB and xylFGH gene clusters. The XyIR was purified to homogeneity by using the maltose binding protein fusion expression and purification systems involving two chromatography steps. The purified XyIR protein was composed of two subunits of 45 kDa, which was determined by both sodium dodecyl sulfate polyacrylamide gel electrophoresis and gel filtration. The purified XyIR was specifically bounded to the xylA promoter, regardless of adding xylose to the reaction mixture, but binding of XylR was specifically bounded to the xylA promoter, regardless of adding xylose to the reaction mixture, but binding of XylR to the xylA promoter was enhanced by adding xylose. The enhanced binding ability of XyIR in the presence of xylose was not diminished by adding glucose. The presumed XyIR binding site is located between 120 bp to 100 bp upstream the xylA initiation codon.

• BMB Reports
• /
• 제37권2호
• /
• pp.159-166
• /
• 2004

Angiostatin is a potent anti-angiogenic protein. To examine the angiostatin-interacting proteins, we used the display-cloning method with a T7 phage library presenting human cDNAs. The specific T7 phage clone that bound to the immobilized angiostatin was isolated, and a novel gene encoding the displayed polypeptide on the isolated T7 phage was identified. The displayed angiostatin-binding sequence was expressed in E. coli as a soluble protein and purified to homogeneity. This novel angiostatin-binding region interacted specifically to angiostatin with a dissociation constant of $3.4{\times}10^{-7}\;M$. A sequence analysis showed that the identified sequence was a part of the large ORF of 1,998 amino acids, whose function has not yet been characterized. A Northern analysis indicated that the gene containing the angiostatin-binding sequence was expressed differentially in the developmental stages or cell types.

• Journal of Microbiology
• /
• 제37권1호
• /
• pp.21-26
• /
• 1999

Two novel calcium-binding proteins, named CAB-I and CAB-II, have been isolated from Streptomyces coelicolor. Purification of the calcium-binding proteins involved heat treatment, fractionation with ammonium sulfate, acid treatment, anion exchange and hydrophobic interaction column chromatography, FPLC gel filtration, and preparative isoelectric focusing. A chelex competitive assay and 45Ca autoradiography verified the calcium-binding ability of the proteins. The major band CAB-II has an apparent molecular weight of 26,000 determined by SDS-polyacrylamide gel electrophoresis and 340,000 determined by gel filtration. The isoelectric point of this molecule showed the acidic nature of the molecule. N-terminal amino acid sequence analysis shows homology to rat Ca2+/calmodulin-dependent protein kinase-II (CAB-II) and yeast phosphoprotein phosphatase (CAB-I).

• Ocean and Polar Research
• /
• 제33권2호
• /
• pp.159-169
• /
• 2011

Antifreeze proteins (AFPs) have ice binding affinity, depress freezing temperature and inhibit ice recystallization which protect cellular membranes in polar organisms. Recent structural studies of antifreeze proteins have significantly expanded our understanding of the structure-function relationship and ice crystal growth inhibition. Although AFPs (Type I-IV AFP from fish, insect AFP and Plant AFP) have completely different fold and no sequence homology, they share a common feature of their surface area for ice binding property. The conserved ice-binding sites are relatively flat and hydrophobic. For example, Type I AFP has an amphipathic, single ${\alpha}$-helix and has regularly spaced Thr-Ala residues which make direct interaction with oxygen atoms of ice crystals. Unlike Type I AFP, Type II and III AFP are compact globular proteins that contain a flat ice-binding patch on the surface. Type II and Type III AFP show a remarkable structural similarity with the sugar binding lectin protein and C-terminal domain of sialic acid synthase, respectively. Type IV is assumed to form a four-helix bundle which has sequence similarity with apolipoprotein. The results of our modeling suggest an ice-binding induced structural change of Type IV AFP. Insect AFP has ${\beta}$-helical structure with a regular array of Thr-X-Thr motif. Threonine residues of each Thr-X-Thr motif fit well into the ice crystal lattice and provide a good surface-surface complementarity. This review focuses on the structural characteristics and details of the ice-binding mechanism of antifreeze proteins.

• BMB Reports
• /
• 제37권2호
• /
• pp.153-158
• /
• 2004

The acid-labile subunit (ALS) is known to interact with the IGF binding protein (IGFBP) in the presence of insulin-like growth factors (IGFs). Studies, however, indicate that ALS forms a doublet with IGFBP3, independent of IGFs. To characterize the structural domain required for the IGF-free ALS-IGFBP3 interaction, seven recombinant human IGFBP3 mutants were generated: three deletion mutants and four site-specific mutants that had altering N-terminal regions of IGFBP3. ALS and IGFBP3 mRNAs were co-injected into Xenopus oocytes, and their products were cross-linked and immunoprecipitated using antisera against ALS or IGFBP3. Among the deletion mutants, the mutant of D40 (deleted in 11-40th amino acids) exerted no effect in the interaction with ALS, while D60 (${\Delta}11$-60) demonstrated a moderate reduction. D88 (${\Delta}11$-88), however, showed a significant decrease. In the case of site-specific mutants, the mutation that alterated the IGF binding site (codons 56 or 80) exerted a significant reduction in the interaction, whereas codons 72 or 87 showed no significant change in the interaction with ALS. The stability of the ALS-IGFBP3 interaction was analyzed according to a time-dependent mode. Consistent with the binding study, mutants on the IGF binding sites (56 or 80) consistently show a weakness in the ALS-IGFBP3 interaction when compared to the mutants that covered the non-IGF binding sites (72 or 87). This study suggests that the N-terminal of IGFBP3, especially the IGF binding site, plays an important role in interacting with ALS as well as in stabilizing the dual complex, independent of IGFs.