• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2241-2244
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• 2017

The structure of concanavalin A (ConA) has been studied intensively owing to its specific interactions with carbohydrates and its heterometal ($Ca^{2+}$ and $Mn^{2+}$) coordination. Most structures from X-ray crystallography have shown ConA as a dimer or tetramer, because the complex formation requires specific crystallization conditions. Here, we reported the monomeric structure of ConA with a resolution of $1.6{\AA}$, which revealed that metal coordination could trigger sugar-binding ability. The calcium coordination residue, Asn14, changed the orientation of carbohydrate-binding residues and biophysical details, including structural information, providing valuable clues for the development and application of detection kits using ConA.

• BMB Reports
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• v.37 no.6
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• pp.663-670
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• 2004

ZNF 333 is a new and sole gene containing two KRAB domains which has been identified currently. It is a member of subfamilies of zinc finger gene complex which had been localized on chromosome 19p13.1. The ZNF333 gene mainly encodes a 75.5 kDa protein which contains 10 zinc finger domains. Using the methods of random oligonucleotide selection assay, electromobility gel shift assay and luciferase activity assay, we found that ZNF333 recognized the specific DNA core binding sequence ATAAT. Moreover, these data indicated that the KRAB domain of ZNF333 really has the ability of transcriptional repression.

• Proceedings of the Microbiological Society of Korea Conference
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• 2002.10a
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• pp.76-78
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• 2002

Heat shock proteins (HSPs) are induced in most living cells by mild heat treatment, ethanol, heavy metal ions and hypoxia. In yeast Saccharomyces cerevisiae, mild heat pretreatment strongly induces Hsp104 and thus provide acquired thermotolerance. The ability of hsp104 deleted mutant $({\triangle}hsp104)$ to acquire tolerance to extreme temperature is severely impaired. In providing thermotolerance, two ATP binding domains are indispensible, as demonstrated in ClpA and ClpB proteases of E. coli. The mechanisms by which Hsp104 protects cells from severe heat stress are not yet completely elucidated. We have investigated regulation of mitochondrial metabolic pathways controlled by the functional Hsp104 protein using $^{13}C_NMR$ spectroscopy and observed that the turnover rate of TCA cycle was enhanced in the absence of Hsp104. Production of ROS, which are toxic to kill cells radiply via oxidative stress, was also examined by fluorescence assay. Mitochondrial dysfunction was manifested in increased ROS levels and higher sensitivity for oxidative stress in the absence of Hsp104 protein expressed. Finally, we have identified mitochondrial complex I and Ferritin as binding protein(s) of Hsp104 by yeast two hybrid experiment. Based on these observations, we suggest that Hsp104 protein functions as a protector of oxidative stress via either keeping mitochondrial integrity, direct binding to mitochonrial components or regulating metal-catalyzed redox chemistry.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.1
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• pp.1-8
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• 1998

To investigate the influences on semen parameters and fertilizing capacity of immunoglobulin (Ig) isotypes and regional distribution of antisperm antibody (ASA) on the human sperm surface. Sixty-seven ASA-positive patients were compared with 96 ASA-negative donors. ASAs in semen showed significant negative effects on both semen parameters and fertilizing capacity; in those with ASAs in the sperm head and/or tail, the reductions were significant. In the head as well as the tail, there was close correlation between fertilizing capacity and both IgG and IgA. Both semen parameters and fertilizing capacity are significantly affected by the presence of ASA in semen. In particular, antibodies IgG to sperm head and/or tail, and antibodies IgA to sperm tail appeared to have a highly detrimental effect on fertilizing capacity.

• Bulletin of the Korean Chemical Society
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• v.14 no.6
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• pp.726-732
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• 1993

A comparative study on cadmium(II) complexation with three well characterized humic acids (SHA: soil humic acid from the Okchun Metamorphic Belt; AqHA: aquatic humic acid from Gorleben underground aquifer, Germany; CoHA: commercially available humic acid from the Aldrich Co.) was carried out in 0.1 M $NaClO_4$ at different solution pH(5.0, 5.5, and 6.0) using the ultrafiltration technique. The maximum binding ability (MBA) of the humic acids for cadmium(II) was observed to vary with their origins and solution pH. The results suggest that 1 : 1 complex predominates within the experimental range, and the conditional stability constants were calculated based on the assumption of cooperative binding, yielding log K values that were quite similar (CoHA: 4.17${\pm}$0.08; AqHA: 4.14${\pm}$0.07; SHA: $4.06{\pm} 0.12\;l\;mol^{-1}$ at pH 6.0) irrespective of humic acid origins or pH. By contrast a nonlinear Schatchard plot was obtained, using the cadmium(II) ion selective electrode speciation analysis method, which indicated that humic acid may have two or more classes of binding sites, with $log\;K_1\;and\;log\;K_2$ of 4.73${\pm}$ 0.08 and $3.31{\pm}0.14\;l\;mol^{-1}$ respectively.

• Bulletin of the Korean Chemical Society
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• v.21 no.4
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• pp.393-400
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• 2000

2,2￠-Dihydroxyazobenzene (DHAB) was attached to poly(ethylenimine) (PEI) to obtain DHAB-PEI. Spectral titration revealed that uranyl, Fe(III), Cu(II), and Zn(II) ion form 1 : 1-type complexes with DHAB attached to PEI. Formation constants for the metal complexes formed by the DHAB moieties of DHAB-PEI were mea-sured by using various competing ligands. The results indicated thatthe concentrations of uranyl, Fe(III), and Cu(II) ions can be reduced to 10 -16 -10 -23 M at p 8 with DHAB-PEI when the concentration of the DHAB moiety is 1 residue M. By using cyanuric chloride as the coupling reagent, DHAB-PEI was immobilized on Sephadex G-25 resin to obtain DHAB-PEI-Seph. Binding of uranyl,Fe(III), Cu(II), and Zn(II) ion by DHAB-PEI-Seph was characterized by using competing ligands. A new method has been developed for characteriza-tion of metal sequestering ability of a chelating resin. Formation constants and metal-binding capacity of two sets of binding sites on the resin were estimated for each metal ion. DHAB-PI-Seph was applied to recovery of metals such as uranium,Fe, Cu, Zn, Pb, V, Mn, and W from seawater. The uranium recovery from seawaterby DHAB-PEI-Seph does not meet the criterion for economical feasibility partlydue to interference by Fe and Zn ions. The seawater used in the experiment was contaminated by Fe and Zn and, therefore, the efficiency of uranium extractionfrom seawater with DHAB-PEI-Seph could be improved if the experiment is carried out in a cleaner sea.

• Bulletin of the Korean Chemical Society
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• v.26 no.12
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• pp.1911-1920
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• 2005

Effective artificial metalloproteases have been designed by using cross-linked polystyrene as the backbone. Artificial active sites comprising Cu(II) complexes as the catalytic site and other metal centers or organic functionalities as binding sites were synthesized. The activity of Cu(II) centers for peptide hydrolysis was greatly enhanced on attachment to polystyrene. By placing binding sites in proximity to the catalytic centers, the ability to hydrolyze a variety of protein substrates at selected cleavage sites was improved. Thus far, the most advanced immobile artificial proteases have been obtained by attaching the aldehyde group in proximity to the Cu(II) complex of cyclen.

• BMB Reports
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• v.33 no.4
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• pp.289-293
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• 2000

Annexin I is a 37 kDa member of the annexin family of calcium-dependent phospholipid binding proteins. Annexin I plays regulatory roles in various cellular processes including cell proliferation and differentiation. Recently we found that annexin I is a heat shock protein (HSP) and displays a chaperone-like function. In this paper we investigated the function of annexin I as an ATPase using 1 to 32 amino acids deleted annexin I (${\Delta}-annexin$ I). ${\Delta}-Annexin$ I hydrolyzed ATP as determined by thin layer chromatography. The ability of ATP hydrolysis was inhibited by ADP, GTP and GDP, but not by the AMP, GMP and cAMP. In view of the ATP hydrolyzing function of HSP, the results support the function of annexin I as a HSP.

• BMB Reports
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• v.32 no.1
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• pp.82-85
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• 1999

The movement protein of cucumber mosaic virus (CMV) is required for cell-to-cell movement of viral RNA. The movement of viral RNA occurs through the plant intercellular connection, the plasmodesmata. The viral movement protein was known to be multi-functional. In this work, a series of deletion mutants of CMV movement protein gene were created to identify the functional domains. The mutated movement proteins were produced as inclusion body in E. coli, and purified and renatured. A polyclonal antibody was raised against the CMV-Kor strain (Korean isolate) movement protein expressed in E. coli. The ability of the truncated proteins to bind to ssRNA was assayed by UV cross-linking and gel retardation analyses. The results indicate that the domain between amino acids 118 and 160 of CMV movement protein is essential for ssRNA binding.

• YAKHAK HOEJI
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• v.35 no.4
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• pp.326-331
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• 1991

Brain serotonin and its utilization was investigated on stressed rats after feeding high tryptophan diet for a month. High tryptophan fed rats displayed significantly higher level of serum tryptophan, brain tryptophan, serotonin (5-hydroxytryptamine; 5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) than the control diet fed rats. When rats were treated with 3 hour immobilization (IMMB) stress, serotonin turnover was slightly increased, but not statistically significant, in control diet group rats. However in high tryptophan diet rats, 3 hr IMMB stress resulted in statistically significantly (p<0.05) decreased the serum tryptophan, brain tryptophan and 5-HT level. The concentration of 5-HIAA was significantly increased indicating accelerated utilization of the brain 5-HT of the high trp. fed rat. The utilization pattern of the serotonin was found to be similar among young and adult rats. Rats on a tryptophan enriched diet displayed higher coping ability to the stress as they exhibited smaller increment of corticosterone level. A possble involvement of opioid system was suggested in serotonin utilization by measuring total $^{3}$[H]-naloxone binding in brain.