• Proceedings of the Korean Biophysical Society Conference
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• 2001.06a
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• pp.37-37
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• 2001

Cyclic nucleotide-gated (CNG) channels are composed of homo or hetero tetramer of ${\alpha}$ and ${\beta}$ subunits. The a subunits of these channels have a conserved glutamate residue within the pore-forming region. This residue determines the selectivity as well as the affinity for the extracellular divalent cations. Using the high affinity mutant (E363D) of bovine retinal CNG channel in which the Glu was replaced to Asp at position 363, we constructed tandem dimers and investigated the binding symmetry of divalent cation to the site.(omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.83.1-83.1
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• 2003

The heterotrimeric G protein subunits (G ) are region-specifically expressed in brain such as hypothalamus and pituitary gland in abundant, suggesting that is may be associated with “stress-axis”. This study was designed to examine the effect of stress on the region-specific expression of various G subunits in rat brain. The localization of mRNAs encoding seven of G and striking region-specific patterns of expression were observed in 12 different regions of both non-stressed and stressed rat brain; (1) frontal cortex area, (2) cerebral cortex area, (3) striatum, (4) hippocampus area, (5) thalamus, (6) brain stem, (7) cerebellum area, (8) hypothalamus, (9) septum, (10) amygdala, (11) preoptic area, and (12) pituitary gland. (omitted)

• Journal of Microbiology and Biotechnology
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• v.8 no.3
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• pp.258-263
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• 1998

${\beta}$-Xylosidase was purified from the recombinant Escherichia coli carrying the Bacillus sp. KK-1 ${\beta}$-xylosidase gene (xylB). The molecular mass of the purified enzyme was estimated to be 62 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. However, the apparent molecular mass of the ${\beta}$-xylosidase was 140 kDa, indicating that the native ${\beta}$-xylosidase has an oligomeric structure composed of two identical subunits. The isoelectric point was determined to be pH 5.5. The enzyme was highly active on p-nitrophenyl-$\beta$-D-xylopyranoside but it barely hydrolyzed xylan substrates, and did not exhibit activity towards carboxymethylcellulose and p-nitrophenyl-${\beta}$-D- glucopyranoside. The enzyme had a pH optimum for its activity at pH 6.5 and a temperature optimum at $40^{\circ}C$. The enzyme activity was completely inhibited by the presence of $Hg^{++}$, and also markedly inhibited by D-xylose and D-glucose.

• Microbiology and Biotechnology Letters
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• v.13 no.3
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• pp.185-189
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• 1985

Extracellular $\beta$-galactosidase from the culture broth of L. sporogenes was purified to apparent homogeniety by procedures including ammonium sulfate fractionation, Sephadex G-200 gel filtration, DEAE-Sephadex A-50 ion exchange chromatography, and Hydroxyapatite adsorption chromatography. The purifying procedures resulted in 347-fold purification with the overall yield of 39.5％ The purified enzyme had a specific activity(using ONPG as a substrate) of about 1, 585 units per mg protein. The molecular weight of the enzyme protein was estimated to be 140, 000 by gel filtration on Sephadex G-200, and SDS-polyacrylamide gel electorphoresis showed that the enzyme consisted of two identical subunits with a molecular weight of 72, 000.

• Korean Journal of Animal Reproduction
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• v.27 no.3
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• pp.197-206
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• 2003

hFSH (human follicle stimulating hormone) is heterodimer consisting of $\alpha$ and $\beta$ subunits. Since assembly of the both subunits in the cell is often the rate-limiting step in production of functional hormone, single-chain hormones have been engineered by genetically linking two different cDNA fragments with a linker sequence. Using retrovirus vector system, the resulting recombinant hFSH gene was transferred in CHO cells and chicken embryos, and the expression of the gene was investigated. In CHO cells, protein synthesis from the single-chain FSH gene was 17 fold higher than that from the heterodimeric counterpart. In the study of transgenic chickens, ten of the eleven chicks hatched from 62 embryos manupulated with recombinant retrovirus stock was determined to carry transgenic genes. RT-PCR analyses confirmed transcription of the single-chain FSH gene, however, no recombinant FSH was detected from the blood samples.

• Molecules and Cells
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• v.19 no.2
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• pp.219-222
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• 2005

The a-subunit of Escherichia coli tryptophan synthase (${\alpha}TS$), a component of the tryptophan synthase ${\alpha}_2{\beta}_2$ complex, is a monomeric 268-residues protein (Mr = 28,600). ${\alpha}TS$ by itself catalyzes the cleavage of indole-3-glycerol phosphate to glyceraldehyde-3-phosphate and indole, which is converted to tryptophan in tryptophan biosynthesis. Wild-type and P28L/Y173F double mutant ${\alpha}$-subunits were overexpressed in E. coli and crystallized at 298 K by the hanging-drop vapor-diffusion method. X-ray diffraction data were collected to $2.5{\AA}$ resolution from the wild-type crystals and to $1.8{\AA}$ from the crystals of the double mutant, since the latter produced better quality diffraction data. The wild-type crystals belonged to the monoclinic space group C2 ($a=155.64{\AA}$, $b=44.54{\AA}$, $c=71.53{\AA}$ and ${\beta}=96.39^{\circ}$) and the P28L/Y173F crystals to the monoclinic space group $P2_1$ ($a=71.09{\AA}$, b=52.70, $c=71.52{\AA}$ and ${\beta}=91.49^{\circ}$). The asymmetric unit of both structures contained two molecules of ${\alpha}TS$. Crystal volume per protein mass ($V_m$) and solvent content were $2.15{\AA}^3\;Da^{-1}$ and 42.95% for the wild-type and $2.34{\AA}^3\;Da^{-1}$ and 47.52% for the double mutant.

• Journal of Microbiology and Biotechnology
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• v.24 no.6
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• pp.788-794
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• 2014

An extracellular ${\beta}$-glucosidase from Aspergillus niger Au0847 was purified to homogeneity by precipitation with ammonium sulfate, anion exchange, and gel filtration. The purified protein was composed of two subunits with molecular masses of 110 and 120 kDa. Au0847 ${\beta}$-glucosidase exhibited relatively high thermostability and pH stability, and its highest activity was obtained at $65^{\circ}C$ and pH 4.6, respectively. As a potential metalloprotein, its enzymatic activity was potently stimulated by manganese ion and DTT. The ${\beta}$-glucosidase displayed avid affinity and high catalytic efficiency for geniposide. Au0847 ${\beta}$-glucosidase has potential value as an industrial enzyme for the hydrolysis of geniposide to genipin.

• Journal of Photoscience
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• v.11 no.3
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• pp.121-127
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• 2004

The${\beta}$-glucosidases occur widely in all living organisms and has in general a tendency to form oligomers of varying numbers of subunits or aggregates, although the functional implications of such diverse oligomerization schemes remain unclear. In particular, the assembly mode of the oat ${\beta}$-glucosidase is very unique in that it multimerizes by linear stacking of a hexameric building block to form long fibrillar multimers. Some structural proteins such as actin and tubulin assemble into long fibrils in a helical fashion and several enzymes such as GroEL and Pyrodictium ATPase functional complexes, 20S proteasome of the archaebacterium Thermoplasma acidophilum, and lutamine synthetase fromblue-green algae, assemble into discrete oligomers upto 4 stacked rings to maintain their enzymatic activities. In particular, oat ${\beta}$-glucosidase exists in vivo as a discrete long fibrillar multimer assembly that is a novel structure for enzyme protein. It is assembled by linear stacking of hollow trimeric units. The fibril has a long central tunnel connecting to the outer medium via regularly distributed side fenestrations. The enzyme active sites are located within the central tunnel and multimerization increases enzyme affinity to the substrates and catalytic efficiency of the enzyme. Although it is suggested that oligomerization may contribute to the enzyme stability and catalytic efficiency of ${\beta}$-glycosidases, the functional implications of such diverse oligomerization schemes remain unclear so far.

• Proceedings of the KSAR Conference
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• 2003.06a
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• pp.31-31
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• 2003

The incidence of reproductive abnormalities in the male has been reported to have increased during the past 50 years. These changes may be attributable to the presence of chemical with oestrogenic activity in our environment. Present study was carried out to determine the effects of maternal exposure to xenoestrogens on the testicular development and on the transcriptional expression of the steroidogenic enzyme and subunits of inhibin/activin in testis of male offspring. Pregnant female mice were administrated with 4-tert-octylphenol (OP; 2, 20, 200mg/kg), Bisphenol A (BPA; 2, 20, 200$\mu\textrm{g}$/kg), $\beta$-estradiol 17-valerate (EV; 2$\mu\textrm{g}$/kg) or vehicle (CV; corn oil) during gestational days 11 to 17. Offsprings were sacrificed on gestational day 18 (fetal 18) and neonatal day 7. Body weights were significantly increased in groups treated with all doses of OP and BPA. Maximum seminiferous tubules diameter on gestational day 18 were not changed in any treatment group, however, they were significantly increased on the neonatal day 7 in the group treated with low-dose of OP (2 mg/kg) and BPA (2 $\mu\textrm{g}$/kg). Increased expression of the P450$_{17a}$-hydroxylase dehydrogenase (P450$_{17a}$), 3$\beta$-hydroxylase dehydrogenase (3$\beta$-HSD), and 17$\beta$-hydroxylase dehydrogenase (17$\beta$-HSD) on gestational day 18 were observed in the groups treated with 2 or 20 mg/kg of OP. However, expression of the steroidogenic enzymes were not changed in the groups treated with all the doses of BPA. In contrast with the results from fetal testis, no expressional changes of these enzymes was found in all the OP-treated group and increased expression of inhibin/activin $\beta$B subunit mRNA were obseued in the 200 $\mu\textrm{g}$/kg BPA-treated group in the neonatal day 7. These results suggest that gestational exposure to low level of xenoestrogen causes a stimulatory effects on the transcriptional expressions of steroidogenic enzymes and subunits of inhibin/activin and on the seminiferous tubule development by their estrogen-like actions.ons.

• Animal cells and systems
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• v.16 no.2
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• pp.127-134
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• 2012

We investigated the effects of fadrozol, an aromatase inhibitor (AI), and $17{\alpha}$-methyltestosterone (MT) on the induction of sex change in juvenile longtooth grouper $Epinephelus$ $bruneus$, via histological observation of gonads. Changes in the mRNA expression of GtH subunits (FSH-${\beta}$ and LH-${\beta}$) in the pituitary, and estradiol-$17{\beta}$ (E2) and 11-ketotestosterone (11-KT) levels in the blood were also surveyed after AI and MT treatment. Juvenile longtooth groupers ($113{\pm}17g\;body\;weight$; $16.2{\pm}1.2cm\;body\;length$) received intramuscular injections of AI at 3 (3-AI) and 5 (5-AI) mg/kg BWdoses and MT at a 5 mg/kg BW (5-MT) dose. At week 7 post-injection, 3-AI and 5-MT oocytes were degenerated, and gonads of the 5-AI group initiated spermatogenesis. At week 21 post-injection, 3-AI- and 5-MT-treated gonads contained spermatogonia and spermatocytes, while 5-AI treatment induced advanced stages of spermatogenesis. The serum E2 level showed no significant differences throughout the experimental period, whereas that of 11-KT was significantly elevated in the 5-AI group at weeks 7 and 21 post-injection. A significant increase in the expression of FSH-${\beta}$ mRNA was evident in the 5-AI group at week 21 post-injection. In contrast, LH-${\beta}$ mRNA expression did not significantly differ among groups during the experimental period. These results imply that sex change has two stages in the longtooth grouper. In the first stage, oocytes are degenerated by the stimulation by 11-KT, and in the second stage spermatogenesis occurs, owing to the co-effects of 11-KT and FSH-${\beta}$.