• BMB Reports
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• v.34 no.4
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• pp.371-378
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• 2001

The Glycoprotein D (gD) gene of the HSV-1 strain F was cloned, sequenced, recombinated into the HcNPV (Hyphantria cunea nuclear polyhedrosis virus) expression vector and expressed in insect cells. The gD gene was located in the 6.43 kb BamHI fragment of the strainF. The open reading frame (ORF) of the gD gene was 1,185 by and codes 394 amino acid residues. Recombinant baculoviruses, GD-HcNPVs, expressing the gD protein were constructed. Spodoptera frugiperda cells, infected with the recombinant virus, synthesized a matured gX-gD fusion protein with an approximate molecular weight of 54 kDa and secreted the gD proteins into the culture media by an immunoprecipitation assay The fusion gD protein was localized on the membrane of the insect cells, seen by using an immunofluorescence assay The deduced amino acid sequence presents additional characteristics compatible with the structure of a viral glycoprotein: signal peptide, putative glycosylation sites and a long C-terminal transmembrane sequence. These results indicate the utility of the HcNPV-insect cell system for producing and characterizing eukaryotic proteins.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.10
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• pp.1164-1170
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• 2017

Protaetia brevitarsis larvae (PBL) has recently been registered as a temporary food in Korea, and this study evaluated the application potential of PBL proteins as health functional food materials. Protein hydrolysates were prepared from PBL powder by enzymatic hydrolysis using five different proteases (alcalase, bromelain, flavourzyme, neutrase, and papain), and based on the results from the peptide content and SDS-PAGE analyses, PBL treated with alcalase or flavourzyme showed a high degree of hydrolysis (HD) value, whereas the HD value of those treated with neutrase, bromelain, or papain was minimal. The protein hydrolysates showing a high HD value were separated further into the fractions of >3 kDa and <3 kDa by a centrifugal filter system and then lyophilized, and according to the $RC_{50}$ values of the protein hydrolysates (<3 kDa) obtained from three different antioxidant analyses; the alcalase hydrolysates showed the highest antioxidant activity. Therefore, the alcalase hydrolysates were tested further for their inhibitory effects on the peroxidation of linoleic acid by measuring the thiobarbituric acid values. The results showed that the peroxidation of untreated linoleic acid increased dramatically during 6 days of incubation, but a pretreatment with the hydrolysates ($100{\sim}800{\mu}g/mL$) significantly inhibited the linoleic acid peroxidation in a dose-dependent manner for 6 days. Our current studies are focused on the identification of active peptide sequences from alcalase hydrolysates.

• Korean Journal of Veterinary Research
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• v.43 no.1
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• pp.129-137
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• 2003

Porcine reproductive and respiratory syndrome (PRRS) is characterized by reproductive failures in sows and respiratory problems in piglets. The nucleocapsid(N) protein, encoded by the open reading frame 7 (ORF7) gene, is known to be the most abundant and antigenic protein in PRRS virus. Therefore, it was suggested that the N protein could be a suitable candidate for the detection of PRRS virus-specific antibodies and diagnosis of PRRS. In the present study, the ORF7 gene encoding the N protein was cloned and expressed as a fusion protein with the glutathione S-transferase (GST) in Escherichia coli. The resulting GST-N recombinant protein was used as an antigen for an indirect sandwich enzyme-linked immunosorbent assay (i-ELISA). Expressed GST-N recombinant protein was migrated at 41 kDa and reacted with ORF7-specific monoclonal antibody by Western blotting. In order to increase the specificity of the ELISA for the detection of PRRS virus-specific antibodes, an i-ELISA was developed using an anti-GST antibody as a capture antibody. The sensitivity and specificity of developed i-ELISA were 92% and 96%, respectively. Based on these results, it was suggested that the i-ELISA is a simple and rapid test for screening a large number of swine sera for the anti-PRRS virus antibodies.

• Korean Journal Plant Pathology
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• v.10 no.3
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• pp.215-221
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• 1994

Polygalacturonase (PG) produced by Botrytis cinerea in the culture broth containing citrus pectin as a carbon source was partially purified and characterized. PG was produced on a range of carbon sources such as starch, glycerol, cellobiose, and Na+-PAG with total activities of 34.8, 32.0, 29.2, 27.8 units, respectively. The specific activity was highest with 2316.7 units on Na+-PGA. Proteins of culture filtrate were concentrated with polyethylene glycol and acetone and applied to a hydroxyapatite column. Among three active fractions collected from the column, the reaction containing the highest PG activity was resolved by a Q-sepharose column. The active fraction from the Q-sepharose column was further purified by HPLC Mono Q column. The partially purified enzyme was analyzed by 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Among a few protein bands revealed, the amount of the protein of which molecular weight estimated to be 43 kDa coincided with the PG activity. The partially purified PG had optimal temperatures between 35~55$^{\circ}C$ and pH between 4.5~5.5.

• Journal of Microbiology and Biotechnology
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• v.23 no.2
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• pp.144-148
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• 2013

Lycopene cyclase converts lycopene to ${\beta}$-carotene by catalyzing the formation of two beta-rings at each end of the linear carotene structure. This reaction takes place as a two-step reaction in which both sides of of the lycopene molecule are cyclized into ${\beta}$-carotene rings via the monocyclic ${\gamma}$-carotene as an intermediate. The crtY gene coding for lycopene cyclase from Paracoccus haeundaensis consists of 1,158 base pairs encoding 386 amino acids residues. An expression plasmid containing the crtY gene (pET44a-CrtY) was constructed and expressed in Escherichia coli, and produced a recombinant protein of approximately 43 kDa, corresponding to the molecular mass of lycopene cyclase. The expressed protein was purified to homogeneity by His-tag affinity chromatography and showed enzymatic activity corresponding to lycopene cyclase. We also determined the lycopene substrate specificity and NADPH cofactor requirements of the purified protein. The $K_m$ values for lycopene and NADPH were 3.5 ${\mu}M$ and 2 mM, respectively. The results obtained from this study will provide a wider base of knowledge on the enzyme characterization of lycopene cyclase at the molecular level.

• Journal of Life Science
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• v.18 no.7
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• pp.931-939
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• 2008

The purpose of this study was to determine the effect of energy supplement on responses of plasma insulin-like growth factor (IGF)-1 and IGF binding proteins (IGFBPs) to growth hormone-releasing peptide-2 (GHRP-2) administration in normal protein-fed wethers, and to observe the effect of GHRP-2 treatment on hepatic growth hormone (GH) receptor in well-fed wethers. Plasma IGF-1 and 39-42 kDa IGFBP-3 during the HENP (CP, crude protein 0.34 and TDN, total digestible nutrients 1.83 kg/day DM, dry matter intake) treatment period were higher than in the LENP (CP 0.32 kg and TDN 0.87 kg/day DM intake) period (P<0.05). The response of GH was stimulated by GHRP-2 ($12.5\;{\mu}g/kg$ body weight/day) administration during both of the feed treatment periods (P<0.05). The area under curve (AUC) increment and average concentration of GH (0-180 min) with GHRP-2 administration was higher during HENP treatment than LENP treatment (P<0.01). During the HENP treatment period from day 1 to day 7 of twice daily GHRP-2 treatment, the plasma IGF-1 increment was increased on days 2, 6 and 7 of GHRP-2 administration (P<0.05). On the basis of ligand blotting, the proportions of plasma 39-43 kDa IGFBP-3 during the HENP treatment period only showed a significant difference on days 6 and 7 with GHRP-2 administration. No significant difference in the specific binding of $^{125}I-labeled$ oGH to hepatic membranes was detected between the saline and GHRP-2 treatments of the HENP-fed wethers. These results suggest that the nutritional balance between energy and protein may affect the endogenous GH / IGF-1 axis as well as plasma IGFBP-3 levels.

• Parasites, Hosts and Diseases
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• v.39 no.1
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• pp.67-76
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• 2001

This experiment was focused on the characterization of anti- Toxoplasma monoclonal antibodies (mAbs) and the effect of mAbs on the parasite invasion of mouse peritoneal macrophages. Twenty eight mAbs including M110, M556, R7A6 and M62l were characterized by Ab titer, immunoglobulin isotyping and western blot pattern. Antibody titer (optical density) of 4 mAbs. Ml 10. M556. R7A6 and M62l. were 0.53,0.67, 0.45 and 0.39 (normal mouse serum; 0.19) with the same IgGl isotypes shown by Enzyme-linked immunosorbent assay (ELISA). Western blot analysis showed that Ml 10. M556. R7A6 and M62l reacted with the 33 kDa (p30),31 kDa (p28),43 kDa and 36 kDa protein. Immuno-gold labelling of mAbs M110, M556, R7A6 and M621 reacted with the surface membrane, dense granules and parasitophorous vacuolar membrane (PVM) , rhoptries and cytoplasm of tachyzoite, respectively. For in vitro assay, preincubation of tachyzoties with four mAbs, Ml 10, M556, R7A6 and M62l resulted in the decrease of the number of infected macrophages (p < 0.05) and the suppression of parasite multiplication at 18 h post-infection. Four monoclonal antibodies including Ml 10 (SAGI) were found to have an important role in the inhibition of macrophage invasion and T. gondii multiplication in vitro, and these mAbs may be suitable for vaccine candidates, diagnostic kit and for chemotherapy.

• Animal cells and systems
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• v.6 no.4
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• pp.341-347
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• 2002

The life cycle of Acanthamoeba is comprised of two distinct stages, tropho-zoite and cyst. During periods of stress, trophozoites undergo cellular differentiation into cyst. In order to understand the cellular differentiation, ore followed changes in profiles of major proteins by 2D-PAGE and ubiqui-tinated proteins by immunoblotting with anti-ubiquitin (Ub) monoclonal antibody (mAb) as a probe. We observed 51 proteins present in trophozoite were lost with the encystment. We found that 43 proteins within 24 h, and 8 proteins in 96 h of encystment. Among them, 17 proteins were staine with anti-Ub mAb. In cysts, 16 proteins including 2 anti-Ub mAb-reactive proteins were newly synthesized. Four proteins were newly detected in 24 h-cyst and disappeared in 96 h-cyst, one protein was synthesized in 24-96 h-cyst and disappeared in 168 h-cyst, and 11 proteins appeared upon en-cystment and were present in all cyst stages. We identified a cyst specific 33 kDa protein as subtilisin-like serine proteinase by N-terminal sequencing. Identification of these proteins lost and newly synthesized with encystment would improve our understanding of cysting protozoan parasites.

• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.773-779
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• 2002

A gene (hap) encoding aminopeptidase from the chromosomal DNA of Bacillus licheniformis was cloned. The gene is 1,347 bp long and encodes a 449 amino acid preproprotein with a major mature region of 401 amino acids (calculated molecular mass 43,241 Da). N-Terminal sequence of the purified protein revealed a potential presence of N-terminal propeptide. The deduced primary amino acid sequence and the mass analysis of the purified protein suggested that a C-terminal peptide YSSVAQ was also cleaved off by a possible endogeneous protease. Tho amino acid sequence displayed 58% identity with that of the aminopeptidase from alkaliphilic Bacillus halodurans. This bacterial enzyme was overexpressed in recombinant Escherichia coli and Bacillus subtilis cells. Clones containing the intact hap gene, including its own promoter and signal sequence, gave rise to the synthesis of extracellular and thrmostable enzyme by B. subtilis transformants. The secreted protein exhibited the same biochemical properties and the similar apparent molecular mass as the B. lichenzyormis original enzyme.

• BMB Reports
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• v.43 no.6
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• pp.427-431
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• 2010

Cyt2Aa2 is a mosquito-larvicidal protein produced as a 29 kDa crystalline protoxin from Bacillus thuringiensis subsp. darmstadiensis. To become an active toxin, proteolytic processing is required to remove amino acids from its N- and C-termini. This study aims to investigate the functional role of amino acid residues on the N-terminal ${\beta}1$ and C-terminal ${\alpha}F$ of Cyt2Aa2 protoxin. Mutant protoxins were constructed, characterized and compared to the wild type Cyt2Aa2. Protein expression data and SDS-PAGE analysis revealed that substitution at leucine-33 (L33) of ${\beta}1$ has a critical effect on dimer formation and structural stability against proteases. In addition, amino acids N230 and I233-F237 around the C-terminus ${\alpha}F$ demonstrated a crucial role in protecting the protoxin from proteolytic digestion. These results suggested that ${\beta}1$ and ${\alpha}F$ on the Nand C-terminal ends of Cyt2Aa2 protoxin play an important role in the molecular interaction and in maintaining the structural stability of the protoxin.