• The Korean Journal of Food And Nutrition
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• v.15 no.2
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• pp.104-111
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• 2002

The peptidyl prolyl sis-trans isomerase (PPIase, EC 5.2.1.8) from bacillus stearothermophilus was extracted from the cells treated with by lysozyme. PPIase was purified from the cell extracts by heat treatment, ammonium sulfate precipitation, ion exchange chromatography and finally gel filtration, sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE). The molecular weight of the purified PPIase was estimated as 18kDa by SDS-PAGE. The 39 amino acid residues from the N-terminus were determined by the protein sequencer. The enzyme showed the optimum pH at 8.0 and was stable at the range of pH 7.0∼8.0. The enzyme was considerably stable after heat treatment at 60$\^{C}$ for 30minutes, and the enzyme was quite stable up to 65$\^{C}$. The presence of the PPIase in the refolding solution accelerated the isomerization rate of the assay peptide. PPIase gene of Bacillus stearothermophilus was screened from a genomic library by plaque hybridization using the A-l primer as a probe. A PPIase positive plaque contained a 3.0kb insert of the chromosomal DNA. A 3.0kb fragment was subcloned into pUC18, resulting pPI-40. A DNA fragment encoding the N-terminal portion of the PPIase in pPI-40 was amplified by polymerase chain reaction(PCR) method using the A-1 and B-2 primers. The amplified fragment was cloned into the Sma I site of pUC18 and recombinant plasmid was designated as pSN-18. The nucleotide sequence of 167bp fragment was determined. The deduced amino acid sequence of PPIase was completely matched with the determined N-terminal amino acid sequence of PPIase B. stearothermophilus.

• IMMUNE NETWORK
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• v.3 no.3
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• pp.219-226
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• 2003

Background: Phage display is the most widely used technique among display methods to produce monoclonal antibody fragment with a specific binding activity. Having a large library for efficient antibody display/selection is quite laborious process to have more than $10^9$ members of transformants. To overcome these limitations, several in vitro selection approaches have been reported. Ribosome display that links phenotypes, proteins, directly to genotype, mRNA, is one of the in vitro display methods. Ribosome display can reach the size of scFv library up to $10^{14}$ molecules and it can be further diversified during PCR steps. To select the high affinity scFv from one pot library, we established ribosome display technique by modifying the previously reported eukaryotic translation system. Methods: To establish the antibody selection system by ribosome display, we used 3D8, anti-DNA antibody. A 3D8 scFv was synthesized in vitro by an in vitro transcription-translation system. The translated 3D8 scFv and the encoding 3D8 mRNA are connected to the ribosome. These scFv-ribosome-mRNA complexes were selected by binding to their specific antigens. The eluted mRNAs from the complexes are reverse transcribed and re-amplified by PCR. To apply this system, antibody library from immunized mouse with terminal protein (TP)-peptide of hepatitis B virus DNA polymerase TP domain was also used. This TP-peptide encompasses the 57~80 amino acid residues of TP. These mRNA/ribosome/scFv complexes by our system were panned three times against TP-peptide. The enrichment of antibody from library was determined by radioimmunoassay. Results: We specifically selected 3D8, anti-DNA antibody, against ssDNA as a model system. The selected 3D8 RNAs sequences from translation complexes were recovered by RT-PCR. By applying this model system, we enriched TP-peptide-specific scFv pools through three cycles of panning from immunized library. Conclusion: We show that our translating ribosome complexes are well maintained and we can enrich the TP-specific scFv pools. This system can be applied to select specific antibody from an antibody library.

• Korean Journal of Agricultural Science
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• v.25 no.1
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• pp.52-67
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• 1998

The investigative research on the mammalian milk purely consisted of the physiological quality of lactoferrin was conducted to reveal the antimicrobial ativity of specifically functional foods with antibiotic characteristics as a basic data in food manufacturing. Bovine lactoferrin were isolated from raw milk samples, and was digested with pepsin, trypsin and chymotrypsin. It was necessary then to separate and purify lactoferrin from bovine raw milk, and in order to analyze the antimicrobial activity of the enzyme-treated bovine lactoferrin in their required quantitative fraction. Afterwards Escherichia coli and Staphylococcus aureus was incubated in it. It was that investigated to enzyme-treated fractions molecular weight and the peptide fragment with antimicrobial effect. 1. The purity of enzyme-treated bovine lactoferrin(BLF) was tested by SDS-PAGE. As a results of 12% SDS-PAGE assay, pepsin-treated LF did not exhibited band until if reaches 14 KDa, while trypsin and chymotrypsin treated LF, known to contain the non-digestive lactoferrin exhibited band at a molecular weight of 33 KDa. 2. Bovine lactoferrin was sucessfully purified through the use of Sephadex G-50 Column. In order to assay LF through the Sephadex G-50 column chromatography, the digestive bovine lactoferrin (BLFs) was eluted with a linear gradient of 0.05% Tris-HCl. When the gel-filtration analysis, pepsin, trypsin and chymotrypsin treatments of BLF fragments was showed 2, 3, and 2 peak, respectively. The results of the HPLC analysis confirmed that had a non-digestive lactoferrin receptor, and trypsin and chymotrypsin treated BLFs has an antimicrobial effect. 3. To measure the strength of the antimicrobial effect of enzyme treated lactoferrin it was compared to the antimicrobial activity taking place at the incubated Escherichia coli and Staphylococcus aureus. This might explain the resistance of the microorganisms for peptide fragment. The pepsin-treated of bovine lactoferrin was markedly reduced by incubation of the cells. Trypsin-treated of BLF was similar to chymotrypsin-treated of BLF. However, trypsin and chymotrypsin treatments of BLFs were showed the antimicrobial effect until eight hours incubation for native bovine lactoferrin. Therefore the enzyme-treated lactoferrin have an antimicrobial effect even non-digestive lactoferrin. 4. The digestive bovine lactoferrin fragments assay was carried out by the use of Sephadex G-50 column chromatography and SDS-PAGE. The pepsin and chymotrypsin-treated fragments has a low molecular weight and trypsin-treated lactoferrin was only showed a band. It was described that characteristics of digestive protein. It appeared that there may be a relation between virulence and resistance to enzyme-treated BLF.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.12
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• pp.1691-1695
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• 2005

The bovine lymphocyte antigen (BoLA)-DRB3 gene encodes cell surface glycoproteins that initiate immune responses by presenting processed antigenic peptides to CD4 T helper cells. DRB3 is the most polymorphic bovine MHC class II gene which encodes the peptide-binding groove. Since different alleles favour the binding of different peptides, DRB3 has been extensively evaluated as a candidate marker for associations with various bovine diseases and immunological traits. For that reason, the genetic diversity of the bovine class II DRB3 locus was investigated by polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP). This study describes genetic variability in the BoLA-DRB3 in Iranian Golpayegani Cattle. Iranian Golpayegani Cows (n = 50) were genotyped for bovine lymphocyte antigen (BoLA)-DRB3.2 allele by polymerase chain reaction and restriction fragment length polymorphism method. Bovine DNA was isolated from aliquots of whole blood. A two-step polymerase chain reaction followed by digestion with restriction endonucleases RsaI, HaeIII and BstYI was conducted on the DNA from Iranian Golpayegani Cattle. In the Iranian Golpayegani herd studied, we identified 19 alleles.DRB3.2${\times}$16 had the highest allelic frequency (14%), followed by DRB3.2${\times}$7 (11%). Six alleles (DRB3.2${\times}$25, ${\times}$24, ${\times}$22, ${\times}$20, ${\times}$15, ${\times}$3) had frequencies = 2%. Although additional studies are required to confirm the present findings, our results indicate that exon 2 of the BoLA-DRB3 gene is highly polymorphic in Iranian Golpayegani Cattle.

• Bulletin of the Korean Chemical Society
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• v.27 no.7
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• pp.1001-1004
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• 2006

The m-calpain activity hydrolyzing a fluorogenic substrate of N-Succinyl-Leu-Leu-Val-Tyr-7-amino-4-methylcourmarin (LLVY-AMC) was significantly stimulated by more than two-fold in the presence of 5$\mu$M $\alpha$synuclein at $15{^{\circ}C}$. The stimulation was also confirmed with azocasein. The stimulation of the peptide hydrolyzing activity required structural intactness of $\alpha$-synuclein since the C-terminally or N-terminally modified proteins such as $\beta$-synuclein, $\alpha$-syn1-97, and $\alpha$-syn61-140 did not increase the proteolytic activity. Instead, however, the N-terminally truncated $\alpha$-syn61-140 was shown to drastically suppress the calpain activity. Since the N-terminal truncation was known to be the primary cleaving event of calpain-mediated proteolysis of $\alpha$-synuclein and the $\alpha$-syn61-140 has been demonstrated to be resistant against the calpain digestion, it has been proposed that the intracellular calpain activity could be regulated in a reciprocal manner by $\alpha$-synuclein and its proteolyzed C-terminal fragment. Based on the results, a possible physiological function of $\alpha$-synuclein has been suggested as a calpain regulator which contains both stimulatory and inhibitory activities.

• Journal of Microbiology and Biotechnology
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• v.21 no.5
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• pp.529-535
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• 2011

Single-chain variable fragment (scFv) is a fusion protein of the variable regions of the heavy (VH) and light (VL) chains of immunoglobulin, connected with a short linker peptide of 10 to about 20 amino acids. In this study, the scFv of a monoclonal antibody against the third domain of human CD4 was cloned from OKT4 hybridoma cells using the phage display technique and produced in E. coli. The expression, production, and purification of anti-CD4 scFv were tested using SDS-PAGE and Western blot, and the specificity of anti-CD4 scFv was examined using ELISA. A 31 kDa recombinant anti-CD4 scFv was expressed and produced in bacteria, which was confirmed by SDS-PAGE and Western blot assays. Sequence analysis proved the ScFv structure of the construct. It was able to bind to CD4 in quality ELISA assay. The canonical structure of anti-CD4 scFv antibody was obtained using the SWISS_MODEL bioinformatics tool for comparing with the scFv general structure. To the best of our knowledge, this is the first report for generating scFv against human CD4 antigen. Engineered anti-CD4 scFv could be used in immunological studies, including fluorochrome conjugation, bispecific antibody production, bifunctional protein synthesis, and other genetic engineering manipulations. Since the binding site of our product is domain 3 (D3) of the CD4 molecule and different from the CD4 immunological main domain, including D1 and D2, further studies are needed to evaluate the anti-CD4 scFv potential for diagnostic and therapeutic applications.

• The KIPS Transactions:PartD
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• v.10D no.2
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• pp.261-266
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• 2003

A protein, which is a linear polymer of amino acids, is one of the most important bio-molecules composing biological structures and regulating bio-chemical reactions. Since the characteristics and functions of proteins are determined by their amino acid sequences in principle, protein sequence determination is the starting point of protein function study. This paper proposes a protein sequence prediction method based on data mining techniques, which can overcome the limitation of previous bio-chemical sequencing methods. After applying multiple proteases to acquire overlapped protein fragments, we can identify candidate fragment sequences by comparing fragment mass values with peptide databases. We propose a method to construct multi-partite graph and search maximal paths to determine the protein sequence by assembling proper candidate sequences. In addition, experimental results based on the SWISS-PROT database showing the validity of the proposed method is presented.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.6
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• pp.474-484
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• 1992

The stock identification of small yellow croaker. Pseudosciaena Polyactis from Mokpo area was carried out using molecular biological methods such as mt-DNA restriction fragment length polymorphism(RFLP) and the N-terminal fragment polymorphism of muscle actin obtained after protease digestion. The entire mt-DNA genomic size from the small yellow croaker at Mokpo area was estimated to be about $16\pm0.2$ Kb. Furthermore, fourteen restriction endonucleases revealed a total of 37 restriction sites to the mt-DNA molecule, however, eight of the fourteen enzymes showed a significant restriction site variation. Six of the enzymes examined produced a single restriction profile for all individuals surveyed, indicating that they don't react on the same mt-DNA obtained from small yellow croaker. The Staphylococcus aureus $V_8$ protease is able to cleave the muscle actin of small yellow croaker and to yield a N-terminal peptide of 26 and 16 KDa, respectively.

• Korean Journal of Agricultural Science
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• v.28 no.2
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• pp.92-98
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• 2001

Lactofenicin is an antibacterial peptide fragment (about 5 kD) derived from lactoferrin (80 kD) that displays the various biological functions. The production of a human lactoferricin (Lactoferricin H) in mouse HC11 mammary epithelial cells was achieved by placing its cDNA under the control of the bovine ${\beta}$-casein gene. To express lactoferricin H in this cell culture system, constructed a hybride-splice signal consisting of bovine ${\beta}$-casein intron I and rabbit ${\beta}$-globin intron II, and a DNA fragment spanning intron 8 of the bovine ${\beta}$-casein gene. Expression of lactofenicin H from this expression vector was identified by RT-PCR, northern and dot blot analysis. RT-PCR using total RNA of HC11 cells transfected with pBL1-cin expression vector yielded a product identified as having a size of the 150bp. Northern blot analysis was identified about 2.3 kb. In dot blot analysis, recombinant lactofenicin H was recognized with anti-human lactofrrnin polyclonal antibody.

• Journal of Life Science
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• v.15 no.5 s.72
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• pp.734-738
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• 2005

A gene coding for xylanase from alkali-tolerant Bacillus alcalophilus AX2000 was cloned into Escherichia coli $DH5\alpha$ using pUC19. Among 2,000 transformants, one transformant showed clear zone on the detection agar plate containing oat-spells xylan. Its recombinant plasmid, named pXTY99, was found to carry 7.0 kb insert DNA fragment. When the nucleotide sequence of the cloned xylanase gene (xynT) was determined, xynT gene was found to consist of 1,020 base-pair open reading frame coding for a poly-peptide of 340 amino acids with a deduced molecular weight of 40 kDa. The coding sequence was preceded by a putative ribosome binding site, and the transcription initiation signals. The deduced amino acid sequence of xylanase is similar to those of the xylanases from Bacillus sp. Nl37 and B. stearothermophilus 21 with $61\%$ and $59\%$ identical residues, respectively.