• Korean Journal of Microbiology
• /
• v.52 no.2
• /
• pp.192-201
• /
• 2016

Recently, Psychrobacter sp. ArcL13 strain showing the extracellular lipase activity was isolated from the Chuckchi Sea of the Arctic Ocean. However, due to the low expression levels of the enzyme in the natural strain, the production of recombinant lipase is crucial for various applications. Identification of the gene for the enzyme is prerequisite for the production of the recombinant protein. Therefore, in the present study, a novel lipase gene (ArcL13-Lip) was isolated from Psychrobacter sp. ArcL13 strain by gene prospecting using PCR, and its complete nucleotide sequence was determined. Sequence analysis showed that ArcL13-Lip has high amino acid sequence similarity to lipases from bacteria of some Psychrobacter genus (84-90%) despite low nucleotide sequence similarity. The lipase gene was cloned into the bacterial expression plasmid and expressed in E. coli. SDS-PAGE analysis of the cells showed that ArcL13-Lip was expressed as inclusion bodies with a molecular mass of about 35 kDa. Refolding was achieved by diluting the unfolded protein into refolding buffers containing various additives, and the highest refolding efficiency was seen in the glucose-containing buffer. Refolded ArcL13-Lip showed high hydrolytic activity toward p-nitrophenyl caprylate and p-nitrophenyl decanoate among different p-nitrophenyl esters. Recombinant ArcL13-Lip displayed maximal activity at $40^{\circ}C$ and pH 8.0 with p-nitrophenyl caprylate as a substrate. Activity assays performed at various temperatures showed that ArcL13-Lip is a cold-active lipase with about 40% and 73% of enzymatic activity at $10^{\circ}C$ and $20^{\circ}C$, respectively, compared to its maximal activity at $40^{\circ}C$.

• Microbiology and Biotechnology Letters
• /
• v.45 no.1
• /
• pp.63-70
• /
• 2017

A functional screen of 60,672 fosmid metagenomic clones amplified from marine sediment obtained from the Dokdo islets in Korea identified the gene EstES1, whose product, EstES1, displayed lipolytic properties on tributyrin-supplemented media. EstES1 is a 576 amino acid protein with a predicted molecular weight of 59.4 kDa including 37 N-terminal leader amino acids. EstES1 exhibited the highest sequence similarity (44%) to a carboxylesterase found in Haliangium ochraceum DSM14365. Phylogenetic analysis indicated that EstES1 belongs to a currently uncharacterized family of lipases. Within the conserved domain, EstES1 retains the catalytic triad that consists of the consensus penta-peptide motif, GESAG. EstES1 demonstrated a broad substrate specificity toward the long acyl group of ethyl esters (C2-C12), and its optimal activity was recorded toward p-Nitrophenyl butyrate (C4) at pH 9.0 and $40^{\circ}C$ (specific activity of 255.4 U/mg). The enzyme remained stable in the ranges of $60-65^{\circ}C$ and pH 9.0-10.5 and in the presence of methanol, ethanol, isopropanol, and dimethyl sulfoxide. Therefore, EstES1 has potential for use in industrial applications involving high temperature, organic solvents, and/or alkaline conditions.

• Food Science of Animal Resources
• /
• v.29 no.2
• /
• pp.151-156
• /
• 2009

The prevalence of food allergies was investigated using questionnaires with 300 subjects whose ages ranged from 19 to 24 years old and the causative food allergens was analyzed using immunological analysis with serum of the subjects who answered that they have/had food allergy. The questionnaire showed that 11.33% of subjects have/had experience of food hypersensitivity, where the main causative foods were fish, beef, chicken, milk, egg, and pork in order. The meat allergy shared 4.65% (2.33% for beef, 1.66% for chicken, 0.66% for pork) in the prevalence of food allergies. The causative beef allergens were investigated with the serum of 6 subjects who have had beef allergy. Western blots were carried out with the serum of P6 subject who showed a positive reaction to beef extract in ELISA. The two specific bands were detected in beef extract on the PVDF membrane, and no band was detected in extracts of pork and chicken. A calculation of the distance of migration by SDS-PAGE enabled the molecular masses of the two bands to be estimated as 67kDa and 31kDa, respectively. The 67kDa was revealed as bovine serum albumin (BSA) which is one of the important beef allergens as reported previously though an analysis of the N-terminal amino acid sequence. However we could not identify the sequence of 31kDa, probably because they comprised several subunits and were modified proteins such as glycoprotein that were unlikely to be easily degraded by the Edman method. The 31kDa band were dyed with the PAS (periodic acid-schiff reagent), suggesting that it might be a glycoprotein. These results suggested that the 31kDa might be considered as a novel potential beef allergen which is not reported previously, although further studies are needed.

• The Korean Journal of Mycology
• /
• v.31 no.2
• /
• pp.59-66
• /
• 2003

Laccase produced by Pycnoporus cinnabarinus SCH-3 isolated from Korea was partially purified using ultrafiltration, anion exchange chromatography and affinity chromatography, The laccase was produced as the predominant extracellular phenoloxidase during primary metabolism. Neither lignin peroxidase nor manganese-dependent peroxidase were detected in the culture fluid. In order to examine the effect of inducers in laccase production, 2,5-xylidine was added in the culture of Pycnoporus cinnabarinus SCH-3. Addition of 2,5-xylidine enhanced 25-fold laccase production. Purified laccase was a single polypeptide having a molecular mass of approximately 66 kDa, as determined by SDS-polyacrylamide gel electrophoresis, and carbohydrate content of 9%. $K_{m}\;and\;V_{max}$ values for laccase with ABTS [2,2-azinobis (3-ethylbenzthiazoline 6-sulfonic acid)] as a substrate (Lineweaver-Burk plot) was determined to be $44.4{\mu}M\;and\;56.0{\mu}mole$, respectively. The optimal pH for laccase activity was found to be 3.0. The enzyme was very stable for 1 hour at $60{\circ}C$. Half-life ($t_{1/2}$) of the enzyme was about 10 min at $80{\circ}C$. Spectroscopic analysis of purified enzyme indicated that the enzyme was typical of copper-containing protein. Substrate specificity and inhibitor studies for laccase also indicated to be a typical fungal laccase. The N-terminal amino acid sequence of the P. cinnabarinus SCH-3 laccase showed 94% of homology to the N-terminal sequences of laccases from P. cinnabarinus PB and P. coccineus.

• Journal of Life Science
• /
• v.19 no.9
• /
• pp.1218-1225
• /
• 2009

Difractose anhydrides (DFAs) is studied as a sweetener for diabetics because of its structural property. DFAs have four types: DFA I, III, IV (degradation of levan) and V (degradation of inulin). Especially, DFA IV has been shown to enhance the absorption of calcium in experiments using rats. Levan fructotransferase is an enzyme for producing di-d-fructose-2,6':6,2-dianhydride (DFA IV). To identify structural characterization, we purified wild-type and mutants (D63A, D195N and N85S) of levan fructotransferase (LFTase) from Microbacterium sp. AL-210. These proteins were purified to apparent homogeneity by Ni-NTA affinity column, Q-sepharose ion exchange and gel filtration chromatography and detected by SDS-PAGE. They were also analyzed by circular dichroism (CD) measurements, JNET secondary structure prediction, activity measurements at various temperatures, and pH analysis. The optimum pH for the enzyme-catalyzed reaction was pH 7.5 and optimum temperature was observed at $55^{\circ}C$. Along with wild-type LFTase, mutants were analyzed by CD measurement, fluorescence analysis and differential scanning calorimetry (DSC). N85S showed less $\alpha$-helix and more $\beta$ strand than others. Also, N85S showed almost the same curve as wild-type in their steady-state fluorescence spectra, whereas mutant D63A and D195N showed higher intensity than wild-type. The amino acid sequence of wild-type LFTase was compared to the sequences of exo-inulinase from Aspergillus awamori, a plant fructan 1-exohydrolase from Cichorium intybus, and Thermotogo maritime (Tm) invertase and showed a high identity with Exo-inulinase from Aspergillus awamori.

• Journal of Microbiology
• /
• v.44 no.6
• /
• pp.622-631
• /
• 2006

In this study we purified a fibrinolytic enzyme from Cordyceps militaris using a combination of ion-exchange chromatography on a DEAE Sephadex A-50 column, gel filtration chromatography on a Sephadex G-75 column, and FPLC on a HiLoad 16/60 Superdex 75 column. This purification protocol resulted in a 191.8-fold purification of the enzyme and a final yield of 12.9 %. The molecular mass of the purified enzyme was estimated to be 52 kDa by SDS-PAGE, fibrin-zymography, and gel filtration chromatography. The first 19 amino acid residues of the N-terminal sequence were ALTTQSNV THGLATISLRQ, which is similar to the subtilisin-like serine protease PR1J from Metarhizium anisopliae var. anisopliase. This enzyme is a neutral protease with an optimal reaction pH and temperature of 7.4 and $37^{\circ}C$, respectively. Results for the fibrinolysis pattern showed that the enzyme rapidly hydrolyzed the fibrin $\alpha$-chain followed by the $\gamma$-$\gamma$ chains. It also hydrolyzed the $\beta$-chain, but more slowly. The A$\alpha$, B$\beta$, and $\gamma$ chains of fibrinogen were also cleaved very rapidly. We found that enzyme activity was inhibited by $Cu^{2+}$ and $Co^{2+}$, but enhanced by the additions of $Ca^{2+}$ and $Mg^{2+}$ ions. Furthermore, fibrinolytic enzyme activity was potently inhibited by PMSF and APMSF. This enzyme exhibited a high specificity for the chymotrypsin substrate S-2586 indicating it's a chymotrypsin-like serine protease. The data we present suggest that the fibrinolytic enzyme derived from the edible and medicinal mushroom Cordyceps militaris has fibrin binding activity, which allows for the local activation of the fibrin degradation pathway.

• BMB Reports
• /
• v.40 no.5
• /
• pp.715-722
• /
• 2007

A new full-length cDNA encoding hyoscyamine $6\beta$-hydroxylase (designated as aah6h, GenBank Accession No. EF187826), which catalyzes the last committed step in the scopolamine biosynthetic pathway, was isolated from young roots of Anisodus acutangulus by rapid amplification of cDNA ends (RACE) for the first time. The full-length cDNA of aah6h was 1380 bp and contained a 1035 bp open reading frame (ORF) encoding a deduced protein of 344 amino acid residues. The deduced protein had an isoelectric point (pI) of 5.09 and a calculated molecular mass of about 38.7 kDa. Sequence analyses showed that AaH6H had high homology with other H6Hs isolated from some scopolamine-producing plants such as Hyoscyamus niger, Datura metel and Atropa belladonna etc. Bioinformatics analyses results indicated AaH6H belongs to 2-oxoglutarate-dependent dioxygenase superfamily. Phylogenetic tree analysis showed that AaH6H had closest relationship with H6H from A. tanguticus. Southern hybridization analysis of the genomic DNA revealed that aah6h belonged to a multi-copy gene family. Tissue expression pattern analysis firstly founded that aah6h expressed in all the tested tissues including roots, stems and leaves and indicated that aah6h was a constitutive-expression gene, which was the first reported tissue-independent h6h gene compared to other known h6h genes.

• Journal of Life Science
• /
• v.21 no.10
• /
• pp.1487-1493
• /
• 2011

E. tarda, a fish pathogen, can survive in seawater under relatively high salt conditions as well as in fish under physiological salt conditions. Bacterial growth under different salt concentrations may influence the expression of genes involved in bacterial structure and physiology. The growth rate of E. tarda culture in high salt (3.5% NaCl) was similar to that in low salt (1.0% NaCl, physiological salt concentration). Interestingly, the strain moved much faster in low salt conditions than in high salt conditions. Electron microscopic observation demonstrated that the bacterial cells grown in high salt had less or no flagellation. Obvious flagellation was observed in the parental strain E. tarda CK41 grown in low-salt condition. Two putative genes coding flagellin were identified in the E. tarda genome sequences. The amino acid sequence comparison of each gene revealed 93% identities. A flagellin gene was PCR amplified and cloned into a cloning vector. Using an E. coli protein expression system, a part of flagellin protein was overexpressed. Using the purified protein, an anti-flagellin antibody was raised in the rabbit. Immunoblot analyses with flagellin specific antibody demonstrated that E. tarda CK41 expressed falgellin in low salt conditions, which is consistent with the results seen in motility assay and microscopic observation. This is the first report of salt regulated flagella expression in E. tarda.

• Asian-Australasian Journal of Animal Sciences
• /
• v.18 no.12
• /
• pp.1701-1707
• /
• 2005

This study deals with the characterization of porcine PIK3C3 and association tests with quantitative traits. PIK3C3 belongs to the class 3 PI3Ks that participate in the regulation of hepatic glucose output, glycogen synthase, and antilipolysis in typical insulin target cells such as those in the such as liver, muscle system, and fat. On the analysis of full-length mRNA sequence, the length of the PIK3C3 CDS was recorded as 2,664 bps. As well, nucleotide and amino acid identities between human and pig subjects were 92% and 99%, respectively. Five SNPs were detected over 5 exons. We performed genotyping by using a SNP C2604T on exon24 for 145 F$_2$ animals (from a cross between Korean native boars and Landrace sows) by PCR-RFLP analysis with Hpy8I used to investigate the relationship between growth and fat depot traits. In the total association analysis, which doesn' consider transmission disequilibrium, the SNP showed a significant effect (p<0.05) on body weight and carcass fat at 30 weeks of age as well as a highly significant effect (p<0.01) on back fat. In an additional sib-pair analysis, C allele still showed positive and significant effects (p<0.05) on back fat thickness and carcass fat. Moreover, the effects of C allele on the means of within-family components for carcass fat and back fat were estimated as 2.76 kg and 5.07 mm, respectively. As a result, the SNP of porcine PIK3C3 discovered in this study could be utilized as a possible genetic marker for the selection of pigs that possess low levels of back fat and carcass fat at the slaughter weight.

• IMMUNE NETWORK
• /
• v.2 no.3
• /
• pp.175-181
• /
• 2002

Background: S100A6 is a calcium-binding protein overexpressed in several tumor cell lines including melanoma with high metastatic activity and involved in various cellular processes such as cell division and differentiation. To detect S100A6 protein in patient' samples (ex, blood or tissue), it is essential to produce a monoclonal antibody specific to the protein. Methods: First, cDNA coding for ORF region of human S100A6 gene was amplified and cloned into the expression vector for GST fusion protein. We have produced recombinant S100A6 protein and subsequently, monoclonal antibodies to the protein. The specificity of anti-S100A6 monoclonal antibody was confirmed using recombinant S100A recombinant proteins of other S100A family (GST-S100A1, GST-S100A2 and GST-S100A4) and the cell lysates of several human cell lines. Also, to identify the specific recognition site of the monoclonal antibody, we have performed the immunoblot analysis with serially deleted S100A6 recombinant proteins. Results: GST-S100A6 recombinant protein was induced and purified. And then S100A6 protein excluding GST protein was obtained and monoclonal antibody to the protein was produced. Monoclonal antibody (K02C12-1; patent number, 330311) has no cross-reaction to several other S100 family proteins. It appears that anti-S100A6 monoclonal antibody reacts with the region containing the amino acid sequence from 46 to 61 of S100A6 protein. Conclusion: These data suggest that anti-S100A6 monoclonal antibody produced can be very useful in development of diagnostic system for S100A6 protein.