• Journal of Ginseng Research
• /
• 제34권1호
• /
• pp.17-22
• /
• 2010

Sesquiterpenes are found naturally in plants and insects as defensive agents or pheromones. They are produced in the cytosolic acetate/mevalonate pathway for isoprenoid biosynthesis. The inducible sesquiterpene synthases (STS), which are responsible for the transformation of the precursor farnesyl diphosphate, appear to generate very few olefinic products that are converted to biologically active metabolites. In this study, we isolated the STS gene from Panax ginseng C.A. Meyer, designated PgSTS, and investigated the correlation between its expression and various abiotic stresses using real-time PCR. PgSTS cDNA was observed to be 1,883 nucleotides long with an open reading frame of 1,707 bp, encoding a protein of 568 amino acids. The molecular mass of the mature protein was determined to be 65.5 kDa, with a predicted isoelectric point of 5.98. A GenBank BlastX search revealed the deduced amino acid sequence of PgSTS to be homologous to STS from other plants, with the highest similarity to an STS from Lycopersicon hirsutum (55% identity, 51% similarity). Real-time PCR analysis showed that different abiotic stresses triggered significant induction of PgSTS expression at different time points.

• Journal of Microbiology and Biotechnology
• /
• 제17권6호
• /
• pp.905-912
• /
• 2007

A novel ${\beta}-glucosidase$ gene, bglA, was isolated from uncultured soil bacteria and characterized. Using genomic libraries constructed from soil DNA, a gene encoding a protein that hydrolyzes a fluorogenic analog of cellulose, 4-methylumbelliferyl ${\beta}-D-cellobioside$ (MUC), was isolated using a microtiter plate assay. The gene, bglA, was sequenced using a shotgun approach, and expressed in E. coli. The deduced 55-kDa amino acid sequence for bglA showed a 56% identity with the family 1 glycosyl hydrolase Chloroflexus aurantiacus. BglA included two conserved family 1 glycosyl hydrolase regions. When using $p-nitrophenyl-{\beta}-D-glucoside$ (pNPG) as the substrate, the maximum activity of the purified ${\beta}-glucosidase$ exhibited at pH 6.5 and $55^{\circ}C$, and was enhanced in the presence of $Mn^{2+}$. The $K_m\;and\;V_{max}$ values for the purified enzyme with pNPG were 0.16 mM and $19.10{\mu}mol/min$, respectively. The purified BglA enzyme hydrolyzed both pNPG and $p-nitrophenyl-{\beta}-D-fucoside$. The enzyme also exhibited substantial glycosyl hydrolase activities with natural glycosyl substrates, such as sophorose, cellobiose, cellotriose, cellotetraose, and cellopentaose, yet low hydrolytic activities with gentiobiose, salicin, and arbutin. Moreover, BglA was able to convert the major ginsenoside $Rb_1$ into the pharmaceutically active minor ginsenoside Rd within 24 h.

• BMB Reports
• /
• 제38권1호
• /
• pp.17-23
• /
• 2005

During the screening of xylanolytic enzymes from locally isolated fungi, one strain BCC14405, exhibited high enzyme activity with thermostability. This fugal strain was identified as Aspergillus cf. niger based on its morphological characteristics and internal transcribed spacer (ITS) sequences. An enzyme with xylanolytic activity from BCC14405 was later purified and characterized. It was found to have a molecular mass of ca. 21 kDa, an optimal pH of 5.0, and an optimal temperature of $55^{\circ}C$. When tested using xylan from birchwood, it showed $K_m$ and $V_{max}$ values of 8.9 mg/ml and 11,100 U/mg, respectively. The enzyme was inhibited by $CuSO_4$, EDTA, and by $FeSO_4$. The homology of the 20-residue N-terminal protein sequence showed that the enzyme was an endo-1,4-$\beta$-xylanase. The full-length gene encoding endo-1,4-$\beta$-xylanase from BCC14405 was obtained by PCR amplification of its cDNA. The gene contained an open reading frame of 678 bp, encoding a 225 amino acid protein, which was identical to the endo-1,4-$\^{a}$-xylanase B previously identified in A. niger.

• Journal of Microbiology and Biotechnology
• /
• 제24권9호
• /
• pp.1260-1268
• /
• 2014

Screening of a gene library from Paenibacillus sp. PBS-2 generated in Escherichia coli led to the identification of a clone with lipolytic activity. Sequence analysis showed an open reading frame encoding a polypeptide of 378 amino acid residues with a predicted molecular mass of 42 kDa. The esterase displayed 69% and 42% identity with the putative ${\beta}$-lactamases from Paenibacillus sp. JDR-2 and Clostridium sp. BNL1100, respectively. The esterase contained a Ser-x-x-Lys motif that is conserved among all ${\beta}$-lactamases found to date. The protein PBS-2 was produced in both soluble and insoluble forms when E. coli cells harboring the gene were cultured at $18^{\circ}C$. The enzyme is a serine protein and was active against p-nitrophenyl esters of $C_2$, $C_4$, $C_8$, and $C_{10}$. The optimum pH and temperature for enzyme activity were pH 9.0 and $30^{\circ}C$, respectively. Relative activity of 55% remained at up to $5^{\circ}C$ with an activation energy of 5.84 kcal/mol, which indicates that the enzyme is cold-adapted. Enzyme activity was inhibited by $Cd^{2+}$, $Cu^{2+}$, and $Hg^{2+}$ ions. As expected for a serine esterase, activity was inhibited by phenylmethylsulfonyl fluoride. The enzyme was remarkably active and stable in the presence of commercial detergents and organic solvents. This cold-adapted esterase has potential as a biocatalyst and detergent additive for use at low temperatures.

• Journal of Microbiology and Biotechnology
• /
• 제20권12호
• /
• pp.1756-1763
• /
• 2010

Pasteurella multocida serogroup D strain, which produces P. multocida toxin (PMT), is a widespread and harmful pathogen of respiratory diseases such as pneumonia and progressive atrophic rhinitis (PAR) in swine. Vaccination has been considered the most desirable and effective approach for controlling the diseases caused by toxigenic P. multocida. To investigate the antigenicity and immunogenicity of partial fragments of recombinant PMT, recombinant proteins of the N-terminal (PMT-A), middle (PMT-B), C-terminal (PMT-C), and middle-C-terminal (PMT2.3) regions of PMT were successfully produced in an Escherichia coli expression system. The molecular masses of PMT-A, PMT-B, PMT-C, and PMT2.3 were ca. 53, 55, 35, and 84 kDa, respectively, purified by nickel-nitrilotriacetic acid (Ni-NTA) affinity column chromatography. All the recombinant proteins except for PMT-A showed immune responses to antisera obtained from a swine showing symptoms of PAR. Moreover, high titers of PMT-specific antibodies were raised from mice immunized with each of the recombinant proteins; however, the immunoreactivities of the antibodies to authentic PMT and heat-inactivated whole bacteria were different, respectively. In the protection study, the highest protection against homologous challenge was shown in the case of PMT2.3; relatively poor protections occurred for the other PMT fragments.

• 한국발생생물학회:학술대회논문집
• /
• 한국발생생물학회 2003년도 제3회 국제심포지움 및 학술대회
• /
• pp.62-62
• /
• 2003

Aquaporin (AQP) family protein은 일종의 수분 전달 통로 역할을 하는 단백질로 AQP를 통한 수분의 조절은 삼투압을 통한 물의 이동과 함께 조직내 정상적인 수분의 상성 유지에 필수적이다. 현재까지 11종의 AQP이 신장·뇌·정소·안구 등에서 발현이 확인되었다. AQP9은 물 뿐 아니라 carbamide, polyol, purine, pyrimidine, urea, glycerol 등의 이동에 관여한다. 본 연구에서는 생쥐에서 출생 후 성체에 이르는 동안 정소 내 AQP9의 발현, Leydig cell의 분화에 따른 AQP9의 발현을 조사하였다. 1, 2, 4, 8주령의 정소로부터 semiquantitative RT-PCR 및 real time PCR 법으로 AQP9의 발현을 분석한 결과 1주령에서는 발현되지 않았고 2주령에서는 미량이 발현되기 시작하였고, 4주령에서는 성체의 1/2수준으로 발현량이 급격히 증가하였고 성체에서는 다량으로 발현됨이 확인되었다. Semiquantitative RT-PCR 법과 real time PCR법을 비교할 때 주령별 발현 양상은 유사하였으나 4주령과 성체에서는 두 시험법 사이에 양적인 차이가 있었다. 면역조직화학염색 결과 주로 Leydig cell에서 AQP9의 발현이 확인되었다. 성체의 정소 균질액의 Western blot 상에서 분자량 80, 55, 35 및 23 kDa의 항원이 검출되어 dimer, trimer 형태로 존재할 가능성과 당쇄 결합에 의한 단백질의 변형이 있는 것으로 추정된다. 미성숙 개체의 정소에서는 23 form이 확인되는 반면 성체에서는 35 kDa form이 주로 발현되므로 정소에서 발현되는 AQP9의 경우 Post-translation 수준에서 AQP9의 변형이 수반되는 것으로 사료되며 AQP9의 기능과의 연관성은 추후 연구되어야 할 것이다. Leydig cell은 fetal 및 adult type 2종의 세포가 정소발달 과정에 출현, 사멸, 분화하며 이들은 각기 정소발달, 성숙과 정자형성에 필요한 steroidogenesis에 관여한다. 정소 내 AQP9의 발현은 17beta HSD의 발현 양상과 같게 나타나므로 성적 성숙에 따른 정소 내 AQP9의 발현의 증가는 adult type Leydig cell의 분화와 관련된 것으로 추측된다. 성체의 정소로부터 분리한 Leydig cell-enriched culture에 hCG를 처리한 결과 배양체의 AQP9의 발현이 증가하므로 AQP9은 LH 수용체 하위 신호전달과정을 통해 Leydig cell의 steroidogenesis 또는 생성된 steroids의 분비에 요구되는 수분 및 중성용질의 이동에 관여하는 것으로 사료된다.

• 한국축산식품학회지
• /
• 제21권4호
• /
• pp.367-373
• /
• 2001

MFGM 당단백질의 하나인 PAS-7을 GPC 및 affinity chromatography에 의해 정제하여 2-AB로 형광 표식한 후, anion-exchange column 및 reversed-phase column을 이용해 5개의 성분을 분리하였다. 그 중 가장 상대량이 많은 성분 e에 대하여 RAAM2000을 이용한 당쇄구조 해석을 실시하여, 성분 e는 RAAM2000 GPC에 의하여 4개의 성분으로 분리되어 각각 calibration standard 12.10, 8.88, 5.84 및 4.86GU의 용출위치에 검출되었다. 이 용출위치와 당쇄구조는 livrary의 component-7457과 일치하며, 12.2GU의 크기로 분자량은 1788로 판단되며 library의 당쇄와 약 85%의 확률로 일치했다. 그 결과 성분 e의 당쇄구조는 환원말단에 $\alpha$1-6결합된 fucose를 1개 함유하며, core부분의 비환원말단에 N-acetyllactosamine branch를 2개 함유한 전형적인 biantennary 당쇄구조인 것으로 추축되어, 이전 HPLC, acetolysis, sequential exoglycosidase 소화, NMR분석에 의해 보고된 성분 7N1A의 구조와 일치함으로써, OGS RAAM2000을 이용한 PAS-7의 당쇄구조 해석의 유용성이 증명되었다.

• 한국미생물·생명공학회지
• /
• 제31권1호
• /
• pp.57-62
• /
• 2003

토양으로부터 $\beta$-mannanase활성이 우수한 균주를 분리하여 형태학적, 생화학적 동정과정을 거쳐 Bacillus subtilis JS-1으로 동정하였다. 분리균이 생산하는 $\beta$-mannanase 효소의 최적활성은 55$^{\circ}C$와 pH 5.0이었다. 탄소원이 다른 배지에서 배양한 분리 균주의 상등액을 전기영동하여 효소활성을 관찰한 결과 탄소원에 상관없이 분자량 130kDa에 해당하는 단일 단백질만이 효소 활성을 나타내었다 Bacillus subtilis JS-1은 탄소원으로 lactose와 locust bean gum이 존재할 때 $\beta$-mannanase 생산성이 크게 증가하는 것으로 나타났으며, lactose와 locust bean gum이 각각 0.5 % 존재할 때 배양 상등액의 $\beta$-mannanase 활성은 30U/ml과 45U/ml로 탄소원이 없는 대조구에 비해 최대 18배 정도 생산성이 증가하였다. 배지에 locust bean gum을 첨가하였을 때 효소 생산성 뿐만 아니라 균체의 성장도 함께 증가하는 것으로 보아 분리균주는 locust bean gum을 분해하여 에너지원으로 이용하는 것으로 판단된다

• Journal of Microbiology and Biotechnology
• /
• 제28권12호
• /
• pp.2036-2045
• /
• 2018

An endo-${\beta}$-1,4-glucanase gene, cel5L, was cloned using the shot-gun method from Bacillus sp.. The gene, which contained a predicted signal peptide, encoded a protein of 496 amino acid residues, and the molecular mass of the mature Cel5L was estimated to be 51.8 kDa. Cel5L contained a catalytic domain of glycoside hydrolase (GH) family 5 and a carbohydrate-binding module family 3 (CBM_3). Chromatography using HiTrap Q and CHT-II resulted in the isolation of two truncated forms corresponding to 50 (Cel5L-p50) and 35 kDa (Cel5L-p35, CBM_3-deleted form). Both enzymes were optimally active at pH 4.5 and $55^{\circ}C$, but had different half-lives of 4.0 and 22.8 min, respectively, at $70^{\circ}C$. The relative activities of Cel5L-p50 and Cel5L-p35 for barley ${\beta}$-glucan were 377.0 and 246.7%, respectively, compared to those for carboxymethyl-cellulose. The affinity and hydrolysis rate of pNPC by Cel5L-p35 were 1.7 and 3.3 times higher, respectively, than those by Cel5L-p50. Additions of each to a commercial enzyme set increased saccharification of pretreated rice straw powder by 17.5 and 21.0%, respectively. These results suggest CBM_3 is significantly contributing to thermostability, and to affinity and substrate specificity for small substrates, and that these two enzymes could be used as additives to enhance enzymatic saccharification.

• Journal of Microbiology and Biotechnology
• /
• 제18권6호
• /
• pp.1081-1089
• /
• 2008

A novel ginsenoside-hydrolyzing ${\beta}$-glucosidase was purified from Paecilomyces Bainier sp. 229 by a combination of Q-Sepharose FF, phenyl-Sepharose CL-4B, and CHT ceramic hydroxyapatite column chromatography. The purified enzyme was a monomeric protein with a molecular mass estimated to be 115 kDa. The optimal enzyme activity was observed at pH 3.5 and $60^{\circ}C$. It was highly stable within pH 3-9 and at temperatures lower than $55^{\circ}C$. The enzyme was specific to ${\beta}$-glucoside. The order of enzyme activities against different types of ${\beta}$-glucosidic linkages was ${\beta}$-(1-6)>${\beta}$-(1-2)>${\beta}$-(1-4). The enzyme converted ginsenoside Rb1 to CK specifically and efficiently. An 84.3% amount of ginsenoside Rb1, with an initial concentration of 2 mM, was converted into CK in 24 h by the enzyme at $45^{\circ}C$ and pH 3.5. The hydrolysis pathway of ginsenoside Rb1 by the enzyme was $Rb1{\to}Rd{\to}F2{\to}CK$. Five tryptic peptide fragments of the enzyme were identified by a newly developed de novo sequencing method of post-source decay (PSD) matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. By comparing the five identified peptide sequences with the NCBI database, this purified ${\beta}$-glucosidase proves to be a new protein that has not been reported before.