• IMMUNE NETWORK
• /
• 제1권3호
• /
• pp.187-195
• /
• 2001

The expression of recombinant proteins fused to 26 kDa glutathione S-transferase (GST) extracted from Schistosoma japonicum represents an attractive system for purifiying proteins of interest in a single step using GST-affinity chromatography. In addition, the GST-tag is used conveniently for detecting fused proteins since its high solubility as well as its relatively small size rarely interferes with the biological activity of the fused protein. In this regard, the GST system is frequently applied for tracing fusion proteins in both prokaryotic and eukaryotic cells to elucidate the physiological interactions and functional compartments of proteins. To provide a further tool in analyzing GST-fusion proteins, a new monoclonal antibody, with a high specificity to the S. japonicum GST was produced. Methods: BALB/c mice were immunized both with recombinant S. japonicum GST proteins, and by the fusion of splenocytes from these mice with myeloma cells. From this, a new anti -GST monoclonal antibody, termed SARAH, was generated. The specificity and reactivity of this antibody was confirmed by ELISA and by Western blot analysis. Results: SARAH showed a high reactivity to recombinant GST and GST fusion protein but not with native mammalian GST proteins as derived from other species including humans, cows, rabbits and rats. The applicability of SARAH was further demonstrated by confocal laser scanning microscopy, where GST proteins that were expressed transiently in mouse fibroblast cells, were specifically detected without interference of endogenous GST. Conclusion: SARAH is new monoclonal antibody with a high specificity to recombinant GST proteins but not to endogenous GST in mammalian cells.

• BMB Reports
• /
• 제44권4호
• /
• pp.279-284
• /
• 2011

The glutathione S-transferase (GST) system is useful for increasing protein solubility and purifying soluble GST fusion proteins. However, purifying half of the GST fusion proteins is still difficult, because they are virtually insoluble under non-denaturing conditions. To optimize a simple and rapid purification condition for GST-pyruvate kinase muscle 2 (GST-PKM2) protein, we used 1% sarkosyl for lysis and a 1 : 200 ratio of sarkosyl to Triton X-100 (S-T) for purification. We purified the GST-PKM2 protein with a high yield, approximately 5 mg/L culture, which was 33 times higher than that prepared using a conventional method. Notably, the GST-high-temperature requirement A2 (GST-HtrA2) protein, used as a model protein for functional activity, fully maintained its proteolytic activity, even when purified under our S-T condition. This method may be useful to apply to other biologically important proteins that become highly insoluble in the prokaryotic expression system.

• 대한바이러스학회지
• /
• 제27권2호
• /
• pp.105-113
• /
• 1997

C 형 간염 바이러스 (Hepatitis C Virus, HCV)는 두종류의 외피당단백질 $E1_{192-383}$ 및 $E2_{384-746}$를 갖고 있다. $E1_{192-383}$ 및 $E2_{384-740}$ 단백질은 glutathione S-transferae (GST) 융합단백질의 형태로 대장균에서 발현되지 않았으나, 이 단백질들의 C말단에 존재하는 소수성영역을 제거하였을 때 $GST-E1_{192-283}$ 융합단백질은 과량으로 가용성 형태로 발현되었고, $GST-E2_{384-649}$ 융합단백질은 비 가용성 형태로 발현되었다. 이 융합단백질들 각각은 HCV 양성환자의 혈청과 특이적으로 반응하였다. Thrombin으로 처리하여 얻은 정제된 $E1_{192-283}$ 단백질 및 융합형태의 $GST-E2_{384-649}$ 단백질 각각을 생쥐에 접종하였을 때 E1 및 E2 특이적인 항체가 생성되었다. 이 결과들은 $E1_{192-383}$ 및 $E2_{384-649}$ 융합단백질 C 말단에 존재하는 소수성영역이 이 단백질들의 발현량 및 가용성에 영향을 주며 $E1_{192-283}$ 단백질 영역내에 HCV 양성환자의 혈청과 특이적으로 반응하는 epitope (s)이 존재한다는 것을 제시해 주고 있다.

• 한국응용약물학회:학술대회논문집
• /
• 한국응용약물학회 1997년도 춘계학술대회
• /
• pp.93-93
• /
• 1997

Analysis of protein is often frustrated by the inability to isolate large amounts of purified protein from a native source. To overcome this problem, fusion protein expression systems such as pGEX system have been widely used. Using pGEX system, the desired protein could be easily obtained in a large amount in E. coli, and then the fusion protein could be used for the study of the function of the given protein. To analyze and purify the GST fusion protein, anti-GST antibody could be used as one of the system of choice. However, the production and characterization of monoclonal anti-GST antibody has not been studied extensively yet. To produce monoclonal anti-GST antibody, GST was purified from E. coli transformed with pGEX-cs, one of the pGEX system and was used as an antigen. The monoclonal antibody was produced by fusion of the immunized spleen cells with SP2-0 myeloma cells. The antibody was characterized by ELISA, western blotting, etc. The monoclonal antibody produced in this study (mAb-GSTA) showed strong and specific immunoreactivity against not only GST but also GST-fusion proteins. Also, mAb-GSTA was successfully used for the immunoaffinity purification of the GST ${\beta}$-Rc.-third intracellular-loop fusion protein. The results of the present study suggest that mAb-GSTA may be used for the identification and purification of GST fusion proteins.

• Parasites, Hosts and Diseases
• /
• 제52권4호
• /
• pp.367-376
• /
• 2014

Recombinant antigenic proteins of Toxoplasma gondii are alternative source of antigens which are easily obtainable for serodiagnosis of toxoplasmosis. In this study, highly antigenic secretory organellar proteins, dense granular GRA2 and GRA3, rhoptrial ROP2, and micronemal MIC2, were analyzed by bioinformatics approach to express as water-soluble forms of antigenic domains. The transmembrane region and disorder tendency of 4 secretory proteins were predicted to clone the genes into pGEX-4T-1 vector. Recombinant plasmids were transformed into BL21 (DE3) pLysS E. coli, and GST fusion proteins were expressed with IPTG. As a result, GST fusion proteins with $GRA2_{25-105}$, $GRA3_{39-138}$, $ROP2_{324-561}$, and $MIC2_{1-284}$ domains had respectively higher value of IgG avidity. The $rGST-GRA2_{25-105}$ and $rGST-GRA3_{39-138}$ were soluble, while $rGST-ROP2_{324-561}$ and $rGST-MIC2_{1-284}$ were not. $GRA2_{31-71}$, intrinsically unstructured domain (IUD) of GRA2, was used as a linker to enhance the solubility. The $rGST-GRA2_{31-71}-ROP2_{324-561}$, a chimeric protein, appeared to be soluble. Moreover, $rGST-GRA2_{31-71}-MIC2_{1-284}$ was also soluble and had higher IgG avidity comparing to $rGST-MIC2_{1-284}$. These 4 highly expressed and water-soluble recombinant antigenic proteins may be promising candidates to improve the serodiagnosis of toxoplasmosis in addition to the major surface antigen of SAG1.

• Journal of Microbiology and Biotechnology
• /
• 제8권6호
• /
• pp.663-668
• /
• 1998

Several neurodegenerative diseases such as Huntington's disease, dentatorubralpallidoluysian atrophy, spinobulbar muscular atrophy, Machado-Joseph disease, and spinocerebellar ataxias type 1 are associated with the aggregation of expanded glutamine repeats within their proteins. Generally, in clinically affected individuals, the expansion of the polyglutamine sequences is beyond 40 residues. To address the length of polyglutamine that forms aggregation, we have constructed plasmids encoding glutathione S-transferase (GST) Machado-Joseph disease gene fusion proteins containing polyglutamine and investigated the formation of aggregates in E. coli. Surprisingly, even $(Gin)_8$, in the normal range as well as $(Gin)_{65}$ in the pathogenic range enhanced the formation of insoluble protein aggregates, whereas $(Ser)_8$, and $(Aia)_8$, did not form aggregates. Our results indicate that the formation of protein aggregates in GST-polyglutamine proteins is specifically mediated by the polyglutamine repeat sequence within their protein structure. Our study may contribute to the understanding of the molecular mechanism of the formation of protein aggregates in neurodegenerative disorders and the development of preventative strategies.

• Bulletin of the Korean Chemical Society
• /
• 제29권2호
• /
• pp.381-388
• /
• 2008

An X-linked skeletal disorder, SEDT (spondyloepiphyseal dysplasia tarda) is a genetic disease characterized by a disproportionately short trunk and short stature caused by mutations in the SEDL gene. This gene is evolutionarily conserved from yeast to human. The yeast SEDL protein ortholog, Trs20p, has been isolated as a member of a large multi-protein complex called the transport protein particle (TRAPP), which is involved in endoplasmic reticulum (ER)-to-Golgi transport. The interaction between SEDL and partner proteins is important in order to understand the molecular mechanism of SEDL functions. We isolated several SEDL-binding proteins derived from rat cells by an immobilized GST-fusion method. Furthermore, the SEDL-homologue proteins were identified using motif based methods. Common motifs between SEDL-binding proteins and SEDL-homologue proteins were classified into seven types and 78 common motifs were revealed. Sequence similarities were contracted to seven types using phylogenetic trees. In general, types I-III and VI were classified as having the function of acetyl-CoA carboxylase, glycogen phosphorylase, isocitrate dehydrogenase, and enolase, respectively, and type IV was found to be functionally related to the GST protein. Types V and VII were found to contribute to TRAPP vesicle trafficking.

• Archives of Pharmacal Research
• /
• 제19권4호
• /
• pp.275-279
• /
• 1996

To study the functional roles of dopamine receptors, we decided to raise antibodies against these proteins. To make antigen, we expressed the whole 3rd cytoplasmic loop of dopamine receptors in a fusion protein with glutathione-S-transferase (GST). $For D_2\; and\; D_3$ receptors, it was successful to express and purify fusion proteins for the whole 3rd cytoplasmic loops. However, we could not express the fusion protein for the whole 3rd cytoplasmic loop of $D_4$ dopamine receptor in the bacteria. To study the causes that prevent the bacterial expression of the GST-fusion protein of the 3rd cytoplasmic loop of $D_4$ dopamine receptor, we conducted more detailed studies on $D_4$ dopamine receptor. To locate the region which prevents bacterial expression, we made sequential constructs in the 3rd cytoplasmic loop decreasing the size step by step, and confirmed their expressions in the SDS PAGE. It was found that certain regions of 3rd cytoplasmic loop of $D_4$ dopamine receptor, located in N-terminal side of the 3rd cytoplasmic loop of $D_4$ dopamine receptor suppress the bacterial expression of fusion protein.

• 생명과학회지
• /
• 제6권3호
• /
• pp.185-192
• /
• 1996

박테리오파지 T7 gene 2.5 단백질은 single-stranded DNA 결합 단백질로 박태리오파지 T7의 DNA복제, 재조합, 및 수선에 필수적으로 요구된다. Gene 2.5 protein은 T7의 DNA 합성과 성장에 필수적인 단백질이다. Gene 2.5 Protein이 중요시 되는 이유는 이 단백질이 T7의 다른 복제 필수단백질인 T7의 다른 복제 필수단백질인 T7 DNA polymerase 와 gene 4 protein(helicase/primase)와 서로 상호작용할 것으로 제안되었기 때문이다. (Kim and Richardson, J. Biol. Chem., 1992;1994). 이 단백질의 단백질 상호작용을 가능하게 하는 domain은 carboxyl-terminal domain일 것으로 여러 실험에서 대두되었기에, 이 domain의 특성을 파악하기 위해 야생형과 변이체 gene 2.5 단백질들을 각각 GST에 융합한후 fusion 단백질을 정제하였다. 정제된 이 융합 단백질들의 carboxyl-terminal domain이 T7 복제 단백질들과 상호작용을 조사하는지를 조사하기 위해 affinity chromatography로 이용하였다. 실험 결과, 아생형 GST-gene 2.5 융합단잭질(GST-2.5 (WT))는 T7 DNA polymerase 와 상호작용을 하였지만. 변이형 융합단백질(GST-2.5$\Delta$21C)는 interaction을 하지 못했다. 이 결과는 carbohyl-terminal domain이 단백질-단백질 상호작용을 하는데 직접적으로 관여하는 것을 증명하였다. 또한,GST2.5(WT)는 gene 4 protein(helicase/primase)와 직접 상호작용을 하나. GST2.5$\Delta$21C는 상호작용을 하지 못하는 것으로 나타났다. 따라서 gene 4 proteins와의 상호작용에도 gene 2.5 protein의 carboxyl-terminal domain이 직접 관여 한다는 것이 증명되었다. 이상의 결과에서 gene 2.5 protein은 박테리오파지 T7 의 유전자 목제 시 단백질-단백질 상호작용에 관혀아며, 특히 gene 2.5 protein의 carboxyl-terminal domain이 이러한 상호작용에 직접적으로 관여하는 domain이라는 것을 알 수가 있었다.

• 한국미생물·생명공학회지
• /
• 제40권2호
• /
• pp.92-97
• /
• 2012

항균 펩타이드(Antimicrobial peptides(AMPs)는 그람 양성, 그람 음성 세균과 진균병원체에 대항하는 생명체에서 중요한 역할을 하는 물질이다. 인간의 Cathelicidin 항균 펩타이드는 임상학적으로 사용할 수 있는 여러 가지의 생물학적 활성을 가진다. 항균 펩타이드의 생산 비용은 재조합 방법으로 낮출 수가 있다. 대장균은 저렴하며 손쉬운 조작이 가능하기 때문에 다른 재조합 단백질처럼 항균 펩타이드의 발현에 훌륭한 숙주가 될 수 있다. 그러나 대장균에서의 항균 펩타이드의 과발현은 항균 펩타이드가 과발현 되었을 때 대장균에 독성을 보일 수 있으므로 어려움이 보고가 되어있다. 본 연구에서는 이러한 문제점을 극복하고자 항균 펩타이드를 Glutathione S-transferase(GST) 결합 단백질에 융합하여 항균펩타이드의 독성을 감소시키도록 설계하여 발현을 시도하였다. 이 때 발현한 항균 펩티드는 LL37과, gaegurin4과 LL37의 잡종 펩타이드 GGN4-LL37(GL32로 명명)를 GST에 융합되도록 벡터를 구축하고 설계하여 대장균에서 GST 융합단백질로 발현시켰다. 융합 단백질은 친화력 컬럼을 사용하여 분리하고 GST를 절단하여 항균펩타이드 만을 분리하였고 분리한 펩타이드는 웨스턴 블롯팅으로 확인하였고 그람 양성, 그람 음성 세균에 대하여 항균 활성을 나타내는 것을 확인하였다.