• Bulletin of the Korean Chemical Society
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• 제28권10호
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• pp.1756-1762
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• 2007

Envelope proteins of virus contain a segment of hydrophobic amino acids, called as fusion peptide, which triggers membrane fusion by insertion into membrane and perturbation of lipid bilayer structure. Potential fusion peptide sequences have been identified in the middle of L or M proteins or at the N-terminus of S protein in the envelope of human hepatitis B virus (HBV). Two 16-mer peptides representing the N-terminal fusion peptide of the S protein and the internal fusion peptide in L protein were synthesized, and their membrane disrupting activities were characterized. The internal fusion peptide in L protein showed higher activity of liposome leakage and hemolysis of human red blood cells than the N-terminal fusion peptide of S protein. Also, the membrane disrupting activity of the extracellular domain of L protein significantly increased when the internal fusion peptide region was exposed to N-terminus by the treatment of V8 protease. These results indicate that the internal fusion peptide region of L protein could activate membrane fusion when it is exposed by proteolysis.

• 자연과학논문집
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• 제15권1호
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• pp.89-95
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• 2005

폐암을 일으키는 것으로 알려진 JSRV는 NIH3T3 세포를 transformation 시키는 성질이 있다는 것으로 알려져 있다. 이 바이러스 중 Envelope 단백질이 NIH3T3를 transformation시키는 것으로 알려져서 이것이 세포내에서 어떤 전사인자를 활성화시키는지를 luciferase 리포터 플라스미드를 이용한 transient transfection 방법으로 조사하였다. 그 결과 Envelope 단백질은 NF-kB와 AP-1의 활성을 높이는 것으로 밝혀졌다.

• BMB Reports
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• 제37권6호
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• pp.726-734
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• 2004

White spot disease (WSD) is caused by the white spot syndrome virus (WSSV), which results in devastating losses to the shrimp farming industry around the world. However, the mechanism of virus entry and spread into the shrimp cells is unknown. A binding assay in vitro demonstrated VP28-EGFP (envelope protein VP28 fused with enhanced green fluorescence protein) binding to shrimp cells. This provides direct evidence that VP28-EGFP can bind to shrimp cells at pH 6.0 within 0.5 h. However, the protein was observed to enter the cytoplasm 3 h post-adsorption. Meanwhile, the plaque inhibition test showed that the polyclonal antibody against VP28 (a major envelope protein of WSSV) could neutralize the WSSV and block an infection with the virus. The result of competition ELISA further confirmed that the envelope protein VP28 could compete with WSSV to bind to shrimp cells. Overall, VP28 of the WSSV can bind to shrimp cells as an attachment protein, and can help the virus enter the cytoplasm.

• 대한바이러스학회지
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• 제27권2호
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• pp.209-216
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• 1997

Three dimensional structures of envelope protein from Korean isolates and Nakayama-NIH strain of Japanese encephalitis virus (JEV) were deduced by a computer program (HyperChem 4.0 Chemplus 1.0) based on the data of the three dimentional structure of Tick-borne encephalitis virus. In the three dimensional structure of envelope protein, neutralizing epitope and T-helper cell recognition site of C-terminal region of Korean isolates were structually similar to those of Nakayama-NIH but the N-terminal region was not. Korean JE isolates were compared with Nakayama-NIH strain by using cross-neutralization antibody test. Neutralizing activities of Korean isolates derived from guinea pigs were higher than those of Nakayama-NIH strain against Korean isolates, although the polyclonal antibody titers of Nakayama-NlH showed 1:160 to 1:640 against Korean isolates. According to the results from three dimentional structures and cross-neutralization analyses, the antigenic difference between Korean JE isolates and Nakayama-NIH strain may be dependent on structural difference of envelope protein.

• Journal of Periodontal and Implant Science
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• 제32권2호
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• pp.351-360
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• 2002

In the study presented here, identification, purification, and partial characterization of a hemin-regulated protein in Prevotella nigrescens were carried out. The results of this study confirm that the availability of hemin influences the expression of a selected membrane protein as well as the growth rate of P. nigrescens ATCC 33563. The 50 kDa cell envelope associated protein, whose expression is hemin regulated, is considered to be a putative hemin-binding protein from P. nigrescens. Disulfide bonds were not present in this protein, and N'-terminal amino acid sequence analysis revealed that this protein belongs to a new, so far undescribed protein. The 50 kDa protein was found to be rich in hydrophilic amino acids, with glycine comprising approximately 60% of the total amino acids. The study described here is the first to identify, purify, and biochemically characterize a putative hemin-binding protein from P. nigrescens. Work is in progress to further characterize the molecular structure of this protein.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2000년도 추계학술발표대회
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• pp.78-82
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• 2000

The AIDS epidemic continues unabated in many part of the world. After near two decades, no vaccine is available to combat the spread of this deadly disease. Much of the HIV -1 vaccine effort during the past decade has focused on the viral envelope glycoprotein, largely because it is the only protein that can elicit neutralizing antibodies (Nabs). Eliciting broadly cross-reactive Nabs has been a primary goal. The intrinsic genetic diversity of the viral envelope, however, has been one of the major impediments in vaccine development. We have recently completed a comprehensive study examining whether it is possible to elicit broadly acting Nabs by immunizing monkeys with mixtures of envelope proteins from multiple HIV -1 isolates. We compared the humoral immune responses elicited by vaccination with either single or multiple envelope proteins and evaluated the importance of humoral and non-humoral immune response in protection against a challenge virus with a homologous or heterologous envelope protein. Our results show that (1) Nab is the correlate of sterilizing immunity, (2) Nabs against primary HIV -1 isolates can be elicited by the live vector-prime/protein boost approach, and (3) polyvalent envelope vaccines elicit broader Nab response than monovalent vaccines. Nonetheless, our findings clearly indicate that the increased breadth of Nab response is by and large limited to strains included in the vaccine mixture and does not extend to heterologous non-vaccine strains. Our study strongly demonstrates how difficult it may be to elicit broadly reactive Nabs using envelope proteins and sadly predicts a similar fate for many of the vaccine candidates currently being evaluated in clinical trials. We have started to evaluate other vaccine candidates (e.g. genetically modified envelope proteins) that might elicit broadly reactive Nabs. We are also exploring other vaccine strategies to elicit potent cytotoxic T lymphocyte responses. Preliminary results from some of these experiments will be discussed.

• 대한바이러스학회지
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• 제27권1호
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• pp.9-17
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• 1997

Hepatitis C virus (HCV) E2 protein is known to be one of putative envelope proteins. To develop a sensitive detection method for HCV infected tissues and cells, monoclonal antibodys (MAbs) to the E2 protein of HCV were prepared from mice immunized with recombinant baculovirus-expressing E2 protein (Bac-E2). Several hybridoma clones secreting various levels of MAb were isolated and isotypes of these MAb were determined. One clone (L.2.3.3) was used for ascites production and the E2-MAb was purified and characterized. The L.2.3.3 reacted well with both Bac-E2 and E. coli expressed glutathione-S-transferase-E2 (GST-E2) fusion proteins. Using HCV patient sera, E2 envelope protein was found to be localized in the cell membrane boundary both in CHO cells and insect cells which express HCV E2 protein. Similar result was obtained when same cells were treated with the MAb L.2.3.3. These results demonstrated that Bac-E2 protein is capable of eliciting high titer antibody production in mice.

• Journal of Periodontal and Implant Science
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• 제36권1호
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• pp.155-165
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• 2006

The results of this study confirm that the availability of hemin influences the expression of selected membrane proteins of Porphyromonas gingivalis, Prevotella intermedia, and Prevotella nigrescens. A 30 kDa (heated 24 kDa) hemin-binding protein whose expression is hemin regulated was identified and purified in P. gingivalis. A strong hemin-binding function was found by LDS-PAGE and TMBZ staining when P. gingivalis cells were grown under hemin-limited conditions. A 50 kDa cell envelope associated protein, whose expression is hemin regulated, is considered to be a putative hemin binding protein from P. intermedia and P. nigrescens, respectively. N-terminal amino acid sequence analysis of CNBr-digested 24 kDa hemin binding protein from P. gingivalis revealed that this protein belongs to a new, so far undescribed hemin-binding class of proteins. N-terminal amino acid sequence of a 50 kDa putative hemin binding protein from P. intermedia was identical with Enolase from Streptococcus intermedia. Work is in progress to further characterize the molecular structure of these proteins.

• Journal of Microbiology and Biotechnology
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• 제22권4호
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• pp.470-478
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• 2012

Recent genome comparisons of E. coli B and K-12 strains have indicated that the makeup of the cell envelopes in these two strains is quite different. Therefore, we analyzed and compared the envelope proteomes of E. coli BL21(DE3) and MG1655. A total of 165 protein spots, including 62 nonredundant proteins, were unambiguously identified by two-dimensional gel electrophoresis and mass spectrometry. Of these, 43 proteins were conserved between the two strains, whereas 4 and 16 strain-specific proteins were identified only in E. coli BL21(DE3) and MG1655, respectively. Additionally, 24 proteins showed more than 2-fold differences in intensities between the B and K-12 strains. The reference envelope proteome maps showed that E. coli envelope mainly contained channel proteins and lipoproteins. Interesting proteomic observations between the two strains were as follows: (i) B produced more OmpF porin with a larger pore size than K-12, indicating an increase in the membrane permeability; (ii) B produced higher amounts of lipoproteins, which facilitates the assembly of outer membrane ${\beta}$-barrel proteins; and (iii) motility- (FliC) and chemotaxis-related proteins (CheA and CheW) were detected only in K-12, which showed that E. coli B is restricted with regard to migration under unfavorable conditions. These differences may influence the permeability and integrity of the cell envelope, showing that E. coli B may be more susceptible than K-12 to certain stress conditions. Thus, these findings suggest that E. coli K-12 and its derivatives will be more favorable strains in certain biotechnological applications, such as cell surface display or membrane engineering studies.

• Journal of Dairy Science and Biotechnology
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• 제36권4호
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• pp.208-219
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• 2018

낙농업 및 유가공 제품의 생산과 유통에서 살모넬라 감염에 의한 살모넬라증의 발생은 빈번하며, 이 세균의 항미생물 제제에 대한 내성 증가 현상 또한 지속되고 있어 새로운 항미생물 제제의 수요는 감소하지 않는다. 세균막의 훼손은 세균 생존을 쉽게 위협할 수 있기 때문에 개발되는 항미생물 제제들은 주로 세균의 막을 표적으로 삼지만, 개발되는 제제들이 실제로 세균막의 훼손을 초래하는지 구별하는 것은 많은 노력과 비용을 수반한다. 본 연구에서는 E. coli 세포막 스트레스에 의해 발현이 유도되고, 세균막 외부공간에서만 위치하며, 그 구조상 많은 단백질의 구조 안정화에 기여할 것으로 예상되는 chaperone 단백질 Spy(spheroplast protein Y)의 유전자에 상응하는 살모넬라 spy 유전자에 gfp(green fluorescence protein) 오페론 융합체를 제조하여, 이 융합체가 Salmonella enterica의 두 혈청형 Enteritidis와 Gallinarum의 세포막 스트레스를 인지하여 GFP 발현량이 크게 증가하는 것을 확인하였다. 또한 세균막 스트레스 신호를 특이적으로 인지하는 이인자 신호전달 체계(two component signal transduction system)인 Bae와 Cpx들이 두 살모넬라 혈청형의 spy 유전자 전사 유도에 필수적임을 확인하였다. 따라서 본 연구에서 사용한 spy-gfp 오페론 융합체는 S. Enteritidis와 S. Gallinarum의 세포막 훼손을 특이적이고 신속하게 인식하는 biosensor로서 활용될 수 있을 것으로 판단된다.