• 정보처리학회논문지D
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• 제19D권1호
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• pp.21-28
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• 2012

모노머 단백질의 상호작용 사이트 예측은 기능을 알지 못하는 단백질에 대해서 이것과 상호작용하는 단백질로부터 기능을 예측하거나 단백질 도킹을 위한 검색 공간의 감소에 중요한 역할을 한다. 그러나 상호작용사이트 예측은 대부분 단백질 상호작용이 세포 내에서 순간적 반응에 일어나는 약한 상호작용으로 실험에 의한 3차원 결정 구조 식별의 어려움이 따르며 이로 인해 3차원의 복합체 데이터가 제한적으로 양산된다. 이 논문에서는 모노머 단백질의 3차원 패치 계산을 통하여 구조가 알려진 복합체의 상호작용사이트와 비상호작용사이트에 대한 패치 속성을 추출하고 이를 기반으로 Support Vector Machine (SVM) 분류기법을 이용한 예측 모델 개발을 제시한다. 타겟 클래스의 데이터 불균형 문제 해결을 위해 under-sampling 기법을 이용한다. 사용된 패치속성은 2차 구조 요소와 아미노산 구성으로부터 총 9개가 추출된다. 147개의 단백질 복합체에 대해서 10 fold cross validation을 통해서 다양한 분류모델의 성능 평가를 하였다. 평가한 분류 모델 중 SVM은 92.7%의 높은 정확성을 보이고 이를 이용하여 분류 모델을 개발하였다.

• 미생물학회지
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• 제36권4호
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• pp.254-258
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• 2000

소장의 상피세포내로 세균 세포가 들어가는 과정(invasion)은 Salmonella의 감염에서 중요한 단계이다. invasion은 Salmonella type III 분비장치에 의해 분비되는 단백질들에 의해 유도된다. type III 분비단백질들은 특이하게, 일반적인 분비단백질들이 가지는 N-말단 분비 신호 펩타이드를 가지고 있지 않는 것을 알려져 있다. Yersinia에서의 최근 연구에서 type III 분비장치에 의해 인지되는 분비신호는 분비 단백질을 암호화하는 mRNA의 5'말단부의가 형성하는 2차 구조에 있을 것이라는 보고가 있다. 본 연구에서는 Salmonella type III 분비장치의 분비신호를 조사하기 위해 type III 분비단백질중 하나인 sopE를 택하여 ompR과의 translational fusion을 만들었다. translational fusion을 위해 사용된 sopE DNA절편은 프로모터와 시작 콘돈으로부터 10, 15 코돈을 포함하는 절편이다. Immunoblot으로 확인한 결과, OmpR을 포함하는 fusion 단백질이 형질전환 Salmonella 세포로부터 분비되었다. 이러한 결과는 Salmonella의 type III 분비신호가 분비단백질을 암호화하는 mRNA의 5'말단에 위치할 가능성을 제시하고 있다. 또한, 이러한 분비신호를 활용하여 유용한 외래 단백질을 세균 세포 내에서 효과적으로 생산, 분비할 수 있는 secretion vector의 원형을 개발하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제14권6호
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• pp.862-879
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• 2001

The walls of all higher plants are organized as a cellulosic, fibrillar phase embedded in a matrix phase composed of non-cellulosic polysaccharides, some proteins and, in most secondary walls, lignin. At the effective utilization of plant biomass, qualitative and quantitative analyses of plant cell walls are essential. Structural features of individual components are being clarified using newly developed equipments and techniques. However, "empirical" procedures to elucidate plant cell walls, which are not due to scientific definition of components, are still applied in some fields. These procedures may give misunderstanding for the effective utilization of plant biomass. In addition, interesting the investigation of wall organization is moving towards not only qualitatively characterisation, but also quantitation of the associations between wall components. These involve polysaccharide-polysaccharide and polysaccharide-lignin cross-links. Investigation of the associations is being done in order to understand the chemical structure, organization and biosynthesis of the cell wall and physiology of the plants. Procedures for qualitative and quantitative analyses based on the definition of cell wall components are reviewed focussing in nutritional elucidation of forage grasses by ruminant microorganisms.

• IMMUNE NETWORK
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• 제2권3호
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• pp.150-157
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• 2002

Background: Although Tat plays a role as a potent transactivator in the viral gene expression from the Human Immunodeficiency Virus type 1 long terminal repeat (HIV-1 LTR), it does not function efficiently in rodent cells implying the absence of a human specific factor essential for Tat-medicated transactivation in rodent cells. In previous experiments, we demonstrated that one of chimeric forms of TAR (transacting responsive element) of HIV-1 LTR compensated the restriction in rodent cells. Methods: To characterize the nature of the compensation, we tested the effects of several upstream binding factors of HIV-1 LTR by simple substitution, and also examined the role of the configuration of the upstream binding factor(s) indirectly by constructing spacing mutants that contained insertions between Sp1 and TATA box on Tat-mediated transactivation. Results: Human Sp1 had no effect whereas its associated factors displayed differential effects in human and rodent cells. In addition, none of the spacing mutants tested overcame the restriction in rodent cells. Rather, when the secondary structure of the chimeric HIV-1 TAR construct was destroyed, the compensation in rodent cells was disappeared. Interestingly, the proper interaction between Sp1 and TATA box binding proteins, which is essential for Tat-dependent transcription, was dispensable in rodent cells. Conclusion: This result suggests that the human-specific Tat cofactor acts to allow Tat to interact effectively in a ribonucleoprotein complex that includes Tat, cellular factors, and TAR RNA, rather than be associated with the HIV-1 LTR upstream DNA binding factors.

• Asian Pacific Journal of Cancer Prevention
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• 제14권7호
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• pp.4167-4175
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• 2013

A najor current challenge and constraint in cervical cancer research is the development of vaccines against human papilloma virus (HPV) epitopes. Although many studies are done on epitope identification on HPVs, no computational work has been carried out for high risk forms which are considered to cause cervical cancer. Of all the high risk HPVs, HPV 16, HPV 18 and HPV 45 are responsible for 94% of cervical cancers in women worldwide. In this work, we computationally predicted the promiscuous epitopes among the E6 proteins of high risk HPVs. We identified the conserved residues, HLA class I, HLA class II and B-cell epitopes along with their corresponding secondary structure conformations. We used extremely precise bioinformatics tools like ClustalW2, MAPPP, NetMHC, Epi,Jen, EpiTop 1.0, ABCpred, BCpred and PSIPred for achieving this task. Our study identified specific regions 'FAFR(K)DL' followed by 'KLPD(Q)LCTEL' fragments which proved to be promiscuous epitopes present in both human leukocyte antigen (HLA) class I, class II molecules and B cells as well. These fragments also follow every suitable character to be considered as promiscuous epitopes with supporting evidences of previously reported experimental results. Thus, we conclude that these regions should be considered as the important for design of specific therapeutic vaccines for cervical cancer.

• 한국자기공명학회논문지
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• 제22권3호
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• pp.71-75
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• 2018

The CRISPR-Cas system is the adaptive immune system in bacteria and archaea against invading phages or foreign plasmids. In the type II CRISPR-Cas system, an endonuclease Cas9 cleaves DNA targets of phages as directed by guide RNA comprising crRNA and tracrRNA. To avoid targeting and destruction by Cas9, phages employ anti-CRISPR (Acr) proteins that act against host bacterial immunity by inactivating the CRISPR-Cas system. Here we report the backbone $^1H$, $^{15}N$, and $^{13}C$ resonance assignments of AcrIIA4 that inhibits endonuclease activity of type II-A Listeria monocytogenes Cas9 and also Streptococcus pyogenesis Cas9 using triple resonance nuclear magnetic resonance spectroscopy. The secondary structures of AcrIIA4 predicted by the backbone chemical shifts show an ${\alpha}{\beta}{\beta}{\beta}{\alpha}{\alpha}$ fold, which is used to determine the solution structure.

• Clinical and Experimental Vaccine Research
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• 제13권2호
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• pp.146-154
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• 2024

Purpose: Infection by the intracellular apicomplexan parasite Toxoplasma gondii has serious clinical consequences in humans and veterinarians around the world. Although about a third of the world's population is infected with T. gondii, there is still no effective vaccine against this disease. The aim of this study was to develop and evaluate a multimeric vaccine against T. gondii using the proteins calcium-dependent protein kinase (CDPK)1, CDPK2, CDPK3, and CDPK5. Materials and Methods: Top-ranked major histocompatibility complex (MHC)-I and MHC-II binding as well as shared, immunodominant linear B-cell epitopes were predicted and linked using appropriate linkers. Moreover, the 50S ribosomal protein L7/L12 (adjuvant) was mixed with the construct's N-terminal to increase the immunogenicity. Then, the vaccine's physicochemical characteristics, antigenicity, allergenicity, secondary and tertiary structure were predicted. Results: The finally-engineered chimeric vaccine had a length of 680 amino acids with a molecular weight of 74.66 kDa. Analyses of immunogenicity, allergenicity, and multiple physiochemical parameters indicated that the constructed vaccine candidate was soluble, non-allergenic, and immunogenic, making it compatible with humans and hence, a potentially viable and safe vaccine candidate against T. gondii parasite. Conclusion: In silico, the vaccine construct was able to trigger primary immune responses. However, further laboratory studies are needed to confirm its effectiveness and safety.

• Parasites, Hosts and Diseases
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• 제51권3호
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• pp.327-334
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• 2013

Vaccination is considered a promising alternative for controlling tick infestations. Haemaphysalis longicornis midgut proteins separated by SDS-PAGE and transferred to polyvinylidene difluoride (PVDF) membrane were screened for protective value against bites. The western blot demonstrated the immunogenicity of 92 kDa protein (P92). The analysis of the P92 amino acid sequence by LC-MS/MS indicated that it was a H. longicornis paramyosin (Hl-Pmy). The full lenghth cDNA of Hl-Pmy was obtained by rapid amplification of cDNA ends (RACE) which consisted of 2,783 bp with a 161 bp 3' untranslated region. Sequence alignment of tick paramyosin (Pmy) showed that Hl-Pmy shared a high level of conservation among ticks. Comparison with the protective epitope sequence of other invertebrate Pmy, it was calculated that the protective epitope of Hl-Pmy was a peptide (LEEAEGSSETVVEMNKKRDTE) named LEE, which was close to the N-terminal of Hl-Pmy protein. The secondary structure analysis suggested that LEE had non-helical segments within an ${\alpha}$-helical structure. These results provide the basis for developing a vaccine against biting H. longicornis ticks.

• Bulletin of the Korean Chemical Society
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• 제27권11호
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• pp.1801-1808
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• 2006

The interaction between whey carrier protein $\beta$-lactoglobulin type A and B (BLG-A and -B) and 2,2'-bipyridin n-hexyl dithiocarbamato Pd(II) nitrate (BPHDC-Pd(II)), a new heavy metal complex designed for anticancer property, was investigated by fluorescence spectroscopy combined with chemometry and circular dichroism (CD) techniques. A strong fluorescence quenching reaction of BPHDC-Pd(II) to BLG-A and -B was observed. Hence, BPHDC-Pd(II) complex can be bound to both BLG-A and -B, and quench the fluorescence spectra of the proteins. The quenching constant was determined using the modified Stern-Volmer equation. The binding parameters were evaluated by fluorescence quenching method. The results of binding study provided evidences presence of two and three sets of binding sites on the BLG-B and -A, respectively, for BPHDC-Pd(II) complex. Using fluorescence spectroscopy and chemometry, the ability of BLG-A and -B to form an intermediate upon interaction with BPHDC-Pd(II) complex was assessed. CD studies displayed that under influence of different concentrations of BPHDC-Pd(II) complex, the regular secondary structure of BLG-B had no significant changes, whereas for BLG-A a transition from $\alpha$-helix to $\beta$-structure was appeared. The results for both of BLG-A and -B displayed that BPHDC-Pd(II) complex can induce a conformational transition from the native form to an intermediate state with a slightly opened conformation, which is detectable with chemometry analyses.

• BMB Reports
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• 제35권2호
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• pp.143-154
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• 2002

The structural and functional aspects of ervatamin B were studied in solution. Ervatamin B belongs to the $\alpha+\beta$ class of proteins. The intrinsic fluorescence emission maximum of the enzyme was at 350 nm under neutral conditions, and at 355 nm under denaturing conditions. Between pH 1.0-2.5 the enzyme exists in a partially unfolded state with minimum or no tertiary structure, and no proteolytic activity. At still lower pH, the enzyme regains substantial secondary structure, which is predominantly $\beta$-sheet conformation and shows a strong binding to 8-anilino-1-napthalene-sulfonic acid (ANS). In the presence of salt, the enzyme attains a similar state directly from the native state. Under neutral conditions, the enzyme was stable in urea, while the guanidine hydrochloride (GuHCl) induced equilibrium unfolding was cooperative. The GuHCl induced unfolding transition curves at pH 3.0 and 4.0 were non-coincidental, indicating the presence of intermediates in the unfolding pathway. This was substantiated by strong ANS binding that was observed at low concentrations of GuHCl at both pH 3.0 and 4.0. The urea induced transition curves at pH 3.0 were, however, coincidental, but non-cooperative. This indicates that the different structural units of the enzyme unfold in steps through intermediates. This observation is further supported by two emission maxima in ANS binding assay during urea denaturation. Hence, denaturant induced equilibrium unfolding pathway of ervatamin B, which differs from the acid induced unfolding pathway, is not a simple two-state transition but involves intermediates which probably accumulate at different stages of protein folding and hence adds a new dimension to the unfolding pathway of plant proteases of the papain superfamily.