• Journal of Microbiology and Biotechnology
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• 제17권10호
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• pp.1607-1615
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• 2007

We investigated the applicability of the TEM-l ${\beta}$-lactamase fragment complementation (BFC) system to develop a strategy for the screening of protein-protein interactions in bacteria. A BFC system containing a human Fas-associated death domain (hFADD) and human Fas death domain (hFasDD) was generated. The hFADD-hFasDD interaction was verified by cell survivability in ampicillin-containing medium and the colorimetric change of nitrocefin. It was also confirmed by His pull-down assay using cell lysates obtained in selection steps. A coiled-coil helix coiled-coil domain-containing protein 5 (CHCH5) was identified as an interacting protein of human uracil DNA glycosylase (hUNG) from the bacterial BFC cDNA library strategy. The interaction between hUNG and CHCH5 was further confirmed with immunoprecipitation using a mammalian expression system. CHCH5 enhanced the DNA glycosylase activity of hUNG to remove uracil from DNA duplexes containing a U/G mismatch pair. These results suggest that the bacterial BFC cDNA library strategy can be effectively used to identify interacting protein pairs.

• Molecules and Cells
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• 제24권2호
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• pp.268-275
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• 2007

Protein phosphorylation plays a key role in signal transduction in cells. Since phosphoproteins are present in low abundance, enrichment methods are required for their purification and analysis. Chemical derivatization strategies have been devised for enriching phosphoproteins and phosphopeptides. In this report, we employed a strategy that replaces the phosphate moieties on serine and threonine residues with a biotin-containing tag via a series of chemical reactions. Ribulose 1,5-bisphosphate carboxylase/oxygenase (RUBISCO)-depleted protein extracts prepared from Arabidopsis seedlings were chemically modified for 'biotin-tagging'. The biotinylated (previously phosphorylated) proteins were then selectively isolated by avidin-biotin affinity chromatography, followed by two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). This led to the identification of 31 protein spots, representing 18 different proteins, which are implicated in a variety of cellular processes. Despite its current technical limitations, with further improvements in tools and techniques this strategy may be developed into a useful approach.

• Genomics & Informatics
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• 제6권4호
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• pp.210-222
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• 2008

Due to the polygenic nature of cancer, it is believed that breast cancer is caused by the perturbation of multiple genes and their complex interactions, which contribute to the wide aspects of disease phenotypes. A systems biology approach for the identification of subnetworks of interconnected genes as functional modules is required to understand the complex nature of diseases such as breast cancer. In this study, we apply a 3-step strategy for the interpretation of microarray data, focusing on identifying significantly perturbed metabolic pathways rather than analyzing a large amount of overexpressed and underexpressed individual genes. The selected pathways are considered to be dysregulated functional modules that putatively contribute to the progression of disease. The subnetwork of protein-protein interactions for these dysregulated pathways are constructed for further detailed analysis. We evaluated the method by analyzing microarray datasets of breast cancer tissues; i.e., normal and invasive breast cancer tissues. Using the strategy of microarray analysis, we selected several significantly perturbed pathways that are implicated in the regulation of progression of breast cancers, including the extracellular matrix-receptor interaction pathway and the focal adhesion pathway. Moreover, these selected pathways include several known breast cancer-related genes. It is concluded from this study that the present strategy is capable of selecting interesting perturbed pathways that putatively play a role in the progression of breast cancer and provides an improved interpretability of networks of protein-protein interactions.

• 식품과학과 산업
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• 제51권4호
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• pp.270-277
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• 2018

대두단백이 인체에 유익한 효과를 주는 양질의 단백질이라는 사실은 수많은 임상연구를 통해 검증됐다. 동물성 단백질의 높은 탄소발자국과 지속가능성에 대한 우려가 증가하고, 식물성 식품의 섭취를 늘릴 것을 권고하는 각국 보건당국의 움직임에 따라 식물성 단백질에 대한 수요가 증가하고 있다. 대두단백은 상용화된 식물성 단백질 중에서는 유일하게 완전단백질 식품으로 알려진 우유 및 달걀과 동등한 영양가를 갖는 단백질이다. 대두단백은 HDL콜레스테의 감소 없이 LDL 콜레스테롤, 총 콜레스테롤 및 중성지방을 감소시키는 효과가 있어 심혈관계 건강 증진에 도움을 주며, 동맥경화 진행을 늦추는 것으로 알려졌다. 대두단백은 다른 고품질 단백질과 마찬가지로 포만감을 증가시켜 체중 조절에 도움을 줄 뿐만 아니라, 체중 감소 시 실질체중(lean body mass) 보존을 도와 체성분 구성을 개선할 수 있도록 한다. 대두단백은 필수 아미노산의 적절한 공급을 통해 근육량을 보존시킬 뿐 아니라, 유청단백질과 카제인 등의 유단백과 함께 섭취함으로써 근육 성장을 더욱 촉진시키는 이점이 있다. 대두단백은 다양한 종류의 제품에 적용할 수 있다. 분산성, 유화 정도, 점도, 밀도, 겔 형성도 및 용해도를 조절한 다양한 분리대두단백 제품이 출시되었기 때문에, 원하는 조직감, 식감, 수화 정도 등에 따라 적절한 제품을 선택하여 적용할 수 있다. 이와 같은 장점 때문에 대두단백은 영양보충용 음료, 뉴트리션 바, 아이스크림 및 푸딩 등에 동물성 단백질의 대체재 혹은 보완재로 사용된다. 또, 대두단백은 육가공품 및 수산가공식품의 동물성단백질을 대체하여 경제적으로 제품의 품질을 향상시키면서도 본래의 식감을 유지할 수 있게 해준다. 마지막으로, 대두단백은 스낵, 시리얼, 음료, 파스타 및 간편식의 단백질 함량을 높이기 위해서도 널리 사용된다.

• 수산해양교육연구
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• 제26권6호
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• pp.1209-1216
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• 2014

This feeding experiment was conducted to investigate the effects of slurry type diet on growth performance and survival rate of growing leptocephalus, eel larva. We need to find new materials of diets for rearing eel larvae. Test diets were formulated with the eggs of the shark, fish soluble concentrate, soybean peptide and fish protein hydrolysate. Fish (average length 6 mm) were fed 3 slurry type diet(A, B and C) based on shark egg for 5 times per day. During feeding experiment, survival rates were significantly different among 3 slurry type diets. Total protein, lipid, moisture, ash and free amino acids contents were analyzed for slurry type diets. Leptocephalus fed the C slurry type diet was grown up to $38.0{\pm}9mm$ at 150 days. But all leptocephalus fed B slurry type diet were died at 100 days, reaching $16.4{\pm}8mm$. This results suggest that basic information for diet development of eel leptocephalus.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.129-130
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• 2005

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권4호
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• pp.275-287
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• 2000

Fermentation strategies for recombinant protein production in Pichia pastoris have been investigated and are reviewed here. Characteristics of the expression system, such as phenotypes and carbon utilization, are summarized. Recently reported results such as growth model establishment, app58lication of a methanol sensor, optimization of substrate feeding strategy, DOstat controller design, mixed feed technology, and perfusion and continuous culture are discussed in detail.

• BMB Reports
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• 제42권8호
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• pp.467-474
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• 2009

The modification of proteins by reversible phosphorylation is a key mechanism in the regulation of various physiological functions. Abnormal protein kinase or phosphatase activity can cause disease by altering the phosphorylation of critical proteins in normal cellular and disease processes. Alzheimer' disease (AD), typically occurring in the elderly, is an irreversible, progressive brain disorder characterized by memory loss and cognitive decline. Accumulating evidence suggests that protein kinase and phosphatase activity are altered in the brain tissue of AD patients. Tau is a highly recognized phosphoprotein that undergoes hyperphosphorylation to form neurofibrillary tangles, a neuropathlogical hallmark with amyloid plaques in AD brains. This study is a brief overview of the altered protein phosphorylation pathways found in AD. Understanding the molecular mechanisms by which the activities of protein kinases and phosphatases are altered as well as the phosphorylation events in AD can potentially reveal novel insights into the role aberrant phosphorylation plays in the pathogenesis of AD, providing support for protein phosphorylation as a potential treatment strategy for AD.

• BMB Reports
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• 제39권1호
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• pp.55-60
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• 2006

We describe a phage display strategy, based on the differential resistance of proteins to denaturant-induced unfolding, that can be used to select protein variants with improved conformational stability. To test the efficiency of this strategy, wild-type and two stable variants of ${\alpha}_1$-antitrypsin (${\alpha}_1AT$) were fused to the gene III protein of M13 phage. These phages were incubated in unfolding solution containing denaturant (urea or guanidinium chloride), and then subjected to an unfavorable refolding procedure (dialysis at $37^{\circ}C$). Once the ${\alpha}_1AT$ moiety of the fusion protein had unfolded in the unfolding solution, in which the denaturant concentration was higher than the unfolding transition midpoint ($C_m$) of the ${\alpha}_1AT$ variant, around 20% of the phage retained binding affinity to anti-${\alpha}_1AT$ antibody due to a low refolding efficiency. Moreover, this affinity reduced to less than 5% when 10 mg/mL skimmed milk (a misfolding-promoting additive) was included during the unfolding/refolding procedure. In contrast, most binding affinity (>95%) remained if the ${\alpha}_1AT$ variant was stable enough to resist unfolding. Because this selection procedure does not affect the infectivity of M13, the method is expected to be generally applicable to the high-throughput screening of stable protein variants, when activity-based screening is not possible.

• Journal of Microbiology and Biotechnology
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• 제33권4호
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• pp.511-518
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• 2023

The use of dietary protein products has increased with interests in health promotion, and demand for sports supplements. Among various protein sources, milk protein is one of the most widely employed, given its economic and nutritional advantages. However, recent studies have revealed that milk protein undergoes fecal excretion without complete hydrolysis in the intestines. To increase protein digestibility, heating and drying were implemented; however, these methods reduce protein quality by causing denaturation, aggregation, and chemical modification of amino acids. In the present study, we observed that Lacticaseibacillus rhamnosus IDCC 3201 actively secretes proteases that hydrolyze milk proteins. Furthermore, we showed that co-administration of milk proteins and L. rhamnosus IDCC 3201 increased the digestibility and plasma concentrations of amino acids in a high-protein diet mouse model. Thus, food supplementation of L. rhamnosus IDCC 3201 can be an alternative strategy to increase the digestibility of proteins.