• 제목/요약/키워드: Molecular Characterization

검색결과 3,085건 처리시간 0.026초

Large scale purification and characterization of recombinant human autotaxin/lysophospholipase D from mammalian cells

  • Song, Yuanda;Dilger, Emily;Bell, Jessica;Barton, William A.;Fang, Xianjun
    • BMB Reports
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    • 제43권8호
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    • pp.541-546
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    • 2010
  • We utilized a mammalian expression system to purify and characterize autotaxin (ATX)/lysophospholipase D, an enzyme present in the blood responsible for biosynthesis of lysophosphatidic acid. The human ATX cDNA encoding amino acids 29-915 was cloned downstream of a secretion signal of CD5. At the carboxyl terminus was a thrombin cleavage site followed by the constant domain (Fc) of IgG to facilitate protein purification. The ATX-Fc fusion protein was expressed in HEK293 cells and isolated from conditioned medium of a stable clone by affinity chromatography with Protein A sepharose followed by cleavage with thrombin. The untagged ATX protein was further purified to essential homogeneity by gel filtration chromatography with a yield of approximately 5 mg/liter medium. The purified ATX protein was enzymatically active and biologically functional, offering a useful tool for further biological and structural studies of this important enzyme.

Reclassification of Xanthomonas Isolates Causing Bacterial Leaf Spot of Euphorbia pulcherrima

  • Li, Bin;Yu, Rongrong;Shi, Yu;Su, Ting;Wang, Fang;Ibrahim, Muhammad;Xie, Guanlin;Wang, Yanli;Sun, Guochang
    • The Plant Pathology Journal
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    • 제27권4호
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    • pp.360-366
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    • 2011
  • Bacterial leaf spot of Euphorbia pulcherrima has been reported in many countries. Characterization by polyphasic approaches indicated that the isolates from India, USA and New Zealand could be distinguished based on rep-PCR profiles and gyrB phylogenies, while the Chinese isolates should be ascribed to Xanthomonas axonopodis pv. poinsettiicola.

Characterization of flavone synthase I from rice

  • Lee, Yoon-Jung;Kim, Jeong-Ho;Kim, Bong-Gyu;Lim, Yoong-Ho;Ahn, Joong-Hoon
    • BMB Reports
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    • 제41권1호
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    • pp.68-71
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    • 2008
  • Flavones are synthesized from flavanones through the action of flavone synthases (FNSs). There are two FNSs, FNS I and II. FNS I is a soluble dioxygenase present in members of the Apiaceae family and FNS II is a membrane bound cytochrome P450 enzyme that has been identified in numerous plant species. In this study, we cloned OsFNS I-1 from rice by RTPCR, expressed it in E. coli, and purified the recombinant protein. By NMR analysis, we found that OsFNS I-1 converted the flavanone (2S)-naringenin into the flavone, apigenin. Moreover, we found that the cofactors oxoglutarate, $FeSO_4$, ascorbate and catalase are required for this reaction. OsFNS I-1 encodes a flavone synthase I. This is the first type I FNS I found outside of the Apiaceae family.

식물체의 면역반응 기작 (Molecular Mechanism of Plant Immune Response)

  • 권택민;남재성
    • Journal of Plant Biotechnology
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    • 제32권2호
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    • pp.73-83
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    • 2005
  • Disease resistance in plants is often controlled by gene-for-gene mechanism in which avirulence (avr) gene products encoding by pathogens are specifically recognized, either directly or indirectly by plant disease resistance (R) gene products and sequential signal transduction pathways activating defense responses are rapidly triggered. As a results, not only exhibit a resistance against invading pathogens but also plants maintain the systemic acquired resistance (SAR) to various other pathogens. This molecular interaction between pathogen and plant is commonly compared to innate immune system of animal. Recent studies arising from molecular characterization of a number of R genes from various plant species that confer resistance to different pathogens and corresponding avr genes from various pathogens resulted in the accumulation of a wealth of knowledge on molecular mechanism of gene-for-gene interaction. Furthermore, new technologies of genomics and proteomics make it possible to monitor the genome-wide gene regulation and protein modification during activation of disease resistance, expanding our ability to understand the plant immune response and develop new crops resistant to biotic stress.

Structural characterization of As-MIF and hJAB1 during the inhibition of cell-cycle regulation

  • Park, Young-Hoon;Jeong, Suk;Ha, Ki-Tae;Yu, Hak Sun;Jang, Se Bok
    • BMB Reports
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    • 제50권5호
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    • pp.269-274
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    • 2017
  • The biological activities of macrophage migration inhibitory factor (MIF) might be mediated through a classical receptor-mediated or non-classical endocytic pathway. JAB1 (C-Jun activation domain-binding protein-1) promotes the degradation of the tumor suppressor, p53, and the cyclin-dependent kinase inhibitor, p27. When MIF and JAB1 are bound to each other in various intracellular sites, MIF inhibits the positive regulatory effects of JAB1 on the activity of AP-1. The intestinal parasite, Anisakis simplex, has an immunomodulatory effect. The molecular mechanism of action of As-MIF and human JAB1 are poorly understood. In this study, As-MIF and hJAB1 were expressed and purified with high solubility. The structure of As-MIF and hJAB1 interaction was modeled by homology modeling based on the structure of Ace-MIF. This study provides evidence indicating that the MIF domain of As-MIF interacts directly with the MPN domain of hJAB1, and four structure-based mutants of As-MIF and hJAB1 disrupt the As-MIF-hJAB1 interaction.

Expression and Biochemical Characterization of the Bacillus thuringiensis Cry4B ${\alpha}1$-${\alpha}5$ Pore-forming Fragment

  • Puntheeranurak, Theeraporn;Leetacheewa, Somphob;Katzenmeier, Gerd;Krittanai, Chartchai;Panyim, Sakol;Angsuthanasombat, Chanan
    • BMB Reports
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    • 제34권4호
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    • pp.293-298
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    • 2001
  • Tryptic activation of the 130-kDa Bacillus thuringiensis Cry4B $\delta$-endotoxin produced protease-resistant products of ca. 47 kDa and ca. 21 kDa. The 21-kDa fragment was identified as the N-terminal five-helix bundle (${\alpha}1-{\alpha}5$,) which is a potential candidate for membrane insertion and pore formation. In this study, we constructed the recombinant clone over-expressing this putative pore-forming (PPF) fragment as inclusion bodies in Escherichia coli. The partially purified inclusions were composed of a 23-kDa protein, which cross-reacted with Cry4B antibodies, and whose N-terminus was identical to that of the 130-kDa protein. Dissimilar to protoxin inclusions, the PPF inclusions were only soluble when the carbonate buffer, pH 9.0, was supplemented with 6 M urea. After renaturation via a stepwise dialysis, the refolded PPF protein appeared to exist as an oligomer and was structurally stable upon trypsin treatment. Unlike the 130kDa protoxin, the refolded protein was able to release entrapped glucose from liposomes, and showed comparable activity to the full-length activated toxin, although it lacks larvicidal activity These results, therefore, support the notion that the PPF fragment that consists of ${\alpha}1-{\alpha}5$ of the activated Cry4B toxin is involved in membrane pore-formation.

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