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排序方式: 共有188条查询结果,搜索用时 15 毫秒
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Urasaki N Tokumoto M Terauchi R Tarora K Chinen I Ban Y Kayano T Tanaka H 《Genes & genetic systems》2000,75(5):293-298
In the course of papaya EST collection, one clone (pRA4-3) encoding partial sequence of papaya small GTP-binding protein gene, pgp1, was obtained. Based on the sequence information of pRA4-3, the entire coding region of pgp1 was cloned using the 3'RACE PCR technique. ORF of pgp1 is 636bp long and deduced molecular weight of the protein is 23,311. Phylogenetic analysis showed that PGP1 belongs to YPT/RAB group of the small GTP-binding protein and is a homologue of RAB2. Southern analysis showed that there are several pgp1-related genes in papaya genome. Northern analysis showed that pgp1 was expressed equally in stems of seedlings that were grown under light and dark conditions. This result shows that PGP1 is not involved in the phytochrome-mediated signal transduction as an auxin signal transducer in stems of papaya seedlings. 相似文献
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Yasuyo Seshime Praveen Rao Juvvadi Katsuhiko Kitamoto Yutaka Ebizuka Takamasa Nonaka Isao Fujii 《Bioorganic & medicinal chemistry letters》2010,20(16):4785-4788
As a novel superfamily of type III polyketide synthases in microbes, four genes csyA, csyB, csyC, and csyD, were found in the genome of Aspergillus oryzae, an industrially important filamentous fungus. In order to analyze their functions, we carried out the overexpression of csyA under the control of α-amylase promoter in A. oryzae and identified 3,5-dihydroxybenzoic acid (DHBA) as the major product. Feeding experiments using 13C-labeled acetates confirmed that the acetate labeling pattern of DHBA coincided with that of orcinol derived from orsellinic acid, a polyketide formed by the condensation and cyclization of four acetate units. Further oxidation of methyl group of orcinol by the host fungus could lead to the production of DHBA. Comparative molecular modeling of CsyA with the crystal structure of Neurospora crassa 2′-oxoalkylresorcylic acid synthase indicated that CsyA cavity size can only accept short-chain acyl starter and tetraketide formation. Thus, CsyA is considered to be a tetraketide alkyl-resorcinol/resorcylic acid synthase. 相似文献
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Dentatorubral-pallidoluysian atrophy is caused by polyglutamine (polyQ) expansion in atrophin-1 (ATN1). Recent studies have shown that nuclear accumulation of ATN1 and cleaved fragments with expanded polyQ is the pathological process underlying neurodegeneration in dentatorubral-pallidoluysian atrophy. However, the mechanism underlying the proteolytic processing of ATN1 remains unclear. In the present study, we examined the proteolytic processing of ATN1 aiming to understand the mechanisms of ATN1 accumulation with polyQ expansion. Using COS-7 and Neuro2a cells that express the ATN1 gene, in which ATN1 was accumulated by increasing the number of polyQs, we identified a novel C-terminal fragment containing a polyQ tract. The mutant C-terminal fragment with expanded polyQ selectively accumulated in the cells, and this was also demonstrated in the brain tissues of patients with dentatorubral-pallidoluysian atrophy. Immunocytochemical and biochemical studies revealed that full-length ATN1 and C-terminal fragments displayed individual localization. The mutant C-terminal fragment was preferentially found in the cytoplasmic membrane/organelle and insoluble fractions. Accordingly, it is assumed that the proteolytic processing of ATN1 regulates the localization of C-terminal fragments. Accumulation of the C-terminal fragment was enhanced by inhibition of caspases in the cytoplasm of COS-7 cells. Collectively, these results suggest that the C-terminal fragment plays a principal role in the pathological accumulation of ATN1 in dentatorubral-pallidoluysian atrophy. 相似文献
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Towards dynamic metabolic network measurements by multi-dimensional NMR-based fluxomics 总被引:3,自引:0,他引:3
Novel technologies for measuring biological systems and methods for visualizing data have led to a revolution in the life sciences. Nuclear magnetic resonance (NMR) techniques can provide information on metabolite structure and metabolic dynamics at the atomic level. We have been developing a new method for measuring the dynamic metabolic network of crude extracts that combines [(13)C(6)]glucose stable isotope labeling of Arabidopsis thaliana and multi-dimensional heteronuclear NMR analysis, whereas most conventional metabolic flux analyses examine proteinogenic amino acids that are specifically labeled with partially labeled substrates such as [2-(13)C(1)]glucose or 10% [(13)C(6)]glucose. To show the validity of our method, we investigated how to obtain information about biochemical reactions, C-C bond formation, and the cleavage of the main metabolites, such as free amino acids, in crude extracts based on the analysis of the (13)C-(13)C coupling pattern in 2D-NMR spectra. For example, the combination of different extraction solvents allows one to distinguish complicated (13)C-(13)C fine couplings at the C2 position of amino acids. As another approach, f1-f3 projection of the HCACO spectrum also helps in the analysis of (13)C-(13)C connectivities. Using these new methods, we present an example that involves monitoring the incorporation profile of [(13)C(6)]glucose into A. thaliana and its metabolic dynamics, which change in a time-dependent manner with atmospheric (12)CO(2) assimilation. 相似文献
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Takahashi S Toyoda A Sekiyama Y Takagi H Nogawa T Uramoto M Suzuki R Koshino H Kumano T Panthee S Dairi T Ishikawa J Ikeda H Sakaki Y Osada H 《Nature chemical biology》2011,7(7):461-468
Spiroacetal compounds are ubiquitous in nature, and their stereospecific structures are responsible for diverse pharmaceutical activities. Elucidation of the biosynthetic mechanisms that are involved in spiroacetal formation will open the door to efficient generation of stereospecific structures that are otherwise hard to synthesize chemically. However, the biosynthesis of these compounds is poorly understood, owing to difficulties in identifying the responsible enzymes and analyzing unstable intermediates. Here we comprehensively describe the spiroacetal formation involved in the biosynthesis of reveromycin A, which inhibits bone resorption and bone metastases of tumor cells by inducing apoptosis in osteoclasts. We performed gene disruption, systematic metabolite analysis, feeding of labeled precursors and conversion studies with recombinant enzymes. We identified two key enzymes, dihydroxy ketone synthase and spiroacetal synthase, and showed in vitro reconstruction of the stereospecific spiroacetal structure from a stable acyclic precursor. Our findings provide insights into the creation of a variety of biologically active spiroacetal compounds for drug leads. 相似文献
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Discovery of a novel superfamily of type III polyketide synthases in Aspergillus oryzae 总被引:2,自引:0,他引:2
Seshime Y Juvvadi PR Fujii I Kitamoto K 《Biochemical and biophysical research communications》2005,331(1):253-260
Identification of genes encoding type III polyketide synthase (PKS) superfamily members in the industrially useful filamentous fungus, Aspergillus oryzae, revealed that their distribution is not specific to plants or bacteria. Among other Aspergilli (Aspergillus nidulans and Aspergillus fumigatus), A. oryzae was unique in possessing four chalcone synthase (CHS)-like genes (csyA, csyB, csyC, and csyD). Expression of csyA, csyB, and csyD genes was confirmed by RT-PCR. Comparative genome analyses revealed single putative type III PKS in Neurospora crassa and Fusarium graminearum, two each in Magnaporthe grisea and Podospora anserina, and three in Phenarocheate chrysosporium, with a phylogenic distinction from bacteria and plants. Conservation of catalytic residues in the CHSs across species implicated enzymatically active nature of these newly discovered homologs. 相似文献