| 1. |
- Duan, Ming-Rui, et al.
(författare)
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DNA binding mechanism revealed by high resolution crystal structure of Arabidopsis thaliana WRKY1 protein
- 2007
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 1362-4962 .- 0305-1048. ; 35:4, s. 54-1145
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Tidskriftsartikel (refereegranskat)abstract
- WRKY proteins, defined by the conserved WRKYGQK sequence, are comprised of a large superfamily of transcription factors identified specifically from the plant kingdom. This superfamily plays important roles in plant disease resistance, abiotic stress, senescence as well as in some developmental processes. In this study, the Arabidopsis WRKY1 was shown to be involved in the salicylic acid signaling pathway and partially dependent on NPR1; a C-terminal domain of WRKY1, AtWRKY1-C, was constructed for structural studies. Previous investigations showed that DNA binding of the WRKY proteins was localized at the WRKY domains and these domains may define novel zinc-binding motifs. The crystal structure of the AtWRKY1-C determined at 1.6 A resolution has revealed that this domain is composed of a globular structure with five beta strands, forming an antiparallel beta-sheet. A novel zinc-binding site is situated at one end of the beta-sheet, between strands beta4 and beta5. Based on this high-resolution crystal structure and site-directed mutagenesis, we have defined and confirmed that the DNA-binding residues of AtWRKY1-C are located at beta2 and beta3 strands. These results provided us with structural information to understand the mechanism of transcriptional control and signal transduction events of the WRKY proteins.
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| 2. |
- Fu, Tian-Min, et al.
(författare)
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Protein preparation, crystallization and preliminary X-ray analysis of the C-terminal domain of human RSK1 serine/threonine protein kinase
- 2007
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Ingår i: Acta Crystallographica. Section F: Structural Biology and Crystallization Communications. - 2053-230X. ; 63:Pt 12, s. 8-1026
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Tidskriftsartikel (refereegranskat)abstract
- As a substrate of extracellular signal-related kinase (ERK), the p90 ribosome S6 kinase 1 (RSK1) is at the terminus of the Ras/ERK pathway. Residues 411-735 of human RSK1, covering the C-terminal serine/threonine kinase catalytic domain and the functionally important tail, were cloned into an Escherichia coli expression vector. The protein was expressed, purified and crystallized. The crystals diffracted to 2.7 A and belonged to space group P2(1), with unit-cell parameters a = 39.8, b = 143.8, c = 59.9 A, beta = 95.7 degrees.
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| 3. |
- Li, Gui-Lan, et al.
(författare)
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Open-closed conformational change revealed by the crystal structures of 3-keto-L-gulonate 6-phosphate decarboxylase from Streptococcus mutans
- 2009
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Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 1090-2104 .- 0006-291X. ; 381:3, s. 33-429
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Tidskriftsartikel (refereegranskat)abstract
- The 3-keto-L-gulonate 6-phosphate decarboxylase (KGPDC) catalyses the decarboxylation of 3-keto-L-gulonate 6-phosphate to L-xylulose in the presence of magnesium ions. The enzyme is involved in L-ascorbate metabolism and plays an essential role in the pathway of glucuronate interconversion. Crystal structures of Streptococcus mutans KGPDC were determined in the absence and presence of the product analog D-ribulose 5-phosphate. We have observed an 8 A alphaB-helix movement and other structural rearrangements around the active site between the apo-structures and product analog bound structure. These drastic conformational changes upon ligand binding are the first observation of this kind for the KGPDC family. The flexibilities of both the alpha-helix lid and the side chains of Arg144 and Arg197 are associated with substrate binding and product releasing. The open-closed conformational changes of the active site, through the movements of the alpha-helix lid and the arginine residues are important for substrate binding and catalysis.
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| 4. |
- Tian, Yu-Peng, et al.
(författare)
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Investigations and facile synthesis of a series of novel multi-functional two-photon absorption materials
- 2007
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 17:34, s. 3646-3654
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Tidskriftsartikel (refereegranskat)abstract
- Six centrosymmetric D-(pi-A)(3) structural triphenylamine derivatives that can be used as two- photon photopolymerization and optical data storage chromophores, tris[ 4-( 4- pyridylethenyl) phenyl] amine ( 1), tris[ 4-( 2- pyridylethenyl) phenyl] amine ( 2), tris( 4- cyanoethenylphenyl) amine ( 3), tris[ 4- butylacrylatephenyl] amine ( 4), tris[ 4- methylacrylatephenyl] amine ( 5) and tris[ 4- acrylicethenylphenyl] amine ( 6), have been successfully synthesized via a triple palladium-catalyzed Heck coupling reaction, and the novel chromophores were fully characterized by elemental analysis, IR, (1)H-NMR and ESIMS. The structure for 3 was determined by single crystal X-ray diffraction study. One- and two-photon absorption and fluorescence in various solvents were experimentally investigated. Two-photon initiated polymerization microfabrication and optical data recording experiments were carried out under 780 nm laser radiation, and the possible polymerization mechanism is discussed based on theoretical calculations. All the six chromophores have relatively large two-photon absorption crosssections, and exhibit optical memory and highly efficient two-photon initiated polymerization abilities.
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| 5. |
- Wang, Yong, et al.
(författare)
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mRNA expression of minichromosome maintenance 2 in colonic adenoma and adenocarcinoma
- 2009
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Ingår i: EUROPEAN JOURNAL OF CANCER PREVENTION. - 0959-8278. ; 18:1, s. 40-45
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Tidskriftsartikel (refereegranskat)abstract
- As proliferation is essential for Progression from normal cells to tumor, certain markers specific to proliferating cells may permit detection of premalignant lesions. Here, we aimed to evaluate the possible value of a proliferation marker, minichromosome maintenance 2 (MCM2), in the early diagnosis of colorectal cancer, by analyzing the difference in MCM2 expression among normal mucosa, adenoma, and adenocarcinoma, and investigating the relationship of MCM2 expression in adenomas with clinicopathologic variables. Using immunohistochemistry and real-time reverse transcription-PCR, we observed that the expression of MCM2 protein was present on basal third to half of colonic crypts in normal mucosa, whereas throughout the epithelium in adenomas and adenocarcinomas, the expression of MCM2 mRNA in adenocarcinomas was significantly higher than in adenomas (P=0.001), whereas the difference between adenoma and normal mucosa was not significant (P=0.184); we also found that the expression of MCM2 mRNA tended to be increased in the adenomas with high-grade dysplasia, or in older patients, respectively, compared with those with low-grade dysplasia, and younger patients. These results suggested the potential value of MCM2 in early diagnosis of colorectal cancer.
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| 6. |
- Brostromer, Erik, et al.
(författare)
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Solid-liquid interface method (SLIM) : a new crystallization method for proteins
- 2009
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Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 1090-2104 .- 0006-291X. ; 386:4, s. 8-634
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Tidskriftsartikel (refereegranskat)abstract
- Despite impressive advances in theories, methods and technologies, crystallization still remains a serious bottleneck in structural determination of macromolecules. Here we present a novel solid-liquid interface method (SLIM) for protein crystallization, based on the pre-adding and drying of a crystallization reagent, and thereafter the dispensing of a protein solution to the dried media to initiate crystallization from the solid-liquid interface. Not only quick and easy to perform, the method also allows for a less concentrated protein solution for setting up crystallization trials.
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| 7. |
- Hering, Bernhard J., et al.
(författare)
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Prolonged diabetes reversal after intraportal xenotransplantation of wild-type porcine islets in immunosuppressed nonhuman primates
- 2006
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Ingår i: Nature Medicine. - : Nature Publishing Group. - 1078-8956 .- 1546-170X. ; 12:3, s. 301-303
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Tidskriftsartikel (refereegranskat)abstract
- Cell-based diabetes therapy requires an abundant cell source. Here, we report reversal of diabetes for more than 100 d in cynomolgus macaques after intraportal transplantation of cultured islets from genetically unmodified pigs without Gal-specific antibody manipulation. Immunotherapy with CD25-specific and CD154-specific monoclonal antibodies, FTY720 (or tacrolimus), everolimus and leflunomide suppressed indirect activation of T cells, elicitation of non-Gal pig-specific IgG antibody, intragraft expression of proinflammatory cytokines and invasion of infiltrating mononuclear cells into islets.
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| 8. |
- Jiang, Jie, et al.
(författare)
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Integrated direct DNA/protein patterning and microfabrication by focused ion beam milling
- 2008
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Ingår i: Advanced Materials. - : John Wiley & Sons. - 0935-9648 .- 1521-4095. ; 20:9, s. 1636-1643
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Tidskriftsartikel (refereegranskat)abstract
- Single and binary component patterning and integrated microfabrication of biomolecules, such as DNA and proteins, can be achieved by focused ion-beam (FIB) biolithography. Well-defined micropatterns are obtained by FIB milling on biomolecules immobilized on SiO2 wafers and protected by a thin Au film. The retention of biofunctionality is excellent (68–90%) and a feature size of down to 500 nm can be achieved for the patterns without significant loss of functionality.
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| 9. |
- Jun, Chen, et al.
(författare)
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A Novel Acceleration Data Compression Scheme for Wireless Sensor Network Application in Fresh Food Tracking System
- 2009
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Ingår i: The Ninth International Conference on Electronic Measurement & Instruments ICEMI’2009. - : IEEE Press. - 9781424438631 ; , s. 3-1-3-5
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Konferensbidrag (refereegranskat)abstract
- An enhanced dual-layer wide area wireless sensor network (WSN) system was developed and applied in fresh food tracking application. The sensor nodes of WSN provide a set of useful measurements about the environmental conditions during the fresh food transportation. Since the 3-axis acceleration data in such application account for more than 99% out of all collected source data, we propose a novel acceleration data compression scheme for this specific application, to overcome the resource and cost limitation imposed on embedded sensing nodes and wireless communication links in WSN. According to general fresh food transport behavior pattern, the acceleration data can be extracted into three components (D waveform, A waveform and P waveform). Each component could be compressed separately according to its distinct characteristic and then packetized as an encoded frame. In this paper we examine the experimental acceleration dataset from a field test (fresh melon fruit transport from Brazil to Sweden in 20 days) as a test case. Experimental results show that a high compression ratio (around 10:1) with the acceptable distortion could be achieved, confirming the effectiveness of the compression scheme proposed in this work.
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| 10. |
- Li, Jie, et al.
(författare)
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Heat stress alters G-protein coupled receptor-mediated function and endothelium-dependent relaxation in rat mesenteric artery
- 2008
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Ingår i: European Journal of Pharmacology. - : Elsevier BV. - 1879-0712 .- 0014-2999. ; 588:2-3, s. 280-285
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Tidskriftsartikel (refereegranskat)abstract
- Heat stress has been demonstrated to have strong cardiovascular effects. However, the underlying mechanism-mediated cardiovascular effects are still not fully understood. The present study was designed to examine if heat stress alters vascular G-protein coupled receptor-mediated vasomotion and endothelium function in rat mesenteric artery. Rats were divided into two groups, heat stress rats and control. The G-protein coupled receptors of endothelin type B (ETB) receptor-, endothelin type A (ETA) receptor-, 5-hydroxytryptamine (5-HT) receptor-, calcitonin gene-related peptide (CGRP) receptor-, alpha-adrenoceptor-mediated vosoactivity and endothelium-dependent relaxation on rat mesenteric artery ring segments were monitored by a myograph system. The plasma level of CGRP was determined by radioimmunological assay. Compared with control arterial segments, the contractile response curves of sarafotoxin 6c, a selective ETB receptor agonist and 5-HT in the arterial segments from heat stress rats were shifted towards left. An increased maximum contraction (E-max) induced by sarafotoxin 6c, but not 5-HT, was seen in the arterial segments from heat stress rats. CGRP-incluced relaxation in endothelium-denuded arterial segments from heat stress rats was enhanced. The relaxation in endothelium-intact arterial segments induced by acetylcholine was significantly decreased in heat stress rats. In addition, the plasma concentration of CGRP was increased in heat stress rats. The endothelium-dependent relaxation was characterized and shown there was a decrease in nitric oxide and endothelium-derived hyperpolarising factor-mediated relaxation in the arterial segments from heat stress rats. In conclusion, heat stress induces an enhanced vascular endothelin ETB-, 5-HT-receptors-mediated contraction, an enhanced CGRP-receptor-induced relaxation and damage to endothelium-dependent relaxation.
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