检索结果-南通市图书馆

The in vitro reconstitution of nucleosome and its binding patterns with HMG1/2 and HMG14/17 proteins

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Cell Research 2003年第5期13卷 351-359页

作者： SHU BING ZHANG, JIAN HUANG, HUI ZHAO, YI ZHANG, CHUN HuI HOU, XIAO DONG CHENG, CHU JIANG, MIN QIAN LI, JUN HU, RUO LAN QIAN 1 Group of Globin Gene Expression and Regulation, state key laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, shanghai Institutes for Biological sciences, chinese academy of sciences, shanghai 200031, China. 2 shanghai Institute of Nuclear Research, chinese academy of sciences, shanghai 201800, China Group of Globin Gene Expression and Regulation State Key Laboratory of Molecular Biology Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai 200031 China

Using atomic force microscopy (AFM), the dynamic process of the in vitro nucleosome reconstitution followed by slow dilution from high salt to low salt was visualized. Data showed that the histone octamers were dissociated from DNA at 1M NaCl. When the salt concentration was slowly reduced to 650 mM and 300 mM, the core histones bound to the naked DNA gradually. Once the salt concentration was reduced to 50 mM the classic 'beads-on-astring' structure was clearly visualized. Furthermore, using the technique of the in vitro reconstitution of nucleosome, the mono- and di- nucleosomes were assembled in vitro with both HS2core (-10681 to -10970 bp) and NCR2 (-372 to -194 bp) DNA sequences in the 5’flanking sequence of human b-globin gene. Data revealed that HMG 1/2 and HMG 14/17 proteins binding to both DNA sequences are changeable following the assembly and disassembly of nucleosomes. We suggest that the changeable binding patterns of HMG 14/17 and HMG1/2 proteins with these regulatory elements may be criti

关键词： atomic force microscopy HMG proteins (HMG1/2 and HMG14/17) human β-globin gene in vitro reconstitution nucleosome.

Conformational flexibility of β-secretase: molecular dynamics simulation and essential dynamics analysis

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Pharmacologica Sinica 2004年第6期25卷 3-11页

作者： Bing XIONG, Xiao-qin HUANG, Ling-ling SHEN, Jian-hua SHEN 2,Xiao-min LUO, Xu SHEN, Hua-liang JIANG2, Kai-xian CHENDrug Discovery and Design Center, state key laboratory of Drug Research, shanghai Institute of Materia Medica,shanghai Institutes for Biological sciences, chinese academy of sciences, shanghai 201203, China Drug Discovery and Design Center State Key Laboratory of Drug Research Shanghai Institute of Materia Medica Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai 201203 China

AIM: Based on the structural analysis to reveal the mechanism of ligand binding to b-secretase and the specificityof each binding sub-site. METHODS: Molecular dynamics was used to simulate on the ligand free b-secretase andligand bound b-secretase. The trajectories were analyzed using the essential dynamics, and the significant confor-mational change was illustrated employing the DynDom program. RESULTS: The essential dynamics and DynDomanalyses clearly showed that the b-secretase experienced a large conformational change upon the substrate orinhibitor binding. The flap structure adopted a swing motion, gradually covering the active site to facilitate theligand binding process. Residues Ser86 and Ile87 served as the hinge point. Inhibitor-enzyme interaction analysisrevealed that residues at P2, P1, and P1 positions of the inhibitor were very important for the binding, and residuesat P2 and P3 positions may be modified to improve the binding specificity. S3 subsite of the enzyme still hadspace to modify the inhibitors in increasing the binding affinity. CONCLUSION: The information presented hereis valuable and could be used to identify small molecular inhibitors of b-secretase.

关键词： molecular dynamics secretase essential dynamics computer simulation Alzheimer disease

Interaction of rice bZIP protein REB with the 5'-upstream region of both rice sbe1 gene and waxy gene

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

chinese Science Bulletin 2002年第4期47卷 310-314页

作者： CAI Yi, XIE Donglu, WANG Zongyang & HONG Mengminstate key laboratory of Plant Molecular Genetics, shanghai Institute of Plant Physiology and Ecology, chinese academy of sciences, shanghai 200032, China state key laboratory of Plant Molecular Genetics Shanghai Institute of Plant Physiology and Ecology Chinese Academy of Sciences Shanghai China

Rice starch branching enzyme 1 (SBE1) and granule-bound starch synthase (GBSS) catalyzed the bio-synthesis of amylopectin and amylose in rice developing en-dosperm respectively, and the genes encoding these two en-zymes, sbe1 and waxy, are mainly expressed in the en-dosperm. Within the 5 ’-upstream region of rice sbel gene, we identified a 53 bp fragment C53 which could interact with the nuclear proteins extracted from rice endosperm. We also found that fragment Ha-2 in the 5 ’-upstream region of rice waxy gene could compete with C53 for its interaction. Fur-ther experiments demonstrated that rice bZIP protein REB could interact with two ACGT elements (G-box and Hex) in the fragment C53 as well as three ACGT elements (WG1, WG2, and WG3) in the fragment Ha-2. The WG1 element could compete well with Hex element for its interaction with REB. These results suggested that the expression of sbel and waxy gene in rice developing endosperm may be coordinately regulated by REB-like bZIP transcriptional factors.

关键词： rice waxy gene sbel gene bZIP protein.

Photosensitized damage to telomere overhang and telomerase RNA by riboflavin

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2008年第4期18卷 401-404页

作者： Yuxia Liu, Fuqiang Du, Weizhen Lin , Tiecheng Tu, Wenxin Li, Nianyun Lin key laboratory of Nuclear Analysis Techniques, shanghai Institute of Applied Physics, chinese academy of sciences, shanghai 201800, China key laboratory of Nuclear Analysis Techniques Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China

By ESR spin elimination and photocleavage assay, the mechanisms of one-electron oxidation damage of oligonucleotides by excited triplet state of riboflavin (Rb) have been elucidated. The results demonstrate that Rb, an endogenous photosensitizer, is capable of cleav- ing single-stranded telomeric overhang and the template region of telomerase RNA under UVA irradiation, resulting in blocking of reverse transcription of telomeric DNA which leads to the apoptosis of cancer cells ultimately.

关键词： Telomere Telomerase Riboflavin ESR spin elimination Excited triplet state

COALESCENCE INDUCED GRADIENT MORPHOLOGY NEAR A WALL IN PHASE SEPARATED POLYMER BLENDS DURING QUIESCENT ANNEALING

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

chinese Journal of Polymer Science 2002年第6期20卷 543-550页

作者： Wei Yu Chi-xing Zhou De-lu Zhao Department of Polymer Science and Engineering, shanghai Jiao Tong University, shanghai 200240 China state key laboratory of Polymer Physics and Chemistry, Institute of Chemistry, chinese academy of sciences Beijing 100080, China shanghai Jiao Tong Univ Dept Polymer Sci & Engn Shanghai 200240 Peoples R China chinese Acad Sci Inst Chem State Key Lab Polymer Phys & Chem Beijing 100080 Peoples R China

A fast coalescence mechanism is proposed to account for the wall effect on the formation of gradient morphology in phase separated polymer blends during quiescent annealing. The existence of solid wall with high polarity is believed to change the potential field around the dispersed particles near the wall. This additional potential interaction between the solid wall and the dispersed particles causes faster coalescence of the dispersed particles near the wall than in the bulk. The gradient phase morphology thus formed can be predicted by combining the wall-particle interaction and the touch-coalescence mechanism. The effect of interfacial tension on the gradient morphology is also discussed.

关键词： gradient morphology wall effect coalescence polymer blends interfacial tension

Enantioselective synthesis of two key intermediates for leukotrienes A_4 and B_4

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Chemistry 1994年第6期12卷 562-564页

作者： WU, Wen-Lian LI, Jing WU, Yu-Linstate key laboratory of Bio-organic & Natural Products Chemistry, shanghai Institute of Organic Chemistry, chinese academy of sciences, 354 Fenglin Road, shanghai 200032, China state key laboratory of Bio‐organic & Natural Products Chemistry Institute of Organic Chemistry chinese academy of Science 354 Fenglin Road Shanghai 20032 China

Leukotrienes, arachidonic acid derived metabolites of great biological signifi-cance, are present in tissue at extremely low concentrations, so that experimentalquaatities are only accessible by chemical synthesis. In various synthetic routes,[S,S-（E）]-3-（hydroxymethyl） oxiranebutanoic acid methyl ester （1） and （S）-5-（ben-zoyloxy）-6-oxohexanoic acid methyl ester （2） have been frequently used as the C-Cfragment of LTA3 and the C-Cfragment of LTB4, respectively. （Scheme1）

关键词： Synthesis leukotriene chiron reductive cleavage reaction.

Distribution and origin of biologically available phosphorus in the water of the Meiliang Bay in summer

在线全文

学校读者我要写书评

暂无评论

Science China Earth sciences 2006年第z1期49卷 146-153页

作者： HUANG Qinghui, WANG Zijian, WANG Donghong, MA Mei & WANG Chunxia state key laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental sciences, chinese academy of sciences, Beijing 100085, China key laboratory of Yangtze Aquatic Environment (Ministry of Education), College of Environmental Science and Engineering, Tongji University, shanghai 200092, China chinese Acad Sci Ecoenvironm Sci Res Ctr State Key Lab Environm Aquat Chem Beijing 100085 Peoples R China Tongji Univ Coll Environm Sci & Engn Minist Educ Key Lab Yangtze Aquat Environm Shanghai 200092 Peoples R China

The investigation and continuous monitoring with an innovative iron oxide embedded cellulose acetate membrane (FeO/CAM) on the concentrations of biologically available phosphorus (BAP) were conducted in the Meiliang Bay of the Taihu Lake during summer in 2004. The results showed that the concentrations of dissolved (FeO-DP), particulate (FeO-PP) and total bioavailable phosphorus (FeO-P) had similar horizontal distribution. The BAP concentrations were the highest in those estuaries in the northern bay. With the decrease of the distance to the estuary or long shore,there was little difference between BAP concentrations in an open lake area. During the observation period, algal blooms occurred in most waters of the northern bay, which was reflected from the high concentrations of chlorophyll a (Chl-a). While they were not highest in the estuarine waters of those major rivers, this is the case for the BAP concentrations. The concentrations of Chl-a had a significantly positive correlation with those of bioavailable phosphorus in the open area of the Meiliang *** the sediment resuspension induced by wind and wave, BAP concentrations increased in a short-term, indicating that the riverine P inputs mainly contribute to the concentrations of BAP in the estuarine water while internal P release was the major source of BAP in the open lake area. In the eutrophic shallow lake, the blooms of alga may cause pH increase and further result in internal P release. The above results showed that the new membrane of FeO/CAM can be used to monitor the concentrations of BAP and provide the scientific justifications for the control strategy of the lake eutrophication.

关键词： phosphorus, bioavailability, eutrophication, resuspension, Taihu Lake.

Suppressed Antiferromagnetism and Superconductivity in As-deficient Iron-based Superconductor of SrFe_(1.8)Co_(0.2)As_x

在线全文

学校读者我要写书评

暂无评论

稀有金属材料与工程 2011年第S3期40卷 358-361页

作者： Liu Zhiyong1, Lu Yuming1, Liu Jinlei1, Qu Chunqing1,2,3, Chen Changzhao1, Cai Chuanbing1, Huang Fuqiang3, Xie Xiaoming2 1 shanghai University, shanghai 200444, China 2 state key laboratory of Functional Materials for Informatics,shanghai Institute of Microsystem and Information technology,chinese academy of sciences,shanghai 2.0050, China 3 shanghai Institute of Ceramics, chinese academy of sciences, shanghai 2.0050, China shanghai Univ Res Ctr Superconductors & Appl Technol Shanghai 200444 Peoples R China chinese Acad Sci Shanghai Inst Microsyst & Informat Technol State Key Lab Funct Mat Informat Shanghai 200050 Peoples R China chinese Acad Sci Shanghai Inst Ceram Shanghai 200050 Peoples R China

Iron-based superconductors namely Sr(Fe1.8Co0.2)As1.8 (FeAs1.8) and Sr(Fe1.8Co0.2)As1.85 (FeAs1.85) with As deficiency are prepared by solid-state reaction. X-ray diffraction reveals that the polycrystalline phase forms in the studied samples, identical to typical SrFe2As2 (122) matrix. Resistive and magnetic measurements show that the superconducting transition temperatures (Tc) are about 19 K for both FeAs1.8 and FeAs1.85. Compared with the performances of typical iron-based 122 superconductors arising from Co doping, the present samples show the suppressed superconductivity. Moreover, the antiferromagnetic (AFM) phase correlated with spin-density-wave (SDW) is reduced as well. The AFM transition temperature decreases to 122 K for FeAs1.85, while such a phase transition is absent at all for FeAs1.8, one sample with less As, implying that the existence of SDW and antiferromagnetism is more sensitive to As content.

关键词： antiferromagnetism superconductivity iron-based superconductors

Identification of a NF-кB site in the negative regulatory element (ε-NRAII) of human ε-globin gene and its binding protein NF-кB p50 in the nuclei of K562 cells

在线全文

学校读者我要写书评

暂无评论

Cell Research 2002年第1期12卷 79-82页

作者： CHUN Hui HOU, JIAN HUANG, Ruo LAN QIAN Group of Globin Gene Expression and Regulation, state key Labortory of Molecular Biology, Institute of Biochemistry and Cell Biology, shanghai Institutes for Biological sciences, chinese academy of sciences, shanghai Group of Globin Gene Expression and Regulation Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences State Key Labortory of Molecular Biology 上海 200031 Group of Globin Gene Expression and Regulation Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences State Key Labortory of Molecular Biology 上海 200031

The developmental control of the human e-globin gene expression is mediated by transcription regulatory elements in the 5’ flanking DNA of this gene. Sequence analysis has revealed a DNA motif (GGGGAATTTGCT) similar to NF-кB consensus sequence resides in the negative regulatory element (-3028bp～ -2902bp, termed ε-NRAII) 5’ to the cap site of this gene. NRF DNA fragment (-3010bp～ -2986bp) containing the NF-кB motif similar sequence was synthesized and used in electrophoresis mobility shift assay (EMSA) and competitive analysis. Data showed that a protein factor from nuclear extracts of K562 cells specifically interacted with NRF DNA fragment. The synthetic NF DNA fragment (containing NF-кB consensus sequence) could competed for the protein binding, but MNF DNA fragment (mutated NF-кB motif) could not, suggesting that the binding protein is a member of NF-кB/Rel family. Western blot assay demonstrated that the molecular weight of NF-кB protein in the nuclei of K562 cells is 50ku. We suggested that NF-кB p50 may play an important role in the regulation of human c-globin gene expression.

关键词： Human ε-globin gene negative regulatory element NE-кB p50.