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981.
本文从数学角度分析和研究了螺旋对称病毒衣壳参数、整理出衣壳参数20多个,对每一个参数的概念、含义等给予了明确的认定。提示了参数间的关系,推导出了一些计算参数值的公式。 相似文献
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Whereas protein disulfide isomerase (PDI) and prolyl isomerase (PPI) are considered as efficient protein folding catalysts, very few large scale processes use them because of economical and technical limitations. PDI and PPI were successfully immobilized on cross-linked agarose beads. PDI inactivation during coupling reaction was overcome by oxidizing active site thiols with dimethylsulfoxide and led to a 64% active enzyme. Alternatively, PPI and PDI biotinylation resulted in 100% and 55-66% active enzymes respectively. The use of these modified catalysts suppresses post-refolding purification and enables the design of biochemical reactors. Several other possible applications are also discussed. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 56: 645-649, 1997. 相似文献
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Rui Wang Jingman Ni Xiaoyu Hu Yaping Ma Xiangqun Li Dingjian Yang Shouliang Dong Xiaowu Yang Xinfu Pan 《中国科学C辑(英文版)》1997,40(5):518-523
The second zinc finger fragment of Sp1 (Sp1-ZF2), its mutant (Sp1-ZF2/HT. E20 → H, R23 → T), and two mimic analogues (ZF20 and ZF15) were synthesized by stepwise solid phase technique. The CD spectra and UV-visible spectrum with CoC12 indicated that the formation of zinc finger structure was affected not only by the hydrophobic amino acids but also by the change of the distance between Cys and His. Gel-retardat ion electrophoresis assays indicated that the Glu and Arg residues are very important for recognition. A single zinc finger like Sp1-ZF2 is able to bind DNA sequence specifically. 相似文献
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The Rev axis of HIV autoregulation is one of two critical viral regulatory pathways required for expression of viral genomic and mRNA and for replication. Consequently it is an attractive therapeutic target. Previous studies have investigated the anti-HIV efficacy of targeting to the RRE (the viral RNA target sequence of the Rev axis) a trans-dominant negative inhibitor mutant Rev, M10. In this study we have fused a portion of the influenza virus NS1 protein (which normally inhibits polyA(+) mRNA transport and splicing) to the Rev M10 gene while deleting the NS1 poly(A) binding region. The resulting chimera demonstrates specific and enhanced inhibition of viral-RRE-containing RNA expression. 相似文献
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Bao-He Qu Elizabeth Strickland Philip J. Thomas 《Journal of bioenergetics and biomembranes》1997,29(5):483-490
Cystic fibrosis (CF) is caused by mutations in the gene that encodes the cystic fibrosis transmembrane conductance regulator, CFTR. Previously we demonstrated that the common F508 mutation in the first nucleotide binding domain (NBD1) alters the ability of the domain to fold into a functional three-dimensional structure, providing a molecular explanation for the observation that the mutant CFTR is retained in the endoplasmic reticulum and does not traffic to the apical membrane of affected epithelial cells. Notably, when conditions are altered to promote folding of the mutant protein, it can assume a functional conformation. Correcting the folding defect may have therapeutic benefit for the treatment of cystic fibrosis. Here we summarize these results and discuss the implications in vitro folding studies have for understanding the pathobiology of CF. 相似文献
990.
Ying Qu Lieve Moons Frans Vandesande 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1997,704(1-2)
An isocratic liquid chromatographic method with electrochemical detection for the determination of
-3,4-dihydroxyphenylalanine, dopamine, norepinephrine, epinephrine, serotonin, and their major metabolites, 3,4-dihydroxyphenylacetic acid, 4-hydroxy-3-methoxyphenylacetic acid and 5-hydroxyindole-3-acetic acid in chicken brain tissue is described. Chickens were killed at different ages, the brains were quickly frozen and 300-μm cryostat sections were made. From these sections, two to six tissue micropunches (1 mm in diameter) were punched out from 20 different areas of the hypothalamus and homogenated in 100 μl 0.1 M perchloric acid which included 0.01% cysteine as antioxidant. Fifty-μl supernatants were injected directly onto the LC system, separated on a 3-μm Phase II ODS column (100×3.2 mm I.D.) and detected by an electrochemical detector at a potential of +0.75 V. Standard curves, recoveries, analytical precision and detection limits were investigated for each monoamine neurotransmitter and its metabolites. The method was applied to study the influence of food restriction on the concentration of monoamine neurotransmitters in different brain areas, known to be involved in feeding and reproductive behaviour of female broiler chickens. Over 1000 micropunched tissue samples from ad libitum fed and food-restricted female broiler chickens were analyzed. Our results provide a possible role for catecholamines and indolamines in the altered feeding and reproductive behaviour of the broiler chicken. 相似文献
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