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植物耐盐基因工程研究进展 总被引:2,自引:0,他引:2
盐害是影响植物生长和作物产量的主要因素之一。用于提高植物耐盐性的基因工程方法很多,最常见的就是在植物中过量表达抗盐相关的功能基因,包括植物信号传导蛋白基因、植物离子通道蛋白基因和合成小分子渗透剂的酶基因等。归纳了近年来植物耐盐基因工程的研究进展,并展望了植物耐盐基因工程的研究前景。 相似文献
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新疆盐生植物的钙调蛋白基因克隆与序列分析 总被引:4,自引:0,他引:4
采用RT-PCR扩增的方法,从新疆盐生植物花花柴(Karelinia caspica)、盐爪爪(Kalidium foliadum)和盐桦(Betula halophila)中分别克隆获得了450bp的cDNA片段.基因测序和序列同源性分析的结果表明,所克隆的基因片段均包含了钙调蛋白基因完整的读码框架.新疆花花柴钙调蛋白基因与盐爪爪钙调蛋白基因同源性达86%,盐爪爪与盐桦同源性达86.77%,花花柴与盐桦同源性达85.11%.新疆盐生植物钙调蛋白基因与其它已发表的植物钙调蛋白基因同源性均在80%以上,显示植物钙调蛋白基因具有高度保守性. 相似文献
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盐胁迫下植物细胞离子稳态重建机制 总被引:24,自引:6,他引:18
土壤盐渍化是困扰世界粮食产量的一大难题。在盐胁迫环境中,植物获得耐盐能力的一个重要策略是建立新的离子稳态(ionic homeostasis)。盐胁迫下植物细胞离子稳态依赖于膜转运蛋白(泵、载体和离子通道)。利用蛋白质的生化功能分析和突变体功能互补等方法,目前已克隆和鉴定了许多参与离子稳态重建的膜转运蛋白。综述了盐胁迫下植物细胞离子稳态重建的最新研究进展。 相似文献
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盐生植物是指能在离子浓度至少200 mmol/L以上的生境中生长并完成生活史的植物。盐生植物可分为稀盐盐生植物、泌盐盐生植物、拒盐盐生植物三类。本文从生长形态、生理和分子3个方面总结三类盐生植物响应盐胁迫的不同策略及研究进展,发现盐生植物在分子水平上主要通过Na+转运蛋白和为其提供能量的两类基因应对体内过高Na+,这可能是引起盐生植物生理和生长形态异于非盐生植物的重要因素。其中稀盐盐生植物主要通过液泡离子区隔化应对盐胁迫,并表现出肉质化生长形态;泌盐盐生植物通过将体内盐分排出体外应对盐胁迫,并进化出特有的生理结构——盐腺或盐囊泡;拒盐盐生植物通过将盐离子积累在皮层细胞液泡和根部木质部薄壁细胞中减少向上运输Na+,同时根部多栓质化减少Na+吸收。本综述旨在为今后研究盐生植物及其耐盐机制提供相关依据,为植物耐盐分子育种奠定基础。 相似文献
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M蛋白是新城疫病毒(Newcastle disease virus,NDV)基因组编码的一种非糖基化膜相关蛋白,主要位于病毒囊膜内表面,构成病毒囊膜与核衣壳连接的支架。研究表明,M蛋白是一种细胞核-细胞质穿梭蛋白,在抑制细胞基因转录和蛋白质合成以及协助病毒粒子组装和出芽方面发挥了重要作用。目前,国内外对NDV毒力和复制的关系研究主要集中在病毒的F、HN和V蛋白以及RNP复合体,但是近年来研究人员利用反向遗传操作技术研究发现M蛋白与NDV毒力和复制也存在一定的联系。因此,本文主要对NDV M蛋白的结构特征、M蛋白对NDV毒力和复制的影响及其作用机制进行综述,以期为NDV M蛋白的功能研究提供新的理论参考。 相似文献
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An alteration of the human c-abl protein in K562 leukemia cells unmasks associated tyrosine kinase activity 总被引:104,自引:0,他引:104
The v-abl protein is known to be a tyrosine-specific protein kinase. However, its normal cellular homolog, c-abl P150, is not detectably phosphorylated on tyrosine in vivo or in vitro. The lack of associated tyrosine kinase activity for the c-abl protein seems paradoxical since it is the c-abl-derived sequences of the v-abl protein that encode the kinase activity. We have detected an altered human c-abl protein (P210) with associated tyrosine kinase activity in the K562 leukemia cell line. K562 cells are known to have a 9:22 chromosomal translocation involving the c-abl locus and have amplified the c-able gene 4 to 8 fold. The altered P210 human c-abl is serologically and structurally related to the normal c-abl protein. A structural alteration of the human c-abl protein. K562 cells may have unmasked its associated tyrosine kinase activity. This altered c-abl protein may have important implications for a mechanism of activation of this oncogene. 相似文献
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Phosphorylation is an effective method of post-translational protein modification but understanding its significance is hindered by its biological complexity. Many protein kinases and phosphatases have been identified that connect signal perception mechanisms to plant defence responses. Recent studies of mitogen-activated protein kinases, calcium-dependent protein kinases and other kinases and phosphatases have revealed some important mechanisms, but have also raised new questions. The regulation of any phosphorylation pathway is complex and dynamic. There are many protein kinases and phosphatases in the plant genome, which makes it hard to delineate the phosphorylation machinery fully. Genomics and proteomics have already identified new components and will continue to influence the study of phosphorylation profoundly in plant-pathogen interactions. 相似文献
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M Mariappan N Selvamurugan C Rajamanickam 《Archives of biochemistry and biophysics》1990,281(2):287-297
A relatively high-molecular-weight polypeptide was found in rat serum within 6 h after aortic constriction in experimental animals. This polypeptide persists for about 7 days of the postoperative period and disappears at later stage of hypertrophy (40%). Further, fractionation and purification of this protein through DEAE-Sepharose and gel filtration chromatography have revealed that this protein is a single polypeptide and its relative molecular weight is 135 kDa. Immunoprecipitation and immunofluorescence microscopic analysis have indicated the presence of the above polypeptide in the nuclear fraction of heart cells. Studies on phosphorylation in vitro have revealed that this protein is a phosphoprotein. DNase I sensitivity and hybridization using a muscle specific gene probe have indicated the involvement of this protein in template associated changes in heart nuclei. Further the possibility of this protein being synthesized by heart cells indicates that this protein could traverse back and forth between heart cells and the extracellular fluid, suggesting an autocrine/paracrine role for this protein during the development of cardiac hypertrophy. 相似文献
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We have purified a nucleoplasmin-like protein from the nuclei of somatic Xenopus laevis cells. This protein possesses a number of the distinctive features of nucleoplasmin isolated from oocytes or unfertilized eggs. The protein is recognized by both monoclonal and polyclonal antisera raised against egg nucleoplasmin. The protein has an oligomeric structure, which must be heated in SDS to completely dissociate, is acidic, phosphorylated and efficiently promotes the in vitro formation of chromatin. We have partially characterized this novel protein and because of its resemblance to nucleoplasmin isolated from oocytes or unfertilized eggs we have named this protein nucleoplasmin S. 相似文献
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Prasad?S. Sarangapani Steven?D. Hudson Ronald?L. Jones Jack?F. Douglas Jai?A. Pathak 《Biophysical journal》2015,108(3):724-737
Recent studies of globular protein solutions have uniformly adopted a colloidal view of proteins as particles, a perspective that neglects the polymeric primary structure of these biological macromolecules, their intrinsic flexibility, and their ability to sample a large configurational space. While the colloidal perspective often serves as a useful idealization in many cases, the macromolecular identity of proteins must reveal itself under thermodynamic conditions in which the native state is no longer stable, such as denaturing solvents and high protein concentrations where macromolecules tend to have screened excluded volume, charge, and hydrodynamic interactions. Under extreme pH conditions, charge repulsion interactions within the protein chain can overcome the attractive hydrogen-bonding interactions, holding it in its native globular state. Conformational changes can therefore be expected to have great significance on the shear viscosity and other rheological properties of protein solutions. These changes are not envisioned in conventional colloidal protein models and we have initiated an investigation of the scattering and rheological properties of model proteins. We initiate this effort by considering bovine serum albumin because it is a globular protein whose solution properties have also been extensively investigated as a function of pH, temperature, ionic strength, and concentration. As we anticipated, near-ultraviolet circular dichroism measurements and intrinsic viscosity measurements clearly indicate that the bovine serum albumin tertiary structure changes as protein concentration and pH are varied. Our findings point to limited validity of the colloidal protein model and to the need for further consideration and quantification of the effects of conformational changes on protein solution viscosity, protein association, and the phase behavior. Small-angle Neutron Scattering measurements have allowed us to assess how these conformational changes influence protein size, shape, and interprotein interaction strength. 相似文献
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We have cloned the cDNA for bovine intestinal vitamin D-dependent calcium-binding protein and, based on the sequence of the DNA, have deduced the structure of the full-length protein. The sequence of the cDNA clone predicts a protein comprised of 78 amino acids with a mol wt of 8788. The mRNA for the protein in bovine duodenum is about 500-600 bases in length. The protein sequence of bovine intestinal calcium-binding protein is 87% homologous with the sequence of porcine intestinal vitamin D-dependent calcium-binding protein and 81% homologous with the sequence of rat intestinal vitamin D-dependent calcium-binding protein. Hydrophilicity plots of the proteins noted above show that despite differences in amino acid sequence the proteins have similar patterns. In addition, the predicted secondary structure of the proteins is similar. Bovine intestinal calcium-binding protein shows 48.6% homology with the alpha-chain and 38.2% homology with the beta-chain of bovine S-100 protein and a similar high degree of homology with the beta-chain of human S-100 protein. The protein also demonstrates 36-43% homology with parvalbumin alpha and beta from various species and with troponin-C. There is some homology with the 28K vitamin D-dependent calcium-binding proteins. Vitamin D-dependent bovine intestinal calcium-binding protein is closely related to other mammalian intestinal calcium-binding proteins and to the S-100 proteins, parvalbumins, and troponin-C. 相似文献
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Intein-mediated ligation and cyclization of expressed proteins 总被引:15,自引:0,他引:15
Protein splicing is a posttranslational processing event that releases an internal protein sequence from a protein precursor. During the splicing process the internal protein sequence, termed an intein, embedded in the protein precursor self-catalyzes its excision and the ligation of the flanking protein regions, termed exteins. The dissection of the splicing pathway, which involves the precise cleavage and formation of peptide bonds, and the identification of key catalytic residues at the splice junctions have led to the modulation of the protein splicing process as a protein engineering tool. Novel strategies have been developed to use intein-catalyzed reactions for the production and manipulation of proteins and peptides. These new approaches have broken down the size limitation barrier of chemical synthetic methods and are less technically demanding. The purpose of this article is to describe how to use self-splicing inteins in protein semisynthesis and backbone cyclization. The first two sections of the article provide a brief review of the distinct chemical steps that underlie protein splicing and intein enabled technology. 相似文献