共查询到20条相似文献，搜索用时 359 毫秒
1.
[目的]筛选可结合Caco-2细胞表面蛋白的副溶血弧菌外膜蛋白。[方法]筛选副溶血弧菌外膜中的黏附蛋白,将Caco-2细胞表面蛋白生物素化并固定于中性卵白素树脂上,进一步利用亲和层析技术来筛选副溶血弧菌的外膜蛋白。[结果]通过LC-MS/MS质谱技术鉴定出3个候选蛋白:ATP synthase subunit alpha、ATP synthase subunit beta和outer membrane protein U。通过对这3个蛋白进行克隆基因和原核表达,成功纯化得到相应重组蛋白。通过进一步的间接免疫荧光试验,发现3种蛋白对于Caco-2细胞均有黏附作用。[结论]推测ATP synthase subunit alpha、ATP synthase subunit beta和outer membrane protein U这3种蛋白可能是潜在的黏附因子。 相似文献
2.
Transforming growth factor-beta (TGF-beta) superfamily members regulate a plethora of developmental processes, and disruption of their activity has been implicated in a variety of human diseases ranging from cancer to chondrodysplasias and pulmonary hypertension. Intense investigations have revealed that SMAD proteins constitute the basic components of the core intracellular signaling cascade and that SMADs function by carrying signals from the cell surface directly to the nucleus. Recent insights have revealed how SMAD proteins themselves are regulated and how appropriate subcellular localization of SMADs and TGF-beta transmembrane receptors is controlled. Current research efforts investigating the contribution of SMAD-independent pathways promise to reveal advances to enhance our understanding of the signaling cascade. 相似文献
3.
Signaling by cell surface receptors and heterotrimeric guanine nucleotide-binding proteins (G proteins) is one of the most exhaustively studied processes in the cell but remains a major focus of molecular pharmacology research. The pheromone-response system in yeast (see the Connections Map at Science's Signal Transduction Knowledge Environment) has provided numerous major advances in our understanding of G protein signaling and regulation. However, the basic features of this prototypical pathway have remained largely unchanged since the mid-1990s. New tools available in yeast are beginning to uncover new pathway components and interactions and have revealed signaling in unexpected locations within the cell. 相似文献
4.
[目的]分析两歧双歧杆菌PRL2010菌体外表面蛋白的功能。[方法]以两歧双歧杆菌PRL2010基因组序列为研究对象,采用Perry等人分析革兰氏阳性菌菌体外表面蛋白(PSE蛋白)的Inmembrane方法,同时采用COG功能数据库对预测的外表面蛋白进行功能注释和聚类分析。[结果]PRL2010外表面蛋白包括28个细胞壁蛋白、12个脂蛋白、182个细胞膜蛋白、38个分泌蛋白。PRL2010外表面蛋白的功能分析结果显示,大多数外表面蛋白与细胞壁、细胞膜的生物合成,无机离子转运与代谢,防御机制,碳水化合物转运与代谢,氨基酸转运与代谢等有关。[结论]该研究可为探讨该菌与宿主相互作用的分子机制奠定基础。 相似文献
5.
[目的]分析动物双歧杆菌AD011暴露外表面蛋白的种类和功能,有助于了解该菌株的各项生理功能以及为探讨该菌与宿主相互作用的分子机制奠定基础。[方法]以动物双歧杆菌AD011基因组序列为研究对象,采用Inmembrane方法和COG功能数据库对预测的外表面蛋白进行功能注释和聚类分析。[结果]AD011菌体暴露外表面蛋白数目为193个,包括11个细胞壁蛋白、20个脂蛋白、暴露外表面的膜蛋白140个、22个细胞外蛋白。AD011外表面蛋白的功能分析结果显示,193个外表面蛋白中,含有较大比例的蛋白没有功能注释(78个),115个蛋白具有COG功能注释。在有功能注释的蛋白中,所占比例较大的是氨基酸转运与代谢(16个),无机离子转运与代谢(14个),细胞壁、细胞膜生物合成(13个),碳水化合物转运与代谢(10个),防御机制(10个)等有关蛋白。[结论]AD011菌体外表面蛋白与营养物质的吸收和转运,细胞壁、细胞膜生物合成,防御机制有关。 相似文献
6.
Chen JG Willard FS Huang J Liang J Chasse SA Jones AM Siderovski DP 《Science (New York, N.Y.)》2003,301(5640):1728-1731
G protein-coupled receptors (GPCRs) at the cell surface activate heterotrimeric G proteins by inducing the G protein alpha (Galpha) subunit to exchange guanosine diphosphate for guanosine triphosphate. Regulators of G protein signaling (RGS) proteins accelerate the deactivation of Galpha subunits to reduce GPCR signaling. Here we identified an RGS protein (AtRGS1) in Arabidopsis that has a predicted structure similar to a GPCR as well as an RGS box with GTPase accelerating activity. Expression of AtRGS1 complemented the pheromone supersensitivity phenotype of a yeast RGS mutant, sst2Delta. Loss of AtRGS1 increased the activity of the Arabidopsis Galpha subunit, resulting in increased cell elongation in hypocotyls in darkness and increased cell production in roots grown in light. These findings suggest that AtRGS1 is a critical modulator of plant cell proliferation. 相似文献
7.
Plexins are cell surface receptors for semaphorin molecules, and their interaction governs cell adhesion and migration in a variety of tissues. We report that the Semaphorin 4D (Sema4D) receptor Plexin-B1 directly stimulates the intrinsic guanosine triphosphatase (GTPase) activity of R-Ras, a member of the Ras superfamily of small GTP-binding proteins that has been implicated in promoting cell adhesion and neurite outgrowth. This activity required the interaction of Plexin-B1 with Rnd1, a small GTP-binding protein of the Rho family. Down-regulation of R-Ras activity by the Plexin-B1-Rnd1 complex was essential for the Sema4D-induced growth cone collapse in hippocampal neurons. Thus, Plexin-B1 mediates Sema4D-induced repulsive axon guidance signaling by acting as a GTPase activating protein for R-Ras. 相似文献
8.
表面烯醇化酶(surface enolase,SEN)和3-磷酸甘油醛脱氢酶(surface glyceraldehydes -3 - phosphate dehydro - genase,sGAPDH)都是A群链球菌(group A Streptococcus,GAS)没有踌膜结构的膜表面蛋白,它们可能在GAS感染中起到重要的作用.在本研究中,对SEN和sGAPDH在M6型GAS不同生长阶段(即在对数期和稳定期)的表达情况进行检测分析.取对数期(OD600 =0.5 -0.6)和稳定期(OD600 =1.5- 1.6)的GAS,分别测定SEN和sGAPDH活性.同时用变溶菌素(mutanolysin)提取这2个生长阶段细胞壁结合蛋白,用Western blot检测该提取物中的SEN和sGAPDH.结果表明在相同菌细胞浊度的条件下,SEN在M6型GAS对数期时的表达量及活性比其稳定期时的高45％左右.虽然sGAPDH的表达量较高但活性很低(＜0.07mM NADH/min),并且在这2个生长阶段没有明显的差异. 相似文献
9.
A glycolipid antigen associated with Burkitt lymphoma defined by a monoclonal antibody 总被引：12，自引：0，他引：12
E Nudelman R Kannagi S Hakomori M Parsons M Lipinski J Wiels M Fellous T Tursz 《Science (New York, N.Y.)》1983,220(4596):509-511
The antigen defined by a rat monoclonal antibody directed to a Burkitt lymphoma cell line was identified as globotriaosylceramide [Gal alpha (1 leads to 4)-Gal beta (1 leads to 4)-Glc beta (1 leads to 1)-ceramide]. The antibody demonstrated a strict steric specificity since it did not react with globoisotriaosylceramide [Gal alpha (1 leads to 3)-Gal beta (1 leads to 4)-Glc beta (1 leads to 1)-ceramide], the positional isomer of the antigen associated with the Burkitt lymphoma. Chemical analysis of various Burkitt lymphoma cell lines revealed that the Burkitt lymphoma cells contained more than 100 times as much of the glycolipid antigen as was found in other human lymphoma and leukemia cell lines. 相似文献
10.
[目的]运用生物信息学方法预测动物双歧杆菌AD011锚定于细胞壁的蛋白并进行功能分析,为后续研究该菌与宿主相互作用的分子机制提供基础资料。[方法]用Phobius和SignalP 4.0软件对动物双歧杆菌AD011全基因组编码蛋白中细胞壁蛋白进行预测,同时采用COG(Cluster of Orthologous Groups of proteins)功能数据库对预测的细胞壁蛋白进行功能注释和聚类分析。[结果]动物双歧杆菌AD011基因组1 518个编码蛋白中,11个蛋白含有细胞壁的锚定基序,6个蛋白含有LP×TG基序,1个蛋白含有Lys M基序,1个蛋白含有PG结合区域,2个蛋白含有SLH结构域,1个蛋白含有NLPC_P60结构域。细胞壁蛋白功能分析结果显示,11个细胞壁蛋白中,9个蛋白没有功能注释,2个蛋白(NLP/P60 protein和1,4-beta-N-acetylmuramidase)参与细胞壁和细胞膜的生物合成。[结论]动物双歧杆菌AD011大多数细胞壁蛋白功能未知,还需在以后的研究中进行进一步的功能注释。 相似文献
11.
采用TRIzol法提取绵羊卵巢组织总RNA,运用RT–PCR技术扩增绵羊微管解聚蛋白基因(STMN1)的编码区序列;通过同源重组技术构建重组诱饵表达载体p GBKT7–STMN1,鉴定该诱饵蛋白在酵母双杂交系统中的自激活活性、细胞毒性和表达情况;利用诱饵质粒p GBKT7–STMN1从绵羊卵巢组织细胞的酵母双杂交cDNA文库筛选互作的宿主蛋白。结果显示：成功构建重组诱饵质粒p GBKT7–STMN1,并对酵母细胞无自激活活性和细胞毒性作用,且能在酵母细胞中正常表达;筛选获得12个与STMN1相互作用的克隆,经测序比对分析和点对点验证,得到CREB和FOXM1共2个互作的宿主蛋白,这2个蛋白可能参与调控细胞的增殖、周期、凋亡等过程。 相似文献
12.
Diversity of G proteins in signal transduction 总被引：123，自引：0，他引：123
The heterotrimeric guanine nucleotide-binding proteins (G proteins) act as switches that regulate information processing circuits connecting cell surface receptors to a variety of effectors. The G proteins are present in all eukaryotic cells, and they control metabolic, humoral, neural, and developmental functions. More than a hundred different kinds of receptors and many different effectors have been described. The G proteins that coordinate receptor-effector activity are derived from a large gene family. At present, the family is known to contain at least sixteen different genes that encode the alpha subunit of the heterotrimer, four that encode beta subunits, and multiple genes encoding gamma subunits. Specific transient interactions between these components generate the pathways that modulate cellular responses to complex chemical signals. 相似文献
13.
Induction of membrane ruffling and fluid-phase pinocytosis in quiescent fibroblasts by ras proteins 总被引：69，自引：0，他引：69
Expression of the ras oncogene is thought to be one of the contributing events in the initiation of certain types of human cancer. To determine the cellular activities that are directly triggered by ras proteins, the early consequences of microinjection of the human H-ras proteins into quiescent rat embryo fibroblasts were investigated. Within 30 minutes to 1 hour after injection, cells show a marked increase in surface ruffles and fluid-phase pinocytosis. The rapid enhancement of membrane ruffling and pinocytosis is induced by both the proto-oncogenic and the oncogenic forms of the H-ras protein. The effects produced by the oncogenic protein persist for more than 15 hours after injection, whereas the effects of the proto-oncogenic protein are short-lived, being restricted to a 3-hour interval after injection. The stimulatory effect of the ras oncogene protein on ruffling and pinocytosis is dependent on the amount of injected protein and is accompanied by an apparent stimulation of phospholipase A2 activity. These rapid changes in cell membrane activities induced by ras proteins may represent primary events in the mechanism of action of ras proteins. 相似文献
14.
半乳糖醛酸酶抑制蛋白(Polygalacturonase inhibitoryprotein,PGIP)是位于植物细胞壁的糖蛋白,能够抑制真菌半乳糖醛酸酶(Polygalacturonase,PGs)对细胞壁的降解,从而达到抵御病原菌侵入的目的。经高盐法提取和凝胶过滤层析,获得相对纯度为18.9倍的PGIP,保留活性分别为100%和51.6%;经SDS-聚丙烯酰胺凝胶电泳(SDS-PAGE)分析表明,相对纯化的白梨PGIP的分子量为29～42 kDa;用径向辐射法和还原糖法试验表明,PGIP活性受pH影响,但对提取液中KCl的浓度及提取时间不敏感;PGIP抑制活性对温度非常敏感,在85℃处理20 min,PGIP失去85%～90%的抑制活性,在100℃下,PGIP活性全部丧失。 相似文献
15.
[目的]采用生物信息学方法预测鼠李糖乳杆菌LGG细胞壁蛋白和功能分析。[方法]以鼠李糖乳杆菌LGG基因组编码蛋白序列为研究对象,采用Phobius和Signal P 4.0软件分析该菌株的细胞壁蛋白,同时采用COG功能数据库对预测的细胞壁蛋白进行功能分析。[结果]鼠李糖乳杆菌LGG基因组中含有41个细胞壁蛋白,这些蛋白的功能分析结果显示,41个细胞壁蛋白中,25个蛋白没有功能注释,16个有功能注释,主要与细胞壁和细胞膜的生物合成,碳水化合物的代谢与转运,蛋白质的翻译后修饰等功能有关。[结论]该研究从结构和功能上分析鼠李糖乳杆菌细胞壁蛋白,为分析益生菌适应环境的分子特征打下基础。 相似文献
16.
[目的]运用生物信息学方法预测两歧双歧杆菌PRL2010锚定于细胞壁的蛋白和功能分析,为后续研究该菌与宿主相互作用的分子机制奠定基础。[方法]用Phobius和Signal P 4.0软件对两歧双歧杆菌PRL2010全基因组编码蛋白中细胞壁蛋白进行预测,同时采用COG(Cluster of Orthologous Groups of proteins)功能数据库对预测的细胞壁蛋白进行功能注释和聚类分析。[结果]两歧双歧杆菌PRL2010基因组1 706个编码蛋白中,28个蛋白含有细胞壁的锚定结构域。细胞壁蛋白功能分析结果显示,28个细胞壁蛋白中,21个蛋白没有功能注释,7个蛋白有功能注释,其中1个蛋白(exo-alpha-sialidase)参与碳水化合物代谢与转运,2个蛋白(bacteriophage endolysin和cell wall-associated protein)参与细胞壁和细胞膜的生物合成,2个蛋白(hypothetical protein BBPR_0440和Subtilisin family peptidase)参与蛋白质翻译后修饰,1个蛋白(beta-n-acetylhexosaminidase Nag Z)参与细胞内运输、分泌和囊泡运输,1个蛋白(metallophosphoesterase)功能只是预测的。[结论]两歧双歧杆菌PRL2010的大多数细胞壁蛋白功能未知,还需要在以后的研究中进一步分析和注释。 相似文献
17.
[目的]运用生物信息学方法预测动物双歧杆菌AD011定位于细胞膜的表面脂蛋白,为后续研究该菌与宿主相互作用的分子机制提供基础资料。[方法]用Signal P 4.0和Lipo P软件对动物双歧杆菌AD011全基因组编码蛋白中表面脂蛋白和信号肽进行预测,同时采用COG功能数据库对预测的脂蛋白进行功能注释和聚类分析。[结果]对动物双歧杆菌AD011基因组1 518个蛋白的表面脂蛋白预测,结果表明,19个蛋白具有脂蛋白信号肽。功能分析显示,该菌株19个脂蛋白中有3个蛋白没有功能注释,16个蛋白有功能注释,其中10个蛋白参与氨基酸代谢与转运、3个蛋白参与碳水化合物代谢与转运,3个蛋白参与无机盐离子代谢与转运。[结论]动物双歧杆菌AD011表面脂蛋白参与的功能主要与营养物质的转运和代谢有关。 相似文献
18.
In situ and orbital exploration of the martian surface has shown that acidic, saline liquid water was intermittently available on ancient Mars. The habitability of these waters depends critically on water activity (aH2O), a thermodynamic measure of salinity, which, for terrestrial organisms, has sharply defined limits. Using constraints on fluid chemistry and saline mineralogy based on martian data, we calculated the maximum aH2O for Meridiani Planum and other environments where salts precipitated from martian brines. Our calculations indicate that the salinity of well-documented surface waters often exceeded levels tolerated by known terrestrial organisms. 相似文献
19.
WHITFIELD RE 《Science (New York, N.Y.)》1963,142(3592):577-579
An application of the rule of six for the estimation of steric hindrance in reactions of dipeptides and polypeptides, and conformational preferences of polypeptides and proteins, is described. 相似文献
20.
ＳＤＳ／ＤＴＡＢ复配体系在体相及气／液表面层中相互作用行为研究表明,添加适量ＤＴＡＢ,混合溶液的胶束生成、表面张力降低能力和表面张力降低效率均得到明显改善,这３项指标均在较大浓度比例范围内产生增效效应．分子相互作用理论计算结果显示,ＳＤＳ和ＤＴＡＢ不论在混合胶束还是在混合表面层中均产生强烈相互作用．两亲分子碳氢链之间的疏水相互作用和相反电性离子头基之间的库仑引力是混合体系产生高表面活性的主要原因,等链长的正／负离子铺展剂复配为较大浓度范围内的表面张力降低能力增效提供了条件． 相似文献