Molecular machinery mediating vesicle budding,docking and fusion

A general machinery buds and fuses transport vesicles which connect intracellular compartments with each other and allow communication with the extracellular environment. Cytoplasmic coat proteins deform membranes to bud vesicles and interact directly or indirectly with cargo molecules. Compartment-specific SNAREs (SNAP receptors) on vesicles and target membranes dock vesicles and provide a scaffolding for the general fusion machinery to initiate lipid bilayer fusion.     

Three-dimensional structure of annexins

Annexins constitute a family of structurally related calcium- and phospholipid-binding proteins whose molecular structure has been investigated in detail in the crystalline and membrane-bound form. Their polypeptide chain is folded into four or eight α-helical domains of similar structure with a central hydrophilic pore. Bound to phospholipid membranes, the four-domain arrangement of the annexin molecule is conserved. A peripheral binding mode has been well documented by electron microscopy and a variety of other techniques.     

Conservation,evolution, and specificity in cellular control by protein phosphorylation

The glycolytic control enzyme phosphofructokinase from the parasitic nematodeAscaris lumbricodies is regulated by reversible phosphorylation. The enzyme is phosphorylated by an atypical cyclic adenosine monophosphate (cAMP)-dependent protein kinase whose substrate specificity deviates from that of the mammalian protein kinase. This variation is explained by structural peculiarities on the surface part of the catalytic groove of the protein kinase. Also, the protein phosphatases responsible for the reversal of phosphorylation appear to act specifically in glycolysis and are different from those participating in regulation of glycogenolysis.     

DNA与蛋白质结合的共振光散射研究及应用

在pH 2.21～4.35的Britton-Robinson(BR)缓冲溶液中,脱氧核糖核酸(DNA)与蛋白质相互作用形成复合物,引起较DNA或蛋白质单独存在时的共振光散射(RLS)信号的强烈增强.用于分析蛋白质与DNA结合的相互作用.实验结果显示:DNA与蛋白质之间存在较强的静电相互作用.在最佳实验条件下,波长315...     

Comparative proteomics analysis of <Emphasis Type="Italic">OsNAS1</Emphasis> transgenic <Emphasis Type="Italic">Brassica napus</Emphasis> under salt stress

Salt stress is one of the major abiotic stresses in agricultural plants worldwide. We used proteomics to analyze the differential expression of proteins in transgenic OsNAS1 and non-transformant Brassica napus treated with 20 mmol/L Na₂CO₃. Total protein from the leaves was extracted and separated through a high-resolution and highly repetitive two-dimensional electrophoresis (2-DE) technology system. Twelve protein spots were reproducibly observed to be upregulated by more than 2-fold between transgenic and non-transformant B. napus. These 12 spots were digested in-gel with trypsin and characterized by matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) to obtain the peptide mass fingerprints. Protein database searching revealed that 5 of these proteins are involved in salt tolerance: dehydrogenase, glutathione S-transferase, peroxidase, 20S proteasome beta subunit, and ribulose-1,5-bisphosphate carboxylase/oxygenase. The potential functions of these identified proteins in substance and energy metabolism, stress tolerance, protein degradation, and cell defense are discussed. The salt tolerance of the transgenic rapeseed was significantly improved by the introduction of the OsNAS1 gene from Brazilian upland rice of Oryza sativa (cv. IAPAR 9).     

耐力训练对大鼠骨骼肌收缩蛋白的影响

目的:探索运动训练对大鼠骨骼肌收缩蛋白的影响,为进一步研究其蛋白水平提供依据。方法:选用清洁级健康雄性Sprague-Dawley(SD)大鼠20只,6周龄,体重135-150g,随机分为2组。A:安静对照组,n=10,B:运动训练组,n=10。运动训练组:进行持续性大运动量跑台训练8周。实验使用SDS-PAGE(十二烷基硫酸钠-聚丙烯凝胶电泳),浓缩胶浓度5%,分离胶浓度10%,电泳电压160V,时间200min。结果:在骨骼肌收缩蛋白SDS-PAGE后,运动训练组电泳图谱上出现大量新的条带,分子量范围为43-200 kDa。结论:本运动模型下,在骨骼肌收缩蛋白SDS-PAGE后,运动训练组图谱上出现大量新的蛋白条带,这些新的条带是肌肉蛋白质的降解产物,还是为了修复运动损伤而合成的新的蛋白质片段,还有待后续研究。     

基于GO的酵母膜系统蛋白相互作用规律研究

引进描述蛋白质相互作用倾向性参数(PIRB),基于GO(Gene Ontology)和相关的数据库中蛋白质功能注释,对酿酒酵母部分膜蛋白相互作用规律进行了研究,构建了基于PIRB的蛋白质相互作用网络图.结果表明各类膜蛋白质之间的相互作用具有明显的偏向性.对这种偏向性的生物学含义作了简要探讨.     

Cry1A型杀虫晶体蛋白活性区的空间结构比较分析

对9种代表性Cry1A型杀虫晶体蛋白成员进行活性区空间结构的同源模建与比较分析.分析结果表明:Domain Ⅰ和Domain Ⅲ相对保守,其中,Domain Ⅰ整体走向及结构基本重叠,只有Cry1Aa和Cry1Af多了一个螺旋;Domain Ⅱ的主要差异体现在loop上;将Domain Ⅲ结构一致的成员Cry1Ab,Cry1Ad,Cry1Ae和Cry1Af归为一个亚型,其他5种成员归为另一个亚型.研究确定了影响Cry1A型杀虫晶体蛋白结构差异的关键氨基酸及关键结构片段.     

印楝Azadirachta Indica A.Juss的冷驯化与抗冻蛋白的研究

采用木本植物材料——印楝,通过组织培养建立快繁体系,然后对其进行冷驯化处理,并分析检测印楝植物体内抗冻蛋白.主要结果如下:①冷驯化处理后印楝的总蛋白一些表现为量的增加同时会有新的蛋白产生.但脱驯化或处理时间过长时,抗冻蛋白在量的表达上会有逐渐减少或消失的现象.②在对印楝的冷驯化中,发现不同的温度处理后蛋白稳定存在的时间不同.抗冻蛋白出现的最早时期为5℃处理2周左右,印楝能耐受的稳定最低温为5℃,所持续的最长时间约为20d.在0℃低温处理后,虽然在处理初期(0～15d)也有抗冻蛋白的产生,但随处理时间的延长,这种差异逐渐减少,在处理30d时完全消失.③得到了分离纯化的抗冻蛋白,其相对分子质量约为3.6×104.     

Presence of serum proteins in submaxillary duct perfusate

Summary The secretory activity of the main excretory duct of rat submaxillary gland was investigated by the technique of luminal perfusion. Immunologic studies of the perfusate revealed the presence of serum antigens and the absence of intrinsic submaxillary gland antigens. It is suggested that the submaxillary duct permits passive transport of serum proteins to saliva from serum.