细胞分裂素对大豆叶片衰老过程中蛋白激酶基因表达的影响

利用真核生物催化丝氨酸／苏氨酸残基磷酸化的蛋白激酶ＶＩ和Ⅷ保守区设计兼并引物,进行ＲＴ－ＰＣＲ扩增反应,研究大豆叶片衰老过程中蛋白激酶基因表达的变化及外源细胞分裂素处理的作用。结果表明人工合成的细胞分裂素－６ＢＡ预处理很可能在转录水平上正向调节一些蛋白激酶基因的表达,而诱导衰老处理则起负调控作用。     

黄旗海产卤虫(Artemiapathenogenetica)成虫干片蛋白质、脂肪酸、氨基酸和矿物质的分析

对黄旗海产卤虫（Ａｒｔｅｍｉａｐａｔｈｅｎｏｇｅｎｅｔｉｃａ）成虫干片的蛋白质、脂肪酸、氨基酸和部分矿物质进行了初步分析．结果表明,粗蛋白含量为５４．１４％,脂肪酸中亚麻酸的含量为１５．０７％,蛋白质中的１７种氨基酸和部分矿物质的含量也很丰富,由此说明从盐碱湖中开发利用卤虫资源,使之成为新的食品源和优质饲料有着广泛的前景．     

5种黄精属植物的蛋白指纹分析

本文用聚丙烯酰胺凝胶电泳（ＳＤＳ—ＰＡＧＥ）技术分析了５种黄精属植物根状茎和叶的蛋白指纹．结果表明：（１）它们的根状茎均含有３８．５、２８、１８．６ｋＤ蛋白质;（２）根状茎和叶的蛋白质种类有很大差异;（３）５种黄精属植物各含有自己特有的蛋白质,它们在本属植物物种鉴定中一定参考价值．     

阳离子反胶团体系提取蛋白质

用阳离子反胶团体系分别对４种蛋白质进行反胶团提取的试验和考察,确定ＰＨ值,离子强度,表面活性剂浓度和助溶剂等影响提取的主要因素。     

超滤法分级和纯化蛋白质的现状和前景(英文)

超滤法具有高产率、低成本、容易放大等显著优点,但其低选择性一直限制其在生物蛋白制品的分级和纯化中的应用。本文总结和分析了超滤法用于蛋白质分级和纯化的近期研究成果,对其低选择性的原因进行了分析,提出并论证了提高超滤选择性的技术途径。     

青海高原春小麦籽粒蛋白质积累规律研究

分析了阿勃,青春５３３,青农４６９、青农４５２等四个春小麦品种（品系）在青海西宁地区籽粒蛋白质相对含量的变化规律和蛋白质绝对含量的积累进程,结果表明,从开花至成熟,籽粒蛋白质相对含量的变化呈“Ｕ”型曲线,并以花后籽粒发育初期含量最花,花后３１天左右是该地区春小麦籽粒中蛋白质相对含量最低的时期。不同品种在花后不同时期蛋白质相对含量各不相同;籽粒蛋白质绝对含量的积累过程呈“Ｓ”形曲线,可用概率转换方程     

The application of the genetic algorithm to the minimization of potential energy functions

We adapted the genetic algorithm to minimize the AMBER potential energy function. We describe specific recombination and mutation operators for this task. Next we use our algorithm to locate low energy conformation of three polypeptides (AGAGAGAGA, A9, and [Met]-enkephalin) which are probably the global minimum conformations. Our potential energy minima are –94.71, –98.50, and –48.94 kcal/mol respectively. Next, we applied our algorithm to the 46 amino acid protein crambin and located a non-native conformation which had an AMBER potential energy 150 kcal/mol lower than the native conformation. This is not necessarily the global minimum conformation, but it does illustrate problems with the AMBER potential energy function. We believe this occurred because the AMBER potential energy function does not account for hydration.     

Identification of formylglycine in sulfatases by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

C(alpha)-Formylglycine, the catalytic amino acid residue in the active site of sulfatases, is generated by post-translational modification of a cysteine or serine residue. We describe a highly sensitive procedure for the detection of C(alpha)-formylglycine-containing peptides in tryptic digests of sulfatase proteins. The protocol is based on the formation of hydrazone derivatives of C(alpha)-formylglycine-containing peptides when using dinitrophenylhydrazine as a matrix for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). The hydrazone derivatives desorb and ionize with high efficiency and can be detected in the sub-femtomole range. The presence of C(alpha)-formylglycine is indicated by a mass increment of 180.13 u, corresponding to the hydrazone moiety, and also by a unique C-terminal fragment ion, characteristic of sulfatases, that becomes prominent in MALDI post-source decay mass spectra of the hydrazone derivatives.     

Preprocessing of rotamers for protein design calculations

We have developed a process that significantly reduces the number of rotamers in computational protein design calculations. This process, which we call Vegas, results in dramatic computational performance increases when used with algorithms based on the dead-end elimination (DEE) theorem. Vegas estimates the energy of each rotamer at each position by fixing each rotamer in turn and utilizing various search algorithms to optimize the remaining positions. Algorithms used for this context specific optimization can include Monte Carlo, self-consistent mean field, and the evaluation of an expression that generates a lower bound energy for the fixed rotamer. Rotamers with energies above a user-defined cutoff value are eliminated. We found that using Vegas to preprocess rotamers significantly reduced the calculation time of subsequent DEE-based algorithms while retaining the global minimum energy conformation. For a full boundary design of a 51 amino acid fragment of engrailed homeodomain, the total calculation time was reduced by 12-fold.     

Evaluation of recombinant green fluorescent protein, under various culture conditions and purification with HiTrap hydrophobic interaction chromatography resins

To determine the influence of various culture conditions, transformed cells of Escherichia coli expressing recombinant green fluorescent protein (GFPuv) were grown in nine cultures with four variable conditions (storage of inoculated broth at 4°C prior to incubation, agitation speed, isopropyl-β-d-thiogalactopyranoside [IPTG] concentration, and induction time). The pelleted cells were resuspended in extraction buffer and subjected to the three-phase partitioning (TPP) extraction method. To determine the most appropriate purification resin, protein extracts were eluted through one of four types of HiTrap hydrophobic interaction chromatography (HIC) columns prepacked with methyl, butyl, octyl, or phenyl resins and analyzed further on a 12% sodium dodecylsulfatepolyacrylamidegel. With Coomassie staining, a single band between 27 (standard GFPuv) and 29 kDa (molecular weight standard) was visualized for every HIC column sample. TPP extraction with HIC elution provided about 90% of the GFPuv recovered and eight-fold GFPuv enrichment related to the specific mass. Rotary speed and IPTG concentration showed, respectively, greater negative and positive influences on GFPuv expression at the beginning of the logarithmic phase for the set culture conditions (37°C, 24-h incubation).