蛋白质三维结构预测问题的求解方法

对蛋白质结构预测问题进行了描述,根据蛋白质结构预测问题在三维欧氏空间的连续模型,通过拟物策略找到了相应的数学模型.由于引入了弹性势能和嵌入势能,将一个有约束的问题转化为一个无约束的问题,并在梯度下降法求解的基础上,设计出一种变步长梯度下降的求解方法.通过实例检测,变步长梯度下降法比梯度下降法大大节省了计算时间,且所得结果的能量比梯度下降法所得结果的能量更低.     

矩阵的弱相似性及其应用

推广了矩阵环Mn(F)中相似性概念，提出了矩阵的弱相似概念，研究了它的基本性质，获得一些有趣结果，此外，指出了文[3]的一个错误，给出了Laffey-Choi一个关键引理的矩阵式的证明。     

相似理论内容的扩充与分析

将相似定理的数量由原来的3个扩充至11个,并提出了相似准数、相似指数方程、基础物理量以及函数物理量等概念,从而增强了相似理论的系统性.     

ADC的结构及其应用

介绍了目前流行的ADC的4种结构及其性能特点。并从其电路实现的复杂程度、采样速度和应用领域等方面进行了对比研究．     

The Caenorhabditis elegans lin-12 gene encodes a transmembrane protein with overall similarity to Drosophila Notch

The lin-12 gene seems to control certain binary decisions during Caenorhabditis elegans development, from genetic and anatomical studies of lin-12 mutants that have either elevated or reduced levels of lin-12 activity. We report here the complete DNA sequence of lin-12: 13.5 kilobases (kb) derived from genomic clones and 4.5 kb from complementary DNA clones. It is of interest that the predicted product is a putative transmembrane protein, given that many of the decisions controlled by lin-12 activity require cell-cell interactions for the correct choice of cell fate. In addition, the predicted lin-12 product may be classified into several regions, based on amino acid sequence similarities to other proteins. These include extensive overall sequence similarity to the Drosophila Notch protein, which also is involved in cell-cell interactions that specify cell fate; a repeated motif found in proteins encoded by the yeast cell-cycle control genes cdc10 (Schizosaccharomyces pombe) and SWI6 (Saccharomyces cerevisiae); and a repeated motif exemplified by epidermal growth factor, found in many mammalian proteins.     

蛋白质拓扑结构Alignment与相似性打分的算法

蛋白质结构分类是当今“后基因组”研究的热点 ,是探索蛋白质折叠 /功能关系的有效方法 .创立一种新型的分类体系就意味着对复杂的蛋白质结构的有了进一步的理解 .本文基于蛋白质结构域的拓扑结构 ,将拓扑量化 ,以Alignment矩阵方法对结构域进行比较 ,并按拓扑结构相似性对任意 2个蛋白质进行打分 .上述算法已经实现了程序化 .依此算法可将一组蛋白质进行新的分类 ,并可望将结构分类与生物功能的关系进行分析 .     

The structure of the protein universe and genome evolution

Despite the practically unlimited number of possible protein sequences, the number of basic shapes in which proteins fold seems not only to be finite, but also to be relatively small, with probably no more than 10,000 folds in existence. Moreover, the distribution of proteins among these folds is highly non-homogeneous -- some folds and superfamilies are extremely abundant, but most are rare. Protein folds and families encoded in diverse genomes show similar size distributions with notable mathematical properties, which also extend to the number of connections between domains in multidomain proteins. All these distributions follow asymptotic power laws, such as have been identified in a wide variety of biological and physical systems, and which are typically associated with scale-free networks. These findings suggest that genome evolution is driven by extremely general mechanisms based on the preferential attachment principle.     

大豆蛋白质纤维(华康)聚集态结构

对大豆蛋白质纤维(华康），聚集态结构进行了研究，认为聚乙烯大分子呈平面锯齿形构象，而大豆蛋白大分子在纺丝前的处理过程中已经变性，由α-螺旋转变为直线形的β-链构象，并共同砌入纤维；由于两组分大分子均带有较多的极性基团。在大分子之间可能形成多种键合，同时大豆蛋白质纤维（华康）成纤后，进行的缩醛化处理在两组分大分子之间形成了化学交联。因此。可以认为大豆蛋白质纤维（华康）的聚集态结构是以直链形大分子网状结构为主体的聚集态结构。X-射线衍射图表明，大豆蛋白质纤维（华康）大分子的结晶能力较弱。二维空间排列有序的向列结晶能力较强。     

多标度数据轮廓相似性的度量公理与计算

为了完善轮廓相似性度量的概念和计算,拓展轮廓相似度计算公式的应用,讨论了样本几何轮廓的序结构和表示定理,修正了轮廓相似性的度量公理与计算公式.在样本几何轮廓和"轮廓优"序的定义下,证明了"轮廓优"序的"严格弱序"结构,证明了在轮廓相似性分析问题中表示定理成立,奠定了约定"轮廓相似性度量公理"的逻辑基础,进而定义了样本几何轮廓的"相似度"序,证明了"相似度"序的"严格偏序"结构,并修正了轮廓相似度计算公式.使轮廓相似分析的概念与相似度计算公式能适应不同背景下的多标度数据分析的要求.     

判定三角形全等与相似的一种新方法及其证明(VI)

三角形的边、中线、角平分线和高称为三角形的主要线段,若一个三角形任意的三条主要线段与另一个三角形的分别与之同名且相对位置完全对应相同的三条主要线段对应相等或成比例,那么这两个三角形全等或相似.此问题共有四十八种互不相同的基本情形,除一种情形尚未给出证明外,其余四十七种情形的证明均已给出.现发表其中的第VI部分(也是最后一部分).     

Close similarity of epidermal growth factor receptor and v-erb-B oncogene protein sequences

Each of six peptides derived from the human epidermal growth factor (EGF) receptor very closely matches a part of the deduced sequence of the v-erb-B transforming protein of avian erythroblastosis virus (AEV). In all, the peptides contain 83 amino acid residues, 74 of which are shared with v-erb-B. The AEV progenitor may have acquired the cellular gene sequences of a truncated EGF receptor (or closely related protein) lacking the external EGF-binding domain but retaining the transmembrane domain and a domain involved in stimulating cell proliferation. Transformation of cells by AEV may result, in part, from the inappropriate acquisition of a truncated EGF receptor from the c-erb-B gene.     

Crystal structure of the bacterial membrane protein TolC central to multidrug efflux and protein export

Diverse molecules, from small antibacterial drugs to large protein toxins, are exported directly across both cell membranes of gram-negative bacteria. This export is brought about by the reversible interaction of substrate-specific inner-membrane proteins with an outer-membrane protein of the TolC family, thus bypassing the intervening periplasm. Here we report the 2.1-A crystal structure of TolC from Escherichia coli, revealing a distinctive and previously unknown fold. Three TolC protomers assemble to form a continuous, solvent-accessible conduit--a 'channel-tunnel' over 140 A long that spans both the outer membrane and periplasmic space. The periplasmic or proximal end of the tunnel is sealed by sets of coiled helices. We suggest these could be untwisted by an allosteric mechanism, mediated by protein-protein interactions, to open the tunnel. The structure provides an explanation of how the cell cytosol is connected to the external environment during export, and suggests a general mechanism for the action of bacterial efflux pumps.     

等离子体理论及其应用研究

本文研究了等离子体化学理论及其在无机合成、化学气相沉积陶瓷薄膜、高分子材料变性等方面的应用。促使这种新理论用于化学反应。     

三层结构及其在数据库系统中的应用

介绍了三层结构的概念及其应用，对比二层结构客户／服务器模式与三层结构客户／服务器模式的不同，阐述了采用中间件技术的三层结构客户／服务器模式在当前企业级应用中的优势．并根据中间件在系统中所起的作用和采用的技术，详细地介绍了其五种类型和各自特点。     

多元一次不定方程解的结构及其应用

初等数论是密码学研究的重要基础理论.引入多元一次不定方程的概念,利用多元一次不定方程解的存在性条件和二元一次不定方程一般解的结构,采用递推的数学归纳法,得到并证明了多元一次不定方程一般解及其特解的结构形式.进一步研究并给出了多元一次同余方程非负整数解的存在性条件,在此基础之上利用这个存在性条件对RSA公钥密码体制进行了密钥多元化的改进,论证了其加解密算法的正确性.最后通过例解说明改进后的RSA公钥密码体制较原密码体制更为安全可靠且易于实现.     

Modeling of 3D-structure for regular fragments of low similarity unknown structure proteins

Because it is hard to search similar structure for low similarity unknown structure proteins dimefly from the Protein Data Bank(PDB)database,3D-structure is modeled in this paper for secondary structure regular fragments(α-Helices,β-Strands)of such proteins by the protein secondary structure prediction software,the Basic Local Alignment Search Tool(BLAST)and the side chain construction software SCWRL3.First.the protein secondary structure prediction software is adopted to extract secondary structure fragments from the unknown structure proteins.Then.regular fragments are regulated by BLAST based on comparative modeling,providing main chain configurations.Finally,SCWRL3 is applied to assemble side chains for regular fragments,so that 3D-structure of regular fragments of low similarity un known structure protein is obtained.Regular fragments of several neurotoxins ale used for test.Simulation results show that the prediction errors are less than 0.06nm for regular fragments less than 10 amino acids,implying the simpleness and effectiveness of the proposed method.     

Transfer of a beta-turn structure to a new protein context

Four-residue beta-turns and larger loop structures represent a significant fraction of globular protein surfaces and play an important role in determining the conformation and specificity of enzyme active sites and antibody-combining sites. Turns are an attractive starting point to develop protein design methods, as they involve a small number of consecutive residues, adopt a limited number of defined conformations and are minimally constrained by packing interactions with the remainder of the protein. The ability to substitute one beta-turn geometry for another will extend protein engineering beyond the redecoration of fixed backbone conformations to include local restructuring and the repositioning of surface side chains. To determine the feasibility and to examine the effect of such a structural modification on the fold and thermodynamic stability of a globular protein, we have substituted a five-residue turn sequence from concanavalin A for a type I' beta-turn in staphylococcal nuclease. The resulting hybrid protein is folded and has full nuclease enzymatic activity but reduced thermodynamic stability. The crystal structure of the hybrid protein reveals that the guest turn sequence retains the conformation of the parent concanavalin A structure when substituted in the nuclease host.