水化磷脂层中蛋白质和多肽的高分辨固体核磁共振波谱学

有序样品的固体核磁共振(NMR)已快速发展成测定蛋白质和多肽在“仿真”水化磷脂层中高分辨结构的重要谱学方法. 由于与膜相连的蛋白质和多肽的结构、动力学和功能往往都和其周边自然环境密切相关,因此人们把蛋白质和多肽有序排列于水化磷脂层中进行固体NMR测量, 从而获得与取向相关的各向异性自旋相互作用. 这些取向约束可作为结构参数重构蛋白质在水化磷脂层中的高分辨三维结构. 近十年来在样品制备,NMR探头和实验方法方面的显著发展,极大地促进了有序样品的固体NMR的发展,并使之成为测定与膜相连的蛋白质和多肽结构的有效方法. 该综述介绍有序样品的固体NMR谱学方法,并总结此领域里的最新研究进展.     

Calculation of α decay half-lives for superheavy elements using the double folding model＊

α decay half-lives of some new synthesized superheavy elements, possibly synthesized superheavy elements and decay products are calculated theoretically within the WKB approximation by using microscopic α-nucleus interaction potentials. These nuclear potentials between the α particle and daughter nuclei are obtained by using the double folding integral of the matter density distribution of the α particle and daughter nuclei with a density-dependent effective nucleon-nucleon interaction, in which the zero-range exchange term is supplemented. The calculated α decay half-lives are compared with those of the different models and experimental data. It is shown that the present calculation successfully provides the half-lives of the observed decays for some new superheavy elements and therefore gives reliable predictions for α decay of possibly synthesized superheavy elements in future experiments.     

核酸识体的研究及应用

核酸识体(aptamer)是近年来发展起来的一类经体外人工进化程序筛选出的寡聚核苷酸。它能高效、特异地结合各种配体，在蛋白质的分析检测、医学诊断治疗、生物传感器和分子开关的开发等方面有很大的应用前景，文章对核酸识体的研究和应用进展进行了综述。     

An electron microscopic study of the archaeal feast/famine regulatory protein 5. Fourier filtration of images

Microcrystals of the feast/famine regulatory protein (FFRP) pot0434017 (FL11) were prepared by sonicating larger crystals. Using the microcrystals a cryo-electron micrograph was obtained, which showed a hexagonal packing of cylinder-like assemblies of FL11. This micrograph was processed by selecting, in the Fourier space, spots reflecting the crystal lattice, thereby removing the noise. The microcrystal was not totally free from distortion, and cylinders in local clusters adopted slightly different orientations. Thus, 25 hexagonal units closest to the ideal, each containing a cylinder at the center surrounded by six others, were manually selected. The averaged image was further processed to yield a perfect six-fold symmetry. These processed images, and some of the original images too, show bridges connecting cylinders, each corresponding to two pairs of N-domains, protruding from the two cylinders and contacting between them in the X-ray structure.     

α螺旋蛋白质螺旋链模型的精确解组

文章运用Maple语言程序,在没有假设的条件下,得到了α螺旋蛋白质螺旋链运动模型方程组的行波精确解组,它涵盖了所有的耦合解组与非耦合解组,具有任意性.耦合解组的算例函数及其特性分析,解释了α螺旋蛋白质螺旋链运动模型的行波孤立子解的耦合效应,揭示了增加、稳定和控制蛋白质活性和功能的方向,文章的研究方法,为求解生物大分子螺旋链运动模型的行波精确解组探索了溪径.     

Intrinsic Fluorescence of Actin

In this work actin is used to illustrate connection of protein fluorescence characteristics with its structure. On one hand, it has been demonstrated what kind of information about the contribution of each tryptophan residues to the bulk fluorescence spectrum can be obtained from the special analysis of protein three-dimensional structure. On the other hand, potentials of intrinsic fluorescence for elucidation of proteins structure, dynamics and processes of folding-unfolding are shown. In particular, using this method a new essentially unfolded kinetic intermediate state of actin was detected and characterized, and the place of inactivated actin and its kinetic predecessor in the process of folding-unfolding was determined. It has been revealed that inactivated actin is not intermediate state between the native and completely unfolded states, as it has been accepted before, but a result of protein misfolding. On the basis of the obtained data a new model of actin folding-unfolding pathway has been proposed.     

Self-Interactions of Strands and Sheets

Physical strands or sheets that can be modelled as curves or surfaces embedded in three dimensions are ubiquitous in nature, and are of fundamental importance in mathematics, physics, biology, and engineering. Often the physical interpretation dictates that self-avoidance should be enforced in the continuum model, i.e., finite energy configurations should not self-intersect. Current continuum models with self-avoidance frequently employ pairwise repulsive potentials, which are of necessity singular. Moreover the potentials do not have an intrinsic length scale appropriate for modelling the finite thickness of the physical systems. Here we develop a framework for modelling self-avoiding strands and sheets which avoids singularities, and which provides a way to introduce a thickness length scale. In our approach pairwise interaction potentials are replaced by many-body potentials involving three or more points, and the radii of certain associated circles or spheres. Self-interaction energies based on these many-body potentials can be used to describe the statistical mechanics of self-interacting strands and sheets of finite thickness.     

Nonextensive Statistical Mechanics Application to Vibrational Dynamics of Protein Folding

The vibrational dynamics of protein folding is analyzed in the framework of Tsallis statistics. We employ exact expressions for classical harmonic oscillators by considering the unnormalized constraints. As q→1, we show that these approximations agree with the result of Gaussian network model.     

乳清分离蛋白-葡聚糖接枝物性质的荧光光谱法分析

乳清分离蛋白与葡聚糖的混合物在干热处理条件下,发生了以褐变为特征的美拉德反应。当葡聚糖分子量由67kD增至150kD时,游离氨基含量分别下降了35.77%和30.53%,糖链越长,其接入到蛋白质肽链的难度越大。采用荧光光谱对乳清分离蛋白-葡聚糖接枝物的性质进行分析。内源荧光光谱图显示,接枝产物在405nm的最大荧光强度显著提高,且350～500nm范围内的荧光强度顺序为:G67>G150,这说明接枝物中有Maillard反应体系所特有的荧光物质生成;由外援荧光光谱图得出,接枝产物在470nm的最大荧光强度均有明显降低,各溶液体系中荧光强度高低顺序依次为:WPI>G150>G67。疏水性指数的测定进一步说明两种不同分子量的葡聚糖接入到蛋白质肽链中,对乳清分离蛋白的疏水性均有一定的屏蔽作用。     

Development of chemically modified glass surfaces for nucleic acid,protein and small molecule microarrays

Microarrays have become a widely used tool to investigate the living cell at different levels. DNA microarrays enable the expression analysis of thousand of genes simultaneously, while protein arrays investigate the properties and interactions of proteins with other proteins and with non-proteinaceous molecules. One crucial step in producing such microarrays is the permanent immobilization of samples on a solid surface. Our goal was to develop diverse linker systems capable of anchoring different biological samples, especially DNA and drug-like small molecules. We developed 6 different chemical surfaces having a 3-D-like linker system for biomolecule immobilization, and compared them to previously described immobilization strategies. The attachment chemistry utilizes the amino reactive properties of acrylic and epoxy functions. The capacity of the support was increased by creating a branching structure holding the reactive functions. The method of anchoring was investigated through a model reaction. From HPLC and mass spectrometry measurements we concluded that the covalent binding of DNA occurs through nucleobases. The tested systems offer the capability to permanently immobilize several biomolecular species in an array format.