Protein separations

Individual proteins can be quantitated in crude mixtures using specific immunoassays, bioassays, or enzymatic assays. They can also be separated by HPLC, and recombinant DNA technology has had a significant impact on the protein field. This article presents an overview of current developments in protein separations.     

Zwitterionic Peptide Cloak Mimics Protein Surfaces for Protein Protection

Inspired by the amino acid composition of natural protein surfaces, we developed a zwitterionic cloak containing multi-layers of short alternating glutamic acid and lysine (EK) peptides as a facile, highly effective and low-immunogenicity approach for the protection and delivery of biotherapeutics. Each EK layer grafted to proteins provides multiple times of new lysine reaction sites for the growth of subsequent EK layers. This unique design allows EK peptides to achieve high coating density on proteins, overcoming the limitation of traditional conjugation strategies that rely on the number of innate lysine groups. A triple-layer EK cloak manifests to successfully eliminate the specific and non-specific interactions of protected asparaginase with biological media while prolong the drug circulation time and significantly mitigate its immunogenicity in vivo, suggesting an EK peptide cloak as a promising approach to improve the safety and efficacy of biotherapeutics.     

蛋白质酪氨酸硝化的研究

蛋白质酪氨酸硝基化是一种重要的蛋白质翻译后修饰,与多种病症相关。经由过氧亚硝酸根(ONOO-)和NO2-/H2O2/血红素过氧化物酶体系是促使蛋白质硝化最主要的两种途径,其反应为自由基机理。本文对体内蛋白质硝基化的途径、机制及其生物学意义作了综述,指出蛋白质的硝化具有选择性,特定酪氨酸残基发生硝化能够改变蛋白质的结构和功能,影响其免疫应答和可能涉及的信号转导过程,从而具有重要的生物学意义。     

Protein array engineering

We have been attempting to establish a universal technology for fabricating two-dimensional protein arrays with the desired molecular orientation in the form of crystalline films. The basic strategy adopted is to explore an interface adequate for connecting two completely dissimilar technologies: ‘nature's technology’ governing the basis of life and ‘human technology’ working in our daily life. The scales of the basic components and elementary devices functioning in the two technologies are dissimilar by a million-fold. To surpass this scale gap and make the mating productive, we have sought an interface in a stable thin liquid film on a substrate that is flat and well defined at the nanometer scale: water solutions of proteins spread on wettable surfaces such as the mercury surface form a stable thin film. The two-dimensional space confined in the thin liquid film is a new working space for protein molecules which moved from their original living space, cell suspension. We have found that protein molecules selfassemble into the form of two-dimensional crystals in the space, maintaining their original functions and structures and exhibiting a novel character as engineering materials.     

蛋白质酪氨酸硝化的研究

蛋白质酪氨酸硝基化是一种重要的蛋白质翻译后修饰,与多种病症相关。经由过氧亚硝酸根（ONOO-）和NO2^-／H2O2／血红素过氧化物酶体系是促使蛋白质硝化最主要的两种途径,其反应为自由基机理。本文对体内蛋白质硝基化的途径、机制及其生物学意义作了综述,指出蛋白质的硝化具有选择性,特定酪氨酸残基发生硝化能够改变蛋白质的结构和功能,影响其免疫应答和可能涉及的信号转导过程,从而具有重要的生物学意义。     

绿色荧光蛋白

绿色荧光蛋白是46多年前从多管水母体内发现的,它可以在蓝光或紫外光激发下发射绿光.由于它稳定的结构和光物理性质,又易于在细胞内表达,近些年作为标记物已经被广泛地应用于生命科学领域.本文简要介绍了水母发光蛋白与绿色荧光蛋白的关系、绿色荧光蛋白的结构、发色团的形成、发光机制、变异体以及它的特点和应用.     

Protein fold recognition

Summary An important, yet seemingly unattainable, goal in structural molecular biology is to be able to predict the native three-dimensional structure of a protein entirely from its amino acid sequence. Prediction methods based on rigorous energy calculations have not yet been successful, and best results have been obtained from homology modelling and statistical secondary structure prediction. Homology modelling is limited to cases where significant sequence similarity is shared between a protein of known structure and the unknown. Secondary structure prediction methods are not only unreliable, but also do not offer any obvious route to the full tertiary structure. Recently, methods have been developed whereby entire protein folds are recognized from sequence, even where little or no sequence similarity is shared between the proteins under consideration. In this paper we review the current methods, including our own, and in particular offer a historical background to their development. In addition, we also discuss the future of these methods and outline the developments under investigation in our laboratory.     

Protein folding invariants

This article discusses the topological invariants associated with an augmented ribbon model of single domain protein. The model is a triple (S, G, J) in S³ where S is a 2-manifold with boundary, G is a circle-with-chords, and J is an arc. The surfaces satisfy an embedding condition called laundry. The invariants are necessary and sufficient conditions for two triples to be equivalent by ambient isotopy. The model describes the native state, the unfolded state, and a unique folding pathway as a single mathematical entity. This may help illuminate some of the remarkable properties of protein. Twist transitions are introduced that allow the surface to pass through itself. A new arithmetic involving the complex numbers is used to represent variable linking numbers.     

基于活性的蛋白质组分析

众多物种基因组解码工作的完成极大地丰富了我们对这些生命体系组成复杂度的认知, 然而下一个更为严峻的挑战是如何快速准确地解析这些基因编码蛋白的分子功能, 这也是当前蛋白质组学领域亟待解决的一个重要科学问题. 基于活性的蛋白质组分析是近些年来一项新兴的技术平台, 它致力于在复杂的生命体系中系统地鉴定某类具有特定功能的蛋白质分子. 在本篇短综述中, 我们将对该化学生物学技术的发展做一个简要的回顾, 重点介绍该技术在未知蛋白的功能解析、小分子抑制剂的筛选以及活性小分子靶标蛋白的鉴定等方面的工作, 最后将对该技术未来发展的走向及其拓展应用做前瞻性的讨论.     

蛋白质高分子结合体

蛋白质高分子结合体是蛋白质与高分子化合物以特定位置或方式结合的产物。其中,蛋白质(包括酶和多肽)分子中氨基酸残基上的氨基、巯基和羧基是常用的结合位点。本文主要对蛋白质高分子结合体的制备方法进行了综述。聚乙二醇是合成高分子中能够有效改善蛋白质性能的修饰剂,而多糖则是用于制备蛋白质高分子结合体较成功的天然高分子化合物。“点击化学”、活性聚合技术等技术已经被成功应用于蛋白质高分子结合体的制备。某些具有特异结合功能基团的化合物(如金属卟啉、生物素等)与高分子共价结合后也可制备蛋白质高分子结合体。在研究蛋白质高分子结合体制备方法的基础上,近年来开始了这类大分子的自组装行为研究,尤其是对巨型双亲性分子自组装行为的研究,这为设计和构筑先进功能材料提供了新的思路。与高分子化合物的结合是改善蛋白质性能和拓宽蛋白质应用范围的重要技术之一。蛋白质高分子结合体不但可用于生物医药领域,而且在纳米技术和材料科学等领域具有潜在的优势。     

In Silico Evidence That Protein Unfolding is a Precursor of Protein Aggregation

We present a computational study on the folding and aggregation of proteins in an aqueous environment, as a function of its concentration. We show how the increase of the concentration of individual protein species can induce a partial unfolding of the native conformation without the occurrence of aggregates. A further increment of the protein concentration results in the complete loss of the folded structures and induces the formation of protein aggregates. We discuss the effect of the protein interface on the water fluctuations in the protein hydration shell and their relevance in the protein-protein interaction.     

蛋白质的检测方法与乳制品中蛋白含量测定

介绍5种常用的蛋白质检测方法,以及凯氏定氮法在食品,特别是乳制品蛋白含量测定中的应用和存在的问题,及其可能的解决方法。     

蛋白质链环和纽结

寻找和合成拓扑新颖结构的蛋白质是目前一个崭新的课题 ,本文介绍了已经发现的M bius蛋白质和蛋白质链环的新奇结构及实验事实     

Protein secondary structure preferencs

This paper addresses the question to what extent steric properties of sequence neighbors effect the preferences of an amino acid residue to assume the-helical or some other secondary structure conformation. We find that an amino acid has increased tendency to be in-helical conformation when its sequence neighbors are bulky. This result is an outcome of our automated method for finding conformational preferences as functions of physical parameters important for protein folding. The steric environment for a given residue in a protein is defined as an average of water-accessible surface areas of its primary structure neighbors in extended conformation for model tripeptides. For all amino acids, including non-helix formers like glycine and arginine, the preference for the helical structure increases if their primary structure neighbors form a larger steric environment.