非天然氨基酸与双肽席夫碱锌配合物的合成与表征

对甲砜基苯丝氨酸;双甘肽;水杨酸;非天然氨基酸与双肽席夫碱锌配合物的合成与表征     

氨基酸氧化酶催化合成非天然手性氨基酸研究进展

<正>非天然手性氨基酸是已经上市的和正在研发的手性药物、手性农药和手性食品添加剂的关键中间体[1-2].随着相关产业的发展,非天然手性氨基酸的市场需求与日俱增.非天然手性氨基酸不能像天然L-氨基酸一样采用发酵法生产,主要制备方法包括化学法和生物法.化学法包括化学不对称合成法和化学拆分法.化学不对称合成法采用价格昂贵的手性源、手性助剂或手性金属催化剂.化学拆分法采用手性酸为拆分剂,经历与消旋氨基酸成盐、解     

蛋白质功能化新策略:嵌入非天然氨基酸

天然蛋白质由20种天然氨基酸组成,这些蛋白质的构筑基元包含功能基团:羧基、氨基、巯基、硫醚、羟基、碱性胺、烷基和芳基。然而,这些有限的功能基团却不足以完成生物体内所有的生物学功能。为了更好地让生命的体现者--蛋白质完成更加精确和多样的生物学功能,自然界会对蛋白质进行翻译后的修饰,包括:磷酸化,甲基化,乙酰化或者羟基化,甚至在某些情况下,进化出一种新型的翻译机制以便插入硒代半胱氨酸或者吡咯霉素。受此启发,生物化学家发展出各种生物或化学方法来改变或插入新的蛋白质构筑基元,使天然蛋白质完成其相应的生物学功能或者使其具有某些特殊的性质,甚至是创造一种新酶。该文将简单介绍这些蛋白质修饰策略以及该领域的最新进展。     

噻吩甲酰基吡唑啉酮缩氨基酸稀土配合物的合成、表征及生物活性

A new amino-acid Schiff base, 1-phenyl-3-methyl-4-(2-thenoyl) pyrazolone-5-β-alanine (HL) and its ten rare earth complexes have been synthesized. On the basis of elemental analysis and molar conductance, the general formula of the complexes, [REL₂NO₃]·nH₂O (RE=La, Nd, Eu, Tb, Y, n=2; RE= Pr, Sm, n=1; RE= Dy, Er, Yb, n=3), is given. They were characterized by IR, UV-visible, ¹H NMR, ¹³C NMR and fluorescence. The results show that the rare earth ions exhibit coordination of eight in the complexes.The antibacterial experiments indicate that they have high antibacterial activities against S. Aureus, B. Subtillis, E. Coli, E. Carotovora and C. Flaccumfaciens.     

应用Arndt-Eistert反应合成手性非天然N-Fmoc-β-氨基酸（Ⅲ）

以重氮甲烷为重氮化试剂，以非天然N—Fmoc—α—氨基酸为原料，成功地运用Amdt—Eistert反应，通过两步反应，高效快捷地合成了8个对应的同系物N—Fmoc—β—氨基酸。     

不对称烯丙基化反应合成含有三苯胺核心单元的荧光非天然氨基酸衍生物

报道了一种钯催化噁唑酮和烯丙醇的不对称烯丙基化反应合成相应的三苯胺核心非天然氨基酸化合物的方法.反应收率高达95%,对映选择性过量值最高为97%ee.该反应操作简单,条件温和,原子经济性好,水为唯一副产物.     

非天然氨基酸引入法制备含有新型赖氨酸翻译后修饰蛋白质

近年来多种天然蛋白质中赖氨酸翻译后修饰被逐渐发现。这些翻译后修饰在蛋白质组中广泛存在,对染色体结构和基因转录表达功能具有重要的调控作用。然而,获得足量的具有特定翻译后修饰的蛋白质并非易事,发展制备方法对于后续表观遗传学研究极为重要。讨论了利用非天然氨基酸引入的手段制备含有这些新型赖氨酸翻译后修饰的蛋白。     

科学家设计出非天然手性氨基酸合成方法

<正>研究人员设计出一种非天然手性氨基酸的简易合成方法,有望推动化学工业尤其制药业的发展。氨基酸是含有氨基和羧基的一类有机化合物的通称,是生物功能大分子蛋白质的基本组成单位。非天然手性氨基酸的分子为对映异构体,其在药物开发、化工合成、催化工业等领域具有重要作用。研究团队负责人、美国斯克里普斯研究所的余金权教授对新华社记者说,天然氨基酸便宜易得,     

氨基酸衍生物的反应、合成和生物活性研究

讨论了我们小组近年来以氨基酸衍生物为主线，在代谢型谷氨酸受体及蛋白激酶C有选择性的调节剂的发现和合成，在发展新反应以及天然产物合成方面所取得的一些结果。     

应用Arndt-Eistert 反应合成手性非天然N-Fmoc-β-氨基酸(III)

以重氮甲烷为重氮化试剂,以非天然N-Fmoc-α-氨基酸为原料,成功地运用Arndt-Eistert 反应,通过两步反应,高效快捷地合成了8个对应的同系物N-Fmoc-β-氨基酸.     

含羟基和咪唑基团新手性肽核酸的设计与合成

以含丝氨酸和组氨酸残基的手性肽核酸单体替换经典肽核酸单体, 采用固相合成方法设计合成了五个新序列含羟基和咪唑基团的10聚体手性肽核酸, 经ESI-MS或MALDI-TOF-MS证实目标物结构正确.     

Synthesis and Adsorption Properties of Polystyrene-supported Chelating Resins Containing Heterocyclic Functional Groups

A series of new chelating resins with incorporating heterocyclic functional groups： pyridine, thiadizole, benzothizole into macroporous chloromethylated polystyrene were synthesized via hydrophilic spacer arm of polyethylene glycol containing sulfur. These chelating resins were found to show high adsorption capacities for Ag^＋, Hg^2＋, Au^3＋ and Pd^2＋, and the presence of spacer arm can enhance adsorption ability due to increase the hydrophilicity of the chelating resins.     

Synthesis and Adsorption Properties of Chelating Resins Containing Sulfoxide and Heterocyclic Functional Groups

Chelating resins containing heterocyclic functional groups and sulfoxide show high affinity for heavy and noble metal ions, so many attempts are under way to anchore such groups onto solid supports1-3. The earlier studies were on the resins containing het…     

Industrial Protease “Alcalase” as a Catalyst in Organic Synthesis: Resolution of Natural and Unnatural Amino Acids

Procedures have been developed for the resolution of natural and unnatural amino acids using soluble or immobilized industrial enzyme “Alcalase” as catalyst. The specificity of enzyme on different amino acids and the stability of both free and immobilized enzyme have been studied.     

Applications of Unnatural Amino Acids in Protease Probes

Since proteases are involved in a wide range of physiological and disease states, the development of novel tools for imaging proteolytic enzyme activity is attracting increasing interest from scientists. Peptide substrates containing proteinogenic amino acids are often the first line of defining enzyme specificity. This Minireview outlines examples of major recent advances in probing proteases using unnatural amino acid residues, which greatly expands the possibilities for designing substrate probes and inhibitory activity‐based probes. This approach already yielded innovative probes that selectively target only one active protease within the group of enzymes exhibiting similar specificity both in cellular assays and in bioimaging research.     

Asymmetric Synthesis of Unnatural Amino Acids and Tamsulosin Chiral Intermediate

An efficient and enantioselective hydrogenation of N-acetylamino phenyl acrylic acids was successfully developed by using ruthenium catalyst. This methodology is important in the field of pharmaceuticals and provides a new process for the preparation of unnatural amino acids and tamsulosin chiral intermediate.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details.]     

Lanthanide(III) Complexes with Two Hexapeptides Incorporating Unnatural Chelating Amino Acids: Secondary Structure and Stability

Unnatural metal‐chelating amino acids bearing aminodiacetate side‐chains have been introduced into two hexapeptides to obtain efficient lanthanide‐binding peptides. The synthesis of the enantiopure Fmoc‐Ada_n(tBu)₂‐OH synthons is described with overall yields of 32 and 50 % for n=2 and n=3 side‐chain carbon atoms, respectively. The two peptides AcWAda_nPGAda_nGNH₂ ( P ⁿ ) were synthesized from the protected synthons by standard solid‐phase peptide synthesis. Studies of the lanthanide complexes of the two peptides P ⁿ by luminescence titrations, mass spectrometry, circular dichroism, and solution NMR spectroscopy demonstrate that the Ada_n chain length has a dramatic effect on the complexation properties. Indeed, the flexible compound P³ forms a mononuclear complex of moderate stability (β₁₁=10^9.9), which tends to transform into a binuclear species in the presence of excess of the metal ion. Interestingly, the more compact peptide P² provides stable Ln³⁺ complexes with the exclusive formation of the mononuclear Ln P² adduct. The stability constant of Tb P² is two orders of magnitude higher (β₁₁=10^12.1) than that measured for P³ . The 800 MHz NMR spectrum of the La³⁺ complex of P² evidences a well‐defined type II β‐turn as well as a hydrophobic Trp(indole)–Pro interaction. These interactions exemplify the non‐innocent character of the peptide spacer in the complex La P² as well as the role of a peptide secondary structure in the stabilization of metal complexes.     

Controlled Genetic Encoding of Unnatural Amino Acids in a Protein Nanopore

Conventional protein engineering methods for modifying protein nanopores are typically limited to 20 natural amino acids, which restrict the diversity of the nanopores in structure and function. To enrich the chemical environment inside the nanopore, we employed the genetic code expansion (GCE) technique to site-specifically incorporate the unnatural amino acid (UAA) into the sensing region of aerolysin nanopores. This approach leveraged the efficient pyrrolysine-based aminoacyl-tRNA synthetase-tRNA pair for a high yield of pore-forming protein. Both molecular dynamics (MD) simulations and single-molecule sensing experiments demonstrated that the conformation of UAA residues provided a favorable geometric orientation for the interactions of target molecules and the pore. This rationally designed chemical environment enabled the direct discrimination of multiple peptides containing hydrophobic amino acids. Our work provides a new framework for endowing nanopores with unique sensing properties that are difficult to achieve using classical protein engineering approaches.     

Synthesis,Characterization and Structure of Chiral Amino Acids and Their Corresponding Amino Alcohols with Camphoric Backbone

1 INTRODUCTION Chiral amino acids and their versatile derivatives are very useful compounds in many fields[1]. In com- parison with well-documented chiral α and β amino acids and amino alcohols, the studies of chiral γ, δ… ω amino acids and amino alcohols deserve more attention. For example, there have been numerous reports on versatile functions of γ aminobutyric acid (GABA) produced from L-glutamic acid in the presence of L-glutamate decarboxylase (GAD)[2]. However, the stereo…