Carboxymethyl poly(L‐histidine) as a new pH‐sensitive polypeptide at endosomal/lysosomal pH

A carboxymethyl poly(L ‐histidine) has been synthesized as a new pH‐sensitive polypeptide at endosomal/lysosomal pH. Because of its poor water solubility at physiological pH, an application of poly(L ‐histidine) with a pK_a around 6.0 has been limited in spite of the native possession of the pH‐dependent property change at endosomal pH. Although the unmodified poly(L ‐histidine) suddenly precipitates out of the aqueous medium above pH 6.0 as the result of the deprotonation of the imidazole groups, the water solubility of the resulting carboxymethyl poly(L ‐histidine) has been improved at physiological pH. A solution turbidity measurement proved that no significant effect on a rapid aggregate formation or phase separation of serum proteins is induced by carboxymethyl poly(L ‐histidine). Hemolysis assay showed that the carboxymethyl poly(L ‐histidine) enhances membrane disruptive ability at endosomal/lysosomal pH. The cellular uptake of luciferase in the presence of the carboxymethyl poly(L ‐histidine) increases intracellular luciferase activity, which suggests that the carboxymethyl poly(L ‐histidine) makes the luciferase escape from lysosomal degradation. The carboxymethyl poly(L ‐histidine) would be the fundamental compound for designing various drug carriers with the pH sensitivity at endosomal/lysosomal pH. Copyright © 2007 John Wiley & Sons, Ltd.     

含丝氨酸和组氨酸残基手性肽核酸单体的合成

设计合成了含组氨酸残基碱基为胸腺嘧啶的手性肽核酸单体, 咪唑氨基的最终保护基为2,4-二硝基苯基(Dnp). 对文献合成方法进行了适当改进, 制备了两种含丝氨酸和组氨酸残基碱基为腺嘌呤的手性肽核酸单体, 以上化合物均可作为制备手性肽核酸的基本构建单元.     

大孔及涂敷硅球作基质的组氨酸拟亲和色谱纯化人免疫球蛋白G

研究用分子组氨酸和配体、大孔硅球为基质的拟亲和色谱分离纯化人免疫蛋白Ｇ（ＩｇＧ），认为键合组氨酸具有半抗原体质而与ＩｇＧ发生免疫亲和作用，以色谱组份重新进样验证了色谱柱对ＩｇＧ亲和专一性，并用包敷Ｄｅｘｔｒａｎ大孔硅球作基质的拟亲和色谱纯化人血清中的ＩｇＧ，减少了色谱峰拖尾，缩短了分离时间。     

Solid‐state complexes of poly(L‐histidine) with metal chlorides from the first row of the d‐block

Solid‐state characterization of poly(L ‐histidine) was obtained via differential scanning calorimetry, thermogravimetric analysis, optical microscopy, and infrared spectroscopy. The glass transition temperature of poly(L ‐histidine) is 169°C. This thermal transition has not been reported previously. Poly(L ‐histidine)'s T_g increases when complexes are produced with the following divalent transition metal chlorides: cobalt chloride hexahydrate, nickel chloride hexahydrate, copper chloride dihydrate, and anhydrous zinc chloride. At 10 mol % salt, nickel chloride increases T_g by 69°C. The enhancement in poly(L ‐histidine)'s T_g correlates well with ligand field stabilization energies for pseudo‐octahedral dⁿ complexes (n = 7, 8, and 10) from the first row of the d‐block. However, d⁹ copper(II) complexes do not conform to this empirical correlation. Infrared spectroscopic evidence indicates that these metal chlorides form complexes with the imidazole ring in the histidine side group and the amide group in the main chain of the polymer. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 301–309, 1999     

一种新型钌(Ⅱ)-组氨酸配合物[RuCl(Me_2SO)_2(L-His)]·H_2O的合成及其结构表征(英文)

本文通过将抗癌活性化合物cisRuCl2Me2SO4与L组氨酸在乙醇溶液中或在溶剂热条件下反应均得到了配合物RuClMe2SO2LHis1。X射线单晶结构分析表明该配合物的晶体属变形八面体,空间群P3121a=b=14.057516c=15.6373分子中含一个结晶水。该配合物中L组氨酸配体分别通过氨基氮、咪唑氮、羧基氧与中心原子钌配位。     

丝组二肽所含基团在其切割DNA反应中的作用

近 2 0年来 ,人工核酸切割试剂的研究一直是化学、生物化学和分子生物学中最为活跃的前沿领域之一[1,2 ] .人工核酸切割试剂可以在足迹技术和核酸高级结构的研究中用作高分辨率的化学探针 ,还可以用于合成定点切割试剂[3] .后者又被称为人工工具酶 ,是一种非常重要的分子生物学工具 ,在疾病的基因治疗、反义 PCR技术等领域中都具有重要的应用 .人工核酸切割试剂的切割机理主要有自由基机理和磷酸酯水解机理两大类 .相对于自由基机理 ,水解机理具有许多优点 ,使得水解型切割试剂具有更为广泛的应用 .对于 DNA,目前文献报道的水解型人工切…     

组胺和组氨酸的生物活性与其电子结构的相关性研究

应用微量量热法测定了组胺和组氨酸对大肠杆菌生长代谢的影响规律,并用量子化学方法从组胺和组氨酸的电子结构方面对这种活性规律进行了初步探讨.     

Fe3O4@Propylsilane@Histidine[HSO4‐] magnetic nanocatalysts: Synthesis,characterization and catalytic application for highly efficient synthesis of xanthene derivatives

The surface of Fe₃O₄ magnetic nanoparticles (MNPs) was modified by chloropropylsilane and histidine. The imidazole group of prepared Fe₃O₄@Propylsilane@Histidine MNPs converted to imidazolium hydrogen sulfate group and Fe₃O₄@Propylsilane@Histidine [HSO₄^‐] as a novel environmentally friendly ionic liquid/ magnetite nanoparticle was prepared, successfully. FT‐IR, XRD, SEM and TEM instruments was used to identifiy the histidine ionic liquids/magnetite nanoparticles (HILMNPs). The catalytic activity of synthesized HILMNPs was appraised for the synthesis of 9‐aryl‐1,8‐dioxooctahydroxanthene and spiro[indoline‐3,9′‐xanthene]trione derivatives. The activity of HILMNPs was much better than the other reported heterogeneous and homogeneous catalysts. Furthermore, the prepared catalyst could be separated from the reaction mixture and reused four times without any significant loss in its activity.     

Selective Monitoring of the Enzymatic Activity of the Tumor Suppressor Fhit

Cancer is a leading cause of death worldwide. Functional inactivation of tumor suppressor proteins, mainly by mutations in the corresponding genes, is a key event in cancer development. The fragile histidine triade protein (Fhit) is a tumor suppressor that is frequently affected in different cancer types. Fhit possesses diadenosine triphosphate hydrolase activity, but although reduction of its enzymatic activity appears to be important for exerting its tumor suppressor function, the regulation of Fhit activity is poorly understood. Here, we introduce a novel fluorogenic probe that is suited to selectively analyze the enzymatic activity of Fhit in extracts derived from human cells. This novel method will allow in‐depth insight into the mechanisms involved in Fhit regulation in biologically relevant setups and, thus, into its role in the development of cancer.     

Clarification of the role of protein in carbonmonoxy myoglobin by investigating electronic states

This article reports the proton tautomerization effects of distal histidine residues in carbonmonoxy myoglobin according to the density functional calculations of the whole protein. The electron eigenstates and electrostatic potential (ESP) distributed around heme and its pocket vary significantly depending on the protonation positions of the distal histidine residues. To investigate the range over which the electronic structures are affected by the proton tautomerization, the quantum mechanics/molecular mechanics (QM/MM) method is applied to probe the QM size to reproduce the atomic partial charges and ESP around the active center. Consequently, we show that these properties converged for the 300 pm QM/MM system in this study. During the analysis, we also find that amino residues such as Phe43, Val68, and Phe138 interact strongly with heme through orbital mixing, indicating that the protein is a medium not only interacting with the reaction center, but also buffering on electrons. © 2013 Wiley Periodicals, Inc.