"Click"化学在药物发现中的应用

“click”化学是最近几年发展起来的一种新技术,它在药物发现的许多方面均有着广泛的应用:快速合成小分子化合物库并从中筛选先导化合物、进行靶标导向的活性小分子合成以及在生物耦联技术等方面的应用。     

Cell stem cell:华人科学家发现提高CRISPR-CAS9效率的小分子化合物

<正>近日,来自Gladstone研究所的科学家们在著名国际期刊cell stem cell发表了一项最新研究成果,他们通过高通量小分子化合物筛选,鉴定出几种小分子化合物能够提高CRISPR-CAS9系统的基因组编辑效率。这项研究不仅找到了一种提高CRISPRCAS9效率的方法,同时首次证明了小分子化合物可以成功的调控基因组工程。研究人员指出,细菌的CRISPR-CAS9系统利用非同源末端连接(NHEJ)的原理进行特异性基因敲除,已经作为一种基因编辑工具得到广泛     

糖核苷酸类化合物的合成与在生物学研究中的应用

糖基化是指在酶的作用下,蛋白质、脂质或小分子等连上糖类化合物的过程.它在生物体内广泛存在并有十分重要的生物学意艾.它是通过糖基转移酶催化完成的,其中糖核苷酸是糖基化过程中糖的供体.本文简要叙述了糖核苷酸类化合物的有机合成和生化合成的方法以及该类化合物在抗生素糖基化途径研究、糖基转移酶的生物化学研究和化学生物学机理研究中的应用.     

小分子化合物在诱导干细胞分化为胰岛素分泌细胞中的研究进展

干细胞具有多向分化潜能,可以被小分子化合物诱导分化为胰岛素分泌细胞,进而移植到体内代替受损的胰岛β细胞,从根本上治愈糖尿病。小分子化合物种类繁多,具有无免疫原性、可控性强等优点,因此,利用小分子化合物诱导干细胞分化为胰岛素分泌细胞来治疗糖尿病是将来比较有前景的治疗方案。该综述主要分类概述了化学诱导法中经常使用的小分子化合物及其在相应阶段发挥的作用。     

植物激素研究中的化学生物学思路与应用

植物激素是植物生长发育过程中必不可少的重要调节物质, 它们直接或间接参与调控从种子萌发到成熟的各个发育阶段以及对生物/非生物胁迫的响应。随着利用小分子化合物探究生物体生理代谢分子机制的不断发展, 植物生物学与化学之间一个新的前沿交叉学科——化学生物学随之诞生, 并在短时间内取得了重要进展。化学生物学的思路与方法在植物激素研究领域中起到了不可替代的作用, 尤其是在激素合成及信号转导研究领域。该文概述了主要植物激素的小分子类似物及其在植物生长发育和生物/非生物胁迫响应等方面的作用机制, 并讨论了激素类似物在实际生产中的应用潜力及未来的研究方向。     

植物激素研究中的化学生物学思路与应用

植物激素是植物生长发育过程中必不可少的重要调节物质,它们直接或间接参与调控从种子萌发到成熟的各个发育阶段以及对生物/非生物胁迫的响应。随着利用小分子化合物探究生物体生理代谢分子机制的不断发展,植物生物学与化学之间一个新的前沿交叉学科——化学生物学随之诞生,并在短时间内取得了重要进展。化学生物学的思路与方法在植物激素研究领域中起到了不可替代的作用,尤其是在激素合成及信号转导研究领域。该文概述了主要植物激素的小分子类似物及其在植物生长发育和生物/非生物胁迫响应等方面的作用机制,并讨论了激素类似物在实际生产中的应用潜力及未来的研究方向。     

全化学诱导体细胞重编程和转分化

终末分化细胞可以通过重编程和转分化转变为其他类型的细胞,对再生医学领域的研究有重要意义。化学小分子由于结构多样性,及作用剂量、时间的可控性,其在重编程和转分化领域的应用前景广阔。我国科学家在该方向的研究中也取得了许多引人瞩目的成就。对体细胞重编程和转分化的方式、小分子化合物在体细胞重编程研究领域的应用以及全化学诱导体细胞重编程和转分化研究的最新进展,尤其是我国科学家在本领域的进展进行综述。     

小分子化合物诱导细胞重编程研究进展

细胞重编程指细胞内的基因表达由一种类型转变为另一种类型,通常包含两层含义:一是分化的细胞重新恢复到多能性或全能性状态;二是从一种分化的细胞转变为另一种分化的细胞。细胞重编程可为临床患者特异性细胞治疗提供无限的细胞资源。细胞重编程的途径有细胞核移植、转染特定转录因子、小分子化合物诱导等方法。核移植技术由于通常需要使用到卵子,而被认为存在伦理问题;转录因子的导入存在引起宿主基因突变的问题,限制了这一技术的临床应用。然而小分子化合物容易合成、细胞渗透性好,并且生物效应具有可塑性,使用小分子化合物诱导细胞重编程,避免了核移植的伦理问题和基因操作潜在的危害。目前,使用小分子化合物从体细胞诱导获得更安全的i PSCs(induced pluripotent stem cells),ci CMs(chemically induced functional cardiomyocyte cells)和ci NSLCs(chemical-induced neural stem cell-like cells)。对小分子化合物诱导细胞重编程,包括小分子化合物诱导多能干细胞;小分子化合物诱导潜能扩展的多能干细胞,以及小分子化合物诱导细胞转分化等方面的研究做了总结,并对小分子化合物诱导的未来发展做了展望,旨在为今后这方面的研究提供借鉴。     

脐血来源造血干细胞体外培养扩增技术研究进展

随着造血干细胞(HSC)移植技术的发展,脐血已成为干细胞的主要来源之一。为突破HSC来源及数量不足的制约,HSC体外扩增技术发展迅速,涉及到细胞因子、小分子化合物的应用以及联合培养及三维培养技术的发展和氧环境在干细胞扩增技术的作用以及基因修饰技术。本文就近年上述技术中采用的主要方法进行综述。     

小分子药物靶标寻找方法研究进展

许多微生物的次生代谢物属于小分子活性化合物,在医疗及农业领域发挥着重要的作用。在基因组学、蛋白质组学与生物信息学等技术的推动下,一些新的小分子药物靶标寻找方法应运而生了,这些新的方法主要是基于细胞中基因或蛋白质的表达量、蛋白质的亲和性、稳定性等各种特性进行靶标寻找的。小分子药物靶标寻找方法的发展加快了阐明小分子药物作用机理的历程,也为发现新的靶标资源以便于进一步筛选活性更高的药物提供了技术保障。     

RGD三肽的潜在作用靶标预测与计算机模拟分析

化学基因组技术是药物作用靶标确认、药物分子在通路中的作用的确证等方面有重要应用,可为新药研发和老药新用提供理论依据,并可降低药物发现中的高额成本.精氨酸-甘氨酸-天冬氨酸(RGD)三肽被证明是与细胞粘附受体特异性结合的特征序列,在生理学上扮演者重要角色.本研究利用化学基因组学中的其中一种方法即基于反向对接和药效团反向匹配搜索技术来研究RGD三肽的潜在作用靶标,并进行计算机模拟分析.反向匹配搜索结果发现计算得到的关键性靶标及其涉及的相关疾病与实验报道的RGD的药理活性相吻合,包括具有抗凝血、抗肿瘤作用,与肾及心血管作用有关等,而且还发现RGD可能是一个潜在的神经氨酸酶的抑制剂.     

电热蒸发-催化热解-原子吸收法直接测定茶叶中镉

重金属镉（Cd）一直是茶叶产品质量安全关注的重点。本研究基于电热蒸发-催化热解-原子吸收光谱仪（SS-ETV-AAS）,使用镍材质样品舟,在300 mL/min空气条件下,350 ℃干燥20 s,350~725 ℃灰化55 s;引入300 mL/min氢气与空气反应形成氮氢混合气氛,在725~800 ℃（50 s）下完成Cd的蒸发;之后,在高岭土填料催化热解炉800 ℃和准直管700 ℃条件下,氮氢火焰原子吸收测定镉的含量。方法检出限（LOD）为0.3 ng/g、定量限（LOQ）为1.0 ng/g,R2>0.998,多次测定的相对标准偏差（RSD）为1.8%~8.6%,多种茶叶样品中Cd的测定值与微波消解石墨炉原子吸收光谱法（GFAAS）无显著性差异（P>0.05）,Cd的回收率在92%~107%之间。试验结果表明,该方法灵敏度高、稳定性好、简单高效,且无需消解处理,样品分析时间仅为3min,适用于茶叶中Cd的快速检测。     

Allenic and cumulenic lipids

Nowadays, about 200 natural allenic metabolites, more than 2700 synthetic allenic compounds, and about 1300 cumulenic structures are known. The present review describes research on natural as well as some biological active allenic and cumulenic lipids and related compounds isolated from different sources. Intensive searches for new classes of pharmacologically potent agents produced by living organisms have resulted in the discovery of dozens of such compounds possessing high anticancer, cytotoxic, antibacterial, antiviral, and other activities. Known allenic and cumulenic compounds can be subdivided on several structural classes: fatty acids, hydrocarbons, terpenes, steroids, carotenoids, marine bromoallenes, peptides, aromatic, cumulenic, and miscellaneous compounds. This review emphasizes the role of natural and synthetic allenic and cumulenic lipids and other related compounds as an important source of leads for drug discovery.     

Exploring natural microbial resources for the discovery of anti-malarial compounds

Microorganisms in nature are highly diverse biological resources, which can be explored for drug discovery. Some countries including Brazil, Columbia, Indonesia, China, and Mexico, which are blessed with geographical uniqueness with diverse climates and display remarkable megabiodiversity, potentially provide microorganismal resources for such exploitation. In this review, as an example of drug discovery campaigns against tropical parasitic diseases utilizing microorganisms from such a megabiodiversity country, we summarize our past and on-going activities toward discovery of new antimalarials. The program was held in a bilateral collaboration between multiple Indonesian and Japanese research groups. In order to develop a new platform of drug discovery utilizing Indonesian bioresources under an international collaborative scheme, we aimed at: 1) establishment of an Indonesian microbial depository, 2) development of robust enzyme-based and cell-based screening systems, and 3) technology transfer necessary for screening, purification, and identification of antimalarial compounds from microbial culture broths. We collected, characterized, and deposited Indonesian microbes. We morphologically and genetically characterized fungi and actinomycetes strains isolated from 5 different locations representing 3 Indonesian geographical areas, and validated genetic diversity of microbes. Enzyme-based screening was developed against two validated mitochondrial enzymes from Plasmodium falciparum, dihydroorotate dehydrogenase and malate:quinone oxidoreductase, while cell-based proliferation assay was developed using the erythrocytic stage parasite of 3D7 strain. More than 17 thousands microbial culture extracts were subjected to the enzyme- and cell-based screening. Representative anti-malarial compounds discovered in this campaign are discussed, including a few isolated compounds that have been identified for the first time as anti-malarial compounds. Our antimalarial discovery campaign validated the Indonesian microbial library as a powerful resource for drug discovery. We also discuss critical needs for selection criteria for hits at each stage of screening and hit deconvolution such as preliminary extraction test for the initial profiling of the active compounds and dereplication techniques to minimize repetitive discovery of known compounds.     

Natural production of fluorinated compounds and biotechnological prospects of the fluorinase enzyme

Fluorinated compounds are finding increasing uses in several applications. They are employed in almost all areas of modern society. These compounds are all produced by chemical synthesis and their abundance highly contrasts with fluorinated molecules of natural origin. To date, only some plants and a handful of actinomycetes species are known to produce a small number of fluorinated compounds that include fluoroacetate (FA), some ω-fluorinated fatty acids, nucleocidin, 4-fluorothreonine (4-FT), and the more recently identified (2R3S4S)-5-fluoro-2,3,4-trihydroxypentanoic acid. This largely differs from other naturally produced halogenated compounds, which totals more than 5000. The mechanisms underlying biological fluorination have been uncovered after discovering the first actinomycete species, Streptomyces cattleya, that is capable of producing FA and 4-FT, and a fluorinase has been identified as the enzyme responsible for the formation of the C–F bond. The discovery of this enzyme has opened new perspectives for the biotechnological production of fluorinated compounds and many advancements have been achieved in its application mainly as a biocatalyst for the synthesis of [¹⁸F]-labeled radiotracers for medical imaging. Natural fluorinated compounds may also be derived from abiogenic sources, such as volcanoes and rocks, though their concentrations and production mechanisms are not well known. This review provides an outlook of what is currently known about fluorinated compounds with natural origin. The paucity of these compounds and the biological mechanisms responsible for their production are addressed. Due to its relevance, special emphasis is given to the discovery, characterization and biotechnological potential of the unique fluorinase enzyme.     

Bicyclic nucleoside inhibitors of Varicella-Zoster virus: the effect of branching in the p-alkylphenyl side chain

Further to the discovery of bicyclic furanopyrimidine nucleoside analogues (BCNAs) as potent anti-VZV agents, a branched series of this family of compounds was synthesised. The aim was to study the impact of the geometry and steric hindrance in the side chain as well as lipophilic role of this moiety on biological activity. The results showed a detrimental effect of branching on antiviral activity, with a different magnitude depending on the position of branching in the side chain. This study again showed the importance of this moiety for biological activity, as well as the limited efficacy of the ClogP value as a tool for predicting the potency of BCNAs, while suggesting an alternative rationale behind the design of future series.     

Advances and applications of binding affinity prediction methods in drug discovery

Nowadays, the improvement of R&D productivity is the primary commitment in pharmaceutical research, both in big pharma and smaller biotech companies. To reduce costs, to speed up the discovery process and to increase the chance of success, advanced methods of rational drug design are very helpful, as demonstrated by several successful applications. Among these, computational methods able to predict the binding affinity of small molecules to specific biological targets are of special interest because they can accelerate the discovery of new hit compounds. Here we provide an overview of the most widely used methods in the field of binding affinity prediction, as well as of our own work in developing BEAR, an innovative methodology specifically devised to overtake some limitations in existing approaches. The BEAR method was successfully validated against different biological targets, and proved its efficacy in retrieving active compounds from virtual screening campaigns. The results obtained so far indicate that BEAR may become a leading tool in the drug discovery pipeline. We primarily discuss advantages and drawbacks of each technique and show relevant examples and applications in drug discovery.     

Discovery of inhibitors of the pentein superfamily protein dimethylarginine dimethylaminohydrolase (DDAH), by virtual screening and hit analysis

An efficient process for the discovery of inhibitors of DDAH enzymes, without the requirement for high throughput screening, is described. Physicochemical filtering of a 308,000-compound library according to drug likeness followed by reciprocal nearest neighbour selection produced a representative subset of 35,000 compounds. Virtual screening on a dual processor PC using FlexX, followed by biological screening, identified two hit series. Similarity searches of commercial databases and chemical re-synthesis of pure compounds resulted in SR445 as an inhibitor of Pseudomonas aeruginosa DDAH at 2 microM.     

Forward chemical genetics: progress and obstacles on the path to a new pharmacopoeia

Forward chemical genetics is a new method to systematize the discovery and use of small molecules as tools for basic biological research. This approach requires three basic components: a library of compounds; an assay, in which the library is screened for a cellular or organismal phenotype; and a method to trace an active compound to its biological target. Bioactive compounds have traditionally been isolated from natural product extracts, although 'diversity-oriented synthesis' and commercial compound collections are gaining in prominence. New techniques, such as image-based screening and the cytoblot method, have increased the throughput of phenotypic assays. Strategies are also being developed to streamline target identification using molecular biological approaches.