Upon the study of small-molecules binding to proteins, the traditional methods for calculating dissociation constants (Kd and Ki) have shortcomings in dealing with the single bind- ing site models. In this paper, two ...Upon the study of small-molecules binding to proteins, the traditional methods for calculating dissociation constants (Kd and Ki) have shortcomings in dealing with the single bind- ing site models. In this paper, two equations have been derived to solve this problem. These two equations are independent of the total concentration or initial degree of saturation of receptor and the activity of the competitive molecule. Through nonlinear fitting against these two equations, Kd value of a probe can be obtained by binding assay, and Ki value of a ligand can be obtained by competitive assay. Moreover, only the total concentrations of receptor([R]t), ligand([L]t) and probe([P]t) are required for the data fitting. In this work, Ki values of some typical ligands of PPARγ were successfully determined by use of our equations, among which the Ki value of PPARγ-LY171883 was reported for the first time.展开更多
An improved synthesis of rupintrivir (AG7088) was accomplished using three amino acids (L-glutamic acid, D-4-fluorophenylalanine, and L-valine) as the building blocks. The key fragment ketomethylene dipeptide isostere...An improved synthesis of rupintrivir (AG7088) was accomplished using three amino acids (L-glutamic acid, D-4-fluorophenylalanine, and L-valine) as the building blocks. The key fragment ketomethylene dipeptide isostere was constructed with the valine derivative and phenylpropionic acid derivative, followed by coupling with a lactam derivative and an isoxazole acid chloride to provide AG7088 totally in eight steps.展开更多
文摘目的挖掘药食同源类中药治疗糖尿病足(diabetic foot,DF)的用药规律并探究其潜在分子机制,为开发针对DF的药膳疗法提供指导。方法通过检索中国知网、万方数据库和中国生物医学文献数据库中中药方剂治疗DF的临床文献,将其中药名称规范化后与药食同源类中药名单比较,得到药食同源来源方药集;采用中医传承辅助系统分析其用药规律,根据关联规则和聚类分析确定对DF具有治疗作用的药食同源类核心中药;获取核心中药的活性成分及其治疗DF的作用靶点,进行蛋白质相互作用(protein-protein interaction,PPI)分析以及基因本体(gene ontology,GO)和京都基因与基因组百科全书(Kyoto encyclopedia of genes and genomes,KEGG)富集分析;利用分子对接及动力学模拟,评估主要活性成分与其对应靶点的结合能力及结合稳定性。结果共筛选出药食同源类中药方剂521条,其性温平,味甘苦,入心、脾经,以补虚和清热药为主;进一步分析得到具有强关联性组合药对4个,获得4个治疗DF的药食同源潜在新组方药;筛选出当归、黄芪、金银花、甘草和桃仁为治疗DF的药食同源类核心中药,其作用机制主要涉及高级糖基化终末产物-受体(advanced glycation end products,AGE-RAGE)、缺氧反应因子-1(hypoxia-inducible factor-1,HIF-1)、丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)等信号通路;核心中药包含的主要活性成分槲皮素和β-谷甾醇分别与治疗DF的关键靶点蛋白基质金属蛋白酶9(matrix metalloproteinase 9,MMP9)及氧化物酶体增殖物激活受体γ(peroxisome proliferator activated receptorγ,PPARγ)具有较好的结合能力及稳定性。结论药食同源类中药主要通过调节气血凝滞、筋脉阻塞等病机发挥治疗DF的作用,其关键活性成分可通过作用于DF主要治疗靶点MMP9、PPARγ等,进而调节AGE-RAGE、HIF-1和胰岛素抵抗等信号通路协同治疗DF,“黄芪-金银花-甘草”是极具潜力的DF药膳疗法新组方。
基金the National Natural Science Foundation of China(Grants No.20372069)the 863 Hi-Tech Program(Grant Nos.2002AA233011,2003AA235030,2001AA235071).
文摘Upon the study of small-molecules binding to proteins, the traditional methods for calculating dissociation constants (Kd and Ki) have shortcomings in dealing with the single bind- ing site models. In this paper, two equations have been derived to solve this problem. These two equations are independent of the total concentration or initial degree of saturation of receptor and the activity of the competitive molecule. Through nonlinear fitting against these two equations, Kd value of a probe can be obtained by binding assay, and Ki value of a ligand can be obtained by competitive assay. Moreover, only the total concentrations of receptor([R]t), ligand([L]t) and probe([P]t) are required for the data fitting. In this work, Ki values of some typical ligands of PPARγ were successfully determined by use of our equations, among which the Ki value of PPARγ-LY171883 was reported for the first time.
基金financial support from the National Natural Science Foundation of China (20872153, 21021063, 20720102040 and81025017)the National Basic Research Program of China grant(2009CB918502)+2 种基金the Chinese Academy of Sciences (XDA01040305)the SILVER project of the European Commission (contract HEALTH-F3-2010-260644)supported by a Chinese Academy of Sciences Visiting Professorship for Senior International Scientists (2010T1S6)
文摘An improved synthesis of rupintrivir (AG7088) was accomplished using three amino acids (L-glutamic acid, D-4-fluorophenylalanine, and L-valine) as the building blocks. The key fragment ketomethylene dipeptide isostere was constructed with the valine derivative and phenylpropionic acid derivative, followed by coupling with a lactam derivative and an isoxazole acid chloride to provide AG7088 totally in eight steps.