交流阻抗技术研究DNA与天青Ⅰ的相互作用

将天青Ⅰ自组装在金电极表面，以交流阻抗技术和光谱技术研究了天青Ⅰ自组装膜与DNA分子的相互作用．天青Ⅰ与DNA作用使电极的本体阻抗发生变化并结合光谱分析技术研究，发现这种作用既包括静电作用又包括镶嵌作用．该方法不仅可以反映DNA与小分子间发生了作用，同时还可以对DNA进行半定量分析，是一种快速、简便、廉价的检测DNA与小分子相互作用的新方法．     

DNA与小分子化合物相互作用的研究进展与展望

脱氧核糖核酸(DNA)是生物体中重要的遗传物质,它对遗传信息的储存、复制及转录具有重要的作用.为了进一步探索和认识DNA的性质、结构、行为、形态,揭示生命的奥秘,人们研究了不同类型的小分子化合物与DNA之间的相互作用.通常小分子与DNA作用有三种结合方式:嵌插作用、沟结合和静电作用.现有许多技术和方法来研究小分子化合物与DNA的相互作用,例如紫外光谱、荧光光谱、凝胶电泳和粘度测量等多种研究手段.     

交流阻抗技术研究巯基丙酸/中性红修饰电极上DNA的响应

中性红(NR)可吸附在巯基丙酸自组装修饰金电极表面,并进而与DNA发生嵌插作用.以交流阻抗技术研究了DNA在巯基丙酸自组装/中性红修饰电极上的响应.结果表明,交流阻抗方法不仅可以反映DNA与小分子间发生的作用,还可以对DNA进行定量分析,响应在DNA浓度为0.4～8mg·L-1范围内呈线性关系,相关系数r=0.9973,检出下限为0.03 mg·L-1.该法是一种快速、简便、廉价的研究DNA及与小分子相互作用的方法.     

甲苯胺蓝荧光探针法测定核酸

核酸的定量测定在生物分析化学中是一个十分重要的课题[1].利用核酸对小分子荧光探针的荧光增强或猝灭作用来研究小分子探针和DNA的相互作用或进行核酸的定量分析,方法比较简单,应用较广[2].     

光谱法研究小分子与蛋白质间相互作用的进展

小分子与蛋白质之间相互作用会影响蛋白质构象变化,研究小分子与蛋白质相互作用的机理,对阐明小分子在生物体内的吸收、分布、代谢等过程具有重要意义。综述了近年来紫外光谱法、荧光光谱法、傅里叶变换红外光谱法和圆二色光谱法等技术在该领域的研究进展,分析了这些方法的特点和应用,展望了外源性小分子与蛋白质之间相互作用的发展前景。     

二氢嘧啶-2-酮衍生物与DNA相互作用研究

DNA是遗传信息的携带者和基因表达的物质基础,药物分子与DNA的结合能够阻碍DNA的复制,使癌细胞的生长得到有效抑制.研究药物小分子与生物大分子的相互作用,有助于从分子水平上理解某些抗癌药物的作用机理,对设计临床上更为有效、毒副作用更低的新药具有十分重要的意义[1,2].     

核酸与药物分子相互作用模式及研究进展

介绍了核酸与药物分子相互作用模式,并围绕药物小分子与核酸相互作用的模式-非共价作用、共价作用、剪切作用,探讨了对这种作用模式进行研究的方法进展。提出了综合应用多种分析方法进行研究药物分子和核酸的作用模式。     

基于荧光蛋白FRET特性DasR与效应小分子的相互作用

本研究利用黄色荧光蛋白(YFP)和青色荧光蛋白(CFP)构建含有DasR蛋白的双荧光蛋白融合蛋白,以效应小分子与DasR作用前后导致的双荧光蛋白FRET效应变化为指标考察DasR与效应小分子的相互作用。研究结果表明:效应小分子与DasR的相互作用可以通过荧光蛋白FRET特性有效的呈现;该荧光蛋白系统能够反映出单独的DasR小分子结合结构域与效应物质的相互作用。本研究方法为研究调控蛋白与效应小分子相互作用、调控蛋白效应分子的高通量筛选等方面提供了理论借鉴与方法学参考。     

配合物与G-四链体DNA相互作用的研究

端粒在维持基因组稳定、癌症和衰老相关的生理过程中发挥着重要作用,鸟嘌呤通过形成G-四分体平面堆积成G-四链体结构,DNA二级结构参与一些重要的生物调控过程。人们已经在生物体内发现G-四分体结构的存在,它们大量存在于基因的启动区域表明G-四链体可能参与调节基因表达。以G-四链体为新靶标设计能与G-四链体DNA相互作用的小分子,为开发抗癌药物提供了新途径。最近的许多研究证明金属配合物与G-四链体DNA具有有效的相互作用,有望开发成新的抗癌药物。     

蛋白质等电点的理论计算

蛋白质的等电点 pI 是蛋白质的重要理化性质之一。了解蛋白质的 pI,对蛋白质的分离纯化,鉴定小分子肽或酶的活性位点,预测不同蛋白质之间或蛋白质与其他大分子之间的离子相互作用,判断 pI 值对测定温度的依赖关系,设计由已知顺序的 DNA 合成的肽的纯化程序等都是很有意义的。蛋白质的 pI 值通常采用等电点聚焦或层析聚焦等实验方法测定。由于实验方法的灵     

电化学研究亚甲蓝与DNA的相互作用

The interaction of small molecules with DNA is of interest because it is important in the design of new and more efficient drugs targeted to DNA. The metal complexes, natural antibiotics, and a lot of other planar heterocyclic cations, have been investigated for their DNA     

Discovery and demonstration of small circular DNA molecules derived from Chinese tomato yellow leaf curl virus

Tomato yetlow leaf curl viruses betong to Begomoviruses of geminiviruses. In this work, we first found and demonstrated that the small circular DNA molecules were derived from Chinese tomato yetlow leaf curl viruses (TYLCV-CHI). These small circular DNA molecules are about 1,3 kb, which are half the full-length of TYLCV-CHI DNA A. It was shown by sequence determination and analysis that there was unknown-origin sequence insertion in the middle of the small molecules. These sequences of unknown-origin were neither homologous to DNA A nor to DNA B, and were formed by recombination of virus DNA and plant DNA. Although various defective molecules contained different unknown-origin sequence insertion, all the molecules contained the intergenic region and part of the AC1 (Rep) gene. But they did not contain full ORF.     

A new DNA algorithm to solve graph coloring problem

Using a small quantity of DNA molecules and little experimental time to solve complex problems successfully is a goal of DNA computing. Some NP-hard problems have been solved by DNA computing with lower time complexity than conventional computing. However, this advantage often brings higher space complexity and needs a large number of DNA encoding molecules. One example is graph coloring problem. Current DNA algorithms need exponentially increasing DNA encoding strands with the growing of problem size. Here we propose a new DNA algorithm of graph coloring problem based on the proof of four-color theorem. This algorithm has good properties of needing a relatively small number of operations in polynomial time and needing a small number of DNA encoding molecules (we need only 6R DNA encoding molecules if the number of regions in a graph is R).     

A new DNA algorithm to solve graph coloring problem

Using a small quantity of DNA molecules and little experimental time to solve complex problems successfully is a goal of DNA computing. Some NP-hard problems have been solved by DNA computing with lower time complexity than conventional computing. However, this advantage often brings higher space complexity and needs a large number of DNA encoding molecules. One example is graph coloring problem. Current DNA algorithms need exponentially increasing DNA encoding strands with the growing of problem size. Here we propose a new DNA algorithm of graph coloring problem based on the proof of four-color theorem. This algorithm has good properties of needing a relatively small number of operations in polynomial time and needing a small number of DNA encoding molecules (we need only 6R DNA encoding molecules if the number of regions in a graph is R).     

Bacterial chromatin organization by H-NS protein unravelled using dual DNA manipulation

Both prokaryotic and eukaryotic organisms contain DNA bridging proteins, which can have regulatory or architectural functions. The molecular and mechanical details of such proteins are hard to obtain, in particular if they involve non-specific interactions. The bacterial nucleoid consists of hundreds of DNA loops, shaped in part by non-specific DNA bridging proteins such as histone-like nucleoid structuring protein (H-NS), leucine-responsive regulatory protein (Lrp) and SMC (structural maintenance of chromosomes) proteins. We have developed an optical tweezers instrument that can independently handle two DNA molecules, which allows the systematic investigation of protein-mediated DNA-DNA interactions. Here we use this technique to investigate the abundant non-specific nucleoid-associated protein H-NS, and show that H-NS is dynamically organized between two DNA molecules in register with their helical pitch. Our optical tweezers also allow us to carry out dynamic force spectroscopy on non-specific DNA binding proteins and thereby to determine an energy landscape for the H-NS-DNA interaction. Our results explain how the bacterial nucleoid can be effectively compacted and organized, but be dynamic in nature and accessible to DNA-tracking motor enzymes. Finally, our experimental approach is widely applicable to other DNA bridging proteins, as well as to complex DNA interactions involving multiple DNA molecules.     

增强拉曼光谱和电势调节红外光谱对偶极-偶极相互作用的研究

本文讨论了最近用SERS、PDIR研究在电极溶液界面处吸附在电极表面的分子(或离子)之间的偶极-偶极相互作用。该法不仅能用于研究小分子(或离子).如CO、CN~-等,且已能用于苯、吡啶等较大的分子间的偶极-偶极耦合作用,并可探讨光谱与吸附方向间的关系。