基于链置换循环无标记检测端粒酶RNA的荧光法

以氧化石墨烯(GO)作为DNA载体和荧光猝灭剂, SYBR Green Ⅰ(SGⅠ)为荧光信号探针, 发夹核酸探针为分子识别探针, 基于目标物启动的发夹核酸探针链置换循环反应, 建立了一种利用荧光共振能量转移和链置换循环放大技术检测端粒酶RNA(hTR)的荧光新方法. 发夹核酸探针hpDNA1和hpDNA2吸附在GO表面, 嵌插在发夹DNA探针茎部的SGⅠ的荧光信号被GO猝灭. 当人工合成的目标物(T1)存在时, T1与hpDNA1杂交打开hpDNA1的茎-环结构而引发hpDNA2与T1之间的链置换循环反应, 由此累积产生大量的hpDNA1/hpDNA2杂交双链. 刚性的双链DNA脱离GO表面, 导致所嵌插的SGⅠ产生较强的荧光信号. 基于荧光信号的变化, 可定量检测0.2~50 nmol/L的T1, 检出限为90 pmol/L. 该方法为端粒酶RNA检测提供了一种高灵敏、 高特异性且无需标记的荧光新途径.     

Computational Analysis Reveals Monomethylated Triazolopyrimidine as a Novel Inhibitor of SARS-CoV-2 RNA-Dependent RNA Polymerase (RdRp)

The human population is still facing appalling conditions due to several outbreaks of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) virus. The absence of specific drugs, appropriate vaccines for mutants, and knowledge of potential therapeutic agents makes this situation more difficult. Several 1, 2, 4-triazolo [1, 5-a] pyrimidine (TP)-derivative compounds were comprehensively studied for antiviral activities against RNA polymerase of HIV, HCV, and influenza viruses, and showed immense pharmacological interest. Therefore, TP-derivative compounds can be repurposed against the RNA-dependent RNA polymerase (RdRp) protein of SARS-CoV-2. In this study, a meta-analysis was performed to ensure the genomic variability and stability of the SARS-CoV-2 RdRp protein. The molecular docking of natural and synthetic TP compounds to RdRp and molecular dynamic (MD) simulations were performed to analyse the dynamic behaviour of TP compounds at the active site of the RdRp protein. TP compounds were also docked against other non-structural proteins (NSP1, NSP2, NSP3, NSP5, NSP8, NSP13, and NSP15) of SARS-CoV-2. Furthermore, the inhibition potential of TP compounds was compared with Remdesivir and Favipiravir drugs as a positive control. Additionally, TP compounds were analysed for inhibitory activity against SARS-CoV RdRp protein. This study demonstrates that TP analogues (monomethylated triazolopyrimidine and essramycin) represent potential lead molecules for designing an effective inhibitor to control viral replication. Furthermore, in vitro and in vivo studies will strengthen the use of these inhibitors as suitable drug candidates against SARS-CoV-2.     

信号核酸识体用于药物托普霉素的高灵敏度检测

提出了一种利用RNA核酸识体和光开关化合物[Ru(phen)2dppz\]2+ (RU)高灵敏检测药物分子的荧光分析新方法. 以托普霉素(TOB)为靶分子, 检测限可达到10 nmol/L, 同时该方法有较好的选择性, 能在溶液中实现无需分离的实时检测. 这种无标记检测方法有利于不稳定RNA核酸识体在分析检测中的应用, 简化实验操作, 为其它药物分子的检测提供了新思路.     

离子交换色谱法研究蛋白质与RNA的结合特异性

RNA是以磷酸二酯键相连的核苷酸组成的聚阴离子,而蛋白质在PH小于它的等电点的缓冲溶液中带有正电性.因此,它们在离子交换色谱分子时能出现在差异很大的洗脱组分中.据此.我们设计了用离子交换色谱法研究蛋白质与RNA的结合特异性方法,用以研究位于T细胞核内的具有RNA结合活性的蛋白质人环素33(hCyP33)与不同RNA的结合特性.结果表明,人亲环素33只有ply(A)尾序列结构的mRNA,即poly(A)^ RNA发生特异性结合.     

复合物Ca+-RNA碱基的结构与稳定性

Gas-phase metal ion affinities and optimized structures of RNA nucleic acid bases for the Ca+ were determined at a density functional level employing the hybrid B3LYP exchange correlation potential in connection with the 6-311+G(2df,2p) basis set. All the molecular complexes, obtained by the interaction between several low-lying tautomers of RNA nucleic acid and Ca+ on the different binding sites, were considered. For Cytosine, the most stable complex was obtained starting from the most stable tautomer of the free nucleic acid base tautomers. As to thymine, the bond energy of the ion with the most stable tautomer of the free nucleic acid base is the weakest among the three tautomer’s complexes, and that of the ion with least stable tautomer of the free nucleic acid base is the strongest . Uracil is similar to thymine. The two kinds of relation, bond energy and total energy for the complex, are in disagreement, as the metal affinities of RNA bases for the Ca+ depend on binding sites, and total energy of complex (Ca+-RNA base) relies on all atoms and their relative positions in the complex.