HIV-1整合酶链转移反应抑制剂的荧光筛选方法

整合酶被认为是抗HIV-1药物研究的理想靶点之一。为了建立便捷高效的整合酶链转移反应抑制剂筛选方法,首先将HIV-1整合酶原核表达载体pNL-IN转化入大肠杆菌感受态细胞BL21(DE3)进行原核表达,并用镍琼脂糖凝胶进行亲和纯化,获得了纯度和活性均较高的整合酶重组蛋白;然后设计了生物素标记的供体DNA和FITC标记的靶DNA,用链霉亲和素磁珠捕获反应体系中的DNA产物;最后用荧光分析仪检测DNA产物的荧光信号,并计算待测样品的抑制率。用已知整合酶抑制剂S-1360和MK-0518对筛选方法进行了验证,测定结果与已有实验数据相当,表明本筛选方法能够有效应用于HIV-1整合酶链转移反应抑制剂的筛选。与现有的整合酶链转移反应抑制剂筛选方法相比,本筛选方法步骤更为简化、耗时更短、成本更低。     

蛋白质组学在妊娠期高血压疾病中的研究进展

蛋白质组学的兴起能快速筛选并鉴定疾病的特异性生物标志物,有助于研究妊娠期高血压疾病的病因、发生机制,通过特异性生物标志物进行早期诊断,从而改善母儿结局,降低母儿严重发病率和死亡率。本文综述近年来与妊娠期高血压疾病相关的蛋白质研究及其在妊娠期高血压疾病患者血液、脑脊液、尿液、羊水、滋养细胞中差异蛋白质谱的分析,为进一步研究提供思路。     

Wnt5a抑制Wnt3a促黑素细胞黑素生成的作用探究

目的：研究WntSa对Wnt3a处理过的melan—a细胞分泌黑色素的影响。方法：体外培养黑色素细胞（melan-a细胞）,分别进行GFP、Wnt3a、Wnt3a＋WntSa处理,比较细胞的突起,酪氨酸酶的活性以及黑素合成相关基因（TYR、TRP2、MITF）表达情况。结果：Wnt3a促进黑色素细胞突起的生长和TYR、TRP2、MITF的表达,而Wnt5a逆转了Wnt3a对黑色素细胞的作用。结论：Wnt5a抑制Wnt3a促黑素细胞黑素生成的作用,表明在melan．a黑素细胞中Wnt5a可有效抑制wnt经典通路。     

联合用药靶控静脉麻醉在纤维支气管镜检查术中的麻醉效果分析

目的：分析纤维支气管镜检查术中丙泊酚联合右美托咪啶靶控静脉麻醉的效果,为临床麻醉提供参考。方法：选取73例行纤维支气管镜检查术的患者作为研究对象,按麻醉方式不同分为观察组38例（采用右美托咪啶联合丙泊酚麻醉）和对照组35例（单用丙泊酚麻醉）。观察分析各时点心率、呼吸次数、平均动脉压、血氧饱和度、镇静效果评分、苏醒时间以及不良反应发生率等指标。结果：Ramsay评分：对照组6分的例数为22例（62．9％）,观察组为32（84．2％）,差异有统计学意义;丙泊酚总用量：观察组为（334．5±54．6）mg,对照组为（463．2±60．5）mg,差异有统计学意义,医生满意度：观察组为92．1％,对照组为74.3％,差异有统计学意义。结论：丙泊酚联合右美托咪啶靶控静脉麻醉安全有效,效果显著,适合纤维支气管镜检查术。     

Extracellular expression of pullulanase from Bacillus naganoensis in Escherichia coli

The pullulanase encoding gene from Bacillus naganoensis was successfully overexpressed in Escherichia coli both intracellularly and extracellularly using expression vector pET22b (+). The distribution of recombinant protein was significantly affected by temperature and carbon and nitrogen sources. The highest levels of extracellular and intracellular production of the target protein were observed at 25 and 20 °C, respectively. The addition of maltose, dextrin, pullulan, and soluble starch to the culture medium caused significant increases in the extracellular yield of pullulanase, while glucose strongly inhibited pullulanase production. The results show that the optimal conditions for maximum yield of extracellular pullulanase required high levels of carbon source and a limited nitrogen supply, while low concentrations of carbon and nitrogen source favored intracellular pullulanase expression. High concentrations of nitrogen source strongly inhibited the production of pullulanase.     

Investigation of the binding network of IGF-I on the cavity surface of IGFBP4

Insulin-like growth factor-binding proteins (IGFBPs) control bioactivity and distribution of insulin-like growth factors (IGFs) through high-affinity complex of IGFBP and IGF. To get more insight into the binding interaction of IGF system, the site-directed mutagenesis and force-driving desorption methods were employed to study the interaction mechanism of IGFBP4 and IGF-I by molecular dynamics (MD) simulation. In IGF-I, residues Gly7 to Asp12 were found to be the hot spots and they mainly anchored on the N-domain of IGFBP4. The contact area, the shape and size of protein, the surroundings of the binding site, the hydrophobic and electrostatic interaction between the two proteins worked as a complex network to regulate the protein-protein interaction. It was also found that the unfolding of the helix was not inevitable in the mutant, and it could be regulated by careful selection of the substituted amino acid.

Looking for high energy density compounds among polynitraminepurines

A series of purine derivatives with nitramine groups are calculated by using density functional theory (DFT). The molecular theory density, heats of formation, bond dissociation energies and detonation performance are investigated at DFT-B3LYP/6-311G** level. The isodesmic reaction method is employed to calculate the HOFs of the energies obtained from electronic structure calculations. Results show that the position of nitramine groups can influence the values of HOFs. The bond dissociation energies and the impact sensitivity are analyzed to investigate the thermal stability of the purine derivatives. The calculated bond dissociation energies of ring-NHNO₂ and NH-NO₂ bond show that the NH-NO₂ bond should be the trigger bond in pyrolysis processes. The H₅₀ of most compounds are larger than that of CL-20 and RDX.     

Computational studies on polynitropurines as potential high energy density materials

As part of a search for high energy density materials (HEDMs), a series of purine derivatives with nitro groups were designed computationally. The relationship between the structures and the performances of these polynitropurines was studied. Density functional theory (DFT) at the B3LYP/6-311G** level was employed to evaluate the heats of formation (HOFs) of the polynitropurines by designing an isodesmic reaction method. Results indicated that the HOFs were influenced by the number and positions of substituent groups. Detonation properties were evaluated using the Kamlet–Jacobs equations, based on the theoretical densities and heats of formation of the polynitropurines. The relative stabilities of the polynitropurines were studied via the pyrolysis mechanism and the UB3LYP/6-311G** method. Homolysis of the ring–NO₂ bond is predicted to be the initial step in the thermal decomposition of these purine derivatives. Considering their detonation properties and relative stabilities, the tetranitropurine (D1) derivatives may be regarded as potential candidates for practical HEDCs. These results may provide useful information for further investigations.     

Highlighting a π–π interaction: a protein modeling and molecular dynamics simulation study on Anopheles gambiae glutathione S-transferase 1-2

Cytosolic insect theta class glutathione S-transferases (GSTs) have not been studied completely and their physiological roles are unknown. A detailed understanding of Anopheles gambiae GST (Aggst1-2) requires an accurate structure, which has not yet been determined. A high quality model structure of Aggst1-2 was constructed using homology modeling and the ligand–protein complex was obtained by the docking method. Molecular dynamics (MD) simulations were carried out to study conformational changes and to calculate binding free energy. The results of MD simulation indicate that Aggst1-2 undergoes small conformational changes after ligands dock to the protein, which facilitate the catalytic reaction. An essential hydrogen bond was found between the sulfur atom of glutathione (GSH) and the hydrogen atom of hydroxyl group in Ser9, which was in good agreement with experimental data. A π–π interaction between Phe204 and CDNB ligand was also found. This interaction seems to be important in stabilization of the ligand. Further study of binding free energy decomposition revealed a van der Waals interaction between two ligands that may play a key role in nucleophilic addition reaction. This work will be a good starting point for further determination of the biological role of cytosolic insect theta class GSTs and will aid the design of structure-based inhibitors.