三种金属硫蛋白聚合体的疏水性相互作用研究

通过分子表面的计算考察了三类金属硫蛋白 (大鼠金属硫蛋白亚型II,兔肝金属硫蛋白亚型I和II)二聚体和三聚体中组成单元之间的疏水性相互作用。计算结果表明二聚体和三聚体中各组成单元之间均可以形成较好的几何匹配。对于二聚体而言 ,单体和单体之间存在一定的疏水性相互作用 ,但作用力不强。在三聚体中 ,单体和二聚体之间的疏水残基能通过好的空间匹配形成很强的疏水性相互作用。对于这三种金属硫蛋白 ,二聚体中单体和单体之间的疏水性相互作用不存在明显差别 ,但对于三聚体中单体和二聚体之间的疏水性相互作用 ,大鼠金属硫蛋白亚型II和兔肝金属硫蛋白亚型II要明显强于兔肝金属硫蛋白亚型I。

以聚乙二醇为层析伴侣同时制备SOD、过氧化氢酶和血红蛋白

发展了一条从红细胞裂解液中同时制备超氧化物歧化酶(SOD)、过氧化氢酶和血红蛋白的新工艺。采用0 75 %的聚乙二醇6 0 0作为层析伴侣,使血红蛋白直接流过阴离子交换层析柱,同时吸附SOD和过氧化氢酶。经过梯度洗脱获得SOD和过氧化氢酶组分,再经过疏水性相互作用层析与凝胶过滤层析相串联,使SOD和过氧化氢酶得到纯化。纯化后的SOD和过氧化氢酶的比活力分别达到15 932u mg和6 5 918u mg ,血红蛋白的纯度达到99 9%以上。总回收率为:SOD ,4 7 4 % ;过氧化氢酶,2 9 6 % ;血红蛋白,88 7%。

Molecular Dynamics Simulation of Effect of Salt on the Compromise of Hydrophilic and Hydrophobic Interactions in Sodium Dodecyl Sulfate Micelle Solutions

The presence of salt has a profound effect on the size,shape and structure of sodium dodecyl sulfate(SDS)micelles.There have been a great number of experiments on SDS micelles in the presence and absence of salt to study this complex problem.Unfortunately,it is not clear yet how electrolyte ions influence the structure of micelles.By describing the compromise between dominant mechanisms,a simplified atomic model of SDS in presence of salt has been developed and the molecular dynamics(MD)simulations of two series of systems with different concentrations of salt and charges of ion have been performed.Polydispersity of micelle size is founded at relatively high concentration of SDS and low charge of cation.Although the counter-ion pairs with head groups are formed,the transition of micelle shape is not observed because the charge of cation is not enough to neutralize the polar of micelle surface.

Peach skin effect:a quasi-superhydrophobic state with high adhesive force

The surface of a peach is known to exhibit spe- cial wettability and adhesion behaviors. We disclose that the peach surface is covered with long and short indumentums. The long indumentums are covered mainly with hydrophobic wax molecules, while the short indumentums are coated mostly with hydrophilic polysaccharides. Thus, the peach surface exhibits a quasi-superhydrophobic property and high adhesive force. A water droplet on the surface of a peach is a quasi-sphere, which is unable to roll off even when the peach is turned upside down. This is defined as the peach skin effect. We present that the quasi-superhydrophobic state with high adhesive force is attributed to the special coexisting Wenzel＇s and Cassie＇s state for water droplets, thus creating the strong interaction between the water droplet and surface.

Efficient removal of chlorophenols from water with a magnetic reduced graphene oxide composite

A magnetic reduced graphene oxide composite(MRGO) was successfully prepared by a simple and green method. MRGO was then used as an adsorbent and found to exhibit enhanced removal efficiency for various chlorophenols(CPs) from water compared with its precursors, graphene oxide(GO) and reduced graphene oxide. The CPs were o-chlorophenol, p-chlorophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol. Among them, 2,4,6-trichlorophenol, which exhibited the lowest water solubility and highest molecular weight, most easily bound to MRGO. The preferential interactions between MRGO and CPs were hydrophobic interactions(?-? stacking and hydrophobic effect). This result was confirmed by the equilibrium adsorption behavior in which isotherms were all well described by Freudlich model, indicating heterogeneous and multilayer adsorption. Therefore, CP adsorption was more favored under neutral and acidic conditions, and the decreased removal efficiency of MRGO at higher p H levels was due to the improved hydrophilicity of CPs for deprotonation effect. Moreover, MRGO showed fast removal of each CP, achieving adsorption equilibrium within 10.0 min, presented efficient separation from water under an external magnetic field, and was easily regenerated using dilute Na OH aqueous solution after reaching saturated adsorption. Adsorption capacity of the regenerated MRGO had almost no loss until after five cycles. In summary, MRGO was an efficient adsorbent for the removal of various CPs and had considerable application potential in water treatment.

Self-assembly of surfactant-like peptides and their applications

Numerous peptides derived from naturally occurring proteins or de novo designed have been found to self-assemble into various nanostructures.These well-defined nanostructures have shown great potential for a variety of biomedical and biotechnological applications.In particular,surfactant-like peptides(SLPs)have distinctive advantages in their length,aggregating ability,and water solubility.In this article,we report recent advances in the mechanistic understanding of the self-assembly principles of SLPs and in their applications,most of which have been made in our laboratory.Hydrogen bonding between peptide backbones,hydrophobic interaction between hydrophobic side chains,and electrostatic repulsion between charged head groups all have roles in mediating the self-assembly of SLPs;the final self-assembled nanostructures are therefore dependent on their interplay.SLPs have shown diverse applications ranging from membrane protein stabilization and antimicrobial/anticancer agents to nanofabrication and biomineralization.Future advances in the self-assembly of SLPs will hinge on their large-scale production,the design of new functional SLPs with targeted properties,and the exploitation of new or improved applications.