固相金属亲和层析纯化全长人PPARγ重组蛋白

建立全长人PPARγ重组蛋白的固相金属亲和层析纯化方法.利用E.coli BL21 (DE3)细胞外源性表达出全长人PPARγ重组蛋白,采用固相金属亲和层析法纯化目标蛋白.通过考察咪唑浓度对纯化的影响,确定在8 mol/L尿素下,用含50 mmol/L咪唑的缓冲液冲洗,200mmol/L咪唑缓冲液洗脱,可获得纯度为95％的目标蛋白,透析复性后经放射配体受体饱和结合实验测定全长人PPARγ重组蛋白的解离常数Kd为106士6nmol/L.结果表明本文所建立的方法能够成功纯化出高纯度的目标蛋白,经复性后,可获得用于结构和功能研究的全长人PPARγ重组蛋白.     

First principles calculations of electronic and optical properties of Mo and C co-doped anatase TiO2

Using the first principles calculations, the electronic and optical properties of C, Mo and Mo-C-doped anatase TiO₂ are studied. For the Mo mono-doped TiO₂, the band gap reduces little, and the largest perturbation occurs at the CBM of TiO₂. C mono-doping suppresses the effective band gap, but the partially occupied subbands in the gap probably also serve as the recombination centers for electrons and holes. Therefore, the Mo-C co-doping is investigated for the charge compensation consideration. We discuss six doped configurations and find that the total energy of the system is increased with increasing distance of C and Mo. It is found that co-doped configurations with C nearest to Mo possess the lowest total energy. Then, we focus on discussing three possible Mo-C adjacent co-doped configurations. The subbands mainly induced by C-2p states in the band gap become fully occupied because the Mo atom contributes sufficient electrons to C anion for compensation. At the same time, the effective band gap is narrowed about 0.9 eV and the perturbation at the CBM occurred in Mo mono-doped TiO₂ disappears, which means the band edges of doped system still straddle the redox potentials of water. Furthermore, the optical properties of the compensated Mo-C adjacent co-doped TiO₂ and pure TiO₂ are calculated. The optical absorption edges of the Mo-C co-doped TiO₂ shift towards the visible light region.     

Late-Stage Direct o-Alkenylation of Phenols by PdII-Catalyzed C−H Functionalization

o-Alkenylation of unprotected phenols has been developed by direct C−H functionalization catalyzed by Pd^II. This work features phenol group as a directing group and realizes highly site-selective C−H bond functionalization of phenols to achieve the corresponding products in moderate to excellent yields at 60 °C. The advantages of this reaction include unprecedented C−H functionalization using phenol as a directing group, high regioselectivity, good substrate scope, mild reaction conditions, and high efficiency. To the best of our knowledge, this is the first example of a regioselective C−H alkenylation of unprotected phenols utilizing phenolic hydroxyl group as a directing group. The alkenylation of unprotected tyrosine and intramolecular cyclization are also successfully carried out under this catalytic system in good yields. Furthermore, this novel method enables a late-stage modification of complex phenol-containing bioactive molecules toward a diversity-oriented drug discovery.     

A Phosphorescent Platinum(II) Bipyridyl Supramolecular Polymer Based on Quadruple Hydrogen Bonds

A platinum(II) bipyridyl complex bearing bis‐ureidopyrimidinone (Pt‐bisUPy) has been designed and its self‐assembling behavior has been thoroughly investigated by ¹H NMR, DOSY NMR, Ubbelohde viscometry analysis, UV/Vis, and emission spectroscopies. Pt‐bisUPy underwent concentration‐dependent ring‐chain polymerization in apolar solvents. Hydrogen‐bonding interactions play an important role during the formation of the supramolecular polymers. Hydrogen‐bonded supramolecular polymers were transformed to nanoparticles in water through the miniemulsion method. These nanoparticles showed strong π–π excimeric emission. Metal‐metal‐to‐ligand charge transfer (MMLCT) from Pt–Pt interactions was not significant in the emission spectrum. The phosphorescence of the nanoparticle persisted even under aerobic conditions. The triplet state of these phosphorescent nanomaterials were long‐lived and possessed moderate emission quantum yields. Furthermore, the low toxicity of these materials promises a place for them in in vitro and in vivo bioimaging.     

Synchronization for chaotic systems and chaos-based secure communications via both reduced-order and step-by-step sliding mode observers

This paper considers the problems of the chaos synchronization and chaos-based secure communication when the observer matching condition is not satisfied. An auxiliary drive signal vector which may satisfy the observer matching condition is constructed. By using the drive signals of original system, a step-by-step sliding mode observer is considered to obtain the exact estimates of the auxiliary drive signals and their derivatives. A reduced-order observer is designed to asymptotically estimate the states of the drive system. By using the estimates of states and the derivatives of the auxiliary signals, an information signal recovery method which does not use any derivative information of original drive system is developed. Finally, a numerical simulation example is given to illustrate the effectiveness of the proposed methods.