Construction of Hybrid Enzyme from HEC-SOD and Cu,Zn-SOD

Human extracellular superoxide dismutase(hEC-SOD) is a secreted tetrameric protein involved in the protection of a human body from oxygen free radicals. Its three-dimensional structure has not been confirmed, hEC-SOD couldn′t be expressed in E.coll. We constructed a hybrid enzyme, which comprises the Nterminal and C-terminal domains from hEC-SOD, fused it to human Cu, Zn-SOD. The hybrid enzyme is expressed successfully in E. coli. Further, we analyzed the expression of hEC-SOD in E. coli by mRNA differential displaying.     

Selective bonding of pyrazine to silicon(100)-2x1 surfaces: the role of nitrogen atoms

The covalent binding of pyrazine on Si(100) have been investigated using high-resolution electron energy loss spectroscopy (HREELS) and x-ray photoelectron spectroscopy. Experimental results clearly suggest that the attachment occurs exclusively through the bonding of the two para-nitrogen atoms with the surface without the involvement of the carbon atoms, as evidenced from the retention of the (sp2) C-H stretching mode in HREELS and a significant down shift of 1.6 eV in the binding energy of N 1s. The binding mechanism for pyrazine on Si(100) demonstrates that reaction channels for heteroatomic aromatic molecules are strongly dependent on the electronic properties of the constituent atoms.     

大孔高镍LiNi0.8Co0.1Mn0.1O2正极材料的制备及其电化学性能研究

本工作以聚甲基丙烯酸甲酯(PMMA)微球组装成的胶晶模板作为铸模,溶胶-凝胶法辅助获得大孔LiNi0.8Co0.1Mn0.1O2 (NCM811)正极材料.结果 表明,利用PMMA作为造孔剂,形成了由100nm的颗粒堆积而成的大孔结构,这种结构有效地提高了材料的倍率性能和循环稳定性.大孔NCM811在0.1C的首次放电...     

The Barrier to Proton Transfer in the Dimer of Formic Acid: A Pure Rotational Study

The rotational spectra of three C‐deuterated isotopologues of the dimer of formic acid have been measured, thanks to the small dipole moment induced by asymmetric H→D substitution(s). For the DCOOH–HCOOH species, the concerted double proton transfer of the two hydroxy hydrogen atoms takes place between two equivalent minima and generates a tunneling splitting of 331.2(6) MHz. This splitting can be reproduced by a 3D model with a barrier of 2559 cm^?1 (30.6 kJ mol^?1) as obtained from theoretical calculations.     

Thermally Responsive Materials for Bioimaging

The last decade has witnessed multiple thermally responsive materials emerge as a significant class of stimuli‐responsive materials. These materials are elaborately designed and exert interesting properties. Herein, an overview of thermally responsive materials with respect to design strategies, fabrication procedures, and their applications is presented. Recently reported thermally responsive materials are highlighted. Then, applications of thermally responsive materials in bioimaging are summarized.     

Highly stereoselective anti-aldol reactions catalyzed by simple chiral diamines and their unique application in configuration switch of aldol products

Chiral derivatives of trans-1,2-diaminocyclohexane with different N,N-dialkyl groups in well-defined orientations have been synthesized, and applied as catalysts for the asymmetric aldol reaction between a variety of aldehydes and ketones. Enantiomeric catalyst 1j catalyzed the reaction in ethanol and provided excellent diastereoselectivity and enantioselectivity. Significantly, simple replacement of organic solvents with water switched the products of the aldol reactions from anti to syn configuration. Such catalytic reactions led to the products with anti to syn diastereoselectivity up to 99:1 in ethanol, while in water gave the products with syn to anti diastereoselectivity up to 99:1.     

From Zero‐dimensional to One‐dimensional: Use of Metal‐­Ligand Affinity in Supramolecular Assembly

The self‐assembly of 4 ‐ MTPP [ 4 ‐ MTPP = 2‐(methylthio)‐4‐(pyridin‐4‐yl)pyrimidine] with Cu(NO₃)₂ and AgNO₃ was structurally investigated. For Cu(NO₃)₂, a discrete mononuclear Cu^II coordination compound, [Cu( 4 ‐ MTPP )₂(NO₃)₂] ( 1 ), resulted that is exclusively based on Cu–N coordination. For AgNO₃, a unique one‐dimensional double‐chain structure ( 2 ) was obtained with the Ag–N distances varying from 2.181(9) to 2.223(9) Å, and the average Ag–S distance being 2.98 Å. Compared to zero‐dimensional 1 , the extension to one‐dimensional 2 is considered to result from the specific affinity between Ag⁺ and the ligand 4 ‐ MTPP that is attributed to the strong coordinating tendency of silver for aromatic nitrogen and thioether sulfur atoms.     

A Facile Synthesis of Prumycin

Abstract

Benzyl 2,3-anhydro-4-azido-4-deoxy-α-L-ribopyranoside (7), an intermediate for the synthesis of Prumycin was synthesized in 72% yield in seven steps from D-arabinose. Ammonolysis of 7 followed by N-protection with the benzyloxycarbonyl group gave benzyl 4-azido-2-(benzyloxycarbonyl)amino-2,4-dideoxy-α-L-arabinopyranoside (8), which was easily converted to Prumycin.     

Isolation and identification of nondestructive desulfurization bacterium

A nondestructive desulfurization microorganism has been isolated. The metabolism product analyses show that the strain can be a kind of biocatalyst to oxidize dibenzothiophene (DBT) into 2-hydroxydiphenyl (HBP), therefore the sulfur in DBT is removed selectively. The 16SrRNA information, cell wall analysis, physical, biochemical properties and morphological properties suggest that the isolated strain is Rhodococcus erythropolis. The strain can grow in the basal salts medium (BSM) that DBT concentration is no more than 10 mmol/L, and the optimal DBT concentration for growth is 1 mmol/L, however, the optimal DBT concentration for desulfurization is 0.5 mmol/L. The further research shows that the strain can also desulfur some other or-ganosulfur-containing compounds such as thianaphthene, phenyl sulfide and 4,6-dimethyldiben-zothiophene (4,6-DMDBT).     

Study on the interaction mechanism between aromatic amino acids and quercetin

In this paper, we selected quercetin and aromatic amino acids (tryptophan, tyrosine, phenylalanine) as the research objects to investigate the change rules in the reaction process. The thermodynamic functions (Ka, ΔG, and ΔS) of the interactions between quercetin and aromatic amino acids (tryptophan, tyrosine, phenylalanine) were measured by isothermal titration calorimetry. The values of binding constant (Ka) reached maximum at 25°C; the entropies and Gibbs free energies were both negative at different temperatures. The kinetic parameters of quercetin and amino acids in the interaction process was determined by microcalorimetry. The results inferred that the driving force of the reaction was hydrogen bond or van der Waals force.