Molecular dynamics simulations of A-DNA in bivalent metal ions salt solution

A-DNA is one of the biologically active double helical structure. The study of A-DNA structure has an extensive application for developing the field of DNA packaging in biotechnology. In aqueous solution, the A-DNA structure will have a free transformation, the A-DNA structure will be translated into B-form structure with the evolution of time, and eventually stabilized in the the B-DNA structure. To explore the stability function of the bivalent metal ions on the A-DNA structure, a series of molecular dynamics simulations have been performed on the A-DNA of sequence (CCCGGCCGGG). The results show that bivalent metal ions (Mg2+, Zn2+, Ca2+) generate a great effect on the structural stability of A-DNA in the environment of high concentration. As the interaction between metal ions and electronegative DNA chains, the stability of A-DNA in solution is gradually improved with the increasing of the solution concentration of ions. In metal salt solution with high concentration, metal ions can be easily distributed in the solvation shells around the phosphate groups and further lead to the formation of shorter and more compact DNA structure. Also, in the condition of the same concentration and valency of the metal ions, the stability of A-DNA structure is different. The calculations indicate that the structure of A-DNA in CaCl2 solution is less stable than in MgCl2 and ZnCl2 solution.

Antibacterial Activity and DNA Binding Properties of Bivalent Metal Complexes of Cuminaldehyde Acetoylhydrazone

Metallo-hydrazones having the formula [M(IBAH)2] (where, M = Ni(II), Cu(II) and Zn(II); IBAH = p-Isopropylbenzaldehyde acetoylhydrazone) are prepared and confirmed on the basis of physico-chemical and spectral analyses. Conductivity data revealed that the complexes are non-electrolytes. Metal-DNA interactions are investigated using absorption spectrophotometry. Binding constant (Kb) data revealed that the copper complex interact DNA more strongly than other complexes. Antibacterial activity studies indicated higher activity for complexes than the metal free hydrazone ligand. The copper compound displays higher activity. DNA binding constants are correlated with the activity of metal compounds in this article.

Improved Photovoltaic Performance of CsPbI2Br Perovskite Films via Bivalent Metal Chloride Doping

Cesium-based all-inorganic perovskite absorbers have attracted increasing attention due to their superior thermal stability, compared to their organic–inorganic counterparts. Up to now, it is a challenge to fabricate high-efficiency all-inorganic perovskite solar cells (PSCs) with low defect densities. Herein, we used bivalent metal chloride salts (SrCl2 and NiCl2) to optimize CsPbI2Br films. The experimental results indicate that this method could deliver high-quality films with improved electronic property. As a result, the champion device based on the 0.01 M SrCl2–doped CsPbI2Br film achieved a power conversion efficiency (PCE) of 16.07% with a high open voltage (VOC) of 1,322 mV, which is about 18% higher than that of the pristine device.

Identification of a Novel Thermostable Alkaline Protease from Bacillus megaterium-TK1 for the Detergent and Leather Industry

An increased need by the green industry for enzymes that can be exploited for eco-friendly industrial applications led us to isolate and identify a unique protease obtained from a proteolytic Bacillus megaterium-TK1 strain from a seawater source. The extracellular thermostable serine protease was processed by multiple chromatography steps. The isolated protease displayed a relative molecular weight (MW) of 33 kDa (confirmed by zymography), optimal enzyme performance at pH 8.0, and maximum enzyme performance at 70 °C with 100% substrate specificity towards casein. The proteolytic action was blocked by phenylmethylsulfonyl fluoride (PMSF), a serine hydrolase inactivator. Protease performance was augmented by several bivalent metal cations. The protease tolerance was studied under stringent conditions with different industrial dispersants and found to be stable with Surf Excel, Tide, or Rin detergents. Moreover, this protease could clean blood-stained fabrics and showed dehairing activity for cow skin with significantly reduced pollution loads. Our results suggest that this serine protease is a promising additive for various eco-friendly usages in both the detergent and leather industries.