National Chemical Laboratory

About: National Chemical Laboratory is a facility organization based out in Pune, Maharashtra, India. It is known for research contribution in the topics: Catalysis & Nanoparticle. The organization has 8891 authors who have published 14837 publications receiving 387600 citations.

Single-strand-specific nucleases

Abstract: Single-strand-specific nucleases are multifunctional enzymes and widespread in distribution. Their ability to act selectively on single-stranded nucleic acids and single-stranded regions in double-stranded nucleic acids has led to their extensive application as probes for the structural determination of nucleic acids. Intracellularly, they have been implicated in recombination, repair and replication, whereas extracellular enzymes have a role in nutrition. Although more than 30 single-strand-specific nucleases from various sources have been isolated till now, only a few enzymes (S1 nuclease from Aspergillus oryzae, P1 nuclease from Penicillium citrinum and nucleases from Alteromonas espejiana, Neurospora crassa, Ustilago maydis and mung bean) have been characterized to a significant extent. Recently, some of these enzymes have been cloned, their crystal structures solved and their interactions with different substrates have been established. The detection, purification, characteristics, structure–function correlations, biological role and applications of single-strand-specific nucleases are reviewed.

Isothermal Titration Calorimetry Studies on the Binding of Amino Acids to Gold Nanoparticles

Abstract: Isothermal titration calorimetry (ITC) is a powerful and highly sensitive technique commonly used to study interactions between biomolecules in dilute aqueous solutions, both from thermodynamic and kinetics points of view. In this report, we show that ITC may be used to follow the binding of ligands such as amino acids to the surface of inorganic materials such as gold nanoparticles. More specifically, we have studied the binding of one basic amino acid, lysine, and an acidic amino acid, aspartic acid, with aqueous gold nanoparticles at physiological pH. Strong binding of aspartic acid with the gold nanoparticles under these conditions is indicated by ITC, while weak binding was observed in the case of lysine. The differences in binding are attributed to protonation of amine groups in lysine at physiological pH (pI 9.4) while they are not protonated for aspartic acid (pI 2.77). That this is the likely mechanism is indicated by the ITC measurement of binding of lysine with nanogold at pH 11 (when the amine groups are not protonated). The binding of the amino acids with gold nanoparticles has been validated with other techniques such as gel electrophoresis and X-ray photoemission spectroscopy.

High-Temperature X-ray Diffraction Studies on the Crystalline Transitions in the α- and γ-Forms of Nylon-6

Abstract: The crystallization of nylon-6 from the melt was monitored in situ by X-ray diffraction. The nylon-6 was found to crystallize into a high-temperature α‘-phase as indicated by the two-peak nature of the diffractogram. On cooling from the crystallization temperature to room temperature, nylon-6 retained the two-peak nature. However, data analysis indicates a change from high-temperature (HT) α‘-phase to low-temperature α-phase at ∼180 °C. On heating, the α-phase transformed into the α‘-phase at about 190 °C and melted in the α‘-phase. The transition took place over a temperature range where both phases coexisted. However, samples crystallized from the melt at temperatures 140 and 180 °C showed the α-phase at room temperature, but on heating the α-phase first transformed into a pseudohexagonal phase and before melting the pseudohexagonal phase further transformed into the α‘-phase. The α-phase was transformed into the γ-phase, by potassium iodide−iodine treatment, and the behavior of the γ-phase with tempera...

Zinc ion interactions in a two-dimensional covalent organic framework based aqueous zinc ion battery

Abstract: The two-dimensional structural features of covalent organic frameworks (COFs) can promote the electrochemical storage of cations like H+, Li+, and Na+ through both faradaic and non-faradaic processes. However, the electrochemical storage of cations like Zn2+ ion is still unexplored although it bears a promising divalent charge. Herein, for the first time, we have utilized hydroquinone linked β-ketoenamine COF acting as a Zn2+ anchor in an aqueous rechargeable zinc ion battery. The charge-storage mechanism comprises of an efficient reversible interlayer interaction of Zn2+ ions with the functional moieties in the adjacent layers of COF (−182.0 kcal mol−1). Notably, due to the well-defined nanopores and structural organization, a constructed full cell, displays a discharge capacity as high as 276 mA h g−1 at a current rate of 125 mA g−1.