The interaction of isoxazolcurcumin (IOC), a synthetic derivative of curcumin, with calf thymus-DNA (ct-DNA) has been investigated by UV–Vis, fluorescence, circular dichroism spectroscopies, ...viscosity measurements and docking studies. From these analyses, the binding constant, number of binding sites and mode of binding of IOC to ct-DNA has been determined. The binding constant of IOC to DNA calculated from both UV–Vis and CD spectra was found to be in the 10
4
M
−1 range. Analyses of fluorescence spectra, viscosity measurements and molecular modeling of IOC–DNA interactions indicate that IOC is a minor groove binder of ct-DNA and preferentially binds to AT rich regions. Ethidium bromide displacement studies revealed that IOC did not have any effect on ethidium bromide bound DNA which is indicative of groove binding. To elucidate the preferred region of binding of IOC to DNA, docking studies have been performed and changes in accessible surface area (ΔASA) of nucleobases determined due to IOC–DNA complexation.
Photocatalysis, a unique process that occurs in the presence of light radiation, can potentially be utilized to control environmental pollution, and improve the health of society. Photocatalytic ...removal, or disinfection, of chemical and biological species has been known for decades; however, its extension to indoor environments in public places has always been challenging. Many efforts have been made in this direction in the last two–three years since the COVID-19 pandemic started. Furthermore, the development of efficient photocatalytic nanomaterials through modifications to improve their photoactivity under ambient conditions for fighting with such a pandemic situation is a high research priority. In recent years, several metal oxides-based nano-photocatalysts have been designed to work efficiently in outdoor and indoor environments for the photocatalytic disinfection of biological species. The present review briefly discusses the advances made in the last two to three years for photocatalytic viral and bacterial disinfections. Moreover, emphasis has been given to the tailoring of such nano-photocatalysts in disinfecting surfaces, air, and water to stop viral/bacterial infection in the indoor environment. The role of such nano-photocatalysts in the photocatalytic disinfection of COVID-19 has also been highlighted with their future applicability in controlling such pandemics.
Anharmonicity and impurities have a significant impact on the dynamic and optical properties of crystalline solids. In this report, we have performed temperature-dependent Raman spectroscopy in the ...range of 300–800 K for hydrothermally synthesized titanium dioxide (TiO2) nanorod composed microflowers doped with Cu. X-ray diffraction and high resolution transmission electron microscopy confirm the pure rutile phase of both pristine and Cu doped TiO2. The most intense Eg and A1g modes exhibit a frequency redshift, and the linewidth increases with temperature, which leads to Fano line shape type asymmetry. The anharmonicity induced phonon frequency shift as a function of temperature was well fitted using the Klemens model by combining three and four-phonon coupling processes. The Raman modes soften with the increasing concentration of Cu doping. The Cu dopant acts as an impurity, which manifests defect states to tune the bandgap and shorten the phonon lifetime and anharmonicity. Such an anharmonic effect can lead to applications in the sensing devices with suitable thermal and electrical conductivities.
The 3D-printing technology offers an innovative approach to develop energy storage devices because of its ability to create facile and low cost customized electrodes for modern electronics. Among the ...recently explored 2D nanomaterials beyond graphene, molybdenum sulfide (MoSx) has been found as a promising material for electrochemical energy storage devices. In this study, a nanocarbon-based conductive filament was 3D-printed and then activated by solvent treatment, followed by electrodeposition of MoSx on the printed nanocarbon electrode's surface. The conductive nanocarbon fibers allow a coaxial deposition of a thin MoSx layer. The MoSx layer contributes to pseudocapacitive charge storage mechanisms to obtain higher capacitances. In a three-electrode test system with 1 M H2SO4 as electrolyte, the MoSx coated 3D-printed electrode (MoSx@3D-PE) electrode shows a capacitance of 27 mF cm−2 at the scan rate of 10 mV s−1, and a capacitance of 11.6 mF cm−2 at the current density of 0.13 mA cm−2. Extending to solid-state supercapacitor (SS-SC), the cells were fabricated using the MoSx@3D-PE with different designs and polyvinyl alcohol (PVA)/H2SO4 as gel electrolyte. An interdigital-shaped SS-SC provided a specific capacitance of 4.15 mF cm−2 at a current density of 0.05 mA cm−2. Moreover, it showed a stable cycle life where 10% capacitance loss was found after 10 000 cycles. Briefly, this study reports the integration of 3D-printing and room-temperature electrodeposition techniques allowing a simple way of fabricating customized free-standing 3D-electrodes for use in SC applications.
Novel coronavirus disease 2019 (COVID-19) emerges as a serious threat to public health globally. The rapid spreading of COVID-19, caused by severe acute respiratory syndrome (SARS) coronavirus 2 ...(SARS-CoV-2), proclaimed the multitude of applied research needed not only to save the human health but also for the environmental safety. As per the recent World Health Organization reports, the novel corona virus may never be wiped out completely from the world. In this connection, the inhibitors already designed against different targets of previous human coronavirus (HCoV) infections will be a great starting point for further optimization. Pinpointing biochemical events censorious to the HCoV lifecycle has provided two proteases: a papain-like protease (PLpro) and a 3C-like protease (3CLpro) enzyme essential for viral replication. In this study, naphthyl derivatives inhibiting PLpro enzyme were subjected to robust molecular modelling approaches to understand different structural fingerprints important for the inhibition. Here, we cover two main aspects such as (a) exploration of naphthyl derivatives by classification QSAR analyses to find important fingerprints that module the SARS-CoV PLpro inhibition and (b) implications of naphthyl derivatives against SARS-CoV-2 PLpro enzyme through detailed ligand–receptor interaction analysis. The modelling insights will help in the speedy design of potent broad spectrum PLpro inhibitors against infectious SARS-CoV and SARS-CoV-2 in the future.
Graphical Abstract
α-Crystallin is a small heat shock protein and molecular chaperone. Binding of Cu2+ and Zn2+ ions to α-crystallin leads to enhanced chaperone function. Sequestration of Cu2+ by α-crystallin prevents ...metal-ion mediated oxidation. Here we show that binding of human γD-crystallin (HGD, a natural substrate) to human αA-crystallin (HAA) is inversely related to the binding of Cu2+/Zn2+ ions: The higher the amount of bound HGD, the lower the amount of bound metal ions. Thus, in the aging lens, depletion of free HAA will not only lower chaperone capacity but also lower Cu2+ sequestration, thereby promoting oxidation and cataract.
ABSTRACT3D printing has become a powerful technique in electrochemistry for fabricating electrodes, thanks to readily available conductive nanocomposite filaments, such as those based on carbon ...fillers (i.e., carbon nanotubes (CNTs) or carbon black (CB)) within an insulating polymeric matrix like polylactic acid (PLA). Inspired by inorganic heterostructures that enhance the functional characteristics of nanomaterials, we fabricated hetero-layered 3D printed devices based on carbon allotropes using a layer-by-layer assembly approach. The heterolayers were customised through the alternate integration of different carbon allotrope filaments via a multi-material 3D printing technique, allowing for a time-effective method to enhance electrochemical performance. As a first demonstration of applicability, CNT/PLA and CB/PLA filaments were utilised to construct ordered hetero-layered carbon-based electrodes. This contrasts with conventional methods where various carbon species are mixed in the same composite-based filament used for building electrochemical devices. Multi-material 3D-printed carbon electrodes exhibit improved electrochemical performance in energy conversion (e.g., hydrogen evolution reaction or HER) and sensing applications (e.g., ascorbic acid detection) compared to single-material electrodes. This work paves the way for manufacturing advanced 3D-printed heterolayered electrodes with enhanced electrochemical activity through multi-material 3D printing technology.
The cataract-associated Pro23 to Thr (P23T) mutation in human γD-crystallin (HGD) has a variety of phenotypes and is geographically widespread. Therefore, there is considerable interest in ...understanding the molecular basis of cataract formation due to this mutation. We showed earlier Pande, A., et al. (2005) Biochemistry 44, 2491−2500 that the probable basis of opacity in this case is the severely compromised, retrograde solubility and aggregation of P23T relative to HGD. The dramatic solubility change occurs even as the structure of the mutant protein remains essentially unchanged in vitro. We proposed that the retrograde solubility and aggregation of P23T were mediated by net hydrophobic, protein−protein interactions. On the basis of these initial findings for P23T and related mutants, and the subsequent finding that they show atypical phase behavior McManus, J. J., et al. (2007) Proc. Natl. Acad. Sci. U.S.A. 104, 16856−16861, we concluded that the protein clusters formed in solutions of the mutant proteins were held together by net hydrophobic, anisotropic interactions. Here we show, using chemical probes, that the surface hydrophobicities of these mutants are inversely related to their solubility. Furthermore, by probing the isolated N-terminal domains of HGD and P23T directly, we find that the increase in the surface hydrophobicity of P23T is localized in the N-terminal domain. Modeling studies suggest the presence of sticky patches on the surface of the N-terminal domain that could be engaged in the formation of protein clusters via hydrophobic protein−protein interactions. This work thus provides direct evidence of the dominant role played by net hydrophobic and anisotropic protein−protein interactions in the aggregation of P23T.
Silver Nanoparticles (AgNPs) were found to modulate the fibrillation of Bovine Β-Lactoglobulin (BLG).
To gain an insight regarding the mechanism of BLG aggregation modulation by AgNPs at molecular ...level, studies on the interactions between BLG and AgNPs were carried out.
Protein-ligand interactions were studied based on Trp fluorescence quenching (at four different temperatures), synchronous and three-dimensional fluorescence and circular dichroism spectroscopy (far-UV and near-UV).
Protein-nanoparticles association constant was in the range of 106 -1010 M-1 and the quenching constant was determined as ~107 M-1. Ground state complexation between the protein and nanoparticles was predicted. Change in polarity surrounding the Trp residue was not detected by synchronous and three-dimensional fluorescence spectroscopy. AgNPs caused a global change in the secondary and tertiary structure of the protein as revealed from far-UV and near-UV CD spectroscopy. Enthalpy driven complexation between the protein and nanoparticles indicates the involvement of hydrogen bonding and/or van der Waals interactions.
Modulation of BLG aggregation by AgNPs is due to strong binding of the nanoparticles with BLG, which also causes structural perturbations of the protein.
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