The technique of facile co-precipitation was employed to prepare the pure ZnO and Gd doped ZnO photocatalysts. The physio-chemical properties of the prepared samples were analysed through various ...analytical techniques. The X-ray diffraction analysis clearly shows that higher amount of Gd dopant creates the secondary phase in addition to normal peaks of ZnO crystals. The visible light absorption increases with increasing the Gd amount in ZnO which is evident from UV–Vis DRS analysis. The as synthesized 3% Gd doped ZnO exhibits the highest photocatalytic activity on Methylene blue dye degradation under visible light irradiation compared to other photocatalysts. The enhanced degradation activity of the photocatalyst demonstrates the improved visible light absorption of the materials due to the incorporation of Gd ions into the ZnO lattice. The possible reaction mechanism and degradation pathway of the photocatalyst has been discussed in detail and the stability of the catalyst have been confirmed by recycle process.
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•Facile co-precipitation method was used to prepare the pure and Gd doped ZnO photocatalyst.•The visible light absorption increases with increasing the percentage of Gd.•The Methylene blue dye degradation efficiency reaches 93% under visible light irradiation over 3% Gd doped ZnO.
To understand the rules governing the protein folding process it is essential to study the stability and unfolding of small monomeric proteins. Here, I present the pH dependent thermal unfolding ...energetics and conformational stability analysis of monomeric Dynein light chain protein (DLC8) in the pH range 3.5–2.0. DLC8 is the smallest and the most conserved light chain among the light chains of the dynein motor assembly. Thermal unfolding of DLC8 monomer is much complex with the presence of transient intermediates, which is in contrast to the notion that small proteins unfold via simple two-state process. The unfolding seems to be more cooperative at lower pH and the temperature of highest conformational stability (
T
s) is found to be maximum (295.7
K) at pH 2.76. Stability curves have been simulated to understand the thermodynamic parameters that govern the shapes of the experimentally obtained curves. Further, an effort has been made to correlate the observed differences in the denaturation energetics with the protein sequence in order to throw light on the structure-folding paradigm of the DLC8 monomer.
Understanding protein stability at residue level detail in the native state ensemble of a protein is crucial to understanding its biological function. At the same time, deriving thermodynamic ...parameters using conventional spectroscopic and calorimetric techniques remains a major challenge for some proteins due to protein aggregation and irreversibility of denaturation at higher temperature values. In this regard, we describe here the NMR investigations on the conformational stabilities and related thermodynamic parameters such as local unfolding enthalpies, heat capacities and transition midpoints in DLC8 dimer, by using temperature dependent native state hydrogen exchange; this protein aggregates at high (>65°C) temperatures. The stability (free energy) of the native state was found to vary substantially with temperature at every residue. Significant differences were found in the thermodynamic parameters at individual residue sites indicating that the local environments in the protein structure would respond differently to external perturbations; this reflects on plasticity differences in different regions of the protein. Further, comparison of this data with similar data obtained from GdnHCl dependent native state hydrogen exchange indicated many similarities at residue level, suggesting that local unfolding transitions may be similar in both the cases. This has implications for the folding/unfolding mechanisms of the protein.
Adult T cell lymphoma/leukemia is a peripheral T-cell neoplasm caused by human T-cell lymphotrophic virus-1, affects mostly adults with systemic involvement and poor prognosis. Diagnosis of adult ...T-Cell leukemia/Lymphoma is challenging. The clinico-pathologic and immuno-phenotypic features of the three cases will be presented.
We present circular dichroism (CD), steady state fluorescence and multidimensional NMR investigations on the equilibrium unfolding of monomeric dynein light chain protein (DLC8) by urea and guanidine ...hydrochloride (GdnHCl). Quantitative analysis of the CD and fluorescence denaturation curves reveals that urea unfolding is a two-state process, whereas guanidine unfolding is more complex. NMR investigations in the native state and in the near native states created by low denaturant concentrations enabled residue level characterization of the early structural and dynamic perturbations by the two denaturants. Firstly,
15N transverse relaxation rates in the native state indicate that the regions around N10, Q27, the loop between β2 and β4 strands, and K87 at the C-terminal are potential unfolding initiation sites in the protein. Amide and
15N chemical shift perturbations indicate different accessibilities of the residues along the chain and help identify locations of the early perturbations by the two denaturants. Guanidine and urea are seen to interact at several sites some of which are different in the two cases. Notable among the common interaction site is that around K87 which is in close proximity to W54 on the protein structure, but the interaction modes of the two denaturants are different. The secondary chemical shifts indicate that the structural perturbation by 1
M urea is small, compared to that by guanidine which is more encompassing over the length of the chain. The probable (
ϕ,
ψ) changes at the individual residues have been calculated using the TALOS algorithm. It appears that the helices in the protein are significantly perturbed by guanidine. Further, comparison of the spectral density functions of the native and the two near native states in the two denaturants implicate greater loosening of the structure by guanidine as compared to that by urea, even though the structures are still in the native state ensemble. These differences in the early perturbations of the native state structure and dynamics by the two denaturants might direct the protein along different pathways, as the unfolding progresses on further increasing the denaturant concentration.
In this work, we have fabricated hybrid nanocomposites of WS2/rGO using facile hydrothermal method for room temperature based NO2 gas detection. The synthesized WS2/rGO nanocomposites showed p-type ...response with improved sensitivity and selectivity towards NO2 gas. The pristine WS2 nanosheets showed response around 21 % whereas the WS2/rGO nanocomposites showed an improved response of 82 % towards 10 ppm NO2 gas molecules. The response and recovery time towards 10 ppm NO2 gas was around 26 s/553 s and 58 s/627 s for pristine WS2 and WS2/rGO nanocomposites, respectively. The prepared WS2/rGO nanocomposites showed high selectivity towards NO2 gas. Further, the long-term stability and repeatability studies were carried out and the results indicate the potential utilization of WS2/rGO nanocomposite towards NO2 gas detection at room temperature.
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•rGO/WS2 nanocomposites were successfully synthesized using facile hydrothermal method and subsequent annealing technique.•The gas sensing performance of WS2 and rGO/WS2 nanocomposites were investigated showing excellent selectivity of NO2 at RT.•GW-10 shows enhanced response of 85 % towards 10 ppm NO2 with short response/ recovery time of 58 s / 627 s respectively.•Gas sensing mechanism of rGO/WS2 nanocomposites were discussed.
The detailed characterization of the structure, dynamics and folding process of a protein is crucial for understanding the biological functions it performs. Modern biophysical and nuclear magnetic ...resonance (NMR) techniques have provided a way to obtain accurate structural and thermodynamic information on various species populated on the energy landscape of a given protein. In this context, we review here the structure-function-folding relationship of an important protein, namely, dynein light chain protein (DLC8). DLC8, the smallest subunit of the dynein motor complex, acts as a cargo adaptor. The protein exists as a dimer under physiological conditions and dissociates into a pure monomer below pH 4. Cargo binding occurs at the dimer interface. Dimer stability and relay of perturbations through the dimer interface are anticipated to be playing crucial roles in the variety of functions the protein performs. NMR investigations have provided great insights into these aspects of DLC8 in recent years.
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