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Advanced oxidation technology based on peroxonosulfate (PMS) has attracted extensive attention in water treatment research due to its fast reaction speed and wide pH range adaptability. Cobalt-based catalysts are considered to be one of the most effective reagents for PMS activation in various PMS activation methods. However, Co-ion leaching and difficulty in recovery have greatly hindered its practical applications. Herein, we developed a robust membrane constructed by nitrogen-doped carbon nanotubes embedded with cobalt nanoparticles (Co-NC) to concurrently address the Co-ion leaching and recovery issues. Based on our customization, continuous water flow reactor, the Co-NC membrane exhibited excellent catalytic activity and stability, in which it demonstrated a remarkable sterilization efficiency of 99.9999% against E. coli, and it retained a superior stability of 96.29% after 40 repeated cycles. Fewer attempts to put such efficient heterogeneous advanced oxidation processes (AOPs) into practical application, to mimic real-life applications, the performance of the Co-NC/PMS system was extended to the water taken from Qiuxi River. Remarkably, there is no deterioration in performance over 12 h of continuous real sewage processing. Mechanistic studies revealed that abundant high-valence metals (CoIV=O) were generated in the system, which can attack and penetrate into the cell membrane to destroy its intracellular defense system. This work provides useful insights into designing robust membranes with superior efficiency and stability for PMS-based advanced oxidation technology. [ABSTRACT FROM AUTHOR]

Fe-Nx nanoparticles-embedded porous carbons with a desirable superstructure have attracted immense attention as promising catalysts for electrochemical oxygen reduction reaction. Herein, we employed Fe-coordinated covalent triazine polymer for the fabrication of Fe-Nx nanoparticle-embedded porous carbon nanoflorets (Fe/N@CNFs) employing a hypersaline-confinement-conversion strategy. Presence of tailored N types within the covalent triazine polymer interwork in high proportions contributes to the generation of Fe/N coordination and subsequent Fe-Nx nanoparticles. Owing to the utilization of NaCl crystals, the resultant Fe/N@CNF-800 which was generated by pyrolysis at 800 °C showed nanoflower structure and large specific surface area, which remarkably suppressed the agglomeration of high catalytic active sites. As expect, the Fe/N@CNF-800 exhibited unexpected oxygen reduction reaction catalytic performance with an ultrahigh half-wave potential (0.89 V vs. reversible hydrogen electrode), a dominant 4e− transfer approach and great cycle stability (> 92% after 100000 s). As a demonstration, the Fe/N-PCNF-800-assembled zinc—air battery delivered a high open circuit voltage of 1.51 V, a maximum peak power density of 164 mW·cm−2, as well as eminent rate performance, surpassing those of commercial Pt/C. This contribution offers a valuable avenue to exploit efficient metal nanoparticles-based carbon catalysts towards energy-related electrocatalytic reactions and beyond. [ABSTRACT FROM AUTHOR]

Chemical cross-linking of proteins coupled with mass spectrometry is widely used in protein structural analysis. In this study we develop a class of non-hydrolyzable amine-selective di-ortho-phthalaldehyde (DOPA) cross-linkers, one of which is called DOPA2. Cross-linking of proteins with DOPA2 is 60–120 times faster than that with the N-hydroxysuccinimide ester cross-linker DSS. Compared with DSS cross-links, DOPA2 cross-links show better agreement with the crystal structures of tested proteins. More importantly, DOPA2 has unique advantages when working at low pH, low temperature, or in the presence of denaturants. Using staphylococcal nuclease, bovine serum albumin, and bovine pancreatic ribonuclease A, we demonstrate that DOPA2 cross-linking provides abundant spatial information about the conformations of progressively denatured forms of these proteins. Furthermore, DOPA2 cross-linking allows time-course analysis of protein conformational changes during denaturant-induced unfolding. Conformations sampled by a protein while it unfolds are difficult to visualize. Here, the authors develop di-ortho-phthalaldehyde cross-linkers for rapid chemical cross-linking mass spectrometry analysis and demonstrate that this method captures the conformations of protein unfolding intermediates. [ABSTRACT FROM AUTHOR]

Molecular glues are a class of small molecular drugs that mediate protein-protein interactions, that induce either the degradation or stabilization of target protein. A structurally diverse group of chemicals, including 17-β-estradiol (E2), anagrelide, nauclefine, and DNMDP, induces apoptosis by forming complexes with phosphodiesterase 3A (PDE3A) and Schlafen 12 protein (SLFN12). They do so by binding to the PDE3A enzymatic pocket that allows the compound-bound PDE3A to recruit and stabilize SLFN12, which in turn blocks protein translation, leading to apoptosis. In this work, we report the high-resolution cryo-electron microscopy structure of PDE3A-SLFN12 complexes isolated from cultured HeLa cells pre-treated with either anagrelide, or nauclefine, or DNMDP. The PDE3A-SLFN12 complexes exhibit a butterfly-like shape, forming a heterotetramer with these small molecules, which are packed in a shallow pocket in the catalytic domain of PDE3A. The resulting small molecule-modified interface binds to the short helix (E552-I558) of SLFN12 through hydrophobic interactions, thus "gluing" the two proteins together. Based on the complex structure, we designed and synthesized analogs of anagrelide, a known drug used for the treatment of thrombocytosis, to enhance their interactions with SLFN12, and achieved superior efficacy in inducing apoptosis in cultured cells as well as in tumor xenografts. Anagrelide, nauclefine and DNMDP induce apoptosis by forming complexes with phosphodiesterase 3A (PDE3A) and Schlafen 12 protein (SLFN12). Here, the authors present the cryo-EM structures of PDE3A-SLFN12 complexes with these compounds as molecular glues. Based on the complex structure, they developed an anagrelide analog that shows a higher potency in inducing apoptosis in cultured cells and also promotes tumor growth inhibition in tumor xenografts, which is of interest for cancer drug development. [ABSTRACT FROM AUTHOR]

Multiple SARS-CoV-2 variants of concern (VOCs) have been emerging and some have been linked to an increase in case numbers globally. However, there is yet a lack of understanding of the molecular basis for the interactions between the human ACE2 (hACE2) receptor and these VOCs. Here we examined several VOCs including Alpha, Beta, and Gamma, and demonstrate that five variants receptor-binding domain (RBD) increased binding affinity for hACE2, and four variants pseudoviruses increased entry into susceptible cells. Crystal structures of hACE2-RBD complexes help identify the key residues facilitating changes in hACE2 binding affinity. Additionally, soluble hACE2 protein efficiently prevent most of the variants pseudoviruses. Our findings provide important molecular information and may help the development of novel therapeutic and prophylactic agents targeting these emerging mutants. The SARS-CoV-2 spike (S) protein mediates viral entry by binding of its receptor-binding domain (RBD) to the human angiotensin-converting enzyme 2 (ACE2) receptor and mutations of the S protein may have a great impact on virus transmissibility. Here, the authors characterize the interactions of six different SARS-CoV-2 RBD variants among them Alpha, Beta and Gamma and present crystal structures of these ACE2-RBD complexes. [ABSTRACT FROM AUTHOR]

Pregnane X receptor (PXR, NR1I2), a member of the nuclear receptor superfamily, is a crucial regulator of nutrient metabolism and metabolic detoxification such as metabolic syndrome, xenobiotic metabolism, inflammatory responses, glucose, cholesterol and lipid metabolism, and endocrine homeostasis. Notably, much experimental and clinical evidence show that PXR senses xenobiotics and triggers the detoxification response to prevent diseases such as diabetes, obesity, intestinal inflammatory diseases and liver fibrosis. In this review we summarize recent advances on remarkable metabolic and regulatory versatility of PXR, and we emphasizes its role and potential implication as an effective modulator of self-detoxification in animals and humans. [ABSTRACT FROM AUTHOR]

Cobalt sulfide counter electrodes for the dye-sensitized solar cell (DSSC) were successfully prepared on fluorine-doped tin oxide (FTO) glass substrates by a facial one-step in situ solvothermal method. The influences of prepared temperature on the synthesized phase, surface morphology, electrocatalytic, and photovoltaic performances of the cobalt sulfide counter electrodes were investigated with X-ray diffraction (XRD), field-emission scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), Tafel, and photocurrent density-voltage ( J- V) measurements. The results indicated that very thin CoS nanoparticle thin films grew on the FTO substrates and the CoS counter electrode prepared at 180 °C showed superior electrocatalytic activity, chemical stability, and photovoltaic performance. The DSSC based on the CoS counter electrode prepared at 180 °C exhibited an efficiency of 6.59 % which was comparable to the solar cell based on the sputtering Pt counter electrode (6.82 %). It indicated that CoS in situ growing on FTO glass substrate at 180 °C is a potential candidate to replace Pt as a low-cost and efficient counter electrode of DSSC. [ABSTRACT FROM AUTHOR]

Chemical cross-linking of proteins coupled with mass spectrometry analysis (CXMS) is widely used to study protein-protein interactions (PPI), protein structures, and even protein dynamics. However, structural information provided by CXMS is still limited, partly because most CXMS experiments use lysine-lysine (K-K) cross-linkers. Although superb in selectivity and reactivity, they are ineffective for lysine deficient regions. Herein, we develop aromatic glyoxal cross-linkers (ArGOs) for arginine-arginine (R-R) cross-linking and the lysine-arginine (K-R) cross-linker KArGO. The R-R or K-R cross-links generated by ArGO or KArGO fit well with protein crystal structures and provide information not attainable by K-K cross-links. KArGO, in particular, is highly valuable for CXMS, with robust performance on a variety of samples including a kinase and two multi-protein complexes. In the case of the CNGP complex, KArGO cross-links covered as much of the PPI interface as R-R and K-K cross-links combined and improved the accuracy of Rosetta docking substantially. Cross-linking mass spectrometry can provide insights into protein structures and interactions but its scope depends on the reactivity of the cross-linker. Here, the authors develop Arg-Arg and Lys-Arg cross-linkers, which provide structural information elusive to the widely used Lys-Lys cross-linkers. [ABSTRACT FROM AUTHOR]

Hexagonal single crystal CoS1.097 nanoplates with the size of 200~500 nm have successfully in situ grown on flexible graphite paper (GP) and FTO substrates with a one-step hydrothermal method, which are used as counter electrodes (CEs) of dye-sensitized solar cells (DSSCs) and show different microstructures and different electrocatalytic activities for I3− reduction. The DSSC based on CoS1.097/GP CE shows larger fill factor and higher short-circuit current density than the DSSCs with Pt/FTO CE and CoS1.097/FTO CE, which attribute to the excellent electrical conductivity of GP and predominant electrocatalytic activity of hexagonal single crystal CoS1.097 nanoplates with the addition of a small electrocatalytic contribution of GP. Therefore, the DSSC with the CoS1.097/GP CE shows the highest photoelectric conversion efficiency (6.99%) among these DSSCs. Furthermore, the CoS1.097/GP CE still shows excellent electrochemical and mechanical stability in the iodine-based electrolyte after enduring the S-type mechanical perturbation. This work indicates the flexible CoS1.097/GP electrode is a promising candidate to replace Pt/FTO CE as a Pt-free, FTO-free, low cost, exceptionally stable, and high-efficient CE of DSSC. [ABSTRACT FROM AUTHOR]