SARS-CoV-2 is the pathogen responsible for the COVID-19 pandemic. The SARS-CoV-2 papain-like cysteine protease (PLpro) has been implicated in playing important roles in virus maturation, dysregulation of host inflammation, and antiviral immune responses. The multiple functions of PLpro render it a promising drug target. Therefore, we screened a library of approved drugs and also examined available inhibitors against PLpro. Inhibitor GRL0617 showed a promising in vitro IC50 of 2.1 μM and an effective antiviral inhibition in cell-based assays. The co-crystal structure of SARS-CoV-2 PLproC111S in complex with GRL0617 indicates that GRL0617 is a non-covalent inhibitor and it resides in the ubiquitin-specific proteases (USP) domain of PLpro. NMR data indicate that GRL0617 blocks the binding of ISG15 C-terminus to PLpro. Using truncated ISG15 mutants, we show that the C-terminus of ISG15 plays a dominant role in binding PLpro. Structural analysis reveals that the ISG15 C-terminus binding pocket in PLpro contributes a disproportionately large portion of binding energy, thus this pocket is a hot spot for antiviral drug discovery targeting PLpro.
A simple strategy to synthesize ultrathin, amorphous and alloyed structural cobalt–vanadium hydr(oxy)oxide catalysts with enhanced water oxidation catalytic activity.
Nonaqueous potassium ion batteries (KIBs) are one of the emerging electrochemical energy storage technologies due to the abundance of potassium resources, but the difficulties of intercalation of large size K‐ions into electrode materials hinder the development of KIBs. Here, a layered potassium vanadate K0.5V2O5 is proposed as a potential cathode material for KIBs. Despite the large size of K‐ions, the as‐fabricated material is capable of delivering a reversible capacity around 90 mAh g−1 at 10 mA g−1 in the voltage range of 1.5–3.8 V (vs K+/K), and also exhibits a fast rate capability with a capacity of 60 mAh g−1 at 200 mA g−1 and good cycling stability with 81% capacity retention after 250 cycles at 100 mA g−1. Ex situ X‐ray diffraction and X‐ray photoelectron spectroscopy reveal that the layered potassium vanadate exhibits a highly stable and reversible structure change with a transition between V4+ and V5+ upon potassiation/depotassiation. Additionally, galvanostatic intermittent titration technique results show that the kinetics of potassiation/depotassiation is mainly determined by K‐ion diffusion in the active material. The present study may open up further exploration of potassium vanadates and other layered transition metal oxides in the field of KIBs.
Potassium-ion batteries (KIBs) are promising electrochemical energy storage systems because of their low cost and high energy density. However, practical exploitation of KIBs is hampered by the lack of high-performance cathode materials. Here we report a potassium manganese hexacyanoferrate (K2Mn[Fe(CN)6]) material, with a negligible content of defects and water, for efficient high-voltage K-ion storage. When tested in combination with a K metal anode, the K2Mn[Fe(CN)6]-based electrode enables a cell specific energy of 609.7 Wh kg−1 and 80% capacity retention after 7800 cycles. Moreover, a K-ion full-cell consisting of graphite and K2Mn[Fe(CN)6] as anode and cathode active materials, respectively, demonstrates a specific energy of 331.5 Wh kg−1, remarkable rate capability, and negligible capacity decay for 300 cycles. The remarkable electrochemical energy storage performances of the K2Mn[Fe(CN)6] material are attributed to its stable frameworks that benefit from the defect-free structure.
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