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Thermophilic polyester hydrolases (PES-H) have recently enabled biocatalytic recycling of the mass-produced synthetic polyester polyethylene terephthalate (PET), which has found widespread use in the packaging and textile industries. The growing demand for efficient PET hydrolases prompted us to solve high-resolution crystal structures of two metagenome-derived enzymes (PES-H1 and PES-H2) and notably also in complex with various PET substrate analogues. Structural analyses and computational modeling using molecular dynamics simulations provided an understanding of how product inhibition and multiple substrate binding modes influence key mechanistic steps of enzymatic PET hydrolysis. Key residues involved in substrate-binding and those identified previously as mutational hotspots in homologous enzymes were subjected to mutagenesis. At 72 °C, the L92F/Q94Y variant of PES-H1 exhibited 2.3-fold and 3.4-fold improved hydrolytic activity against amorphous PET films and pretreated real-world PET waste, respectively. The R204C/S250C variant of PES-H1 had a 6.4 °C higher melting temperature than the wild-type enzyme but retained similar hydrolytic activity. Under optimal reaction conditions, the L92F/Q94Y variant of PES-H1 hydrolyzed low-crystallinity PET materials 2.2-fold more efficiently than LCC ICCG, which was previously the most active PET hydrolase reported in the literature. This property makes the L92F/Q94Y variant of PES-H1 a good candidate for future applications in industrial plastic recycling processes.

The first two cage based crystalline covalent organic frameworks, cage-COF-1 and cage-COF-2, were constructed from a prism-like three-aldehyde-containing molecular cage. The cage contains two horizontal phloroglucinol and three vertical triazine moieties forming three identical V-shaped cavities. By reacting with p-phenylenediamine and 4,4′-biphenyldiamine, the two cage-COFs were formed with a hexagonal skeleton and possess a unique structure. Due to the pillared cage nodes, the linkers are hanging with their π-surfaces but not C–H sites exposed to the pore, and enjoy certain rotational dynamics as suggested by 13C CP/MAS NMR. The antidirection of the diimine linkages leads to rippled layers which pack in unique ABC mode through alternate stacking of the cage twosided faces in both AB and AC layers. Such packing forms trigonal channels along c axis which are interconnected in ab plane due to the large open space created across the hanging linkers, resembling the porous characteristics of 3D COFs. The cage-COFs have a permanent porosity and can adsorb CO2 facilitated by the intrinsic cage cavities that serve as prime adsorption sites. The unprecedented cage-COFs not only merge the borderline of 2D and 3D COFs but also bridge porous organic cages to extended crystalline organic frameworks.

Systematic cold biases exist in the simulation for 2 m air temperature in the Tibetan Plateau (TP) when using regional climate models and global atmospheric general circulation models. We updated the albedo in the Weather Research and Forecasting (WRF) Model lower boundary condition using the Global LAnd Surface Satellite Moderate-Resolution Imaging Spectroradiometer albedo products and demonstrated evident improvement for cold temperature biases in the TP. It is the large overestimation of albedo in winter and spring in the WRF model that resulted in the large cold temperature biases. The overestimated albedo was caused by the simulated precipitation biases and over-parameterization of snow albedo. Furthermore, light-absorbing aerosols can result in a large reduction of albedo in snow and ice cover. The results suggest the necessity of developing snow albedo parameterization using observations in the TP, where snow cover and melting are very different from other low-elevation regions, and the influence of aerosols should be considered as well. In addition to defining snow albedo, our results show an urgent call for improving precipitation simulation in the TP.

Anion-π interactions have been widely studied as new noncovalent driving forces in supramolecular chemistry. However, self-assembly induced by anion-π interactions is still largely unexplored. Herein we report the formation of supramolecular amphiphiles through anion-π interactions, and the subsequent formation of self-assembled vesicles in water. With the π receptor 1 as the host and anionic amphiphiles, such as sodium dodecylsulfate (SDS), sodium laurate (SLA), and sodium methyl dodecylphosphonate (SDP), as guests, the sequential formation of host-guest supramolecular amphiphiles and self-assembled vesicles was demonstrated by SEM, TEM, DLS, and XRD techniques. The intrinsic anion-π interactions between 1 and the anionic amphiphiles were confirmed by crystal diffraction, HRMS analysis, and DFT calculations. Furthermore, the controlled disassembly of the vesicles was promoted by competing anions, such as NO3 (-) , Cl(-) , and Br(-) , or by changing the pH value of the medium.

We present J HCN 4 3 =  and J HCO 4 3 =  + maps of six nearby star-forming galaxies, NGC 253, NGC 1068, IC 342, M82, M83, and NGC 6946, obtained with the James Clerk Maxwell Telescope as part of the MALATANG survey. All galaxies were mapped in the central 2′×2′region at 14″ (FWHM) resolution (corresponding to linear scales of ∼0.2-1.0 kpc). The L IR -L′ dense relation, where the dense gas is traced by the J HCN 4 3 =  and the J HCO 4 3 =  + emission, measured in our sample of spatially resolved galaxies is found to follow the linear correlation established globally in galaxies within the scatter. We find that the luminosity ratio, L IR /L′ dense , shows systematic variations with L IR within individual spatially resolved galaxies, whereas the galaxy-integrated ratios vary little. A rising trend is also found between L IR /L′ dense ratio and the warm-dust temperature gauged by the 70 μm/100 μm flux ratio. We find that the luminosity ratios of IR/HCN (4-3) and IR/HCO + (4-3), which can be taken as a proxy for the star formation efficiency (SFE) in the dense molecular gas

Benzene triimide (BTI, or mellitic triimide) is a C 3-symmetric backbone with a highly electron-deficient, extended π surface and three easy functionalization sites. Here, we report the first BTI-based cage composed of two face-to-face BTIs pillared by three m-xylylene spacers and efficient and selective binding of azide through cooperative anion−π interactions. The cage was easily synthesized in two steps from benzene triimide. Crystal structures showed that the two BTI planes can be separated at about 5–6 Å and form a well-defined electron-deficient cavity. Among a series of anions tested, the cage was found able to bind N3 –, SCN–, and I–. In particular, the binding toward N3 – is very strong (K a = 11098 ± 46 M–1) and highly selective, over 150 and 250 times higher than SCN– and I–, respectively. The control single BTI, however, showed only very weak binding (K a < 5 M–1). The crystal structure showed that N3 – is tightly trapped within the cavity through multiple, very short anion−π interactions. The slow enter–release of N3 – from the cavity was observed in the NMR. The charge-transfer and electron-transfer character of the interactions was also discussed.

An artificial channel molecule 1 that mimics the shape and function of the ClC channel selective pore was described. To facilitate the transport of chloride along a unimolecular pathway, anion−π interactions were introduced as the noncovalent driving force. The hourglass-like shape of 1 was constructed with 1,3-alternate tetraoxacalix­[2]­arene­[2]­triazine as the narrowest (central) unit. Two diglycolamine-linked imide arms were tethered as the extending part, and phenylalanine moieties were fixed as the terminal anchoring groups. The ion transport activity was examined by a combination of vesicle and planar bilayer conductance techniques (BLM). The fluorescence analysis on the vesicle indicated that 1 is an efficient chloride transporter with high activity (EC50 = 1.50 μM; 1/lipid = 1:89). The ion channel characteristics were confirmed by BLM measurements, showing an average conductance of 20.8 ± 1.0 pS in symmetric KCl solutions (cis/trans = 1.0 M/1.0 M). Anion/cation selectivity with a permeability ratio P Cl –/P K + = 1.90 in an asymmetric KCl solution (cis/trans = 1.0 M/0.25 M) and anion/anion selectivity with P Cl –/P Br – = 22.83 in a KCl/KBr solution (cis/trans = 1.0 M KCl/1.0 M KBr) were demonstrated.