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Ergothioneine (ESH) and ovothiol A (OSHA) are two natural thiol‐histidine derivatives. ESH has been implicated as a longevity vitamin and OSHA inhibits the proliferation of hepatocarcinoma. The key biosynthetic step of ESH and OSHA in the aerobic pathways is the O2‐dependent C−S bond formation catalyzed by non‐heme iron enzymes (e.g., OvoA in ovothiol biosynthesis), but due to the lack of identification of key reactive intermediate the mechanism of this novel reaction is unresolved. In this study, we report the identification and characterization of a kinetically competent S=1 iron(IV) intermediate supported by a four‐histidine ligand environment (three from the protein residues and one from the substrate) in enabling C−S bond formation in OvoA from Methyloversatilis thermotoleran, which represents the first experimentally observed intermediate spin iron(IV) species in non‐heme iron enzymes. Results reported in this study thus set the stage to further dissect the mechanism of enzymatic oxidative C−S bond formation in the OSHA biosynthesis pathway. They also afford new opportunities to study the structure‐function relationship of high‐valent iron intermediates supported by a histidine rich ligand environment. [ABSTRACT FROM AUTHOR]

Isonitrile group has been identified in many natural products. Due to the broad reactivity of N≡C triple bond, these natural products have valuable pharmaceutical potentials. This review summarizes the current biosynthetic pathways and the corresponding enzymes that are responsible for isonitrile‐containing natural product generation. Based on the strategies utilized, two fundamentally distinctive approaches are discussed. In addition, recent progress in elucidating isonitrile group formation mechanisms is also presented. [ABSTRACT FROM AUTHOR]

N‐alkylisonitrile, a precursor to isonitrile‐containing lipopeptides, is biosynthesized by decarboxylation‐assisted ‐N≡C group (isonitrile) formation by using N‐alkylglycine as the substrate. This reaction is catalyzed by iron(II) and 2‐oxoglutarate (Fe/2OG) dependent enzymes. Distinct from typical oxygenation or halogenation reactions catalyzed by this class of enzymes, installation of the isonitrile group represents a novel reaction type for Fe/2OG enzymes that involves a four‐electron oxidative process. Reported here is a plausible mechanism of three Fe/2OG enzymes, Sav607, ScoE and SfaA, which catalyze isonitrile formation. The X‐ray structures of iron‐loaded ScoE in complex with its substrate and the intermediate, along with biochemical and biophysical data reveal that ‐N≡C bond formation involves two cycles of Fe/2OG enzyme catalysis. The reaction starts with an FeIV‐oxo‐catalyzed hydroxylation. It is likely followed by decarboxylation‐assisted desaturation to complete isonitrile installation. [ABSTRACT FROM AUTHOR]

Nowadays, research on CSCs is still in an initial stage, and there are few studies reporting the successful isolation and identification of CSCs. In the present study, we attempted to isolate CSCs through cultivating the cell line MKN45 in defined serum‐free medium and study the expression of stem cell markers or related proteins (Oct3/4, Sox2, Nanog and CD44) in CSCs. Moreover, immunofluorescence staining was performed to validate the stem cell markers of spheroid body‐forming cells. Further experiments were used to evaluate the SPOP expression in tumorsphere cells. In addition, ADAMTS9‐AS2 is a lncRNA that contributes to the genesis and development of many cancers, including gastric cancer (GC). We found ADAMTS9‐AS2 functioned as an anti‐oncogene and positively correlated with the expression of SPOP in GC tissues by combining bioinformatics analyses. Furthermore, we reported that ADAMTS9‐AS2 regulated the expression of SPOP in GC cells and tumorsphere cells to inhibit GC progression. Together, our results demonstrated that SPOP and ADAMTS9‐AS2 can be potential targets for GC treatment. [ABSTRACT FROM AUTHOR]

Light olefins production utilizes the energy intensive process of steam cracking. Fischer‐Tropsch to olefins (FTO) synthesis potentially offers a more sustainable alternative. Here we show a promising FTO catalyst comprised of iron oxide nanoparticles supported on carbon nanosheets (CNS) fabricated from the carbonization of potassium citrate, which incorporates well dispersed K‐promoter throughout the CNS support. This catalyst exhibits, to the best of our knowledge, the highest iron time yield of 1790–1990 μmolCO/gFe ⋅ s reported in the literature, 41 % light olefins selectivity, and over 100 hours stable activity, making it one of the best performing FTO catalysts. Detailed characterization illustrates that the CNS support facilitates iron oxide reduction to metallic iron, leading to efficient transformation to the active iron carbide phase during FTO reaction. Since K is a commonly used promoter, our K‐promoted CNS support potentially has broad utility beyond the FTO reactions demonstrated in the current study. Iron it out! A K promoted, carbon nanosheets supported iron oxide catalyst shows robust and extremely high activity for Fischer‐Tropsch to olefins (FTO) synthesis. The carbon nanosheets support is shown to stabilize metallic Fe during the catalyst activation step which leads to more efficient transformation to catalytically active Fe5C2 under FTO conditions. [ABSTRACT FROM AUTHOR]

Abstract: Dynamically engineering the interfacial interaction of nanoparticles has emerged as a new approach for bottom‐up fabrication of smart systems to tailor molecular diffusion and controlled release. Janus zwitterionic nanoplates are reported that can be switched between a locked and unlocked state at interfaces upon changing surface charge, allowing manipulation of interfacial properties in a fast, flexible, and switchable manner. Combining experimental and modeling studies, an unambiguous correlation is established among the electrostatic energy, the interface geometry, and the interfacial jamming states. As a proof‐of‐concept, the well‐controlled interfacial jamming of nanoplates enabled the switchable molecular diffusion through liquid–liquid interfaces, confirming the feasibility of using nanoparticle‐based surfactants for advanced controlled release. [ABSTRACT FROM AUTHOR]

The Cover Feature illustrates Fe5C2 nanoparticle catalysts supported on carbon nanosheets for Fischer‐Tropsch to Olefins (FTO) synthesis, which converts syngas (CO and H2) to industrially important light olefins. In their Full Paper, Y. Zhou et al. discover that the carbon nanosheets support with uniformly distributed K promoters can enhance the transformation of iron oxide nanoparticles in the fresh catalyst to catalytically active iron carbide under FTO reaction conditions. This leads to FTO catalysts with extremely high activity, excellent selectivity and robust stability. More information can be found in the Full Paper by Y. Zhou et al. on page 1625 in Issue 6, 2019 (DOI: 10.1002/cctc.201802022). [ABSTRACT FROM AUTHOR]