Karlssonfunder1481

Since pepticinnamin E was discovered almost 30 years ago, no other pepticinnamin family of natural products has been reported to date. Here, we report the discovery of pepticinnamins G-I (1-3) from a marine Streptomyces sp. PKU-MA01144 and pepticinnamins J-M (4-7) from several mutants, and these new compounds contain different N-methyl-l-alanine and l-tyrosine residues compared to pepticinnamin E. Genome sequencing, heterologous expression, gene deletion, and reconstitution of enzymatic reaction in vitro identified the biosynthetic gene cluster of 1-7 and first experimentally established the biosynthesis of the nonproteinogenic 2-chloro-3-hydroxy-4-methoxy-l-phenylalanine residue by a biopterin-dependent hydroxylase Pep10, an O-methyltransferase Pep9, and a flavin-dependent halogenase Pep1. The biosynthetic research and heterologous expression system in this study set the stage for pathway engineering for more pepticinnamins generation in the future.We report a siloxane-protected donor (7) for the highly stereoselective formation of β-(2,3-cis)-xylulofuranosyl bonds. Glycosylation reactions with 7 gave >80% yields, and only β-xylulofuranosides were isolated in all cases. The utility of 7 for the synthesis of complex glycans was shown by its successful application to the preparation of the repeating unit from the lipopolysaccharide O-antigen of Yersinia enterocolitica serovars O5/O5,27. This structure is a pentasaccharide with two β-xylulofuranose residues; using 7, both were introduced simultaneously with excellent stereocontrol.High-valent nonheme FeIV-oxido species are key intermediates in biological oxidation, and their properties are proposed to be influenced by the unique microenvironments present in protein active sites. Microenvironments are regulated by noncovalent interactions, such as hydrogen bonds (H-bonds) and electrostatic interactions; however, there is little quantitative information about how these interactions affect crucial properties of high valent metal-oxido complexes. To address this knowledge gap, we introduced a series of FeIV-oxido complexes that have the same S = 2 spin ground state as those found in nature and then systematically probed the effects of noncovalent interactions on their electronic, structural, and vibrational properties. The key design feature that provides access to these complexes is the new tripodal ligand [poat]3-, which contains phosphinic amido groups. An important structural aspect of [FeIVpoat(O)]- is the inclusion of an auxiliary site capable of binding a Lewis acid (LAII); we used this unique feature to further modulate the electrostatic environment around the Fe-oxido unit. Experimentally, studies confirmed that H-bonds and LAII s can interact directly with the oxido ligand in FeIV-oxido complexes, which weakens the Fe═O bond and has an impact on the electronic structure. We found that relatively large vibrational changes in the Fe-oxido unit correlate with small structural changes that could be difficult to measure, especially within a protein active site. 1-Azakenpaullone supplier Our work demonstrates the important role of noncovalent interactions on the properties of metal complexes, and that these interactions need to be considered when developing effective oxidants.The silicon atom in LSiCl or LSiMes (L = PhC(NtBu)2, Mes = 2,4,6-Me3C6H2) inserts into the B-X bond of RBX2 (R = Ph, Mes, N(SiMe3)2; X = Cl, Br), which is followed by the migration of the amidinate ligand and the halide atom. By this way, LB(R)SiCl3 (R = Ph, 2; Mes, 3; N(SiMe3)2, 4) and LB(R)SiX2Mes (R = Ph, X = Cl, 5; R = Mes, X = Cl, 6; R = Mes, X = Br, 7) were obtained. Furthermore, a silylene-borane adduct LClSi → BPhCl2 (1) was obtained as an intermediate in the formation of compound 2. Compounds 2-7 are rare examples of borylhalosilanes.Interfacial solar-driven evaporation is an effective and sustainable approach to convert solar energy to heat for desalination. However, maintaining a rapid evaporation rate and long-term stability is a critical challenge that needs to be addressed urgently to facilitate practical applications of this technology. Here, taking advantage of the inherent porosity, wettability, and low thermal conductivity of wood, we develop a flexible and mildew-resistant aerogel derived from natural wood as the substrate of evaporators for stable and efficient solar desalination. The wood-derived aerogel not only possesses good hydrophilicity, low thermal conductivity, and light weight, which are favorable to realize heat localization and efficient water evaporation, but also avoids fragility and mildew problems that seriously restricted long-term stability of wood-based evaporators. With high absorbance (>95%) of Au-rGO coating, the evaporator showed a high solar to vapor efficiency of 90.1% and an evaporation rate of 1.394 kg m-2 h-1 under 1 sun. During 120 h desalination, the evaporator transports brine for evaporation in the day and achieves dissolution of salt residues in the night, exhibiting a repetitive self-cleaning behavior, which enables the recovery of desalination stability. The multiple functionalities of the wood-derived aerogel make the evaporator promising as an attractive device for stable and continuous solar desalination.As a novel approach to the in situ real-time investigation of an ITO electrode during the wet etching process, step-excitation Fourier-transform electrochemical impedance spectroscopy (FT-EIS) was implemented. The equivalent circuit parameters (e.g., Rct, Cdl) continuously obtained by the FT-EIS measurements during the entire etching process showed an electrode activation at the initial period as well as the completion of etching. The FT-EIS results were further validated by cyclic voltammograms and impedance measurements of partially etched ITO films using ferri- and ferrocyanide solution in combination with FESEM imaging, EDS, XRD analyses, and COMSOL simulation. We also demonstrated that this technique can be further utilized to obtain intact interdigitated array (IDA) electrodes in a reproducible manner, which is generally considered to be quite tricky due to delicacy of the pattern. Given that the FT-EIS allows for instantaneous snapshots of the electrode at every moment, this work may hold promise for in situ real-time examination of structural, electrokinetic, or mass transfer-related information on electrochemical systems undergoing constantly changing, transient processes including etching, which would be impossible with conventional electroanalytical techniques.