Atom transfer radical polymerization (ATRP) can be carried out in a flask completely open to air using a biocatalytic system composed of glucose oxidase (GOx) and horseradish peroxidase (HRP) with an active copper catalyst complex. Nanomolar concentrations of the enzymes and ppm amounts of Cu provided excellent control over the polymerization of oligo(ethylene oxide) methyl ether methacrylate (OEOMA500), generating polymers with high molecular weight (
- Award ID(s):
- NSF-PAR ID:
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Page Range / eLocation ID:
- p. 16157-16161
- Medium: X
- Sponsoring Org:
- National Science Foundation
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l‐cysteine conjugated antifouling amphiphilic conetwork (APCN) is synthesized through end‐crosslinking of well‐defined triblock copolymers poly(allyl methacrylate)‐ b‐poly(ethylene glycol)‐ b‐poly(allyl methacrylate) via a combination of reversible addition‐fragmentation chain transfer (RAFT) polymerization and thiol–ene “click” chemistry. The synthesized poly(ethylene glycol) macro‐RAFT agent initiates the polymerization of allyl methacrylate in a controlled manner. The vinyl pendant groups of the precursor partially conjugate with l‐cysteine and the rest fully crosslink with mercaptopropyl‐containing siloxane via thiol–ene click chemistry under UV irradiation into APCNs, which show distinguished properties, that is, excellent biocompatibility, more than 39.6% water content, 101 barrers oxygen permeability, optimized mechanical properties, and more than 93% visible light transmittance. What's more, the resultant APCNs exhibit eminent resistance to protein adsorption, where the bovine serum albumin and lysozyme adsorption are decreased to 12 and 21 µg cm−2, respectively. The outstanding properties of APCNs depend on the RAFT controlled method, which precisely designs the hydrophilic/hydrophobic segments and eventually greatly improves the crosslinking efficiency and homogeneity. Meantime, the l‐cysteine monolayer can effectively reduce the surface hydrophobicity and prevent protein adsorption, which exhibits the viability for antifouling surface over and under ophthalmic devices, suggesting a promising soft contact lens. image
Good control of tacticity, molecular weight, and architecture is attained via atom transfer radical polymerization (ATRP) of
N‐hydroxyethyl acrylamide (HEAA), in a one‐pot process in the presence of Y(OTf)3. The effect of temperature, ratio of [Y(OTf)3]/[HEAA], and ATRP procedure on the tacticity and degree of control over the polymerization is investigated in detail. Under optimal conditions, using photo ATRP and 15% Y(OTf)3,the content of meso dyads ( m) can be increased from 42% to 80% in a homopolymer with a dispersity D= 1.22. Well‐defined stereoblock copolymers, atactic‐ ‐isotactic poly(HEAA), with b D= 1.27, are obtained by adding Y(OTf)3at a specific conversion, initially started without Y(OTf)3.
SUMOylation as one of the protein post‐translational modifications plays crucial roles in multiple biological processes of eukaryotic organisms.
Botrytis cinereais a devastating fungal pathogen and capable of infecting plant hosts at low temperature. However, the molecular mechanisms of low‐temperature adaptation are largely unknown in fungi.
Combining with biochemical methods and biological analyses, we report that SUMOylation regulates pathogen survival at low temperature and oxidative DNA damage response during infection in
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SUMOylated BcSsb regulates β‐tubulin accumulation, thereby affecting the stability of microtubules and consequently mycelial growth at low temperature. On the contrary, SUMOylated BcRad18 modulates mono‐ubiquitination of the sliding clamp protein proliferating cell nuclear antigen (PCNA), which is involved in response to oxidative DNA damage during infection.
Our study uncovers the molecular mechanisms of SUMOylation‐mediated low‐temperature survival and oxidative DNA damage tolerance during infection in a devastating fungal pathogen, which provides novel insights into low‐temperature adaptation and pathogenesis for postharvest pathogens as well as new targets for inhibitor invention in disease control.
N/B co‐doped nanocarbon (NBC) is emerging as promising candidate in various applications. However, most synthetic approaches require complex heteroatom/carbon precursors, and suffer from poor porosity control and inevitable formation of electrochemically inactive N─B bonded species. In this study, we propose a new route to produce NBC from a single copolymer precursor, polyacrylonitrile‐
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Myxococcus xanthusdevelopmental program. A long‐standing model proposed that MrpC activity is controlled by the Pkn8/Pkn14 serine/threonine kinase cascade, which phosphorylates MrpC on threonine residue(s) located in its extreme amino‐terminus. In this study, we demonstrate that a stretch of consecutive threonine and serine residues, T21T22S23S24,is necessary for MrpC activity by promoting efficient DNA binding. Mass spectrometry analysis indicated the TTSS motif is not directly phosphorylated by Pkn14 in vitrobut is necessary for efficient Pkn14‐dependent phosphorylation on several residues in the remainder of the protein. In an important correction to a long‐standing model, we show Pkn8 and Pkn14 kinase activities do not play obvious roles in controlling MrpC activity in wild‐type M. xanthusunder laboratory conditions. Instead, we propose Pkn14 modulates MrpC DNA binding in response to unknown environmental conditions. Interestingly, substitutions in the TTSS motif caused developmental defects that varied between biological replicates, revealing that MrpC plays a role in promoting a robust developmental phenotype.