Herein we demonstrated
a novel lipase-catalyzed synthesis of isotactic D-/L-poly(aspartate-octanediol) ester containing
long chain alcohols backbone and discovered their stereocomplex feature
with an increased T
m for the first time.
Simple design of monomer structures not only overcomes the inherent
selectivity limitation of enzyme used, but also achieves totally isotactic
polyester products. By crystallizing the mixed enantiopure isotactic
polyesters in different solvents, the formation of amorphous mixture,
homocrystallites or stereocomplex crystallites were observed, respectively.
This study is expected to open up a new way to prepare various stereocomplex
polyesters containing a long-chain aliphatic alcohol backbone and
a wide variety of functional groups.
The reliable design and prediction of enzyme promiscuity to access transformations not observed in nature remains a long‐standing challenge. Herein, we present the first example of an intramolecular stereoselective Stetter reaction catalyzed by benzaldehyde lyase, guided by the rational structure screening of various ThDP‐dependent enzymes using molecular dynamics (MD) simulations. After optimization, high productivity (up to 99 %) and stereoselectivity (up to 99:1 e.r.) for this novel enzyme function was achieved.
Japanese encephalitis virus (JEV) is one of the pathogens that can invade the central nervous system, causing acute infection and inflammation of brain. SOCS3 protein plays a vital role in immune processes and inflammation of the central nervous system. In this study, Raw264.7 cells and suckling mice were infected with JEV, and SOCS3 expression was analyzed by the gene expression profile, semiquantitative RT-PCR, qRT-PCR, immunohistochemistry (IHC) and Western blot. Results indicated that 520 genes were found to be differentially expressed (fold change ≥ 2.0, p < 0.05) in total. The differentially regulated genes were involved in biological processes, such as stimulus response, biological regulation and immune system processes. JEV early infection could induce SOCS3 expression, upregulating both the mRNA and protein levels in Raw264.7 cells in a time-dependent manner. The SOCS3 expression was much lower in Raw264.7 cells infected with inactivated JEV than wild-type JEV. In vivo, SOCS3 protein was also found to upregulate the expression of mRNA and protein in JEV-infected mouse brain. Taken together, our data showed that JEV early infection could induce the upregulation of SOCS3 expression, both in vitro and in vivo, providing the basic theoretical foundation for future research on the invasion mechanism of JEV.
Here,
we present the chemoenzymatic synthesis of two pairs of configuration-customized
unsaturated chiral polyesters and discover that they are able to self-assemble
into a helical superstructure. The chiral (R)- or
(S)-polyesters with a polar unsaturated main-chain
and an apolar side chain were designed to be stereoregular and amphiphilic-like.
The solvent polarity, stereoregularity, unsaturated bond in the backbone
and the structure of side chains were found to be the key factors
to affect the self-assembly performance of the chiral polyesters.
As the solvent polarity increased, the nanostructures of stereoregular
unsaturated polyesters transformed from spheres to helical fibers,
while there was no such transformation for the racemic or saturated
polyesters.
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