A new manufacturing process for (S)-3-(aminomethyl)-5-methylhexanoic acid (Pregabalin), the active ingredient in Lyrica, has been developed. Using Lipolase, a commercially available lipase, rac-2-carboxyethyl-3-cyano-5-methylhexanoic acid ethyl ester (1) can be resolved to form 2-carboxyethyl-3-cyano-5-methylhexanoic acid (2). A heat-promoted decarboxylation of 2 efficiently generates (S)-3-cyano-5-methylhexanoic acid ethyl ester (3), a known precursor of Pregabalin. This new route dramatically improved process efficiency compared to the first-generation process by setting the stereocenter early in the synthesis and enabling the facile racemization and reuse of (R)-1. The chemoenzymatic process also reduced organic solvent usage resulting in a mostly aqueous process. Compared to the first-generation manufacturing process, the new process resulted in higher yields of pregabalin (40-45% after one recycle of (R)-1), and substantial reductions of waste streams corresponding to a 5-fold decrease in the E factor from 86 to 17.
Mitochondrial antiviral-signaling protein (MAVS) transmits signals from RIG-I-like receptors after RNA virus infections. However, the mechanism by which MAVS activates downstream components, such as TBK1 and IKKα/β, is unclear, although previous work suggests the involvement of NEMO or TBK1-binding proteins TANK, NAP1, and SINTBAD. Here, we report that MAVS-mediated innate immune activation is dependent on TRAFs, partially on NEMO, but not on TBK1-binding proteins. MAVS recruited TBK1/IKKε by TRAFs that were pre-associated with TBK1/IKKε via direct interaction between the coiled-coil domain of TRAFs and the SDD domain of TBK1/IKKε. TRAF2−/−3−/−5−/−6−/− cells completely lost RNA virus responses. TRAFs’ E3 ligase activity was required for NEMO activation by synthesizing ubiquitin chains that bound to NEMO for NF-κB and TBK1/IKKε activation. NEMO-activated IKKα/β were important for TBK1/IKKε activation through IKKα/β-mediated TBK1/IKKε phosphorylation. Moreover, individual TRAFs differently mediated TBK1/IKKε activation and thus fine-tuned antiviral immunity under physiological conditions.
Application of the twelve principles of green chemistry can deliver higher efficiency and reduce the environmental burden during chemical synthesis. As a result of recent advances in genomics, proteomics and pathway engineering, biocatalysis is emerging as one of the greenest technologies. Enzymes are highly efficient with excellent regioselectivity and stereoselectivity. By conducting reactions in water under ambient reaction conditions, both the use of organic solvents and energy input are minimized.
Innate immunity is the first line of host defense against invading pathogens. The detection of aberrant nucleic acids which represent some conserved PAMPs triggers robust type I IFNmediated innate immune responses. Host-or pathogen-derived cytosolic DNA binds and activates the DNA sensor cGAS, which synthesizes the second messenger 2 0 3 0 -cGAMP and triggers STING-dependent downstream signaling. Here, we highlight recent progress in cGAS-cGAMP-STING, the Three Musketeers of cytosolic DNA sensing and signaling, and their essential roles in infection, autoimmune diseases, and cancer. We also focus on the regulation of these critical signal components by variant host/pathogen proteins and update our understanding of this indispensable pathway to provide new insights for drug discovery.
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