- Microbial Production of Natural and Unnatural Monolignols with Escherichia coli
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Phenylpropanoids and phenylpropanoid-derived plant polyphenols find numerous applications in the food and pharmaceutical industries. In recent years, several microbial platform organisms have been engineered towards producing such compounds. However, for the most part, microbial (poly)phenol production is inspired by nature, so naturally occurring compounds have predominantly been produced to date. Here we have taken advantage of the promiscuity of the enzymes involved in phenylpropanoid synthesis and exploited the versatility of an engineered Escherichia coli strain harboring a synthetic monolignol pathway to convert supplemented natural and unnatural phenylpropenoic acids into their corresponding monolignols. The performed biotransformations showed that this strain is able to catalyze the stepwise reduction of chemically interesting unnatural phenylpropenoic acids such as 3,4,5-trimethoxycinnamic acid, 5-bromoferulic acid, 2-nitroferulic acid, and a “bicyclic” p-coumaric acid derivative, in addition to six naturally occurring phenylpropenoic acids.
- Aschenbrenner, Jennifer,Marx, Patrick,Pietruszka, J?rg,Marienhagen, Jan
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p. 949 - 954
(2019/02/26)
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- Structure–activity relationship of caffeic acid phenethyl ester analogs as new 5-lipoxygenase inhibitors
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Leukotrienes (LTs) are a class of lipid mediators implicated in numerous inflammatory disorders. Caffeic acid phenethyl ester (CAPE) possesses potent anti-LTs activity through the inhibition of 5-lipoxygenase (5-LO), the key enzyme in the biosynthesis of LTs. In this study, we describe the design and synthesis of CAPE analogs as radical scavengers and 5-LO inhibitors. Caffeic esters bearing propargyl and allyl linkers between the caffeoyl and aryl moieties (4a–i and 5a–i, respectively) were synthesized by Sonogashira and Heck cross-coupling reactions to probe the effects of flexibility and aryl substitution on 5-LO inhibition. Caffeoyl alcohol and ethers (6, 7a–b) as well as caffeoyl aldehyde and ketones (8a–e) were synthesized to elucidate the importance of the ester linkage for inhibitory activity. All tested compounds proved to be good radical scavengers (IC50 of 10–30?μm). After preliminary anti-LTs activity screening in HEK293 cell models, 5-LO inhibition potential of selected compounds was determined in human polymorphonuclear leukocytes (PMNL). Most screened compounds outperformed CAPE 3 in concentration-dependent assays on PMNL, with ester dimers 4i and 5i along with caffeoyl ethers 7a–b being roughly eight-, seven-, and 16-fold more potent than Zileuton, with IC50 values of 0.36, 0.43, and 0.18?μm, respectively.
- Doiron, Jérémie A.,Leblanc, Luc M.,Hébert, Martin J. G.,Levesque, Natalie A.,Paré, Aurélie F.,Jean-Fran?ois, Jacques,Cormier, Marc,Surette, Marc E.,Touaibia, Mohamed
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p. 514 - 528
(2017/04/06)
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- A biocompatible alkene hydrogenation merges organic synthesis with microbial metabolism
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Organic chemists and metabolic engineers use orthogonal technologies to construct essential small molecules such as pharmaceuticals and commodity chemicals. While chemists have leveraged the unique capabilities of biological catalysts for small-molecule production, metabolic engineers have not likewise integrated reactions from organic synthesis with the metabolism of living organisms. Reported herein is a method for alkene hydrogenation which utilizes a palladium catalyst and hydrogen gas generated directly by a living microorganism. This biocompatible transformation, which requires both catalyst and microbe, and can be used on a preparative scale, represents a new strategy for chemical synthesis that combines organic chemistry and metabolic engineering. Reduction to practice: A hydrogenation reaction has been developed that employs hydrogen generated in situ by a microorganism and a biocompatible palladium catalyst to reduce alkenes on a synthetically useful scale. This type of transformation, which directly combines tools from organic chemistry with the metabolism of a living organism for small-molecule production, represents a new strategy for chemical synthesis.
- Sirasani, Gopal,Tong, Liuchuan,Balskus, Emily P.
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p. 7785 - 7788
(2014/08/05)
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- Identification of cinnamic acid derivatives as novel antagonists of the prokaryotic proton-gated ion channel GLIC
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Pentameric ligand gated ion channels (pLGICs) mediate signal transduction. The binding of an extracellular ligand is coupled to the transmembrane channel opening. So far, all known agonists bind at the interface between subunits in a topologically conserved "orthosteric site" whose amino acid composition defines the pharmacological specificity of pLGIC subtypes. A striking exception is the bacterial proton-activated GLIC protein, exhibiting an uncommon orthosteric binding site in terms of sequence and local architecture. Among a library of Gloeobacter violaceus metabolites, we identified a series of cinnamic acid derivatives, which antagonize the GLIC proton-elicited response. Structure-activity analysis shows a key contribution of the carboxylate moiety to GLIC inhibition. Molecular docking coupled to site-directed mutagenesis support that the binding pocket is located below the classical orthosteric site. These antagonists provide new tools to modulate conformation of GLIC, currently used as a prototypic pLGIC, and opens new avenues to study the signal transduction mechanism.
- Prevost, Marie S.,Delarue-Cochin, Sandrine,Marteaux, Justine,Colas, Claire,Van Renterghem, Catherine,Blondel, Arnaud,Malliavin, Thérèse,Corringer, Pierre-Jean,Joseph, Delphine
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p. 4619 - 4630
(2013/07/19)
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- A novel and efficient procedure for the preparation of allylic alcohols from α,β-unsaturated carboxylic esters using LiAlH4/BnCl
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A new and efficient method for the reduction of α,β-unsaturated carboxylic esters to allylic alcohols utilizing LiAlH4/BnCl is described. Various α,β-unsaturated esters, including the coumarins bearing α,β-unsaturated lactone skeleton, can be converted smoothly into their corresponding allylic alcohols in high yields under mild conditions with short reaction times.
- Wang, Xiaolong,Li, Xiaodong,Xue, Jijun,Zhao, Yuling,Zhang, Yumei
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experimental part
p. 413 - 415
(2009/05/11)
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- A Convenient Stereoselective Synthesis of Isoamericanol A and Isoamericanin A
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Isoamericanol A 4 and isoamericanin A 5 have been synthesized via a novel effective route. 3,4-dihydroxycinnamic alcohol 3 is self-coupled to afford isoamericanol A 4 which is oxidized to obtain isoamericanin A 5.
- Shi, XueGong,Gu, WenXin,Wu, TongXing,Pan, XinFu
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p. 2625 - 2628
(2007/10/03)
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- A defense Mechanism against Pathogenic Bacteria in the Digestive Tracts of Silkworm Larvae-in vitro Evidence of the Formation of Caffeoquinone, a True Antibacterial Substance, and Synergism of Amino Compounds
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For the defense mechanism against pathogenic bacteria in the digestive tracts of silkworm larvae reared on mulberry leaves, in vitro evidence of the formation of atrue antibacterial substance was obtained. caffeic acid (CA) derived from chlorogenic acid (ChA)was converted into caffeoquinone (CQ) by base-catalyzed oxidation in a buffer solution (pH 10.0).CQ was trapped as 6'phenylsulfonylcaffeic acid (6'sulfone) by the addition of benzenesulfinic acid (BSA).The synergetic effects of amino compounds on the antibacterial activity of CQ are discussed in detail, and the probable reactions of CA with amino and thiol compounds in the alkaline solution are proposed.
- Nakano, Hidenori,Tahara, Satoshi,Iizuka, Toshihiko,Mizutani, Junya
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p. 549 - 556
(2007/10/02)
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