- METHODS FOR PRODUCING D-TRYPTOPHAN AND SUBSTITUTED D-TRYPTOPHANS
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Single-module nonribosomal peptide synthetases (NRPSs) and NRPS-like enzymes activate and transform carboxylic acids in both primary and secondary metabolism; and are of great interest due to their biocatalytic potentials. The single-module NRPS IvoA is essential for fungal pigment biosynthesis. As disclosed herein, we show that IvoA catalyzes ATP-dependent unidirectional stereoinversion of L-tryptophan to D-tryptophan with complete conversion. While the stereoinversion is catalyzed by the epimerization (E) domain, the terminal condensation (C) domain stereoselectively hydrolyzes D-tryptophanyl-S-phosphopantetheine thioester and thus represents a noncanonical C domain function. Using IvoA, we demonstrate a biocatalytic stereoinversion/deracemization route to access a variety of substituted D-tryptophan analogs in high enantiomeric excess.
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Page/Page column 17
(2021/04/01)
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- Tuning the Biological Activity of RGD Peptides with Halotryptophans ?
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An array of l- and d-halotryptophans with different substituents at the indole moiety was synthesized employing either enzymatic halogenation by halogenases or incorporation of haloindoles using tryptophan synthase. Introduction of these Trp derivatives into RGD peptides as a benchmark system was performed to investigate their influence on bioactivity. Halotryptophan-containing RGD peptides display increased affinity toward integrin αvβ3 and enhanced selectivity over integrin α5β1. In addition, bromotryptophan was exploited as a platform for late-stage diversification by Suzuki-Miyaura cross-coupling (SMC), resulting in new-to-nature biaryl motifs. These peptides show enhanced affinity toward αvβ3, good affinity to αvβ8, and remarkable selectivity over α5β1 and αIIbβ3 while featuring fluorogenic properties. Their feasibility as a probe was demonstrated in vitro. Extensive molecular dynamics simulations were undertaken to elucidate NMR and high-performance liquid chromatography (HPLC) data for these late-stage diversified cyclic RGD peptides and to further characterize their conformational preferences.
- Kemker, Isabell,Schr?der, David C.,Feiner, Rebecca C.,Müller, Kristian M.,Marion, Antoine,Sewald, Norbert
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p. 586 - 601
(2021/01/14)
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- Targeted Enzyme Engineering Unveiled Unexpected Patterns of Halogenase Stabilization
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Halogenases are valuable biocatalysts for selective C?H activation, but despite recent efforts to broaden their application scope by means of protein engineering, improvement of thermostability and catalytic efficiency is still desired. A directed evoluti
- Minges, Hannah,Schnepel, Christian,B?ttcher, Dominique,Wei?, Martin S.,Spro?, Jens,Bornscheuer, Uwe T.,Sewald, Norbert
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p. 818 - 831
(2019/12/24)
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- Complete Stereoinversion of l -Tryptophan by a Fungal Single-Module Nonribosomal Peptide Synthetase
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Single-module nonribosomal peptide synthetases (NRPSs) and NRPS-like enzymes activate and transform carboxylic acids in both primary and secondary metabolism and are of great interest due to their biocatalytic potentials. The single-module NRPS IvoA is essential for fungal pigment biosynthesis. Here, we show that IvoA catalyzes ATP-dependent unidirectional stereoinversion of l-tryptophan to d-tryptophan with complete conversion. While the stereoinversion is catalyzed by the epimerization (E) domain, the terminal condensation (C) domain stereoselectively hydrolyzes d-tryptophanyl-S-phosphopantetheine thioester and thus represents a noncanonical C domain function. Using IvoA, we demonstrate a biocatalytic stereoinversion/deracemization route to access a variety of substituted d-tryptophan analogs in high enantiomeric excess.
- Hai, Yang,Jenner, Matthew,Tang, Yi
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supporting information
p. 16222 - 16226
(2019/10/14)
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- Biosynthesis of l-4-Chlorokynurenine, an Antidepressant Prodrug and a Non-Proteinogenic Amino Acid Found in Lipopeptide Antibiotics
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l-4-Chlorokynurenine (l-4-Cl-Kyn) is a neuropharmaceutical drug candidate that is in development for the treatment of major depressive disorder. Recently, this amino acid was naturally found as a residue in the lipopeptide antibiotic taromycin. Herein, we report the unprecedented conversion of l-tryptophan into l-4-Cl-Kyn catalyzed by four enzymes in the taromycin biosynthetic pathway from the marine bacterium Saccharomonospora sp. CNQ-490. We used genetic, biochemical, structural, and analytical techniques to establish l-4-Cl-Kyn biosynthesis, which is initiated by the flavin-dependent tryptophan chlorinase Tar14 and its flavin reductase partner Tar15. This work revealed the first tryptophan 2,3-dioxygenase (Tar13) and kynurenine formamidase (Tar16) enzymes that are selective for chlorinated substrates. The substrate scope of Tar13, Tar14, and Tar16 was examined and revealed intriguing promiscuity, thereby opening doors for the targeted engineering of these enzymes as useful biocatalysts.
- Luhavaya, Hanna,Sigrist, Renata,Chekan, Jonathan R.,McKinnie, Shaun M. K.,Moore, Bradley S.
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supporting information
p. 8394 - 8399
(2019/05/21)
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- One-Pot Biocatalytic Synthesis of Substituted d -Tryptophans from Indoles Enabled by an Engineered Aminotransferase
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d-Tryptophan and its derivatives are important precursors of a wide range of indole-containing pharmaceuticals and natural products. Here, we developed a one-pot biocatalytic process enabling the synthesis of d-tryptophans from indoles in good yields and high enantiomeric excess (91% to >99%). Our method couples the synthesis of l-tryptophans catalyzed by Salmonella enterica tryptophan synthase with a stereoinversion cascade mediated by Proteus myxofaciens l-amino acid deaminase and an aminotransferase variant that we engineered to display native-like activity toward d-tryptophan. Our process is applicable to preparative-scale synthesis of a broad range of d-tryptophan derivatives containing electron-donating or -withdrawing substituents at all benzene-ring positions on the indole group.
- Parmeggiani, Fabio,Rué Casamajo, Arnau,Walton, Curtis J. W.,Galman, James L.,Turner, Nicholas J.,Chica, Roberto A.
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p. 3482 - 3486
(2019/04/13)
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- The facile synthesis of a series of tryptophan derivatives
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This study reports a facile method for the synthesis of a variety of 5- and 6-substituted tryptophan derivatives that are difficult to prepare using alternative enzymatic approaches. Acylation of an activated amino acid, derived from serine in situ, is coupled with an enzymatic resolution step to furnish enantiopure analogues bearing a range of electron withdrawing and releasing substituents. Isolation of a dehydroalanine derivative as a by-product from some reactions provides some insights into the likely mechanism of the reaction.
- Blaser, Georg,Sanderson, John M.,Batsanov, Andrei S.,Howard, Judith A.K.
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p. 2795 - 2798
(2008/09/19)
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- Synthesis of tryptophans
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The preparation of racemic and optically pure tryptophans is described. The D-enantiomers of the 6-substituted compounds possess a potent sweetening capability. Novel intermediates are also disclosed.
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- Salts of the γ-lactone of (-)-threo-hydroxycitric acid with R(+)-α-methyl-p-nitrobenzylamine
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Racemic organic carboxylic acids are efficiently resolved into their enantiomers with antipodes of α-methyl-p-nitrobenzylamine.
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