Biosynthesis of l‐4‐Chlorokynurenine, an Antidepressant Prodrug and a Non‐Proteinogenic Amino Acid Found in Lipopeptide Antibiotics. (13th May 2019)

• Record Type: Journal Article
• Authors: Luhavaya, Hanna; Sigrist, Renata; Chekan, Jonathan R.; McKinnie, Shaun M. K.; Moore, Bradley S.
• Is Part Of: Angewandte Chemie. Volume 131:Number 25(2019)
• Page Start: 8482
• Page End: 8487
• Publication Date: 2019-05-13
• Subjects: Biokatalyse -- Biosynthese -- Chlorokynurenin -- Halogenierung -- Naturstoffe; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201901571
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: 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. Abstract : Zwei Wege trennen sich : Der Biosyntheseweg zu neuroaktivem l ‐4‐Chlorokynurenin wurde durch In‐vitro‐Experimente, Röntgenkristallographie und CRISPR/Cas9‐vermittelte Gendeletion aufgezeigt. Tar13 und Tar16 sind die ersten berichteten Homologe der Tryptophan‐2, 3‐Dioxygenase und Kynurenin‐Formamidase, die vorzugsweise chlorierte Substrate akzeptieren. Die Enzyme sind vielversprechend für den Einsatz in der chemoenzymatischen Synthese.