Fig. 4: Establishing downstream pathways to access molecules from tryptophan.

A Overview of example molecules derived from tryptophan and the applications enabled by them. Molecules in the figure (in general order left to right) include Indole, Kynurenine, Kynurenic acid, Skatole, 3-methyl-2-indolic acid (MIA), Serotonin, Indole-3-acetic acid (auxin), Tryptamine, indole pyruvic acid, 1-acetyl-3-carboxy-beta-carboline, strictosidine, indigo, violacein, rebeccamycin, thaxtomin, vinblastine, cyclomarin A, ergoline, ergotamine, N,N-Dimethyltryptamine, Hapalindole A, melatonin, psilocybine, lysergic acid, physostigmine, pyrrolnitrin, and quinmerac. B Biologically available reaction centers of tryptophan investigated within this study accessible through a single enzymatic step. Note: This list is exemplary, not exhaustive. The modifications to the tryptophan scaffold are represented by colored reaction center dots, with colors corresponding to each reaction center displayed in (C). The green boxes in the product observed column represent the enzymes that converted tryptophan fed to the media into the expected product, as confirmed by LC-MS. C An overview of the halogen-product diversification strategy, utilizing promiscuity downstream enzymes to generate a wide range of halogenated tryptophan-derived products. D The chemical structure of the expected products are shown, with indications of observed and unobserved when 500 μM L-tryptophan was fed to the media.