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.
单模块非
核糖体肽合酶(NRPSs)和类NRPS酶在初级和次级代谢中激活和转化
羧酸,由于其
生物催化潜力,备受关注。单模块NRPS IvoA 对真菌色素
生物合成至关重要。正如本文所披露的,我们展示了IvoA 催化
ATP依赖的
L-色氨酸向
D-色氨酸的单向立体反转,实现了完全转化。虽然立体反转由外消旋(E)结构域催化,但末端缩合(C)结构域具有立体选择性地
水解D-色
氨酰-S-
磷酰巯基
丝氨酸酯,因此代表了非规范的C结构域功能。利用IvoA,我们展示了一种
生物催化的立体反转/去消旋途径,以获得多种取代
D-色氨酸类似物,其旋光异构体过量达到高
水平。