Repurposing the 3-Isocyanobutanoic Acid Adenylation Enzyme SfaB for Versatile Amidation and Thioesterification

Author: Mengyi Zhu, Lijuan Wang, Jing He

Angew Chem Int Engl. 2021 Jan 25. 60(4). 2030-2035

Abstract: SfaB is an adenylation enzyme that adenylates 3-isocyanobutanoic acid for the biosynthesis of diisonitrile natural product SF2768. This enzyme also recognizes a broad range of short-chain fatty acids and their terminally substituted analogues. The substrate flexibility allows the enzymatic synthesis of diverse unnatural N-fatty acyl amides and fatty acyl-CoA/SNAC thioesters using SfaB in vitro, thus expanding the toolbox of biocatalysis. Genome mining of microbial natural products enables chemists not only to discover the bioactive molecules with novel skeletons, but also to identify the enzymes that catalyze diverse chemical reactions. Exploring the substrate promiscuity and catalytic mechanism of those biosynthetic enzymes facilitates the development of potential biocatalysts. SfaB is an acyl adenylate-forming enzyme that adenylates a unique building block, 3-isocyanobutanoic acid, in the biosynthetic pathway of the diisonitrile natural product SF2768 produced by Streptomyces thioluteus, and this AMP-ligase was demonstrated to accept a broad range of short-chain fatty acids (SCFAs). Herein, we repurpose SfaB to catalyze amidation or thioesterification between those SCFAs and various amine or thiol nucleophiles, thereby providing an alternative enzymatic approach to prepare the corresponding amides and thioesters in vitro.

Full Article:https://doi.org/10.1002/anie.202010042