Thioesterase-Mediated Synthesis of Teixobactin Analogues: Mechanism and Substrate Specificity.

A chemoenzymatic approach for the synthesis of teixobactin analogues has been established by using the tandem thioesterase (TE) of the nonribosomal peptide synthase (NRPS) Txo2. We show that, unlike the closely related counterparts involved in lysobactin biosynthesis (in which the N-terminal TE is solely responsible for the lactonization reaction), the two teixobactin TE domains are functionally exchangeable and likely act synergistically, representing an unprecedented off-loading mechanism in NRPS enzymology. The substrate specificity of this tandem TE was also investigated in this study.