InterPro domain: IPR001031

Thioesterase (TE) domains often occur integrated in or associated with peptide synthetases which are involved in the non-ribosomal synthesis of peptide antibiotics [ 1 ]. Thioesterases are required for the addition of the last amino acid to the peptide antibiotic, thereby forming a cyclic antibiotic. Next to the operons encoding these enzymes, in almost all cases, are genes that encode proteins that have similarity to the type II fatty acid thioesterases of vertebrates.

This domain has a crucial role during fungal polyketide synthesis as it is responsible for the release of the finished polyketide intermediate from the polyketide synthase enzyme (PKS). Most TEs from fungal PKSs catalyse product release by intramolecular C-C bond formation but a small number of PKSs have TE domains that catalyze O-C bond formation through macrolactone closure, hydrolysis, and ester or pyrone formation [ 2 ].

1. Genetic evidence for a role of thioesterase domains, integrated in or associated with peptide synthetases, in non-ribosomal peptide biosynthesis in Bacillus subtilis. Arch. Microbiol. 169, 404-10
2. Thioesterase domains of fungal nonreducing polyketide synthases act as decision gates during combinatorial biosynthesis. J. Am. Chem. Soc. 135, 10783-91