Macrolactam formation catalyzed by the thioesterase domain of vicenistatin polyketide synthase

The excited thioesterase (TE) domain from the vicenistatin polyketide synthase (PKS) efficiently catalyzed the macrolactam formation of the N-acetylcysteamine thioester of the seco-amino acid of the aglycon vicenilactam. This result indicates that the vicenistatin PKS TE domain cyclizes the extended polyketide chain on the ACP domain in the PKS. Furthermore, the simple ethyl ester of the seco-amino acid was also found to be used as a substrate of the TE domain with similar efficiency.