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Updated: Jul 2, 2026

Site-Specific Lysine Lactylation via Genetic Code Expansion in E. coli and Mammalian Cells
Published on: February 24, 2026
Enzymatic macrolactonization in the presence of DNA leading to triostin A analogs
Kento Koketsu1, Hiroki Oguri, Kenji Watanabe
1Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, Japan.
Abstract:
Excised thioesterase domains are versatile catalysts for macrocyclization. However, thioesterase-catalyzed cyclization is often precluded due to the occurrence of hydrolysis and product inhibition. To circumvent these obstacles, we devised an unprecedented strategy: coincubation with DNA to capture the cyclic products possessing DNA-binding properties. In experiments involving echinomycin thioesterase-catalyzed macrolactonization leading to the cyclic triostin A analog TANDEM, we found that the addition of DNA drastically improved the yield of TANDEM (19% --> 67%), with a complete reversal of the cyclization:hydrolysis ratio (1:2 --> 18:1). Furthermore, the applicability of this protocol was demonstrated for a variety of substrates. The results described herein provide insight into the mechanism of echinomycin thioesterase-catalyzed conversions and also pave the way for chemoenzymatic synthesis of the quinoxaline antibiotics and their analogs.
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