Enzymatic macrolactonization in the presence of DNA leading to triostin A analogs.
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.
Koketsu
Kento
K
Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, Japan.
Oguri
Hiroki
H
Watanabe
Kenji
K
Oikawa
Hideaki
H
D002384:Catalysis; D003001:Cloning, Molecular; D003500:Cyclization; D003543:Cysteamine / Q000737:chemistry / Q000378:metabolism; D004247:DNA / Q000378:metabolism*; D019281:Dimerization; D004448:Echinomycin / Q000378:metabolism; D005786:Gene Expression Regulation; D007364:Intercalating Agents / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011810:Quinoxalines / Q000737:chemistry / Q000378:metabolism; D013869:Thiolester Hydrolases / Q000737:chemistry / Q000378:metabolism; D013997:Time Factors
D007364:Intercalating Agents; D011810:Quinoxalines; C031945:triostin A; D004448:Echinomycin; D003543:Cysteamine; D004247:DNA; D013869:Thiolester Hydrolases