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Publication Abstract from PubMed

First discovered in 1989, the anthraquinone-fused enediynes are a class of DNA-cleaving bacterial natural products composed of a DNA-intercalating anthraquinone moiety and a 10-membered enediyne warhead. However, until recently, there has been a lack of genetically amenable hosts and sequenced biosynthetic gene clusters available for solving the biosynthetic questions surrounding these molecules. Herein, we have identified and biochemically and structurally characterized TnmK1, a member of the alpha/beta-hydrolase fold superfamily responsible for the C-C bond formation linking the anthraquinone moiety and enediyne core together in tiancimycin (TNM) biosynthesis. In doing so, two intermediates, TNM H and TNM I, in anthraquinone-fused enediyne biosynthesis, containing an unprecedented cryptic C16 aldehyde group, were identified. This aldehyde plays a key role in the TnmK1-catalyzed C-C bond formation via a Michael addition, representing the first example of this chemistry for the alpha/beta-hydrolase fold superfamily. Additionally, TNM I shows sub-nanomolar cytotoxicity against selected cancer cell lines, indicating a new mechanism of action compared to previously known anthraquinone-fused enediynes. Together, the findings from this study are expected to impact enzymology, natural product biosynthesis, and future efforts at enediyne discovery and drug development.

Intramolecular C-C Bond Formation Links Anthraquinone and Enediyne Scaffolds in Tiancimycin Biosynthesis.,Gui C, Kalkreuter E, Liu YC, Adhikari A, Teijaro CN, Yang D, Chang C, Shen B J Am Chem Soc. 2022 Oct 24. doi: 10.1021/jacs.2c08957. PMID:36279548^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.