Design of a new warhead for the natural enediyne dynemicin A. An increase of biological activity

Elfi Kraka, Tell Tuttle, Dieter Cremer

Research output: Contribution to journalArticle

11 Citations (Scopus)


A concept for designing nontoxic enediyne-based antitumor drugs that was previously suggested (J. Am. Chem. Soc. 2000, 122, 8245) is converted into reality by merging amidines with the natural enediyne dynemicin A. The dynemicin-amidines (DADs) resulting from this combination are biologically not active because they form extremely labile singlet biradicals that can no longer abstract H from DNA. However, if protonated in the acidic environment of the tumor cell, they possess increased biological activity, as is reflected by a lowering of the activation enthalpy for the Bergman cyclization from 16.7 (dynemicin A) to 11 - 12 kcal/mol (DADs), kinetic stability of the singlet biradicals formed in the cyclization reaction, increased H abstraction ability of the singlet biradicals, and improved docking properties in the minor groove of the duplex 10-mer B-DNA sequence d(CTACTACTGG)·d(CCAGTAGTAG) throughout the triggering and Bergman reactions. The implications and the consequences of using DADs to exploit the differences between normal and tumor cells and to design a nontoxic antitumor drugs are discussed.

Original languageEnglish
Pages (from-to)2661-2670
Number of pages10
JournalJournal of Physical Chemistry B
Issue number9
Early online date13 Feb 2008
Publication statusPublished - 1 Mar 2008


  • antitumor drugs
  • dynemicin A

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