Mechanistic pathways to unusual outcomes in reactions of iron‐dependent oxygenases

Abstract

Non‐heme‐iron (NH‐Fe) enzymes activate O2 for an array of biomedically, agriculturally, and environmentally important oxidation reactions. Our past decade's work has characterized iron(IV)‐oxo (ferryl) complexes in several such NH‐Fe enzymes.1 In all such systems that transform aliphatic carbon centers, the ferryl complexes generate substrate radicals by abstracting hydrogen (H•),2–6 leading to formation of new C–O,2–4 C–Cl/Br,5,6 or C–S bonds.1 Motivated by our success in rationalizing the divergent outcomes of the NH‐Fe‐ and 2‐ (oxo)glutarate‐dependent aliphatic hydroxylases and halogenases,7 we now seek both to exploit the ferryl manifold for novel, unnatural carbon‐functionalization reactions8 and to explain the structural and mechanistic bases for several other natural reaction types – including 1,3‐dehydrogenation of an alcohol to epoxide,9 stereo‐inversion of a chiral carbon,10 and desaturation and cleavage of C–C bonds – that are initiated by ferryl complexes in other NH‐Fe enzymes. Insight obtained will inform development of new biocatalytic synthetic routes and combinatorial design of new antibiotic and anticancer drugs.Support or Funding InformationNational Institutes of Health GM118812, GM113106, and GM069657; National Science Foundation CHE‐0724084 and MCB‐0642058.