Substrate-Triggered Formation of a Peroxo-Fe2(III/III) Intermediate during Fatty Acid Decarboxylation by UndA. Academic Article uri icon

abstract

  • The iron-dependent oxidase UndA cleaves one C3-H bond and the C1-C2 bond of dodecanoic acid to produce 1-undecene and CO2. A published X-ray crystal structure showed that UndA has a heme-oxygenase-like fold, thus associating it with a structural superfamily that includes known and postulated non-heme diiron proteins, but revealed only a single iron ion in the active site. Mechanisms proposed for initiation of decarboxylation by cleavage of the C3-H bond using a monoiron cofactor to activate O2 necessarily invoked unusual or potentially unfeasible steps. Here we present spectroscopic, crystallographic, and biochemical evidence that the cofactor of Pseudomonas fluorescens Pf-5 UndA is actually a diiron cluster and show that binding of the substrate triggers rapid addition of O2 to the Fe2(II/II) cofactor to produce a transient peroxo-Fe2(III/III) intermediate. The observations of a diiron cofactor and substrate-triggered formation of a peroxo-Fe2(III/III) intermediate suggest a small set of possible mechanisms for O2, C3-H and C1-C2 activation by UndA; these routes obviate the problematic steps of the earlier hypotheses that invoked a single iron.

published proceedings

  • J Am Chem Soc

author list (cited authors)

  • Zhang, B. o., Rajakovich, L. J., Van Cura, D., Blaesi, E. J., Mitchell, A. J., Tysoe, C. R., ... Bollinger, J. M.

citation count

  • 34

complete list of authors

  • Zhang, Bo||Rajakovich, Lauren J||Van Cura, Devon||Blaesi, Elizabeth J||Mitchell, Andrew J||Tysoe, Christina R||Zhu, Xuejun||Streit, Bennett R||Rui, Zhe||Zhang, Wenjun||Boal, Amie K||Krebs, Carsten||Bollinger, J Martin

publication date

  • September 2019