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Science 20 April 2007:
Vol. 316. no. 5823, pp. 453 - 457
DOI: 10.1126/science.1134697
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Reports

Crystal Structures of Fe2+ Dioxygenase Superoxo, Alkylperoxo, and Bound Product Intermediates

Elena G. Kovaleva and John D. Lipscomb*

We report the structures of three intermediates in the O2 activation and insertion reactions of an extradiol ring-cleaving dioxygenase. A crystal of Fe2+-containing homoprotocatechuate 2,3-dioxygenase was soaked in the slow substrate 4-nitrocatechol in a low O2 atmosphere. The x-ray crystal structure shows that three different intermediates reside in different subunits of a single homotetrameric enzyme molecule. One of these is the key substrate-alkylperoxo-Fe2+ intermediate, which has been predicted, but not structurally characterized, in an oxygenase. The intermediates define the major chemical steps of the dioxygenase mechanism and point to a general mechanistic strategy for the diverse 2-His-1-carboxylate enzyme family.

Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.

* To whom correspondence should be addressed. E-mail: lipsc001{at}umn.edu

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THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
The shortest wire.
A.-F. Miller (2008)
PNAS 105, 7341-7342
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From the Cover: Swapping metals in Fe- and Mn-dependent dioxygenases: Evidence for oxygen activation without a change in metal redox state.
J. P. Emerson, E. G. Kovaleva, E. R. Farquhar, J. D. Lipscomb, and L. Que Jr. (2008)
PNAS 105, 7347-7352
   Abstract »    Full Text »    PDF »


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Science. ISSN 0036-8075 (print), 1095-9203 (online)