Crystal structures of Fe2+ dioxygenase superoxo, alkylperoxo, and bound product intermediates

Elena G. Kovaleva, John D. Lipscomb

Research output: Contribution to journalArticlepeer-review

271 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)453-457
Number of pages5
Issue number5823
StatePublished - Apr 20 2007


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