Shall we dance? How a multicopper oxidase chooses its electron transfer partner

Liliana Quintanar, Christopher Stoj, Alexander B. Taylor, P. John Hart, Daniel J. Kosman, Edward I. Solomon

Research output: Contribution to journalArticle

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Abstract

Multicopper oxidases (MCOs) are encoded in the genomes of Eukarya, Bacteria, and Archea. These proteins are unique in that they contain at least four Cu atom prosthetic groups organized into one each of the three spectral classifications of copper sites in biology: type 1 (T1), type 2 (T2), and binuclear type 3 (T3), where the T2 and T3 sites form a trinuclear Cu cluster. With these four redox-active copper sites, the multicopper oxidases catalyze the four-electron (4e-) reduction of dioxygen to 2H2O, an activity that they alone share with the terminal heme-containing oxidases. Most MCOs exhibit broad specificity towards organic reductants, while a relatively small number of family members exhibit equally robust activity towards metal ions like FeII, CuI, and MnII and, thus, are considered metallo-oxidases. This Account analyzes the structure-activity features of multicopper oxidases that determine their relative substrate specificity. Since the substrate oxidation step involves an outer-sphere electron transfer from the reductant to the T1Cu site in the protein, the concepts of Marcus theory are applied to unravel the origin of the substrate specificity of the multicopper ferroxidases.

Original languageEnglish (US)
Pages (from-to)445-452
Number of pages8
JournalAccounts of Chemical Research
Volume40
Issue number6
DOIs
StatePublished - Jun 1 2007

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ASJC Scopus subject areas

  • Chemistry(all)

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