A three-component dicamba O-demethylase from Pseudomonas maltophilia, strain DI-6: Purification and characterization

Sarbani Chakraborty, Mark Behrens, Patricia L. Herman, Alexander F. Arendsen, Wilfred R. Hagen, Deborah L. Carlson, Xiao Zhuo Wang, Donald P. Weeks

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

Dicamba O-demethylase is a multicomponent enzyme that catalyzes the conversion of the herbicide 2-methoxy-3,6-dichlorobenzoic acid (dicamba) to 3,6-dichlorosalicylic acid (DCSA). The three components of the enzyme were purified and characterized. OxygenaseDIC is a homotrimer (α)3 with a subunit molecular mass of approximately 40 kDa. FerredoxinDIC and reductaseDIC are monomers with molecular weights of approximately 14 and 45 kDa, respectively. EPR spectroscopic analysis suggested the presence of a single [2Fe-2S](2+/1+) cluster in ferredoxinDIC and a single Rieske [2Fe-2S](2+; 1+) cluster within oxygenaseDIC. Consistent with the presence of a Rieske iron-sulfur cluster, oxygenaseDIC displayed a high reduction potential of Em,7.0 = -21 mV whereas ferredoxinDIC exhibited a reduction potential of approximately Em,7.0 = -171 mV. Optimal oxygenaseDIC activity in vitro depended on the addition of Fe2+. The identification of formaldehyde and DCSA as reaction products demonstrated that dicamba O-demethylase acts as a monooxygenase. Taken together, these data suggest that oxygenaseDIC is an important new member of the Rieske non-heme iron family of oxygenases.

Original languageEnglish (US)
Pages (from-to)20-28
Number of pages9
JournalArchives of Biochemistry and Biophysics
Volume437
Issue number1
DOIs
StatePublished - May 1 2005

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Keywords

  • Dicamba
  • Ferredoxin
  • Multicomponent enzyme
  • O-Demethylase
  • Oxygenase
  • Pseudomonas maltophilia
  • Reductase
  • Rieske non-heme oxygenase

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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