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Humboldt-Universitaet zu Berlin - Structural Biology / Biochemistry

Humboldt-Universitaet zu Berlin | Department of Biology | Structural Biology / Biochemistry | Publications | The Fe(II) /α-ketoglutarate dependent taurine dioxygenases from Pseudomonas putida and Escherichia coli are tetramers

Stefan Knauer, Olivia Hartl-Spiegelhauer, Stefan Schwarzinger, Petra Haenzelmann, and Holger Dobbek (2012)

The Fe(II) /α-ketoglutarate dependent taurine dioxygenases from Pseudomonas putida and Escherichia coli are tetramers

FEBS Journal, 279(5):816-831.

Fe(II)/α-ketoglutarate dependent oxygenases are versatile catalysts associated with a number of different biological functions, in which they use the oxidizing power of activated dioxygen to convert a variety of substrates. A mononuclear non-heme iron center is used to couple the decarboxylation of the cosubstrate α-ketoglutarate with a two-electron oxidation of the substrate, which is a hydroxylation in most cases. Although Fe(II)/α-ketoglutarate dependent oxygenases have diverse amino acid sequences and substrate specifity, it is assumed that they share a common mechanism. One representative of this enzyme family is the Fe(II)/α-ketoglutarate dependent taurine dioxygenase (TauD) that catalyzes the hydroxylation of taurine yielding sulfite and aminoacetaldehyde. Its mechanism has been studied in detail becoming a model system for the whole enzyme family. However, its oligomeric state and architecture have been disputed. Here, we report the biochemical and kinetic characterization of the Fe(II)/α-ketoglutarate dependent taurine dioxygenase from Pseudomonas putida KT2440 (TauD(Pp) ). We also present three crystal structures of the apo form of this enzyme. Comparisons with TauD from Escherichia coli (TauD(Ec) ) demonstrate that both enzymes are quite similar regarding their spectra, structure and kinetics and only minor differences for the accumulation of intermediates during the reaction have been observed. Structural data and the analytical gelfiltration as well as sedimentation velocity analytical ultracentrifugation show that both TauD(Pp) and TauD(Ec) are tetramers in solution and in the crystals, which is in contrast to the earlier description of TauD from E. coli as a dimer.