PDBsum entry 1gqw

Oxidoreductase

PDB id: 1gqw

Contents

Protein chains

277 a.a. *

Ligands

TAU ×2

AKG ×2

Metals

FE2 ×2

* Residue conservation analysis

References listed in PDB file

Key reference

• Title: X-Ray crystal structure of escherichia coli taurine/alpha-Ketoglutarate dioxygenase complexed to ferrous iron and substrates.
• Authors: J.M.Elkins, M.J.Ryle, I.J.Clifton, J.C.Dunning hotopp, J.S.Lloyd, N.I.Burzlaff, J.E.Baldwin, R.P.Hausinger, P.L.Roach.
• Ref.: Biochemistry, 2002, 41, 5185-5192. [DOI no: 10.1021/bi016014e]
• PubMed id: 11955067

Abstract

Taurine/alpha-ketoglutarate dioxygenase (TauD), a non-heme Fe(II) oxygenase, catalyses the conversion of taurine (2-aminoethanesulfonate) to sulfite and aminoacetaldehyde concurrent with the conversion of alpha-ketoglutarate (alphaKG) to succinate and CO(2). The enzyme allows Escherichia coli to use taurine, widely available in the environment, as an alternative sulfur source. Here we describe the X-ray crystal structure of TauD complexed to Fe(II) and both substrates, alphaKG and taurine. The tertiary structure and fold of TauD are similar to those observed in other enzymes from the broad family of Fe(II)/alphaKG-dependent oxygenases, with closest structural similarity to clavaminate synthase. Using the TauD coordinates, a model was determined for the closely related enzyme 2,4-dichlorophenoxyacetate/alphaKG dioxygenase (TfdA), supporting predictions derived from site-directed mutagenesis and other studies of that biodegradative protein. The TauD structure and TfdA model define the metal ligands and the positions of nearby aromatic residues that undergo post-translational modifications involving self-hydroxylation reactions. The substrate binding residues of TauD were identified and those of TfdA predicted. These results, along with sequence alignment information, reveal how TauD selects a tetrahedral substrate anion in preference to the planar carboxylate selected by TfdA, providing insight into the mechanism of enzyme catalysis.