Substrate-Induced Conformational Changes in Escherichia coli Taurine/α-Ketoglutarate Dioxygenase and Insight into the Oligomeric Structure

The enzymes in the α-ketoglutarate (αKG) dependent dioxygenase superfamily represent the largest class of non-heme iron oxidases and have important medical, ecological, and biotechnological roles. One such enzyme, taurine/α-ketoglutarate dioxygenase (TauD), catalyzes the conversion of 2-aminoethanes...

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Bibliographic Details
Published in:Biochemistry (Easton) 2003-05, Vol.42 (19), p.5547-5554
Main Authors: O'Brien, Jessica R, Schuller, David J, Yang, Victoria S, Dillard, Bret D, Lanzilotta, William N
Format: Article
Language:English
Subjects:
Apoenzymes - chemistry
Apoenzymes - genetics
Apoenzymes - metabolism
Catalytic Domain
Crystallography, X-Ray
Dimerization
Escherichia coli - enzymology
Escherichia coli - genetics
Iron - metabolism
Mixed Function Oxygenases - chemistry
Mixed Function Oxygenases - genetics
Mixed Function Oxygenases - metabolism
Models, Molecular
Protein Conformation
Protein Structure, Quaternary
Substrate Specificity
Taurine - metabolism
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Summary:The enzymes in the α-ketoglutarate (αKG) dependent dioxygenase superfamily represent the largest class of non-heme iron oxidases and have important medical, ecological, and biotechnological roles. One such enzyme, taurine/α-ketoglutarate dioxygenase (TauD), catalyzes the conversion of 2-aminoethanesulfonate (taurine) to sulfite and aminoacetaldehyde while decomposing αKG to succinate and CO2. This αKG dependent dioxygenase is expressed in Escherichia coli under sulfur starvation conditions and allows the cell to utilize taurine, and other similar sulfonates in the environment, as an alternative sulfur source. In this work, we report the structures of the apo and holo forms of TauD to 1.9 Å resolution (R cryst = 21.2%, R free = 24.9%) and 2.5 Å resolution (R cryst = 22.5%, R free = 27.8%), respectively. The models reported herein provide significant new insight into the substrate orientations at the active site and the conformational changes that are induced upon taurine binding. Furthermore, analysis of our crystallographic data coupled with reanalysis of the crystallographic model (resolution = 3.0 Å, R cryst = 28.1, R free = 32.0) presented by Elkins et al. (Biochemistry (2002) 41, 5185−5192) reveals an alternative oligomeric arrangement for the enzyme that is consistent with the conserved primary and secondary structure elements of other αKG dependent dioxygenases.
ISSN:0006-2960
1520-4995
DOI:10.1021/bi0341096