InterPro domain: IPR037237

Two dehydratases, dihydroxy-acid dehydratase ( 4.2.1.9 ) (gene ilvD or ILV3) and 6-phosphogluconate dehydratase ( 4.2.1.12 ) (gene edd) have been shown to be evolutionary related [ 1 ]. Dihydroxy-acid dehydratase catalyses the fourth step in the biosynthesis of isoleucine and valine, the dehydratation of 2,3-dihydroxy-isovaleic acid into alpha-ketoisovaleric acid. 6-Phosphogluconate dehydratase catalyses the first step in the Entner-Doudoroff pathway, the dehydratation of 6-phospho-D-gluconate into 6-phospho-2-dehydro-3-deoxy-D-gluconate. Another protein containing this signature is Escherichia coli YjhG, which has been identified as a D-xylonate dehydratase [ 2 ]. The N-terminal part of the proteins contains a cysteine that could be involved in the binding of a 2Fe-2S iron-sulphur cluster [ 3 ].

The structure of the N-terminal domain contains a large cluster of helices and a mixed beta-sheet of four strands where strands 3 and 4 are parallel.

1. Molecular characterization of the Entner-Doudoroff pathway in Escherichia coli: sequence analysis and localization of promoters for the edd-eda operon. J. Bacteriol. 174, 4638-46
2. Biosynthesis of ethylene glycol in Escherichia coli. Appl. Microbiol. Biotechnol. 97, 3409-17
3. Cloning of the dihydroxyacid dehydratase-encoding gene (ILV3) from Saccharomyces cerevisiae. Gene 137, 179-85