PROSITE documentation PDOC00690

Dihydroxy-acid and 6-phosphogluconate dehydratases signatures

Two dehydratases have been shown [1] to be evolutionary related:

• Dihydroxy-acid dehydratase (EC 4.2.1.9) (gene ilvD or ILV3) which catalyzes the fourth step in the biosynthesis of isoleucine and valine, the dehydratation of 2,3-dihydroxy-isovaleic acid into α-ketoisovaleric acid.
• 6-phosphogluconate dehydratase (EC 4.2.1.12) (gene edd) which catalyzes the first step in the Entner-Doudoroff pathway, the dehydratation of 6-phospho- D-gluconate into 6-phospho-2-dehydro-3-deoxy-D-gluconate.
• Escherichia coli hypothetical protein yjhG.

Both enzymes are proteins of about 600 amino acid residues. We selected two highly conserved regions as signature patterns. The first pattern is located in the N-terminal part and contains a cysteine that could be involved in the binding of a 2Fe-2S iron-sulfur cluster [2]. The second pattern is located in the C-terminal half.