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QuickView for 3-Isopropylmalate dehydratase, catalytic domain (biogroup)
- Description:
- This entry represents the aconitase-like catalytic domain of 3-isopropylmalate dehydratase (IPMI) and related uncharacterized proteins.3-isopropylmalate dehydratase (or isopropylmalate isomerase; ) catalyses the stereo-specific isomerisation of 2-isopropylmalate and 3-isopropylmalate, via the formation of 2-isopropylmaleate. This enzyme performs the second step in the biosynthesis of leucine, and is present in most prokaryotes and many fungal species. The prokaryotic enzyme is a heterodimer composed of a large (LeuC) and small (LeuD) subunit, while the fungal form is a monomeric enzyme. Both forms of isopropylmalate are related and are part of the larger aconitase family. Aconitases are mostly monomeric proteins which share four domains in common and contain a single, labile [4Fe-4S] cluster. Three structural domains (1, 2 and 3) are tightly packed around the iron-sulphur cluster, while a fourth domain (4) forms a deep active-site cleft. The prokaryotic enzyme is encoded by two adjacent genes, leuC and leuD, corresponding to aconitase domains 1-3 and 4 respectively. LeuC does not bind an iron-sulphur cluster. It is thought that some prokaryotic isopropylamalate dehydrogenases can also function as homoaconitase , converting cis-homoaconitate to homoisocitric acid in lysine biosynthesis. Homoaconitase has been identified in higher fungi (mitochondria) and several archaea and one thermophilic species of bacteria, Thermus thermophilus. It is also found in the higher plant Arabidopsis thaliana, where it is targeted to the chloroplast.
- Taxonomy/Path:
- InterPro : Aconitase/3-isopropylmalate dehydratase large subunit, alpha/beta/alpha domain / 3-Isopropylmalate dehydratase, catalytic domain
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