1 Contains
| DB identifier | Type | Name |
|---|---|---|
| IPR002034 | Conserved_site | Alpha-isopropylmalate/homocitrate synthase, conserved site |
| Type: | Domain | Name: | Isopropylmalate/citramalate/homocitrate synthase |
| Description: | Methanogenic archaea contain three closely related homologues of the 2-isopropylmalate synthases (LeuA) represented by . Two of these in Methanococcus janaschii (MJ1392 - CimA []; MJ0503 - AksA []) have been characterised as catalyzing alternative reactions leaving the third (MJ1195) as the presumptive LeuA enzyme. CimA is citramalate (2-methylmalate) synthase, which condenses acetyl-CoA with pyruvate. This enzyme is believed to be involved in the biosynthesis of isoleucine in methanogens and possibly other species lacking threonine dehydratase. AksA is a homocitrate synthase which also produces (homo)2-citrate and (homo)3-citrate in the biosynthesis of Coenzyme B which is restricted solely to methanogenic archaea. Methanogens, then should and apparently do contain all three of these enzymes. Unfortunately, phylogenetic trees do not resolve into three unambiguous clades, making assignment of function to particular genes problematic. Other archaea, which lack a threonine dehydratase (mainly Euryarchaeota), should contain both CimA and LeuA genes. This is true for archaeoglobus fulgidis, but not for the Pyrococci which have none in this clade, but one in and one in which may fulfil these roles. Proteins from other species, which have only one hit to this entry and lack threonine dehydratase, are very likely to be LeuA enzymes. | Short Name: | LEU1_arch |
| DB identifier | Type | Name |
|---|---|---|
| IPR002034 | Conserved_site | Alpha-isopropylmalate/homocitrate synthase, conserved site |
