Pathways & interactions
Crotonase superfamily (IPR001753)
Short name: Crotonase_core_superfam
- Crotonase superfamily (IPR001753)
- 1,4-Dihydroxy-2-naphthoyl-CoA synthase (IPR010198)
- 2-ketocyclohexanecarboxyl-CoA hydrolase (IPR017623)
- 6-oxocyclohex-1-ene-1-carbonyl-CoA hydrolase (IPR017613)
- Benzoyl-CoA-dihydrodiol lyase (IPR017633)
- Carnitinyl-CoA dehydratase (IPR022852)
- Cyclohexa-1,5-dienecarbonyl-CoA hydratase (IPR017602)
- Fatty acid oxidation complex, alpha subunit, mitochondrial (IPR012803)
- Fatty oxidation complex, alpha subunit FadB (IPR012799)
- Fatty oxidation complex, alpha subunit FadJ (IPR012802)
- Phenylacetate degradation probable enoyl-CoA hydratase PaaB (IPR011968)
- [NiFe]-hydrogenase maturation factor, HypX/HoxX type (IPR009188)
The crotonase superfamily is comprised of mechanistically diverse proteins that share a conserved trimeric quaternary structure (sometimes a hexamer consisting of a dimer of trimers), the core of which consists of 4 turns of a (beta/beta/alpha)n superhelix. Some enzymes in the superfamily have been shown to display dehalogenase, hydratase, and isomerase activities, while others have been implicated in carbon-carbon bond formation and cleavage as well as the hydrolysis of thioesters [PMID: 11263873]. However, these different enzymes share the need to stabilise an enolate anion intermediate derived from an acyl-CoA substrate. This is accomplished by two structurally conserved peptidic NH groups that provide hydrogen bonds to the carbonyl moieties of the acyl-CoA substrates and form an "oxyanion hole". The CoA thioester derivatives bind in a characteristic hooked shape and a conserved tunnel binds the pantetheine group of CoA, which links the 3'-phosphate ADP binding site to the site of reaction [PMID: 17198383]. Enzymes in the crotonase superfamily include:
- Enoyl-CoA hydratase (crotonase; EC:22.214.171.124), which catalyses the hydratation of 2-trans-enoyl-CoA into 3-hydroxyacyl-CoA [PMID: 12445775].
- 3-2trans-enoyl-CoA isomerase (or dodecenoyl-CoA isomerise; EC:126.96.36.199), which shifts the 3-double bond of the intermediates of unsaturated fatty acid oxidation to the 2-trans position [PMID: 1958319].
- 3-hydroxbutyryl-CoA dehydratase (crotonase; EC:188.8.131.52), a bacterial enzyme involved in the butyrate/butanol-producing pathway.
- 4-Chlorobenzoyl-CoA dehalogenase (EC:184.108.40.206), a Pseudomonas enzyme which catalyses the conversion of 4-chlorobenzoate-CoA to 4-hydroxybenzoate-CoA [PMID: 8679561].
- Dienoyl-CoA isomerise, which catalyses the isomerisation of 3-trans,5-cis-dienoyl-CoA to 2-trans,4-trans-dienoyl-CoA [PMID: 9739087].
- Naphthoate synthase (MenB, or DHNA synthetase; EC:220.127.116.11), a bacterial enzyme involved in the biosynthesis of menaquinone (vitamin K2) [PMID: 16131752].
- Carnitine racemase (gene caiD), which catalyses the reversible conversion of crotonobetaine to L-carnitine in Escherichia coli [PMID: 11551212].
- Methylmalonyl CoA decarboxylase (MMCD; EC:18.104.22.168), which has a hexameric structure (dimer of trimers) [PMID: 10769118].
- Carboxymethylproline synthase (CarB), which is involved in carbapenem biosynthesis [PMID: 16096274].
- 6-oxo camphor hydrolase, which catalyses the desymmetrisation of bicyclic beta-diketones to optically active keto acids [PMID: 15138275].
- The alpha subunit of fatty oxidation complex, a multi-enzyme complex that catalyses the last three reactions in the fatty acid beta-oxidation cycle [PMID: 5229654].
- AUH protein, a bifunctional RNA-binding homologue of enoyl-CoA hydratase [PMID: 11738050].
- PF00378 (ECH)