Crotonase family

Enoyl-CoA hydratase/isomerase family
Symbol ECH
Pfam PF00378
InterPro IPR001753
SCOP 1dub

The crotonase family comprises 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[1]. However, these different enzymes share the need to stabilize 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[2]. Enzymes in the crotonase superfamily include:

  • Enoyl-CoA hydratase (crotonase; EC, which catalyses the hydratation of 2-trans-enoyl-CoA into 3-hydroxyacyl-CoA[3].
  • 3-2trans-enoyl-CoA isomerase (or dodecenoyl-CoA isomerise; EC, which shifts the 3-double bond of the intermediates of unsaturated fatty acid oxidation to the 2-trans position[4].
  • 3-hydroxbutyryl-CoA dehydratase (crotonase; EC, a bacterial enzyme involved in the butyrate/butanol-producing pathway.
  • 4-Chlorobenzoyl-CoA dehalogenase (EC, a Pseudomonas enzyme which catalyses the conversion of 4-chlorobenzoate-CoA to 4-hydroxybenzoate-CoA[5].
  • Dienoyl-CoA isomerase, which catalyses the isomerisation of 3-trans,5-cis-dienoyl-CoA to 2-trans,4-trans-dienoyl-CoA[6].
  • Naphthoate synthase (MenB, or DHNA synthetase; EC, a bacterial enzyme involved in the biosynthesis of menaquinone (vitamin K2)[7].
  • Carnitine racemase (gene caiD), which catalyses the reversible conversion of crotonobetaine to L-carnitine in Escherichia coli[8].
  • Methylmalonyl CoA decarboxylase (MMCD; EC, which has a hexameric structure (dimer of trimers)[9].
  • Carboxymethylproline synthase (CarB), which is involved in carbapenem biosynthesis[10].
  • 6-oxo camphor hydrolase, which catalyses the desymmetrization of bicyclic beta-diketones to optically active keto acids[11].
  • The alpha subunit of fatty acid oxidation complex, a multi-enzyme complex that catalyses the last three reactions in the fatty acid beta-oxidation cycle[12].
  • AUH protein, a bifunctional RNA-binding homologue of enoyl-CoA hydratase[13].

Human proteins containing this domain



  1. ^ Gerlt JA, Benning MM, Holden HM, Haller T (2001). "The crotonase superfamily: divergently related enzymes that catalyze different reactions involving acyl coenzyme a thioesters". Acc. Chem. Res. 34 (2): 145–57. PMID 11263873. 
  2. ^ Brzozowski AM, Leonard PM, Bennett JP, Whittingham JL, Grogan G (2007). "Structural characterization of a beta-diketone hydrolase from the cyanobacterium Anabaena sp. PCC 7120 in native and product-bound forms, a coenzyme A-independent member of the crotonase suprafamily". Biochemistry 46 (1): 137–44. doi:10.1021/bi061900g. PMID 17198383. 
  3. ^ Wu J, Kisker C, Whitty A, Feng Y, Rudolph MJ, Bell AF, Hofstein HA, Parikh S, Tonge PJ (2002). "Stereoselectivity of enoyl-CoA hydratase results from preferential activation of one of two bound substrate conformers". Chem. Biol. 9 (11): 1247–55. doi:10.1016/S1074-5521(02)00263-6. PMID 12445775. 
  4. ^ Stoffel W, Muller-Newen G (1991). "Mitochondrial 3-2trans-Enoyl-CoA isomerase. Purification, cloning, expression, and mitochondrial import of the key enzyme of unsaturated fatty acid beta-oxidation". Biol. Chem. Hoppe-Seyler 372 (8): 613–624. doi:10.1515/bchm3.1991.372.2.613. PMID 1958319. 
  5. ^ Dunaway-Mariano D, Benning MM, Wesenberg G, Holden HM, Taylor KL, Yang G, Liu R-Q, Xiang H (1996). "Structure of 4-chlorobenzoyl coenzyme A dehalogenase determined to 1.8 A resolution: an enzyme catalyst generated via adaptive mutation". Biochemistry 35 (25): 8103–9. doi:10.1021/bi960768p. PMID 8679561. 
  6. ^ Hiltunen JK, Wierenga RK, Modis Y, Filppula SA, Novikov DK, Norledge B (1998). "The crystal structure of dienoyl-CoA isomerase at 1.5 A resolution reveals the importance of aspartate and glutamate sidechains for catalysis". Structure 6 (8): 957–70. PMID 9739087. 
  7. ^ Baker EN, Johnston JM, Arcus VL (2005). "Structure of naphthoate synthase (MenB) from Mycobacterium tuberculosis in both native and product-bound forms". Acta Crystallogr. D 61 (Pt 9): 1199–206. doi:10.1107/S0907444905017531. PMID 16131752. 
  8. ^ Kleber HP, Elssner T, Engemann C, Baumgart K (2001). "Involvement of coenzyme A esters and two new enzymes, an enoyl-CoA hydratase and a CoA-transferase, in the hydration of crotonobetaine to L-carnitine by Escherichia coli". Biochemistry 40 (37): 11140–8. doi:10.1021/bi0108812. PMID 11551212. 
  9. ^ Gerlt JA, Benning MM, Holden HM, Haller T (2000). "New reactions in the crotonase superfamily: structure of methylmalonyl CoA decarboxylase from Escherichia coli". Biochemistry 39 (16): 4630–9. doi:10.1021/bi9928896. PMID 10769118. 
  10. ^ Schofield CJ, McDonough MA, Sleeman MC, Sorensen JL, Batchelar ET (2005). "Structural and mechanistic studies on carboxymethylproline synthase (CarB), a unique member of the crotonase superfamily catalyzing the first step in carbapenem biosynthesis". J. Biol. Chem. 280 (41): 34956–65. doi:10.1074/jbc.M507196200. PMID 16096274. 
  11. ^ Leonard PM, Grogan G (2004). "Structure of 6-oxo camphor hydrolase H122A mutant bound to its natural product, (2S,4S)-alpha-campholinic acid: mutant structure suggests an atypical mode of transition state binding for a crotonase homolog". J. Biol. Chem. 279 (30): 31312–17. doi:10.1074/jbc.M403514200. PMID 15138275. 
  12. ^ Resibois-Gregoire A, Dourov N (1966). "Electron microscopic study of a case of cerebral glycogenosis". Acta Neuropathol. 6 (1): 70–9. doi:10.1007/BF00691083. PMID 5229654. 
  13. ^ Nureki O, Fukai S, Yokoyama S, Muto Y, Kurimoto K (2001). "Crystal structure of human AUH protein, a single-stranded RNA binding homolog of enoyl-CoA hydratase". Structure 9 (12): 1253–63. doi:10.1016/S0969-2126(01)00686-4. PMID 11738050. 

This article includes text from the public domain Pfam and InterPro IPR001753

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