Enoyl-CoA hydratase

 

Enoyl-CoA hydratase catalyses the hydration of trans-2-enoyl-CoA thiolesters to the corresponding 3(S)-hydroxyacyl-CoA compounds, the second step in the fatty acid beta-oxidation pathway. The enzymes degrade fatty acids of variable tail length from C4 up to at least C16, but the rate of the reaction decreases with increasing tail length. Enoyl-CoA hydratase is a member of the corotonase superfamily of enzymes.

Despite the thermodynamic preference for the aromatic conjugated unsaturated substrate, the enzyme has been shown to catalyse the dehydration of 3-hydroxy-3-phenylpropanoyl-CoA to cinnamoyl-CoA.

 

Reference Protein and Structure

Sequence
P14604 UniProt (4.2.1.17) IPR001753 (Sequence Homologues) (PDB Homologues)
Biological species
Rattus norvegicus (Norway rat) Uniprot
PDB
1ey3 - STRUCTURE OF ENOYL-COA HYDRATASE COMPLEXED WITH THE SUBSTRATE DAC-COA (2.3 Å) PDBe PDBsum 1ey3
Catalytic CATH Domains
3.90.226.10 CATHdb (see all for 1ey3)
Click To Show Structure

Enzyme Reaction (EC:4.2.1.17)

water
CHEBI:15377ChEBI
+
2,3-trans-enoyl CoA(4-)
CHEBI:58856ChEBI
→
(S)-3-hydroxyacyl-CoA(4-)
CHEBI:57318ChEBI
Alternative enzyme names: 2-enoyl-CoA hydratase, 2-octenoyl coenzyme A hydrase, Beta-hydroxyacid dehydrase, Beta-hydroxyacyl-CoA dehydrase, D-3-hydroxyacyl-CoA dehydratase, Trans-2-enoyl-CoA hydratase, ECH, Acyl coenzyme A hydrase, Crotonase, Crotonyl hydrase, Enol-CoA hydratase, Enoyl coenzyme A hydrase (D), Enoyl coenzyme A hydrase (L), Enoyl coenzyme A hydratase, Enoyl hydrase, Hydratase, enoyl coenzyme A, Short chain enoyl coenzyme A hydratase, Short-chain enoyl-CoA hydratase, Unsaturated acyl-CoA hydratase,

Enzyme Mechanism

Introduction

Glu164 deprotonates the catalytic water, which adds to the C3 of the substrate. The intermediate collapses and the C2 of the substrate deprotonates Glu164.

Catalytic Residues Roles

UniProt PDB* (1ey3)
Gly141 (main-N), Ala98 (main-N) Gly141(109)A (main-N), Ala98(66)A (main-N) Acts to stabilise the negatively charged transition state formed through hydrogen bonding interactions. activator, electrostatic stabiliser
Glu144 Glu144(112)A Activates (increases the nucleophilic character) the catalytic water for addition to the C3 of the substrate. increase basicity, hydrogen bond acceptor
Glu164 Glu164(132)A Acts as a general acid/base. Abstracts a proton from the catalytic water, and returns the proton to the C2 of the substrate. hydrogen bond acceptor, hydrogen bond donor, proton acceptor, proton donor
*PDB label guide - RESx(y)B(C) - RES: Residue Name; x: Residue ID in PDB file; y: Residue ID in PDB sequence if different from PDB file; B: PDB Chain; C: Biological Assembly Chain if different from PDB. If label is "Not Found" it means this residue is not found in the reference PDB.

Chemical Components

proton transfer, bimolecular nucleophilic addition, overall reactant used, intermediate formation, overall product formed, native state of enzyme regenerated, intermediate terminated

References

  1. Bahnson BJ et al. (2002), Biochemistry, 41, 2621-2629. Structural Mechanism of Enoyl-CoA Hydratase:  Three Atoms from a Single Water Are Added in either an E1cb Stepwise or Concerted Fashion†,‡. DOI:10.1021/bi015844p. PMID:11851409.
  2. Zhang Y et al. (2017), 75, 494-. Theoretical Insight into the Catalytic Mechanism of Enoyl-CoA Hydratase. DOI:10.6023/A16100559.
  3. Engel CK et al. (1998), J Mol Biol, 275, 847-859. The crystal structure of enoyl-CoA hydratase complexed with octanoyl-CoA reveals the structural adaptations required for binding of a long chain fatty acid-CoA molecule. DOI:10.1006/jmbi.1997.1491. PMID:9480773.

Step 1. Glu164 deprotonates the catalytic water, which adds to the C3 of the substrate.

Download: Image, Marvin File

Catalytic Residues Roles

Residue Roles
Glu164(132)A hydrogen bond acceptor
Glu144(112)A hydrogen bond acceptor, increase basicity
Gly141(109)A (main-N) activator, electrostatic stabiliser
Ala98(66)A (main-N) activator, electrostatic stabiliser
Glu164(132)A proton acceptor

Chemical Components

proton transfer, ingold: bimolecular nucleophilic addition, overall reactant used, intermediate formation

Step 2. The intermediate collapses and the C2 of the substrate deprotonates Glu164.

Download: Image, Marvin File

Catalytic Residues Roles

Residue Roles
Glu164(132)A hydrogen bond donor
Glu144(112)A hydrogen bond acceptor
Gly141(109)A (main-N) activator, electrostatic stabiliser
Ala98(66)A (main-N) activator, electrostatic stabiliser
Glu164(132)A proton donor

Chemical Components

proton transfer, overall product formed, native state of enzyme regenerated, intermediate terminated
Download: Image, Marvin File

Step 1. Glu164 deprotonates the catalytic water, which adds to the C3 of the substrate.

Step 2. The intermediate collapses and the C2 of the substrate deprotonates Glu164.

Products.

Contributors

Gemma L. Holliday, James W. Murray, Craig Porter, James Willey