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ENZYME entry: EC

Accepted Name
(R)-2-hydroxyacyl-CoA dehydratase activating ATPase.
Alternative Name(s)
(R)-2-hydroxyacyl-CoA dehydratase activase.
Reaction catalysed
2 ATP + a reduced flavodoxin + an inactive (R)-2-hydroxyacyl-CoA dehydratase + 2 H(2)O <=> 2 ADP + 2 phosphate + a flavodoxin semiquinone + an active (R)-2-hydroxyacyl-CoA dehydratase
  • Members of the (R)-2-hydroxyacyl-CoA dehydratase family (including EC, EC, EC and EC are two- component systems composed of an activator component and a dehydratase component.
  • The activator is an extremely oxygen-sensitive homodimer with one [4Fe-4S] cluster bound at the dimer interface.
  • Before it can catalyze the dehydration reaction, the dehydratase requires one high-energy electron that is used to transiently reduce the electrophilic thiol ester carbonyl to a nucleophilic ketyl radical anion, facilitating the elimination of the hydroxyl group.
  • The activator, which has been named archerase because its open position resembles an archer shooting arrows, binds two ADP molecules.
  • Upon the reduction of its [4Fe-4S] cluster by a single electron, delivered by a dedicated flavodoxin or a clostridial ferredoxin, the two ADP molecules exchange for two ATP molecules, resulting in a large conformational change.
  • The change allows the activator to bind to the dehydratase component and transfer the electron to it, activating it.
  • During this event the two ATP molecules are hydrolyzed and the activator returns to its resting state.
  • Since the electron is regenerated at the end of each reaction cycle of the dehydratase, the activation is required only once, before the first reaction takes place.
PRIAM enzyme-specific profiles5.6.1.9
KEGG Ligand Database for Enzyme Nomenclature5.6.1.9
IUBMB Enzyme Nomenclature5.6.1.9
MEDLINEFind literature relating to
Rhea expert-curated reactions5.6.1.9

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