Accepted Name |
(R)-2-hydroxyacyl-CoA dehydratase activating ATPase
|
Alternative Name(s) |
(R)-2-hydroxyacyl-CoA dehydratase activase |
archerase |
Reaction catalysed |
2 ATP + a reduced flavodoxin + an inactive (R)-2-hydroxyacyl-CoA dehydratase + 2 H2O = 2 ADP + 2 phosphate + a flavodoxin semiquinone + an active (R)-2-hydroxyacyl-CoA dehydratase |
Comment(s) |
- Members of the (R)-2-hydroxyacyl-CoA dehydratase family (including
EC 4.2.1.54, EC 4.2.1.157, EC 4.2.1.167 and EC 4.2.1.175) 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.
|
Cross-references |
BRENDA | 5.6.1.9 |
EC2PDB | 5.6.1.9 |
ExplorEnz | 5.6.1.9 |
PRIAM enzyme-specific profiles | 5.6.1.9 |
KEGG Ligand Database for Enzyme Nomenclature | 5.6.1.9 |
IUBMB Enzyme Nomenclature | 5.6.1.9 |
IntEnz | 5.6.1.9 |
MEDLINE | Find literature relating to 5.6.1.9 |
MetaCyc | 5.6.1.9 |
Rhea expert-curated reactions | 5.6.1.9 |
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