Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
TreeGrafter-generated GO annotations
Combined Automated Annotation using Multiple IEA Methods
Role of 4-hydroxybutyrate-CoA synthetase in the CO2 fixation cycle in thermoacidophilic archaea.
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Recombinant Msed_0406 and its paralog Msed_0394 both ligate CoA to 4-hydroxybutyrate, with similar Km but an eightfold difference in rate.
"Recombinant versions of these enzymes catalyzed the ligation of CoA to 4HB"
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Msed_0406 is judged the physiologically relevant 4HB-CoA ligase of the cycle.
"Conclusion: Msed_0406 is likely the physiologically relevant enzyme in the cycle."
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In vitro, propionate is the best substrate and 4HB the poorest by kcat/Km; the enzyme is a promiscuous short-chain acid ligase.
"It appears that Msed_0406 is primarily a promiscuous propionate-CoA synthetase."
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The substrate range does not extend beyond C5 acids.
"Both Msed_0394 and Msed_0406 were found to have activity on a broad range of small organic acid substrates of up to five carbons in length."
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Whether both paralogs are needed for autotrophy is unknown.
"It is not clear why two synthetases would be required, or whether both of them are necessary for autotrophic growth."
Conversion of 4-hydroxybutyrate to acetyl coenzyme A and its anapleurosis in the Metallosphaera sedula 3-hydroxypropionate/4-hydroxybutyrate carbon fixation pathway.
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Msed_0406, with the dehydratase, the bifunctional hydratase/dehydrogenase and the thiolase, converts 4HB to acetyl-CoA in vitro.
"were produced recombinantly in Escherichia coli , combined in vitro , and shown to convert 4HB to acetyl-CoA"
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The paralog Msed_0394 is unlikely to contribute significantly to the cycle.
"Given the kinetic properties of the other enzymes of the pathway, it is unlikely that Msed_0394 plays a significant role in the cycle."
A 3-hydroxypropionate/4-hydroxybutyrate autotrophic carbon dioxide assimilation pathway in Archaea.
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Defines the 3HP/4HB cycle in M. sedula, in which 4HB is converted to two acetyl-CoA.
"This intermediate was reduced to 4-hydroxybutyrate and converted into two acetyl-CoA molecules via 4-hydroxybutyryl-CoA dehydratase."
UniProt record A4YDT1 (HBCL1_METS5)