Gene Ontology annotation through association of InterPro records with GO terms

Gene Ontology annotation based on Enzyme Commission mapping

Combined Automated Annotation using Multiple IEA Methods

Enzymes Catalyzing Crotonyl-CoA Conversion to Acetoacetyl-CoA During the Autotrophic CO(2) Fixation in Metallosphaera sedula.

Purified recombinant Msed_1423 oxidises (S)-3-hydroxybutyryl-CoA to acetoacetyl-CoA with NAD+, with a Km of 5 uM for the substrate.

"The purified recombinant Msed_0389 and Msed_1423 catalyzed the NAD-dependent oxidation of (S)-3-hydroxybutyryl-CoA to acetoacetyl-CoA and were highly specific for their substrate (Km 2.6 and 5 μM, respectively; Table 3)."
Msed_1423 is inactive with the C8 substrate (S)-3-hydroxyoctanoyl-CoA.

"Both enzymes were not active with (S)-3-hydroxyoctanoyl-CoA."
Its catalytic efficiency is about 20-fold higher than that of Msed_0399.

"Their kcat/Km values were 3- and 20-fold higher than the corresponding value of Msed_0399 in (S)-3-hydroxybutyryl-CoA dehydrogenase reaction (Table 3)."
The gene clusters with specific HP/HB-cycle genes (Msed_1424, Msed_1426).

"This protein is clustered together with two specific enzymes of the HP/HB cycle, succinic semialdehyde reductase Msed_1424 and acryloyl-CoA reductase Msed_1426 (Figure 2B), further supporting its involvement in autotrophic CO2 fixation."
Msed_1423 homologs are (almost) universal in Sulfolobales and absent only from the heterotroph S. acidocaldarius.

"The only two genes that are (almost) universally distributed in Sulfolobales are the crotonase Msed_0566 gene and the dehydrogenase Msed_1423 gene"
Msed_1423 is the main (S)-3-hydroxybutyryl-CoA dehydrogenase of the cycle.

"show that Msed_1423 is the main (S)-3-hydroxybutyryl-CoA dehydrogenase in the HP/HB cycle in Sulfolobales."
Msed_1423 is estimated at about 1.7% of total cellular protein.

"Comparison of the activities of the characterized (S)-3-hydroxybutyryl-CoA dehydrogenase Msed_1423 and crotonase Msed_0384 with the activities of these reactions in cell extract of M. sedula leads to the values 1.7 and 7.1% of total cellular protein, respectively."

PMID:33472982

Convergent Evolution of a Promiscuous 3-Hydroxypropionyl-CoA Dehydratase/Crotonyl-CoA Hydratase in Crenarchaeota and Thaumarchaeota.

Follow-up paper restating that Msed_1423 carries the main (S)-3-hydroxybutyryl-CoA dehydrogenase flux in M. sedula.

"in M. sedula, the (S)-3-hydroxybutyryl-CoA dehydrogenase reaction is primarily catalyzed by Msed_1423 (which is universally found in autotrophic Sulfolobales)"

PMID:34290692

(S)-3-Hydroxybutyryl-CoA Dehydrogenase From the Autotrophic 3-Hydroxypropionate/4-Hydroxybutyrate Cycle in Nitrosopumilus maritimus.

Compares Msed_1423 with the thaumarchaeal enzyme Nmar_1028; Msed_1423 has the highest Vmax and lowest Km among the characterised M. sedula enzymes.

"Msed_1423 is the main (S)-3-hydroxybutyryl-CoA dehydrogenase in M. sedula with the highest Vmax value (96 U mg–1 protein) and the lowest Km value (5 μM) to its substrate (Table 3)."
Msed_1423, Nmar_1028 and the Msed_0399 dehydrogenase domain are homologous but are proposed to have been recruited independently.

"It appears that despite their homology, these three proteins evolved independently from each other, confirming the proposed convergent evolution of HP/HB cycle in Cren- and Thaumarchaeota."

PMID:18079405

A 3-hydroxypropionate/4-hydroxybutyrate autotrophic carbon dioxide assimilation pathway in Archaea.

Defines the 3HP/4HB cycle, in which 4-hydroxybutyrate is converted to two acetyl-CoA.

"converted into two acetyl-CoA molecules via 4-hydroxybutyryl-CoA dehydratase."

file:METS5/Msed_1423/Msed_1423-uniprot.txt

UniProt entry A4YGM9

Domain architecture is one NAD-binding domain and two 3-hydroxyacyl-CoA dehydrogenase C-terminal domains, with no enoyl-CoA hydratase domain.

"3-hydroxyacyl-CoA dehydrogenase C-terminal"