N-terminal ACT domain of the Escherichia coli IlvH-like regulatory subunit of acetohydroxyacid synthase (AHAS)
ACT_AHAS: N-terminal ACT domain of the Escherichia coli IlvH-like regulatory subunit of acetohydroxyacid synthase (AHAS). AHAS catalyses the first common step in the biosynthesis of the three branched-chain amino acids. The first step involves the condensation of either pyruvate or 2-ketobutyrate with the two-carbon hydroxyethyl fragment derived from another pyruvate molecule, covalently bound to the coenzyme thiamine diphosphate. Bacterial AHASs generally consist of regulatory and catalytic subunits. The effector (valine) binding sites are proposed to be located in two symmetrically related positions in the interface between a pair of N-terminal ACT domains with the C-terminal domain of IlvH contacting the catalytic dimer. Plants Arabidopsis and Oryza have tandem IlvH subunits; both the first and second ACT domain sequences are present in this CD. Members of this CD belong to the superfamily of ACT regulatory domains.
Feature 1:putative valine binding site [chemical binding site]
Evidence:
Comment:based on similarity to 3PGDH and properties of mutants, the effector (valine) binding sites are proposed to be located in two symmetrically related positions in the interface between a pair of ACT domains.
Jiyao W et al.(2023). "The conserved domain database in 2023.",