nucleotide-binding domain (NBD) of sedoheptulokinase (SHK) and similar proteins
SHK (EC 2.7.1.14), also called heptulokinase, or carbohydrate kinase-like protein (CARKL), is encoded by the carbohydrate kinase-like (CARKL/SHPK) gene. It acts as a modulator of macrophage activation through control of glucose metabolism. SHK catalyzes the ATP-dependent phosphorylation of sedoheptulose to produce sedoheptulose 7-phosphate and ADP. The presence of Mg2+ or Mn2+ might be required for catalytic activity. Members of this subfamily belong to the FGGY family of carbohydrate kinases, the monomers of which contain two large domains, which are separated by a deep cleft that forms the active site. This model includes both the N-terminal domain, which adopts a ribonuclease H-like fold, and the structurally related C-terminal domain.
Comment:catalytic residues (Asp, Thr, Asp) conserved in the FGGY family
Comment:Two Asp residues probably form a metal cofactor binding site and the second Asp residue acts as a catalytic base.
Comment:It has been proposed that the first Asp coordinates and positions the MgATP, and (in concert with the Mg2+) stabilizes the ADP leaving group during the phospho transfer. The second Asp would act as a general base during catalysis, assisting the removal of a proton from the attacking hydroxyl group. The Thr could stabilize the transition state.
Jiyao W et al.(2023). "The conserved domain database in 2023.",