InterPro domain: IPR004006

Dihydroxyacetone (Dha) kinases are a family of sequence-conserved enzymes thatphosphorylate dihydroxyacetone, glyceraldehyde and other short-chain ketosesand aldoses. They can be divided into two groups according to the source ofhigh-energy phosphate that they utilise, either ATP or phosphoenolpyruvate(PEP). The ATP-dependent forms are the two-domain Dha kinases (DAK), whichoccur in animals, plants and eubacteria. They consist of a Dha binding (K) andan ATP binding (L) domain. The PEP-dependent forms occur only in eubacteria and a few archaebacteria and consist of three subunits. Two subunits, DhaK and DhaL, are homologous to the K and L domains. Intriguingly, the ADP moiety is not exchanged for ATP but remains permanently bound to the DhaL subunit where it is rephosphorylated in situ by the third subunit, DhaM, which is homologous to the IIA domain of the mannose transporter of the bacterial PEP:sugar phosphotransferase system (PTS) [ 1 , 2 ].

The DhaK domain consists of two alpha/beta-folds, each containing a six-stranded mixed beta-sheet surrounded by six and three helices, respectively. Dha is bound in hemiaminal linkage to the imidazole nitrogen of an invariant histidine [ 3 , 4 ].

1. Crystal structure of the nucleotide-binding subunit DhaL of the Escherichia coli dihydroxyacetone kinase. J. Mol. Biol. 359, 539-45
2. X-ray structures of the three Lactococcus lactis dihydroxyacetone kinase subunits and of a transient intersubunit complex. J. Biol. Chem. 283, 35789-96
3. Crystal structure of the Citrobacter freundii dihydroxyacetone kinase reveals an eight-stranded alpha-helical barrel ATP-binding domain. J. Biol. Chem. 278, 48236-44
4. A mechanism of covalent substrate binding in the x-ray structure of subunit K of the Escherichia coli dihydroxyacetone kinase. Proc. Natl. Acad. Sci. U.S.A. 100, 8188-92