FGGY carbohydrate kinases carry out ATP-dependent phosphorylation on one out of at least nine distinct sugar substrates []. These enzymes include L-ribulokinase () (gene araB); Erythriol kinase () (gene eryA); L-fucolokinase () (gene fucK); gluconokinase () (gene gntK); glycerol kinase () (gene glpK); xylulokinase () (gene xylB); L-xylulose kinase () (gene lyxK), D-ribulokinase () (gene rbtK); and rhamnulokinase () (gene rhaB). This family also contains a divergent subfamily functioning in quorum sensing, which phosphorylates AI-2, a bacterial signaling molecule derived from 4,5-dihydroxy-2,3-pentanedione (DPD) [].
This entry represents a subfamily of the FGGY family of carbohydrate kinases, including FGGY carbohydrate kinase domain-containing proteins from mammals and D-ribulokinase YDR109C from S. cerevisiae, which catalyse ATP-dependent phosphorylation of D-ribulose at C-5 to form D-ribulose 5-phosphate []. These proteins may function in a metabolite repair mechanism by preventing toxic accumulation of free D-ribulose formed by non-specific phosphatase activities, and may also play a role in regulating D-ribulose 5-phosphate recycling in the pentose phosphate pathway.This subfamily is closely related to a set of ribulose kinases, and many members are designated ribitol kinase. However, the member from Klebsiella pneumoniae, rbtK, from a ribitol catabolism operon, accepts D-ribulose and to a lesser extent D-arabinitol and ribitol [].
This entry includes a group of metazoan putative glycerol kinases (GK), which may be coded by the GK-like gene, GK5. Sequence comparison shows members of this group are homologues of bacterial GKs, and they retain all functionally important residues. However, GK-like proteins in this family do not have detectable GK activity. The reason remains unclear. It has been suggested that the conserved catalytic residues might facilitate them performing a distinct function. GKs 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 entry is composed of a group of putative bacterial L-ribulokinases (RBK; ) and similar proteins. L-RBK catalyzes the MgATP-dependent phosphorylation of a variety of sugar substrates. Members of this subfamily belong to the FGGY family of carbohydrate kinases.
Proteins in this entry are L-fuculokinases including the Escherichia coli enzyme []. They catalyse the second step in fucose catabolism and belong to the FGGY family of carbohydrate kinases. These enzymes are encoded by the kinase (K) gene of the fucose (fuc) operon.
Sedoheptulokinase (SHK, also known as D-altro-heptulose or heptulokinase, ) catalyzes the ATP-dependent phosphorylation of sedoheptulose to produce sedoheptulose 7-phosphate and ADP []. In mammals, it acts as a modulator of macrophage activation through control of glucose metabolism []. It belongs to the FGGY kinase family.
FGGY carbohydrate kinases carry out ATP-dependent phosphorylation on one out of at least nine distinct sugar substrates []. These enzymes include L-ribulokinase () (gene araB); Erythriol kinase () (gene eryA); L-fucolokinase () (gene fucK); gluconokinase () (gene gntK); glycerol kinase () (gene glpK); xylulokinase () (gene xylB); L-xylulose kinase () (gene lyxK), D-ribulokinase () (gene rbtK); and rhamnulokinase () (gene rhaB). This family also contains a divergent subfamily functioning in quorum sensing, which phosphorylates AI-2, a bacterial signaling molecule derived from 4,5-dihydroxy-2,3-pentanedione (DPD) [].This entry represents conserved regions found in the central and C-terminal regions of these enzymes.
This family of proteins includes thermoresistant and thermosensitve isozymes of gluconate kinase (gluconokinase) in E. coli and other related proteins; members of this family are often named by similarity to the thermostable isozyme. These proteins show homology to shikimate kinases and adenylate kinases but not to gluconate kinases from the FGGY family of carbohydrate kinases. The structure of the E. coli thermoresistant gluconate kinase GntK has been revealed []. GntK catalyzes the phosphoryl transfer from ATP to gluconate. The resulting product gluconate-6-phoshate is an important precursor of gluconate metabolism. GntK acts as a dimmer composed of two identical subunits [, ].
FGGY carbohydrate kinases carry out ATP-dependent phosphorylation on one out of at least nine distinct sugar substrates []. These enzymes include L-ribulokinase () (gene araB); Erythriol kinase () (gene eryA); L-fucolokinase () (gene fucK); gluconokinase () (gene gntK); glycerol kinase () (gene glpK); xylulokinase () (gene xylB); L-xylulose kinase () (gene lyxK), D-ribulokinase () (gene rbtK); and rhamnulokinase () (gene rhaB). This family also contains a divergent subfamily functioning in quorum sensing, which phosphorylates AI-2, a bacterial signaling molecule derived from 4,5-dihydroxy-2,3-pentanedione (DPD) [].This entry represents the N-terminal domain of these proteins. It adopts a ribonuclease H-like fold and is structurally related to the C-terminal domain [, ].All described members of this enzyme family are composed of two homologous actin-like ATPase domains. A catalytic cleft is formed by the interface between these two domains, where the sugar substrate and ATP co-substrate bind.
FGGY carbohydrate kinases carry out ATP-dependent phosphorylation on one out of at least nine distinct sugar substrates []. These enzymes include L-ribulokinase () (gene araB); Erythriol kinase () (gene eryA); L-fucolokinase () (gene fucK); gluconokinase () (gene gntK); glycerol kinase () (gene glpK); xylulokinase () (gene xylB); L-xylulose kinase () (gene lyxK), D-ribulokinase () (gene rbtK); and rhamnulokinase () (gene rhaB). This family also contains a divergent subfamily functioning in quorum sensing, which phosphorylates AI-2, a bacterial signaling molecule derived from 4,5-dihydroxy-2,3-pentanedione (DPD) [].All described members of this enzyme family are composed of two homologous actin-like ATPase domains. A catalytic cleft is formed by the interface between these two domains, where the sugar substrate and ATP co-substrate bind.This entry represents the C-terminal domain of these proteins. It adopts a ribonuclease H-like fold and is structurally related to the N-terminal domain [, ].
This entry corresponds to a group of metazoan glycerol kinases (GKs), coded by X chromosome-linked GK genes, and glycerol kinase (GK)-like proteins, coded by autosomal testis-specific GK-like genes GK2, GK3 and Gykl1 (in mouse). These are thought to have arise by the transposition of Gk located on the Xchromosome []. Sequence comparison shows that metazoan GKs and GK-like proteins in this family are closely related to the bacterial GKs, which catalyze the Mg-ATP dependent phosphorylation of glycerol to yield glycerol 3-phosphate (G3P). The metazoan GKs do have GK enzymatic activity. However, the GK-like metazoan proteins do not exhibit GK activity and their biological functions are not yet clear []. Some of them lack important functional residues involved in the binding of ADP and Mg2+, which may result in the loss of GK catalytic function. Others that have conserved catalytic residues have lost their GK activity as well; the reason remains unclear. It has been suggested the conserved catalytic residues might facilitate them performing a distinct function. GK2 seem to be necessary for the formation of the mitochondrial sheath during spermatogenesis [, ].GKs 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 [].
