Biochemical adaptations of two sugar kinases from the hyperthermophilic archaeon Pyrococcus furiosus.
The hyperthermophilic archaeon Pyrococcus furiosus possesses a modified Embden-Meyerhof pathway, including an unusual ADP-dependent glucokinase (ADP-GLK) and an ADP-dependent phosphofructokinase. In the present study, we report the characterization of a P. furiosus galactokinase (GALK) and its comparison with the P. furiosus ADP-GLK. The pyrococcal genes encoding the ADP-GLK and GALK were functionally expressed in Escherichia coli, and the proteins were subsequently purified to homogeneity. Both enzymes are specific kinases with an optimal activity at approx. 90 degrees C. Biochemical characterization of these enzymes confirmed that the ADP-GLK is unable to use ATP as the phosphoryl group donor, but revealed that GALK is ATP-dependent and has an extremely high affinity for ATP. There is a discussion about whether the unusual features of these two classes of kinases might reflect adaptations to a relatively low intracellular ATP concentration in the hyperthermophilic archaeon P. furiosus.
Verhees
Corné H
CH
Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, The Netherlands. corne.verhees@algemeen.micr.wau.nl
Koot
Denise G M
DG
Ettema
Thijs J G
TJ
Dijkema
Cor
C
de Vos
Willem M
WM
van der Oost
John
J
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D001669:Biochemical Phenomena; D001671:Biochemistry; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000378:metabolism; D005686:Galactokinase / Q000737:chemistry*; D005941:Glucokinase / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D020027:Pyrococcus furiosus / Q000201:enzymology*; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013696:Temperature
D000255:Adenosine Triphosphate; C420842:ADP-dependent glucokinase; D005941:Glucokinase; D005686:Galactokinase