A galactokinase-like protein from the liver fluke Fasciola hepatica.
Exp Parasitol
; 192: 65-72, 2018 Sep.
Article
in En
| MEDLINE
| ID: mdl-30040960
ABSTRACT
Galactokinase catalyses the ATP-dependent phosphorylation of galactose. A galactokinase-like sequence was identified in a Fasciola hepatica EST library. Recombinant expression of the corresponding protein in Escherichia coli resulted in a protein of approximately 50â¯kDa. The protein is monomeric, like galactokinases from higher animals, yeasts and some bacteria. The protein has no detectable enzymatic activity with galactose or N-acetylgalactosamine as a substrate. However, it does bind to ATP. Molecular modelling predicted that the protein adopts a similar fold to galactokinase and other GHMP kinases. However, a key loop in the active site was identified which may influence the lack of activity. Sequence analysis strongly suggested that this protein (and other proteins annotated as "galactokinase" in the trematodes Schistosoma mansoni and Clonorchis sinensis) are closer to N-acetylgalactosamine kinases. No other galactokinase-like sequences appear to be present in the genomes of these three species. This raises the intriguing possibility that these (and possibly other) trematodes are unable to catabolise galactose through the Leloir pathway due to the lack of a functional galactokinase.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Fasciola hepatica
/
Galactokinase
/
Galactose
Type of study:
Prognostic_studies
Limits:
Animals
Language:
En
Journal:
Exp Parasitol
Year:
2018
Document type:
Article
Affiliation country: