Identification and characterization of two arginine kinases from the parasitic insect Ctenocephalides felis.
Arginine kinase (ATP:l-arginine omega-N-phosphotransferase, EC2.7.3.3.; AK) is an enzyme crucial for the energy metabolism of insects and other invertebrates, that has known allergenic potential in humans and that has been proposed as a pesticidal drug target. Here we report the identification, cDNA cloning, genomic gene structure and functional expression of AK genes from Ctenocephalides (C.) felis (cat flea). In contrast to other insect species investigated so far, C. felis possesses two AK genes, cfak1 and cfak2, encoding the functional enzymes CfAK1 and CfAK2 that can be distinguished by their guanidino substrate specificity and the kinetic parameters for their natural substrates. Molecular modelling on CfAK1 and CfAK2 based on the Limulus polyphemus AK X-ray structure (Zhou et al., 1998) and substrate docking studies provide a potential rational for the observed specificities. Evidence is provided that adult fleas express predominantly CfAK1 as an abundant soluble protein, and that in vivo in C. felis, the AK metabolites are present in concentration ranges relevant for this enzyme.
Werr
Margaret
M
Intervet Innovation GmbH, Zur Propstei, 55270 Schwabenheim, Germany.
Cramer
Jörg
J
Ilg
Thomas
T
D000595:Amino Acid Sequence; D000818:Animals; D001122:Arginine Kinase / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D002371:Cat Diseases / Q000469:parasitology*; D002415:Cats; D003001:Cloning, Molecular; D019476:Insect Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D007313:Insecta / Q000145:classification / Q000235:genetics; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment; D005423:Siphonaptera / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity
D019476:Insect Proteins; D001122:Arginine Kinase