Trypanosoma cruzi arginine kinase characterization and cloning: a novel energetic pathway in protozoan parasites.

PEREIRA, CA; ALONSO, GUILLERMO; PAVETO, CRISTINA; IRIBARREN, ADOLFO; LAURA CABANAS,; TORRES, HECTOR; FLAWIA, MIRTHA

JOURNAL OF BIOLOGICAL CHEMISTRY

Lugar: Estados Unidos; Año: 2000 vol. 275 p. 1495 - 1501

0021-9258

This work contains the first description of a guanidinokinase in a flagellar unicellular parasite. Theenzyme phosphorylates L-arginine and was characterizedin preparations from Trypanosoma cruzi, the ethiologicalagent of Chagas’ disease. The activity requiresATP and a divalent cation. Under standard assay conditions(1 mM L-arginine), the presence of 5-fold higherconcentrations of canavanine or histidine produced agreater than 50% enzyme inhibition. The base sequenceof this enzyme revealed an open reading frame of 357amino acids and a molecular weight of 40,201. The aminoacid sequence shows all of the characteristic consensusblocks of the ATP:guanidino phosphotransferase familyand a putative “actinin-type” actin-binding domain. Thehighest amino acid identities of the T. cruzi sequence,about 70%, were with arginine kinases from Arthropoda.Southern and chromosome blots revealed that the kinaseis encoded by a single-copy gene. Moreover, Northernblot analysis showed an mRNA subpopulation ofabout 2.0 kilobases, and Western blotting of T. cruzisolublepolypeptides revealed a 40-kDa band. The findingin the parasite of a phosphagen and its biosyntheticpathway, which are totally different from those in mammalianhost tissues, points out this arginine kinase as apossible chemotherapy target for Chagas’ disease.