Protein geranylgeranyltransferase-I of Trypanosoma cruzi.

摘要: Protein geranylgeranyltransferase type I (PGGT-I) and protein farnesyltransferase (PFT) occur in many eukaryotic cells. Both consist of two subunits, the common alpha subunit a distinct beta subunit. In gene database protozoa Trypanosoma cruzi, causative agent Chagas' disease, putative that consists 401 amino acids with approximately 20% acid sequence identity to PGGT-I other species was identified, cloned, characterized. Multiple alignments show T. cruzi ortholog contains all three zinc-binding residues several uniquely conserved PGGT-I. Co-expression this PFT Sf9 insect cells yielded dimeric forms tight complex selectively [(3)H]geranylgeranyl pyrophosphate, indicating key characteristic functional Recombinant showed activity specificity toward C-terminal CaaX motif substrates compared mammalian PFT. Most CaaX-containing proteins X=Leu are good PGGT-I, those X=Met for both whereas unlike X=Phe poor Several candidates or containing found database. Among five peptides tested, peptide Ras-like ending CVLL geranylgeranylated by Other CTQQ (Tcj2 DNAJ protein), CAVM (TcPRL-1 tyrosine phosphatase), CHFM (a small GTPase like CQLF (TcRho1 GTPase) were specific but not The mRNA detected life-cycle stages cruzi. Cytosol fractions from trypomastigotes (infectious stage) epimastigotes (insect shown contain levels 100-fold lower than activity. mimetics known as inhibitors very low potency against enzyme, suggesting potential develop selective parasite enzyme.