title: Enzymatic activity, protein expression, and gene sequence of cruzipain in virulent and attenuated Trypanosoma cruzi strains.
abstract: Protein expression, characterized in Western blots and gelatinolytic activity, of cruzipain (Cr), the major Trypanosoma cruzi cysteine proteinase, was compared among 3 attenuated T. cruzi strains (TUL 0, TCC, and Y null) and their virulent counterparts (TUL 2, Tulahuen, and Y). All attenuated strains displayed a weaker gelatinolytic activity as compared with their virulent counterparts. The electrophoretic mobility and immunological reactivity revealed quantitative and qualitative differences, with the attenuated parasites showing bands of less density in all strains and lower mobility in 2 of them, as compared with the virulent strains. Sequence analysis of 1 Cr gene in the Tulahuen and TCC strains indicated 37/1404 base pair substitutions, corresponding to 20 amino acid changes in the attenuated strain. A similar comparative analysis of 1 Cr gene between Y and Y null strains showed 13/1404 base pair substitutions, corresponding to 8 amino acid changes in the attenuated strain. Although enough variability exists in the Cr gene to allow for less- or nonfunctional isoforms of the protein, further clones should be analyzed to establish whether attenuation is regularly associated with specific sequence changes of this enzyme.
authors.affiliation: Instituto de Investigaciones Biotecnológicas, Universidad de San Martin, INTI, Provincia de Buenos Aires, Argentina.
authors.forename: V G
authors.initials: VG
authors.lastname: Duschak
authors.forename: M
authors.initials: M
authors.lastname: Ciaccio
authors.forename: J R
authors.initials: JR
authors.lastname: Nassert
authors.forename: M A
authors.initials: MA
authors.lastname: Basombrio
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D003546:Cysteine Endopeptidases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005780:Gelatin / Q000378:metabolism; D017125:Genes, Protozoan; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D015800:Protozoan Proteins; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014349:Trypanosoma cruzi / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity; D014774:Virulence
chemical_list: D015800:Protozoan Proteins; D005780:Gelatin; D003546:Cysteine Endopeptidases; C063214:cruzipain