R13 peptide (EEEDDDMGFGLFD, representing the C-terminal region of TcP2β) was synthesized by the solid-phase method of Merrifield. This peptide corresponds to the C-terminal region of Trypanosoma cruzi ribosomal P1 and P2 proteins (EEEDDDMGFGLFD), a sequence that differs from the other eukariotic P consensus sequence (EESDDDMGFGLFD) only in a nonconservative amino acid substitution.