Figure 4. Binding of Apt68 is specific to T. cruzi and not to other related parasites, T. brucei and L. donovani.

³²P-GTP labeled Apt68 was used in binding assays as in Figure 2. Apt68 is highly specific for the mammalian stage of the parasite and showed dose depended saturable binding compared to T. brucei blood stream form (A). Apt68 also did not interact significantly with L. donovani promastigotes (B). Each data point represents triplicate values and the error bars represent the standard deviation. As Apt68 did not show significant binding to the L. donovani and T. brucei parasites, above that of the scrambled aptamer, Bmax and Kd could not be calculated.