Figure 2. Characterization of the affinity and specificity of the CA motif aptamer using competitive column elution. (A) Elution of the CA motif aptamer from a GTP-agarose column with free GTP. (B) Elution of the CA motif aptamer from a GTP-agarose column as a function of free GTP concentration. (C) Elution of the CA motif aptamer from a GTP-agarose column in the presence of various GTP analogs. (D) Competitive column elution data mapped onto the chemical structure of GTP. The CA motif construct GG(GCAACA)₆ was used for these experiments. Values reflect the average of three independent experiments, and error bars indicate one standard deviation.