Chemical diversity enhances interaction between an X-Aptamer and its target. Numerous modifications have been incorporated in X-Aptamer bead-based libraries, including:
Several are especially effective:
- Phosphorodithioate (PS2)
- Indole-dU (tryptophan functionality)
- Phenol-dU (tyrosine functionality)
To demonstrate how well these chemical modifications improve interaction with targets, AM Biotech selected several well characterized aptamers from some respected scientific journals and synthesized variants that contain the modifications used in X-Aptamers. The results were stunning. With just one or two modifications included in the aptamer sequences, binding affinity improved by as much as 1000X (from nanomolar to picomolar) without impacting specificity.
You can purchase the phosphoramidites used to synthesize PS2 DNA, PS2 RNA TBDMS, and PS2 2’-OMe oligonucleotides from AM Biotech or from Glen Research.