Secondary structures formed by single-stranded DNA aptamers can allow for the binding of small-molecule ligands. Some of these secondary structures are highly stable in solution and are great candidates for use in the development of biosensors for disease markers, environmental impact, and many other applications. In this research, we explored these unique properties of aptamers in developing a fluorescence-based biosensor for ATP (adenosine triphosphate) and related small molecules. The effectiveness of the biosensor was determined by measuring the binding affinity and specificity of the ATP biosensor on a molecular level, towards different, but structurally similar, ligands. We observed strong and similar binding affinity towards ATP and ATP analogs with Kd range (73-347 µM). However, when probed against other deoxyribonucleotide triphosphates (dNTPs), little to no binding was observed indicating the biosensor specifically targets only ATP analogs. The ATP aptamer sequence can also form noncanonical G4 secondary structure depending on the solution conditions. We investigated the involvement of the G-quartets in the aptamer sequence in ligand binding and found that both G-quartets contribute to ligand binding.
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Edwards, Aleah N. and Yangyuoru, Philip, "Development of a Nucleic Acid Based Fluorescence ATP Biosensor" (2022). Celebration of Student Scholarship. 35.