Ligand Binding by the Cocaine-Binding Aptamer
Professor, Department of Chemistry
York University, Toronto
Wednesday, November 21, 2018
C2-361 (Reading Room)
Abstract: The cocaine-binding DNA aptamer is one of the most commonly studied aptamers and many researchers employ it as a model system for biosensor development. Despite being such a well-studied molecule, little was known about how this molecule functions. We have used isothermal titration calorimetry (ITC) and NMR spectroscopy to study the structure and binding mechanism of the cocaine-binding aptamer. We have shown that this aptamer binds quinine and quinine-based anti-malarial compounds tighter than cocaine and that this aptamer can bind two copies of its ligand in solution conditions of low concentrations of NaCl. We have also used NMR-based imino proton exchange rate measurement to see how the dynamics in the molecule change with ligand binding. This work demonstrates that in vitro selected biomolecules can have functions as complex as those found in nature.
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