Weak Binding of Levamisole by the Cocaine-Binding Aptamer Does Not Interfere with an Aptamer-Based Detection Assay.

ABSTRACT: Levamisole is a common and harmful adulterant of street samples of cocaine and can cause electrochemical tests for cocaine to give false negative results. To see if levamisole would interfere with aptamer-based bioassays, we analyzed the binding of levamisole to the cocaine-binding DNA aptamer. At low aptamer concentrations (0.5 to 20 μM) using isothermal titration calorimetry methods and thermal stability measurements, no binding of levamisole to the cocaine-binding aptamer was observed. At higher levamisole concentrations (500 μM), weak binding to the cocaine-binding aptamer was detected using nuclear magnetic resonance (NMR) spectroscopy chemical shift perturbations. NMR-detected titrations show that levamisole binding is competitive with cocaine binding, indicating that both ligands sh

SUBMITTER: Shoara AA 

PROVIDER: S-EPMC8459413 | biostudies-literature | 2021 Sep

REPOSITORIES: biostudies-literature