DNA abasic (AP) sites are one of the most frequent lesions in the genome and have a high mutagenic potential if unrepaired. After selective attachment of 2-aminomethyl-18-crown-6 (18c6), individual AP lesions are detected during electrophoretic translocation through the bacterial protein ion channel α-hemolysin (α-HL) embedded in a lipid bilayer. Interactions between 18c6 and Na+produce characteristic pulse-like current amplitude signatures that allow the identification of individual AP sites in single molecules of homopolymeric or heteropolymeric DNA sequences. The bulky 18c6-cation complexes also dramatically slow the DNA motion to more easily recordable levels. Further, the behaviors of the AP-18c6 adduct are different with respect to the directionalities of DNA entering the protein channel, and they can be precisely manipulated by altering the cation (Li+, Na+ or K+) of the electrolyte. This method permits detection of multiple AP lesions per strand, which is unprecedented in other work. Additionally, insights into the thermodynamics and kinetics of 18c6-cation interactions at a singlemolecule level are provided by the nanopore measurement.
CITATION STYLE
An, N., Fleming, A. M., White, H. S., & Burrows, C. J. (2012). Crown ether-electrolyte interactions permit nanopore detection of individual DNA abasic sites in single molecules. Proceedings of the National Academy of Sciences of the United States of America, 109(29), 11504–11509. https://doi.org/10.1073/pnas.1201669109
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