Referenced in: none

Automatically associated channels: Slo1

Title: Crown ether-electrolyte interactions permit nanopore detection of individual DNA abasic sites in single molecules.

Authors: Na An, Aaron M Fleming, Henry S White, Cynthia J Burrows

Journal, date & volume: Proc. Natl. Acad. Sci. U.S.A., 2012 Jul 17 , 109, 11504-9

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/22711805

Abstract
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 single-molecule level are provided by the nanopore measurement.