Unzipping Kinetics of Double-Stranded DNA in a Nanopore

TL;DR

This study investigates the unzipping process of double-stranded DNA in a nanopore, providing direct experimental evidence, kinetic modeling, and estimates of energetic parameters relevant to DNA translocation.

Contribution

It presents the first direct proof of DNA unzipping in a nanopore system and introduces a kinetic model to analyze unzipping times and energetic barriers.

Findings

Confirmed DNA unzipping via PCR analysis

Modeled unzipping times with a kinetic framework

Estimated enthalpy barriers and nucleotide charge

Abstract

We studied the unzipping kinetics of single molecules of double-stranded DNA by pulling one of their two strands through a narrow protein pore. PCR analysis yielded the first direct proof of DNA unzipping in such a system. The time to unzip each molecule was inferred from the ionic current signature of DNA traversal. The distribution of times to unzip under various experimental conditions fit a simple kinetic model. Using this model, we estimated the enthalpy barriers to unzipping and the effective charge of a nucleotide in the pore, which was considerably smaller than previously assumed.