Virgile Viasnoff

Viasnoff et al JPCM 22 454122 2010

We experimentally study the statistical distributions and the voltage dependence of the
unzipping time of 45 base-pair-long double-stranded DNA through a nanopore. We then
propose a quantitative theoretical description considering the nanopore unzipping process as a
random walk of the opening fork through the DNA sequence energy landscape biased by a
time-fluctuating force. To achieve quantitative agreement fluctuations need to be correlated over
the millisecond range and have an amplitude of order kBT/bp. Significantly slower or faster
fluctuations are not appropriate, suggesting that the unzipping process is efficiently enhanced by
noise in the kHz range. We further show that the unzipping time of short 15 base-pair hairpins
does not always increase with the global stability of the double helix and we theoretically study
the role of DNA elasticity on the conversion of the electrical bias into a mechanical unzipping
force.