Passage times for polymer translocation pulled through a narrow pore

Abstract

We study the passage times of a translocating polymer of length N in three dimensions, while it is pulled through a narrow pore with a constant force F applied to one end of the polymer. At small to moderate forces, satisfying the condition FNv/kBT≳ 1, where v ≈ 0.588 is the Flory exponent for the polymer, we find that N, the mean time the polymer takes to leave the pore, scales as N2+v independent of F, in agreement with our earlier result for F = 0. At strong forces, i.e., for, FNv/kBT≫ 1, the behavior of the passage time crosses over to N ∼ N2/F. We show here that these behaviors stem from the polymer dynamics at the immediate vicinity of the pore-in particular, the memory effects in the polymer chain tension imbalance across the pore. © 2008 by the Biophysical Society.