  Polymer translocation through a nanometer-scale pore assisted by chaperones
binding to the polymer is a process encountered in vivo for proteins. Studying
the relevant models by computer simulations is computationally demanding.
Accordingly, previous studies are either for stiff polymers in three dimensions
or flexible polymers in two dimensions. Here, we study chaperone-assisted
translocation of flexible polymers in three dimensions using Langevin dynamics.
We show that differences in binding mechanisms, more specifically, whether a
chaperone can bind to a single or multiple sites on the polymer, lead to
substantial differences in translocation dynamics in three dimensions. We show
that the single-binding mode leads to dynamics that is very much like that in
the constant-force driven translocation and accordingly mainly determined by
tension propagation on the cis side. We obtain $\beta \approx 1.26$ for the
exponent for the scaling of the translocation time with polymer length. This
fairly low value can be explained by the additional friction due to binding
particles. The multiple-site binding leads to translocation whose dynamics is
mainly determined by the trans side. For this process we obtain $\beta \approx
1.36$. This value can be explained by our derivation of $\beta = 4/3$ for
constant-bias translocation, where translocated polymer segments form a globule
on the trans side. Our results pave the way for understanding and utilizing
chaperone-assisted translocation where variations in microscopic details lead
to rich variations in the emerging dynamics.
