  Using an Ising-like model of protein mechanical unfolding, we introduce a
diffusive dynamics on its exactly known free energy profile, reducing the
nonequilibrium dynamics of the model to a biased random walk. As an
illustration, the model is then applied to the protein translocation
phenomenon, taking inspiration from a recent experiment on the green
fluorescent protein pulled by a molecular motor. The average translocation time
is evaluated exactly, and the analysis of single trajectories shows that
translocation proceeds through an intermediate state, similar to that observed
in the experiment.
