  With the help of force spectroscopy, several analytical theories aim at
estimating the rate coefficient of folding for various proteins. Nevertheless,
a chief bottleneck lies in the fact that there is still no perfect consensus on
how does a force generally perturb the crystal-coil transition. Consequently,
the goal of our work is in clarifying the generic behavior of most proteins in
force spectroscopy; in other words, what general signature does an arbitrary
protein exhibit for its rate coefficient as a function of the applied force? By
employing a biomimetic polymer in molecular simulations, we focus on evaluating
its respective activation energy for unfolding, while pulling on various pairs
of its monomers. Above all, we find that in the vicinity of the force-free
scenario, this activation energy possesses a negative slope and a negative
curvature as a function of the applied force. Our work is in line with the most
recent theories for unfolding, which suggest that such a signature is expected
for most proteins, and thus, we further reiterate that many of the classical
formulae, that estimate the rate coefficient of the crystal-coil transition,
are inadequate. Besides, we also present here an analytical expression which
experimentalists can use for approximating the activation energy for unfolding;
importantly, it is based on measurements for the mean and variance of the
distance between the beads which are being pulled. In summary, our work
presents an interesting view for protein folding in force spectroscopy.
