  Monte Carlo simulations show that long-range interactions play a major role
in determining the folding rates of 48-mer three-dimensional lattice polymers
modelled by the Go potential. For three target structures with different native
geometries we found a sharp increase in the folding time when the relative
contribution of the long-range interactions to the native state's energy is
decreased from ~50% towards zero. However, the dispersion of the simulated
folding times depends strongly on the native geometry and Go polymers folding
to one of the target structures exhibit folding times spanning three orders of
magnitude. We have also found that, depending on the target geometry, a strong
geometric coupling may exist between local and long-range contacts meaning
that, when this coupling exists, the formation of long-range contacts is forced
by the previous formation of local contacts. The absence of a strong geometric
coupling leads to kinetics that are more sensitive to the interaction energy
parameters; in this case the formation of local contacts is not sufficient to
promote the establishment of long-range ones when these are strongly penalized
energetically, leading to longer folding times.
