  The dynamical characterization of proteins is crucial to understand protein
function. From a microscopic point of view, protein dynamics is governed by the
local atomic interactions that, in turn, trigger the functional conformational
changes. Unfortunately, the relationship between local atomic fluctuations and
global protein rearrangements is still elusive. Here, atomistic molecular
dynamics simulations in conjunction with complex network analysis show that
fast peptide relaxations effectively build the backbone of the global
free-energy landscape, providing a connection between local and global atomic
rearrangements. A minimum-spanning-tree representation, built on the base of
transition gradients networks, results in a high resolution mapping of the
system dynamics and thermodynamics without requiring any a priori knowledge of
the relevant degrees of freedom. These results suggest the presence of a local
mechanism for the high communication efficiency generally observed in complex
systems.
