  Allosteric effects are often underlying the activity of proteins and
elucidating generic design aspects and functional principles which are unique
to allosteric phenomena represents a major challenge. Here an approach which
consists in the in silico design of synthetic structures which, as the
principal element of allostery, encode dynamical long-range coupling among two
sites is presented. The structures are represented by elastic networks, similar
to coarse-grained models of real proteins. A strategy of evolutionary
optimization was implemented to iteratively improve allosteric coupling. In the
designed structures allosteric interactions were analyzed in terms of strain
propagation and simple pathways which emerged during evolution were identified
as signatures through which long-range communication was established. Moreover,
robustness of allosteric performance with respect to mutations was
demonstrated. As it turned out, the designed prototype structures reveal
dynamical properties resembling those found in real allosteric proteins. Hence,
they may serve as toy models of complex allosteric systems, such as proteins.
