  A simple approach is proposed to investigate the protein structure. Using a
low complexity model, a simple pairwise interaction and the concept of global
optimization, we are able to calculate ground states of proteins, which are in
agreement with experimental data. All possible model structures of small
proteins are available below a certain energy threshold. The exact lowenergy
landscapes for the trp cage protein (1L2Y) is presented showing the
connectivity of all states and energy barriers.
