  As protein folding is a NP-complete problem, artificial intelligence tools
like neural networks and genetic algorithms are used to attempt to predict the
3D shape of an amino acids sequence. Underlying these attempts, it is supposed
that this folding process is predictable. However, to the best of our
knowledge, this important assumption has been neither proven, nor studied. In
this paper the topological dynamic of protein folding is evaluated. It is
mathematically established that protein folding in 2D hydrophobic-hydrophilic
(HP) square lattice model is chaotic as defined by Devaney. Consequences for
both structure prediction and biology are then outlined.
