We suggest that Davidov's solitons, propagating through the backbone of a protein, can mediate conformational transition and folding of a protein to its native state. A simple toy model is presented in which a Non Linear Schrodinger (NLS) field interacts with another field phi, corresponding to the conformation angles of the protein. The interaction provides the conformation field with the energy needed in order to overcome energy barriers for folding, thus avoiding the need for stochastic thermal activation. Such a transition is therefore a deterministic controled process.The soliton is compensated for its energy loss by absorption of the energy gained in the folding process. This scenario does not change significantly even in the presence of imposed disorder, provided that the initial momentum of the soliton is large enough.