Are the synthetic proteins relevant to the problem of protein folding?

The possibility to derive the analogs of native proteins by the chemical synthesis is considered to be a serious argument for the concept of posttranslational protein folding. The present paper analyzes for the first time chemically synthesized proteins to reveal whether they are relevant to the problem of protein folding. The results enable the following conclusions to be drawn. The acquisition of the peculiar conformations by the chemically synthesized proteins to exhibit the specific functions is conditioned by the highly marked features of the secondary and tertiary structures of the corresponding native proteins. These features will make themselves evident only if favorable conditions are carefully chosen during the experiments for each individual protein. Thus, in our opinion, the possibility to derive a synthetic protein is hardly evidence for the posttranslational folding of proteins.