[On the optimal folding of protein molecules]

The process of globular structure formation from a long molecular chain has been examined. In the course of this process, various regions of the chain interact with one another. We classify the bonds formed during this process as "correct" and "erroneous" ones. The term "correct" bonds implies the bonds characteristic for a completely formed native globular structure. All other bonds can be treated as "erroneous". It was demonstrated that the process of globule formation may proceed actually without the formation and the following decay of "erroneous" bonds. Our model permits one to avoid the examination of numerous "erroneous" variants since, between the regions of the chain that form "correct" bonds, long-distance interactions characterized simultaneously by high selectivity take place. The existence of interactions of this kind facilitates the drawing together and subsequent interaction of just these regions of the chain that yield "correct" bonds. Based on the data bank analysis, it was demonstrated that the model elaborated is valid not only for abstract structures but also for real polypeptide chains capable of forming protein globules and superhelical fibrils.