Study of conformational mobility of insulin,proinsulin, and insulin-like growth factors

The goal of the work was to perform by the method of molecular dynamics a comparative analysis of conformational mobility of evolutionary related peptides—insulin, proinsulin, IGF1, and IGF2. The proinsulin molecule has been shown to have the highest mobility, whereas IGF1—the lowest. Rotation radius (Rg) of insulin, IGF1, and IGF2 changes insignificantly, Rg of proinsulin decreases by reaching plateau after 6000 ps. The graphs of the mean square deviations (RMSD) from initial positions for A- and B-domains are practically identical, which indicates integrity of the carcass formed by A- and B-domains. The proinsulin C-domain behaves sufficiently chaotically. The IGF1 and IGF2 C-domains form ordered structures resembling horseshoe and an elongated hairpin. The D-domain makes the greatest contribution to the IGF2 mobility, but remains virtually immobile in IGF1, which might be the cause of high IGF1 stability. The obtained data can be used in development of new effective drugs for treatment of diabetes mellitus, which are based on the principle of evolutionary relationship of peptides.